Runnig RIch, first post

[skimour]

This is my first post on here, lets go for a wild ride.

So i have an E30 325i 1989 that is running rich (dosnt pass smog, black smoke and bad MPG) I know there are tons of threads about it, but mine is really stumping me.

The car has new head, new valves, timing belt, water pump, injectors rebuilt, good compression new 02 sensor, new plugs valve clearance is good, new temp sensor, new cat, tps functions, all stock. Tons of new stuff.

the tricky part is that everything i have checked says the car SHOULD run lean. slightly low fuel pressure, low ohms on temperature sensor. The car gets richer (more smoke) the hotter i get. no check engine light on, the car starts fine (cold and hot), idles fine, runs fine, just rich. This is my first e30 and honestly i want to drive it off a cliff as of right now. :(

[skimour]

also as a side note, it passed smog at the higher speed (barely). Failed at the lower speed. When im driving the car it hangs at around 1/4 on my temp gauge. if it sits, it will slowly rise towards half. also when its hot ill shoot out soot onto the ground when i rev it up. and my OBC which seems to be perfectly accurate, says the temp is at -30 all the time.

[AndrewBird]

Bad ECU temp sensor will cause it to run rich and even more rich when warm. You mention "low ohms on temperature sensor", the the resistance will change depending on temp. If it's faulty and not changing, you will have issues. Read here:

http://www.e30zone.net/e30zonewiki/index.php/Blue_Plug

[jlevie]

If the rail fuel pressure is correct (or nearly so) and the engine has stock injectors, I'd first investigate to see if a bad FPR is leaking fuel into the intake. After that something that is causing the injectors to be open more than normal, like a bad engine harness or bad DME.

[tightithrash]

Just drive it hard waffleswaffleswaffleswaffleswaffles!

[skimour]

I tested the sensor and it does change, also replaced it with a good one.

I checked to see if the fpr was leaking, I pulled off the vaccume line and nothing was in there. Also tested the sensor wiring to the ecu and it was all good. I'm currently trying to test the ecu. How do I do that???

[jlevie]

You diagnose a possible DME issue by replacing it with a known good unit.

[skimour]

I do have a buddy with a shop. I will ask him for a unit to try out

Could my lower degree thermostat be an issue? Previous owner says he put in a cooler one for summer. Not sure how good of a mechanic he is/was

[jlevie]

A cooler than normal thermostat could make the engine run slightly richer, but the DME should learn to reduce fuel to get to stoich condition.