CONSTANT miss, throws 300 code.

Anything related to the factory RPO Crew Cab.

Moderator: F9K9

CONSTANT miss, throws 300 code.

Postby Torskdoc » Wed Jul 22, 2015 8:57 am

My 02' has a constant miss, that feels like it's multiple cylinders, since about 45000 miles. It now has 83500 miles. It shudders at idle intermittently. Once in gear, and above 800rpm you can feel it up to about 3000rpm steady state. Under WOT You can't feel it.

Ignition has been checked with timing light on ALL wires at idle and all cylinders show an intermittent.

Parts that have been replaced (some multiple times)

1.) IGNITION
Plugs (now has Autolite 602, the # that Brule recommends, gapped to spec)
New Wires (twice) currently has AC/Delco wires. NO CROSS-ARCING DETECTED at night with lights out.
New Cap and Rotor (AC/Delco)
NEW COIL.
Swapped the IGN Module mounted with coil with the one in my '95 Jimmy (No Change)

MAF has been taken out and cleaned yearly with CRC MAF Cleaner.

2.) FUEL INJ

Fuel system checked per GM spec for pressure and bleed down. It's tight per spec.
REPLACED Fuel Filter yearly
Complete NEW SPIDER (DELPHI) with new regulator (3rd regulator since I bought trk in 07)
NEW INTAKE GASKET Kit (Felpro) replacing Deathcool damaged set.
Idle Air Control and Map sensors. (Kept old ones in case)


The only OBVIOUS things I haven't replaced are the Crankshaft sensor and the Distributor. I'm leaning more toward the distributor having either a loose shaft bearing/bushing causing side to side wobbling, although I don't see any damage to the individual cylinder pins on the cap.

One thing I did notice the other day, was that the problem is not apparent when 1st started up from COLD!(sitting overnight and cooled off to ambient temp. 2-3 minutes after starting the stumbling/miss begins.


It throws a 300 code (Multiple cylinder miss) and occasionally if I let the light go for too long without resetting the codes, a Cylinder 3 or Cylinder 4 or Cylinder 5 code. Not always, but always after the 300 code.

alternator is checked out an putting out 105Amps @ 12.96V running at 1000rpm. Lite load or float charge is 14.5V
Battery is less than 1 year old, with NEW B+ and Ground cables. New 2Ga grounds between block and chassis bolted to wirebrushed shiny metal. Ohm'ed out to les than 1ohm (limits of meter). All connections treated with CAIG DeOxit D-5 and G-5.

All Accessory box B+ connections cleaned to bright metal, and treated with DeOxit D-5 and G-5.


I'm getting tired of having the old broad complain about the Service Engine light. She drives it during the summer as it has A/C and the Jimmy doesn't right now. With the Grandkids (4 and 2) she needs the A/C more than I do.

I DID NOTICE that ROCK AUTO has the UNITED IGNITION (ALL ALUMINUM) distributor. $92. and change. Complete to the cap and rotor. No more broken screw stubs!


HELP! Any IDEAS WELCOME. Thermite grenades are a distinct possibility at this point
:crazy:
Last edited by Torskdoc on Sun Jul 26, 2015 3:23 pm, edited 1 time in total.
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md

Re: CONSTANT miss, throws 300 code.

Postby HenryJ » Wed Jul 22, 2015 3:29 pm

Really reaching as you seem to have tried quite a bit. I think the distributor is a likely suspect too. Here are some more suspects:
Have you tried the fuel pressure check to see if there is a fuel pressure regulator problem? (I assume you have )
Have you checked the intake and hoses for a vacuum leak?
Could the EGR valve be stuck, or the passage plugged?
Is it possible the cat is plugging? Pull the forward o2 sensors and see if it runs better? Running better at WOT kinda discounts this suspect? Still , it could happen.
Are the O2 sensors ruled out? Runs better closed loop?

"Speed doesn't kill, suddenly becoming stationary does." - Richard Hammond
"Speed is just a matter of Money - How fast do YOU want to go?"-Mechanic from Mad Max-
If at first you don't succeed - Don't take up Skydiving!
- ThunderII KE7CSK
User avatar
HenryJ
Admin K Elite
Admin K Elite
 
Posts: 12693
Joined: Tue Oct 01, 2002 9:14 pm
Location: Ontario, Oregon

Re: CONSTANT miss, throws 300 code.

Postby LoneWolf04 » Wed Jul 22, 2015 8:50 pm

Being that it's an '02 it shouldn't have an EGR on the truck. I know some of the cylinders heads had valve issues where a valve wouldn't rotate, but that was usually just one. Since you're seeing it on more than one cylinder I doubt that is it though.

I would believe the next step would be the distributor. I know when I pulled mine out at around 80k the gear was heavily worn which will mess with timing especially on acceleration.

I also believe there's a tsb for the crank sensor, but I will have to double check on that.
LoneWolf04
Crew Elite
Crew Elite
 
Posts: 205
Joined: Sun Dec 19, 2010 9:18 pm
Location: Grand Blanc, MI

Re: CONSTANT miss, throws 300 code.

Postby Torskdoc » Thu Jul 23, 2015 7:01 am

Henry J;
1.) No EGR
2.) Fuel Pressures are per spec. I've checked so many times I can do it in my sleep, blindfolded, and with both hands tied behind back. 61psi Ign On, Not Runnning. 58psi Engine Running. Shut down, wait 10 minutes 57psi. Wait 30 minutes 56psi.
3.) O2 sensors were replaced at 75000. No change with them pulled or in. No change closed or open loop
4.) No Vacuum leaks. Steady state Vacuum gauge needle at all times. No indications of a sticky valve, low compression, etc. Vacuum @ idle is 19 inches of mercury. Deceleration gets me 24-26 inches depending on if I hold a lower gear when towing. Intake has been sealed subsequent to spider replacement(1st and hpefully last) with 3rd regulator since 07. Funny thing is I can hold 65mph (by foot) with 13" of vacuum on freeway, and get 24-25mpg consistantly. With the cruise control set to same speed I only get 19-20.

.) Something I remembered after I posted. I was going around the DC Beltway from the entrance ramp, and had backed off the throttle after getting up to speed and was feathering the throttle, showing 16-17 inches of vacuum (I have a permanently mounted Vacuum gauge). This was on a slightly downhill part of the road. After about 1/2 mile of this it threw the codes and the light went on. If I keep a load on it and not feather it, the lights and codes tend to stay off. This is what's leading me toward the distributor.

If i do get a distributor, NO MORE PLASTIC body. I really like that United Electrics unit. Looks well built (full aluminum body all the way up to the cap joint) and from what little I've read on the forum about it everyone likes it.

I did a quicky google of TSB's for the 2002 S-10. I found a title/summary on AUTOMD as follows that describes most of what's happening. But no answers............



2002 Chevrolet S10 Engine And Engine Cooling Service Bulletin 132756

Action Number: 10000725 (This is the NHTSA #)
Service Bulletin Number: 132756 <-----This number is different from the search page Service Bulletin Number
which is Service Bulletin Number: 020604059

Report Date: Dec 01, 2002
Component: Engine And Engine Cooling

Summary: Engine runs rough, service engine soon light on, diagnostic trouble codes p0300 or p0335 set. *tt


I'm updating my alldata subscription for this truck, so i'll be able to see what they say about this particular TSB. And it's more indepth than a Store Bought manual.

Larry
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md

Re: CONSTANT miss, throws 300 code.

Postby Torskdoc » Thu Jul 23, 2015 5:35 pm

Purchased the UNITED ELECTRIC Aluminum Distributor. Complete with Brass insert cap and rotor. $92.79 & priority mail brought it up to $98.69. Such a Deal. When they 1st came out in '09 they avg'ed $130.00. Beats a Cardone Rebuild anyday of the week and twice on Sunday.

Should be here mid-late next week. Will advise.

I was debating on getting just the gear, but @ almost $50. it didn't make sense.

I think this "WELLS Electric" video is relevant to the CC. They have an 02 Blazer with the 4.3L in the video with a P0300.
https://www.youtube.com/watch?v=ljiDxVCsWr4
Plugs, Wires, Cap Rotor, Pull and inspect the distributor. removed the vent screens. No more P0300. I'll check the screens when I change the distributor.
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md

Re: CONSTANT miss, throws 300 code.

Postby rlrnr53 » Thu Jul 23, 2015 8:00 pm

I've run into the P0300 a couple of times in the last couple of months. It only pops up when I'm on a pull above about 3400 rpm. Can't really feel a miss, but it has been sluggish at times. I replaced the cap, rotor, wires, distributor, and spider when I replaced the intake gaskets. Fuel pressure was at 57 lbs running, and about 61 lbs with the engine off. This is not worry some, just annoying when it happens.
Mitch
2001 Polo Green Metallic, no mods,(can't afford any)
User avatar
rlrnr53
Crew Elite
Crew Elite
 
Posts: 557
Joined: Wed Dec 28, 2005 2:04 pm
Location: Prosperty, West Virginia

Re: CONSTANT miss, throws 300 code.

Postby roadrunner » Thu Jul 23, 2015 9:16 pm

I'm sure this will sound strange. Have you double checked for exhaust leaks throughout the system (causing air to leak into the exhaust)? Don't forget to check the air injection system if it has one as my 01 did for bad check valves or rotted out tubes. Have you installed a new computer before or since this code and miss started. I have experienced the P0300 in both instances. An exhaust leak will certainly cause it. And failure to perform crank relearn procedure after changing a computer will as well. Finally, have you made sure your battery connections are clean and tight and not just tight bolts but tight to the battery. I have also had this cause this code because the cable bolts were tight but for some reason one of them kept working the captive nut loose inside the lead battery connection. Perhaps the cable was too short or the engine torqued it enough to wiggle it loose. Don't know but it was always a problem on my truck. Is there any light dimming or blinking accompanying the miss/rough running? This is a certain indication of a battery cable/ground failure. Hope some of this may help you out.
2001 CC LS, pewter, stock, 4.3,Wait4meperformance, CFM throttle blade, Helix throttle body spacer, 4spd auto, 3button electric 4x4 shift, heavy duty factory suspension, Bilsteins, 1" rear wheel spacers, skid plates.
User avatar
roadrunner
Crew K Elite
Crew K Elite
 
Posts: 1254
Joined: Wed Dec 05, 2007 5:39 pm
Location: NW KS

Re: CONSTANT miss, throws 300 code.

Postby Torskdoc » Fri Jul 24, 2015 7:24 am

roadrunner. Thanks for the info. No intake leaks, or exhaust leaks. Vacuum gauge (on "A" Pillar) sits at 19" and doesn't twitch, move or drift except when I punch it. ) Up to speed it sits steady at what ever setting I have my foot set at on the throttle. No drop off like there would be if there was an exhaust plug, or low reading due to timing issues. No crank relearn needed on the 02 as the distributor is not adjustable(as i found out last year when I replaced everything from the lower intake gasket up, except for the distributor). All battery cables are good (ohm out to less than 5 ohms for the + cable and less than 3 ohms for the - cables.). connections are tight, and have been abrasively cleaned (wirebrush) to white metal and then treated with DeOxit D-5 and DeOxit Gold G-5 (I restore tube audio electronic gear and DeOxit is a must, so I use it on the car/truck on electrical connections for about 5 years now). I have a tertiary ground cable to the alternator in addition to a 4ga cable from the + terminal of the alternator to the battery. No dimming of any lights, nor is there any blinking.



No AIR system on the 02, nor is there an EGR.

I have two computers for this truck. Stock for non towing, and a Wait4Me set up for towing. No relearn needed. It will throw the code indiscriminately, but mainly if I'm feathering the throttle so that the engine is just loafing along and not really pulling. It will stumble, or miss at any rpm. It's more noticible when it's below 3000 rpm. It is more noticible with the W4M ECU as it has the performance timing curves. In any event, it acts up no matter what has been done so far. The only things left are the distributor, the Crank sensor or the Cam sensor. The distributor is the #1 suspect now.


Larry
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md

Re: CONSTANT miss, throws 300 code.

Postby LoneWolf04 » Fri Jul 24, 2015 8:46 am

Now knowing that you have a separate ECM that has different timing curves and it does it more when installed I would definitely say the distributor is causing the issue. The ECM can only compensate so much for the variations and may work fine with a good distributor gear, using one that's wore is going outside the boundaries that it can correct, causing the misfire. When you receive the new distributor and install it if you have access to a scan tool that will display cam/crank variation I would suggest borrowing it. When the new distributor is in and torqued you should be between +2 and -2 degrees while running. You may have to back off the hold down bolt and rotate the distributor slightly and re-tighten to get it correct. A ratcheting wrench helps immensely to get in there without having to remove anything to loosen the hold down bolt.
LoneWolf04
Crew Elite
Crew Elite
 
Posts: 205
Joined: Sun Dec 19, 2010 9:18 pm
Location: Grand Blanc, MI

Re: CONSTANT miss, throws 300 code.

Postby roadrunner » Fri Jul 24, 2015 5:11 pm

Not to argue with you but when I got my wait4me computer from Jesse Bubb (who did the programming) he informed me a crank relearn procedure WAS necessary when I installed it or went back to OEM computer. Without relearn The phantom P0300 codes would keep recurring. While you may indeed have other issues it might be helpful to be able to eliminate one from the code list. The relearn procedure is not a particular function of the distributor it is better described as computer/vehicle/vin/emission system matching. I had a local mechanic do the procedure and insisted he change nothing else with the programming and my P0300 codes immediately went away.
Don't take my word for it. Contact Jesse and he will tell you the hows and whys and is way smarter than me on the programming end.
By the way the distributor on my 01 model was not adjustable either. I'm not aware if any of the crews were or not.

PS: If you've not bought the new dist yet and are thinking of the gear instead I currently have this item listed in the classifieds here on this site. 1 10457356 AC Delco dist drive gear washer and pin kit $30.00. That is total cost for the gear and no extra for shipping to lower 48.
2001 CC LS, pewter, stock, 4.3,Wait4meperformance, CFM throttle blade, Helix throttle body spacer, 4spd auto, 3button electric 4x4 shift, heavy duty factory suspension, Bilsteins, 1" rear wheel spacers, skid plates.
User avatar
roadrunner
Crew K Elite
Crew K Elite
 
Posts: 1254
Joined: Wed Dec 05, 2007 5:39 pm
Location: NW KS

Re: CONSTANT miss, throws 300 code.

Postby LoneWolf04 » Sat Jul 25, 2015 10:02 am

All the distributors have slight at in them. They aren't adjustable like the old carb motors though.
LoneWolf04
Crew Elite
Crew Elite
 
Posts: 205
Joined: Sun Dec 19, 2010 9:18 pm
Location: Grand Blanc, MI

Re: CONSTANT miss, throws 300 code.

Postby Torskdoc » Sun Jul 26, 2015 3:32 pm

I got my W4M ECM in 2009. At that time I got nothing from Jesse re: re-learn. Basically it was disconnect both battery cables for 3-5 minutes, then start. At that time the truck had 38000 on it and it didn't start up with the missing/P0300 until 45000 or so. This and individual cylinders (after 2-3 times of P0300 and not clearing them) are the only codes this truck has ever thrown.

The Crab top distributor in the 02, and also my 95 Jimmy(same motor) are not adjustable. The Jimmy was built late spring of 95 so it's more of a 96, which is fun for getting some parts.

The new distributor is due tomorrow by usps. Tuesday I'll be putting it in, and getting back spasms for my troubles. I haven't found a combination of sockets, extensions and universal joints that will undo the bolt yet. But a Craftsman 10mm Box/open, heated and bent in a 80-90* fashion 1/2" from the box end works well. I never straightened it out from when I pulled the lower intake last year.

Let me get the new one in and see what happens.

Larry
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md

Re: CONSTANT miss, throws 300 code.

Postby Torskdoc » Tue Jul 28, 2015 1:34 am

So today, knowingthat the distributor would come in the mail, I got my tools together and about 30 minutes before the mailman arrived started removing the hood so I could getto the distr. without killing myself, and still have plenty of light.

Mailman arrived, I opened the pkg in high anticipation, and what to I see? A United electric 9366 Distributor for a smallblock 305/350. I was so damned mad I put it back in the box, and got online, got an RMA with a return shipping label, and wrote a note on the packing slip: PLEASE!!!!!!! Get some help in your WAREHOUSE that can READ AND COMPREHEND ENGLISH and can UNDERSTAND THE DIFFERENCE BETWEEN A 9363 distributor for a '4.3L V-6 and a 9366 distributor for a 5.0L/5.7L V-8 (which incidentally may fit the V-6 but will NEVER WORK!!!). AND Whoever filled this should be reprimanded for 1.) not doing his job (by failing to pack the correct part)correctly, AND 2.) failing to sign and date the packing slip, so he/she can avoid responibility of having SCREWED UP! Why have the line for signature and date if you aren't going to enforce it for QC purposes."

I wrote it in cursive, and just my luck I'll get some 20 something customer support rep walking around with a dull and glazed look in his / her eyes trying to figure out what it is. (So much for higher Education).

After shipping it back Fedex, I now have to wait another week or so with this thing shaking and studdering like whore in church. At least they paid the return shipping. Hopefully the note will be read by someone high enough who cares what the customer is saying.

RANT OVER!!!!

Larry
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md

Re: CONSTANT miss, throws 300 code.

Postby LoneWolf04 » Tue Jul 28, 2015 10:41 pm

Welcome to mail order parts... And you thought going to the parts store was bad.
LoneWolf04
Crew Elite
Crew Elite
 
Posts: 205
Joined: Sun Dec 19, 2010 9:18 pm
Location: Grand Blanc, MI

Re: CONSTANT miss, throws 300 code.

Postby Torskdoc » Sat Aug 01, 2015 2:06 pm

Image

Image

Image

Image

Well the new Distributor (the RIGHT ONE THIS TIME) arrived thrusday evening. I got up today and had to go to Sears and got this nifty little 6pt socket / universal joint all in one (# 43201) for $8.49 plus tax. Beat having to heat up and bend a 6pt box/open wrench to get the holdown bolt loose. The bolt is long enough that you either have to raise up the distributor while undoing the bolt, or just un do the bolt a few turns then hand loosen it. Image

Pulled the old one out and it was apparent that the gear was really causing the problem. It was worn almost to a knife edge on the teeth. The teeth also verify what I was seeing in the oil(iron sludge on the end of the magnetic bolt) . So this should stop. Otherwise the distributor looks good. So I'll clean it up, remove the "screen/filters", put a new gear on, and set it in storage for future use either in the 02, or the 95 Jimmy (late 95 model year with the 96 Crabtower distributor).

The new distributor is all cast / machined aluminum. Fit and finish is good. Brass contacts on the cap and rotor. Rotor has two pins and a lock block. The vents underneath are NOT on the bottom of the tube. They are drilled into the BACK side of the vent tubes.

Took me 13 minutes to change out the distributors from 1st wire pulled to last wire installed and started. Ran for 10 minutes at idle to make sure it wasn't binding, and that oil pressure was good (actually it went up a couple pounds). IDLE was smooth with no intermittent studder, and absolutely NO OFF IDLE MISS/SHUDDER. Engine speeds by my scanner at idle was tighter than before. Timing used to vary from 11.0 to 22.0 degrees. Now it varies between 17 and 20 at idle.

On the road performance is like night and day. Before you could feel the miss and it felt like it had bad u-joints or at least one with lots of slop. Now it's quiet, smooth and a with good deal more pep to it. Throttle reponse is VERY GOOD!
@ 55mph in 4th I can cruise @ 14-15" on the vacuum gauge (using my foot). Before it was 11-12 and it would dog on the slightest incline. Now it just takes it in stride. Torque converter started locking up again too, for some reason. So highway gas mileage has gone UP too. Before with 11-12" mercury, I could get 16-18, Now with 14-15" I'n getting instant economy of 27-28 which should translate to about 23-24mpg full tank running on the highway. Using Cruise control is tantamount ot throwing gasoline out the window. using cruise, Vacuum on level ground to between 8-12, constantly varying. and on the slightest incline dips to sub 5". What a waste. But GM still insists that we have it in the trucks/cars.


I'm happy with it from a performance standpoint. Wife is happy because it doesn't throw her around when it shudders.

Larry
Attachments
100_4798.JPG
100_4797.JPG
100_4796.JPG
100_4793.JPG
100_4792.JPG
Last edited by Torskdoc on Sat Aug 01, 2015 2:20 pm, edited 1 time in total.
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md

Re: CONSTANT miss, throws 300 code.

Postby Torskdoc » Sat Aug 01, 2015 2:17 pm

LoneWolf04 wrote:Welcome to mail order parts... And you thought going to the parts store was bad.

I can usually get what I need at the parts store, except for a few parts and not get the wrong part.

I dabble in 50's to 70's audio gear and went to Radio Shack a few years ago to get a stylus for my phonograph cartridge. So I walk in and tell the "Kid" (he was some goth punker late teens/early 20's.....I'm in my late 50's at this point), needed a stylus for a SHURE R47XT (Ratshacks number for that cartridge). Kid looks at me like I had 3 heads, and snakes coming out of my ears and walks over to the Palmpilot display and picks up a plastic stick in a fancy package for $19.99.

The manager was standing there watching all of this. We both lookedat each other and shook our heads. I then had to explain that the R47XT was a phonograph cartridge with a needle (which is also a stylus) that played music. Kid goes "Oh yeah, like that monster console my grandparent have. We don't have any of those". Didn't mention the catalog or offer to look it up/order it.

At that point I just told the manager I'd see him later and walked out. Went to another shack and got it there. I went back a few weeks later and the manager told me he fired the kid.

The Idiots and Morons are trying to take over the world. But luckily there aren't enough of them to fill the shallow end of the Gene pool.
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md

Re: CONSTANT miss, throws 300 code.

Postby HenryJ » Sat Aug 01, 2015 2:38 pm

Problems now solved 100%?

"Speed doesn't kill, suddenly becoming stationary does." - Richard Hammond
"Speed is just a matter of Money - How fast do YOU want to go?"-Mechanic from Mad Max-
If at first you don't succeed - Don't take up Skydiving!
- ThunderII KE7CSK
User avatar
HenryJ
Admin K Elite
Admin K Elite
 
Posts: 12693
Joined: Tue Oct 01, 2002 9:14 pm
Location: Ontario, Oregon

Re: CONSTANT miss, throws 300 code.

Postby Torskdoc » Mon Aug 03, 2015 10:08 am

So far. Runs like a new engine. Just the slightest ripple from a glass of water set on the engine @ idle. Timing @ idle stays between 17 and 20* instead of 11-22*. No miss, no stumble, no hesitation. 200 miles since Saturday and absolutely NO CODES!
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md

Re: CONSTANT miss, throws 300 code.

Postby HenryJ » Mon Aug 03, 2015 3:34 pm

Awesome! This will be very helpful for someone in the future I am sure.

"Speed doesn't kill, suddenly becoming stationary does." - Richard Hammond
"Speed is just a matter of Money - How fast do YOU want to go?"-Mechanic from Mad Max-
If at first you don't succeed - Don't take up Skydiving!
- ThunderII KE7CSK
User avatar
HenryJ
Admin K Elite
Admin K Elite
 
Posts: 12693
Joined: Tue Oct 01, 2002 9:14 pm
Location: Ontario, Oregon

Re: CONSTANT miss, throws 300 code.

Postby okaussiee » Mon Aug 03, 2015 4:22 pm

I have something similar. Mine throws the code after about 45 minutes of highway driving. Then goes away, the reappears. The difference in mine is, is that mine did not start this until my ECM was replaced. All the other codes and issues went away after the ECM was replaced, and now I have this, which was never there.

My engine has 204K on it and has only the intake gaskets replaced. No other engine related problems.

I think I might have to take it back to the shop and reprogram the ECM. My engine has no rough idle or anything as reported above. Just the code.

Bill
okaussiee
Enthusiast
Enthusiast
 
Posts: 46
Joined: Wed Sep 24, 2014 12:51 pm

Re: CONSTANT miss, throws 300 code.

Postby Torskdoc » Sat Aug 22, 2015 2:09 am

Bill; From what I've read the 02' ECM was a single year item. Not sure about the 01, 03 and 04 ECM's. It's possible that the ECM is set for a tighter variance in timing and if the distributor is worn it will exceed the variance. You might pull the distributor and check the gear. If one side is very worn, I would recommend a new distributor. Get the United Electric dist. and you won't have to worry about breaking the cap tabs anymore.

Mine is so quiet and smooth now, I sometimes turn the key and grind the starter gear inadvertantly not realizing it's running. Mileage on hwy is now 25-26mpg @ 65mph with the tach showing about 1900. City is still about 14mpg.

Larry
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md

Re: CONSTANT miss, throws 300 code.

Postby okaussiee » Sat Aug 22, 2015 2:31 pm

This new code just showed up today. p0135 02 sensor heater circuit. Now I have two codes that never showed up until the ECM was replaced.

I checked the timing advance and is between 12 and 17 degrees.

I am thinking of taking it back to the shop that programmed it to see if they missed something. It runs smooth as silk at any speed for any length of time. That is what makes me think that these are bogus errors.

Bill
okaussiee
Enthusiast
Enthusiast
 
Posts: 46
Joined: Wed Sep 24, 2014 12:51 pm

Re: CONSTANT miss, throws 300 code.

Postby LoneWolf04 » Sat Aug 22, 2015 6:45 pm

The heater circuit for the 02 is most likely a shot 02. Happens to them all the time. The heater is used at start up to get the sensor up to temp as quick as possible. It is detecting the sensor taking too long to warm up. Can you be more specific about the driving conditions setting the p0300? Is the engine in 4th with the torque converter locked when it comes on? Down shift from going up an incline?
LoneWolf04
Crew Elite
Crew Elite
 
Posts: 205
Joined: Sun Dec 19, 2010 9:18 pm
Location: Grand Blanc, MI

Re: CONSTANT miss, throws 300 code.

Postby okaussiee » Sat Aug 22, 2015 7:25 pm

I drove it for about 2 hours straight. City stop and go driving as well as highway at speeds of 70mph. No errors what so ever.

In Oklahoma everything is flat, no inclines. It only happens after warming up and running highway speeds. Never cold and never in city driving at 35mph.

As I said earlier, I drove it alot today without any errors and no errors pending.

BTW mine is an 02 with 204k on it and the ECM was just replaced last month. These errors never showed up until after the ECM was replaced.

Bill
okaussiee
Enthusiast
Enthusiast
 
Posts: 46
Joined: Wed Sep 24, 2014 12:51 pm

Re: CONSTANT miss, throws 300 code.

Postby LoneWolf04 » Sun Aug 23, 2015 6:34 am

At 204k anything is possible. Was this an independent shop that installed / programmed the ECM or dealer? A lot of ECMs if bought aftermarket are programmed before they're shipped so it is just a plug and play operation. Usually if it a misprogrammed ECM you would be having consistent problems and not random as you're describing. It more so sounds as if a part it getting worn and reaching its tolerances.
LoneWolf04
Crew Elite
Crew Elite
 
Posts: 205
Joined: Sun Dec 19, 2010 9:18 pm
Location: Grand Blanc, MI

Re: CONSTANT miss, throws 300 code.

Postby okaussiee » Sun Aug 23, 2015 9:49 am

It was an independent shop. It is a rebuilt Delphi unit. They programmed it. They first tried one from the bone yard and my truck wouldn't even start. So they bought the Delphi unit and it started right up then went in and programmed it.

It just seems funny not ever having these errors then all the sudden they show up AFTER the ECM was replaced. And intermittent too at that. Drove it today and had no errors whatsoever.

I am going to put some SeaFoam in the gas tank to clean the injectors next. I also find it interesting that it is a multiple misfire but the truck runs as slick as glass.

Bill
okaussiee
Enthusiast
Enthusiast
 
Posts: 46
Joined: Wed Sep 24, 2014 12:51 pm

Re: CONSTANT miss, throws 300 code.

Postby Torskdoc » Thu Sep 24, 2015 7:27 pm

Put a vacuum gauge on it and drive it on the highway so the engine is just barely pulling. about 14-15inches. This is where mine would throw the code, on a light down incline with the engine just loafing. If it was under load it wouldn't throw the P0300. Just when it was loafing or off load. And by off load I mean between pulling, and braking de-acceleration. when it's loafing the cam gear/ distrubutor drive floats and the distrib wobbles causing a misfire indication. Otherwise the cam gear/distrbutor drive is under constant tension and won't throw a code.
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md

Re: CONSTANT miss, throws 300 code.

Postby okaussiee » Sat Sep 26, 2015 1:32 pm

Mine never throws it except highway speeds at or above 60mph.

I can drive in town at slow speeds all day long and it never throws it. I go out on the highway and it shows up within 15 minutes.

I reset the codes and wait, it only shows up only under the condition listed above. The truck still runs smooth without any feeling of misfire, loss of vacuum etc.

That is why I think the code is bogus. I feel no signs that anything is wrong. Gas mileage is still around 20mpg on the highway with that error.

When I get the time and money, I will take it back and have them look at it.

TIA

Bill
okaussiee
Enthusiast
Enthusiast
 
Posts: 46
Joined: Wed Sep 24, 2014 12:51 pm

Re: CONSTANT miss, throws 300 code.

Postby Torskdoc » Mon Apr 18, 2016 8:55 am

The gremlin is back but it's very selective as to when it wants to show it's fugly head.

50 to 60 mph in 3rd gear(manually). Holding 3rd gear and steady state speed (feathering the throttle to hold between the engine actually putting a load on the drivetrain and it using the engine braking. RPM's are about 3K-3.2K. distributor variance in timing is still btwn 17 and 20deg. It should be closer but I'm not complaining (much). With a load on the distributor and cam gear dont float against each other with the distrib gear flopping back and forth. I'm thinking that the cam gear is worn enough so it's out of spec. allowing the distributor timing to vary out of spec.

I can hold it in 3rd gear and pull the trailer all day with out it setting the code. So it's a light or NO LOAD condition that set's the code. Cam replacement is out of the picture unless I replace the whole engine. I can't see replacing the whole engine just because the cam gear is worn. I'll wait until it drives a con rod thru the side of the block.

If I leave it in 4th (OD) and drive normally, it doesn't toss the code out. It only throws the code in 3rd and feathering the throttle @ 3K rpm. It's definately dropped the frequency of occurances since the new distributor, which is why I'm leaning on the cam gear being worn. See pics above of old distributor gear. Either the cam gear wasn't hardened correctly or there is an alignment problem with the distributor and cam gears. As I haven't seen this in other S-10's or other vehicles with the 4.3L that I have owned I'm leaning toward an improperly hardened distributor gear.



Larry
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md

Re: CONSTANT miss, throws 300 code.

Postby rlrnr53 » Mon Apr 18, 2016 12:58 pm

Have you checked the timing chain? it could be stretched
Mitch
2001 Polo Green Metallic, no mods,(can't afford any)
User avatar
rlrnr53
Crew Elite
Crew Elite
 
Posts: 557
Joined: Wed Dec 28, 2005 2:04 pm
Location: Prosperty, West Virginia

Re: CONSTANT miss, throws 300 code.

Postby Torskdoc » Mon Apr 18, 2016 6:25 pm

It's tight. I had to replace a bad front main seal back in January. I checked the chain while I was in there. Less than 1/8" deflection in middle between gears, using a straight edge and a 6" ruler. This is gear lash left over from the old distributor gear. I'll live with it until the motor blows up. I've never seen a distributor gear so eaten up before. Like I said in previous post, it's either from improper hardening of the gear, or misalignment of the distributor/cam gears. I've got a 95 Jimmy with the same drive train and the distributor gear looks as good as a new one and it's got 126.000 on it.
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md

Re: CONSTANT miss, throws 300 code.

Postby LoneWolf04 » Tue Apr 19, 2016 7:45 am

You sound like you've been having a similar issue to what I've been dealing with as well. Even though mine will throw a 300 random misfire, upon actually having a scan tool hooked up it was just one cylinder, cylinder 3 that will misfire. It happens after a hard accel onto the freeway and when you back off on the throttle and it up shifts is when it starts misfiring. I've done all the usually as you have, getting ready to replace the fuel pump as the more I've hooked up a pressure gauge and ran with it for awhile I've been getting different idle pressure readings and prime readings. The other thing it may be is a valve issue. There's a TSB on valves sticking on these heads.
LoneWolf04
Crew Elite
Crew Elite
 
Posts: 205
Joined: Sun Dec 19, 2010 9:18 pm
Location: Grand Blanc, MI

Re: CONSTANT miss, throws 300 code.

Postby Torskdoc » Wed May 11, 2016 5:41 pm

I've had a scan tool and intentionally made it throw the code and the 0300 comes up every time (did it 10 times) with the scan showing absolutely random cylinder misfire. no rhyme or reason to the order missed. 3 only showed up once with 1,2,4,5 twice, 6 once. When it get's drier and warmer out, and I replace the front cover on the Jimmy, I'm gonna pull the distributor on the truck and look at the cam gear on the back. The funny thing is this thing idles smooth enough I can set a glass of water on the air tube and there is barely a vibration on the water. No random miss, no roughness, and it pulls a steady 19.5 inches of vacuum @ 650rpm. Actually smoother than the jimmy. We shall see.
2002 S-10 ZR-5 Quad-CAB
1995 GMC Jimmy 4Dr. SLT
User avatar
Torskdoc
Crew Elite
Crew Elite
 
Posts: 171
Joined: Sun Oct 28, 2007 9:00 am
Location: Glen Burnie, Md


Return to Stock Crew Cab



Who is online

Users browsing this forum: Google [Bot] and 1 guest