tune up an now I am getting 10mpg help

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bradjh
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tune up an now I am getting 10mpg help

Post by bradjh »

I did a tune up new plugs wires rotor and cap plus a fuel filter and had the leaking intake manifold gasket fixed and now i smell fuel in the cab of the truck mainly not any leaks anywhere to be found around new fuel filter is dry and no smell under truck i mainly smell it near drivers door.. and rear drivers door area... getting 10-11 mpg ??? runs better and smoother than ever I am confused? could it be anything with my hypertech tuner i know at the shop my battery was disconnected for a while?/?

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Re: tune up an now I am getting 10mpg help

Post by bradjh »

also i am getting the code for oxygen sensors...which i had before tune up...
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Re: tune up an now I am getting 10mpg help

Post by 04crewvt »

Bad O2 sensor could mean ECM is seeing a lean condition causing you to run rich, I would change whichever of them are throwing a code and see if that fixes the problem.
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Re: tune up an now I am getting 10mpg help

Post by HenryJ »

Check out the thread on the plugged cat?

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Re: tune up an now I am getting 10mpg help

Post by SleeperSS »

Check the fuel lines at the back of the motor.
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Re: tune up an now I am getting 10mpg help

Post by F9K9 »

Code numbers? P0XXX?
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Re: tune up an now I am getting 10mpg help

Post by bradjh »

code is po155 been doing it for 6months or so been putting it off.. also found out this morning no heat it was about 34 here in cincy truck up to operating temp blowing cool air on heat all the way?


which check lines at engine and read up on plugged cat any other ideas?
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Re: tune up an now I am getting 10mpg help

Post by barch97 »

bradjh wrote: also found out this morning no heat it was about 34 here in cincy truck up to operating temp blowing cool air on heat all the way?
You're still running dexcool, aren't you? :!:

GM claims it's good for 100k miles and probably would be as long as you don't get any air in the cooling system. Once you do get air in and you will, dexcool begins to gel. This gelling clogs the lines to and from the heater core blocking the flow of coolant. So, the coolant that's in the heater core, stays in there and never gets warmed by the engine's heat.

The heater blowing cool air is one of the first signs of dexcool contamination. Hopefully you've caught this in time or you could be looking at much more costly repairs.

You'll need a radiator flush kit. One can be found at any parts store for around $5. Pick up a new radiator cap and two gallons of traditional green antifreeze while you're there. Drain all the dex out of your cooling system. Install the tee that comes with the flush kit and flush the system thoroughly with clean water. I cannot stress enough just how important it is to get ALL the dexcool out. Mixing anything with dexcool will accelerate the gelling process that has already begun. Refill with 50/50 mix of antifreeze and water. This is a really good time to replace your thermostat as well. Lastly scrape the "dexcool" logo off your overflow reservoir cap with a razor knife so no one mistakenly mixes dex with the green antifreeze.

Total cost for this DIY project including flush kit, antifreeze, radiator cap, and thermostat should be around $50 or so. I will take a few hours to repeatedly fill the cooling system with clean water, run the engine up to temp, let it cool and flush again a few times to ensure that ALL the dex has been flushed out.

Or you could take it to a repair shop and have the cooling system flushed and refilled for around $75-$100 but I don't recommend this route as you will not get the flushing tee installed and you'll likely get refilled with dexcool.

Note: This is a wet sloppy job that I for one would not want to do when it's 34 degrees outside. Good luck.
Last edited by barch97 on Wed Apr 28, 2010 4:37 am, edited 1 time in total.
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Re: tune up an now I am getting 10mpg help

Post by bradjh »

still have dex cool in there. where exactly is the t stat?
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Re: tune up an now I am getting 10mpg help

Post by barch97 »

There's a black metal pipe (about 1-1.5" diameter) that comes forward from under the air intake and bends down to a flange in front of the throttle body. Remove the two nuts holding this pipe down and under it you'll find your thermostat. The thermostat is NOT what's causing the heater problem however. The cooling system NEEDS to be flushed ASAP.
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Re: tune up an now I am getting 10mpg help

Post by barch97 »

There's a write up on the Modifications Page that explains the thermostat replacement procedure pretty well with photos of parts and locations. Whether you choose to switch to a lower temp is another issue but installation is identical in either case.

A universal flush kit is $3.99 at Autozone.
Image

I modified that yellow spout by cutting a slice through an old bicycle inner tube and hose clamping it to the end to direct flow down to a 5 gallon bucket on the ground. I find this very much better than just allowing water, antifreeze/dex to spray out of the spout and all over the engine, grill, bumper, ground, etc.

Cheap-o radiator cap is $4.99

The super fancy pressure release lever type is $7.99
Image

They've even got a replacement plastic cap for the overflow reservoir for $5.99 but scraping the dex logo off with a razor knife is free and only takes a minute.

Thermostat is $8.99 for OEM 195* or $14.99 for low temp 180* both include gasket/seal.

I got antifreeze from a local joint for $10 a gallon. I'm sure some will tell you that it's worth the extra money to get a high quality name brand but, I change mine about once a year or so and I am notoriously miserly.
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Re: tune up an now I am getting 10mpg help

Post by bradjh »

ok what oxygen sensor do i need to replace when i get po155? what is the location of the sensor? I am going to fix the sensor and flush the dex cool out after work...


chevy dealer wants $169 each for sensor


I am gona try autozones bosch direct replacement $53
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Re: tune up an now I am getting 10mpg help

Post by bradjh »

well i followed the fuel lines and i cannot see anything however i have a very strong fuel odor right by the brake fluid resorvoir. I think that the fuel lines come up to the top of the engine and go in the back near the fire wall from what I can see.. There is a Big plastic cover on top of the engine and it connects the hose to the air filter it looks like the fuel lines go in under that...


I guess i will take it back to the guy who did intake gasket would he have had to mess with the fuel lines to do the repair?


Any ideas where the smell would be coming from?
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Strong Fuel smell in cab and engine bay

Post by bradjh »

Recently i noticed a strong fuel smell in cab and engine bay mainly right after i shut it off.. Recently had some work done a tune up new fuel filter and a intake manifold gasket.. Getting 10 mpg and have a strong smell in engine bay near the brake fluid continer and around the back of engine..

No fuel leaks found, follewed from the fuel line from the filter to engine as much as i could but cant really see where it goes in engine, no fuel smell on underside of truck just the engine bay and in the cab on drivers side mainly..

any sugestions before I take it back to the shop that did the work..