car running super rich

[matt0300]

Ok so car is running rich, check for vac leaks but haven't smoke tested. I know I need to. Changed o2 sensor, don't know what it is. Temp sensor? Tps? Oh yea Its an 88 IX, it backfires when I speed up and let off the gas, and I'm getting 10mpg, not throwing any codes. Doesn't feel like its getting all power till around 4g's.

[jlevie]

The first thing I'd do would be to check the rail fuel pressure, statically and while the car is being driven. If that is okay I'd check to make sure the injectors aren't leaking, replace the ECT and ignition wires, plugs, cap, and rotor. I'd also verify cam timing, adjust the valves, and replace the CPS. If the backfires still occur I'd swap in a different DME.

[matt0300]

The cap and rotor are brand new, double checked my timing marks and tried 2 other dmes. Haven't checheck fuel pressure, *warning noob question* how?

[jlevie]

The cap and rotor are brand new, double checked my timing marks and tried 2 other dmes. Haven't checheck fuel pressure, *warning noob question* how?

Tee in a pressure gauge on the line that feeds the rail. If you tie the gauge to a windshield wiper you can see what the pressure is while driving the car

[matt0300]

Thanks, it should be at 44psi right?

[buguhrich]

Yup. Stock FP is 3bar ~ 44psi.

It's not your TPS, otherwise your car would be bucking around anywhere besides WOT.

Have you checked/replaced your plug wires and plugs? If not, do so. Try checking your fuel pump per bentley manual and replacing your fuel filter as well.

[gtdragon980]

i would highly suggest checking the running temp of the car with a infared thermometer, because that was what was causing my rich issues. I replaced pretty much all the sensors, injectors, checked fuel pressure, vac leaks, you name it!

edit: Oh! and how are you calculating your gas mileage?? by ODO? mine started going bad and i didnt realize it, but it was counting 1 mile for every 10 or so miles.

[matt0300]

Yea odo and u can also hear the back fire from all the unburnt fuel hitting the exhaust. What did u do after u realized it was running hot?

[matt0300]

Fuel filter was changed less than 2 months ago stomp test threw me a 1222. So I guess I'm just gonna test the left side of me engine haha

[jlevie]

A back fire is more likely to be the result of the engine running lean than rich. It can also be caused by timing errors. If the engine is running lean, partial misfires can make it seem (from the exhaust smell) like it is running rich. A better clue that the engine is running rich is the condition of plugs.

[matt0300]

Well the backfire was because of unburt fuel hitting the exhaust manifolds and figured it out, it was another tare in the intake boot ordered the new one. Thanks for the help.

[gtdragon980]

well just for future reference my car wasn't actually running hot, it was running too cold. it was the cause of all my rich symptoms.

[matt0300]

Oh yea that makes sense