Update and a question

[Evil97kitty]

Hey Guys and Gals...Just a little update for some of you following SHOgirls bad gas milage thread.

I changed out the FPR, hoping that might be part of the problem. Cleared the codes and her milage went up a little.

Now for the bad news. CE came right back on. Took it to Autozone and they got code 174. Lean Left Side 02. Thats a new o2 so I know /hope thats not the problem. I can still smell raw fuel coming out of the exhaust tips too. This would be because the EEC is trying to compensate right?

This isnt a constant CE. It is on all the time but it has its moments that it will go off. Always comes back on within a minute.

You guys have any ideas. Im thinking Fuel Vapor Canister (Where is that on a 95 3.2 anyway), weak injector pulse, MAF maybe? Better yet I dont know what Im thinking. This almost has me stumped.

As always your thoughts are appreciated.

Evil97kitty

 

[AutoSHO]

What are the driveability symptoms? Reduced power? Miss? None at all?

 

[IT-Purrrs]

When i was getting really bad gas milage i had just put a used 80mm Pro FLo MAF on and the check engine light came on right away when i would start it. I could see when i rev it a bit the raw gas coming out of the exaust. When i changed the MAF back to the stock one it fixed that. The Pro Flo must have had bad electronics. That might be the problem but im not positive. shrug

 

[Evil97kitty]

It really has no symptoms. I would imagine its down on power with all the gas that it is eating but its been going on for some time, probably feels normal to her. (Not my car, I just do the wrench turning wink ) No miss that I notice while driving it.

Plugs, wires, fuel filter, and O2's were changed about 1K ago.

She still has the stock MAF on the car.

Shes throwing a lot of money out the window with the milage shes getting. (Stock car, doesnt beat on it, 200-225 miles / tank if she's lucky)

 

[sdpatt]

Exactly what brand and model of oxygen sensor was installed? If the only code is the 174 and there is raw gas coming out of the exhaust, then there is an engine control system problem that could be due to faulty oxygen sensor signals. Has the EEC been reset since the 80mm MAF has been removed? Try this.

 

[projectSHO89]

It is highly unlikely that "raw gas" is coming out the tailpipe.

That just doesn't happen. You are probably seeing water combined with fuel and exhaust residue.

Steve

 

[Evil97kitty]

Misunderstandings. I cant see the "raw fuel" but I can smell it. Unburned. VERY rich.

She has the stock MAF on the car, it has never been changed out. Not an aftermarket. Any easy way to tell if that is the problem?

What does that "setting the idle" have to do with poor gas milage? Please explain.

<small>[ August 07, 2003, 06:34 PM: Message edited by: Evil97kitty ]</small>

 

[IT-Purrrs]

try unplugging the MAF and run it for a while and see if it gets any better, if that doesnt work check what kind of 02 sensors u put in the car they should be boshe (spelling wrong?) 02 sensors if their not those that might be the problem. shrug

If i am correct the MAF tells how much fuel to put into the engine depending on how much air comes in through the MAF. Ive heard of some people leaving the MAF unplugged and its running great. shrug

 

[Mr Anonymous]

Given the symptoms you describe, IIWM, I'd first double-check the condition of plugs & wires (and verify spark), then clean the MAF elements, then verify that the correct O2 sensors were installed, then look for vacuum leaks, then check the t-stat to make sure its not stuck open.

Unplugging the MAF (as well as a stuck-open t-stat) puts the PCM in 'open-loop' mode, which runs full rich.

 

[AutoSHO]

Have you checked the fuel pressure? Edit: Just re-read the first post. I assume the fuel pressure is in spec.

What about the Engine Coolant Temp Sensor? If it is telling the computer the engine is cold, then it stays in open-loop (warm up) mode. That is a very rich state typically, and if run for a long period of time like that will cause poor fuel mileage and **** the Catalytic convertors.

<small>[ August 07, 2003, 10:23 PM: Message edited by: AutoSHO ]</small>

 

[Evil97kitty]

I will check what you guys suggested tomorrow night.

Expect an update.

Thanks.

(You guys need a pulling your hair out smilie )