Author Topic: Strange (Read 5973 times)

e3002is · « **on:** June 25, 2009, 09:29:07 PM »

Hi guys, I have an e30m42 that began to run extremely rich from cold start on and wouldnt clean up untill about 4k. Wouldnt idle and was essentialy undrivable. So I did the norm, pulled off the TB clean and check for obvious Vac leaks. Found a deteriated FPR hose and a damaged Temp sensor wire. Fixed both and thought that might do it. Stumled alittle on start up after test and accually seemed ok , untill it reached temp and began the same symptoms all over again. Hands in the air, I went to the local shop and checked for codes and came up with a AFM code. So I bit the bullet and replaced it. I figured OK, this car has 230k on it. Replaced the AFM and now the car will only idle. Will not rise above 750. Hard to tell if its rich or lean, I don't see the black smoke like I did before, but it won't rev past idle at all.
I thought I should add this as well. I had inadvertianly left the key on ( windows down,pouring rain)for an hour or so. With the heater fan and the reverse light left on, it seemed to drain the battery. So I put the trickle charger on over night. A day or so after this happened the car started to act up. Just thought I would mention that. LOve this car, but I'm starting to think about roasting some marshmellows with it. LOL Thanks for any input.

e3002is · « **Reply #1 on:** June 25, 2009, 10:05:45 PM »

I should also add, I just went out and started the car again and it would lope at idle like it was rich untill I tried to increase rpms to no avail, but it did smooth out the idle. JUst can't drive the damn thing. I checked the ohms on the temp sender. 590 ohms @ operating temp, checked icv. 20 ohms. I'm assuming crank and cam sensors if bad would have have showed up on comp. scan. I also removed breather hose while the car was running and it made no difference @ idle. ICFTFO... HELP....... LOL

DesktopDave · « **Reply #2 on:** June 25, 2009, 10:19:29 PM »

Crank sensor won't set a code. It'll just stop the engine. I'd test out that new AFM too if it won't get much over an idle. Here's my $0.02:

I think it's the O2 sensor, but testing them usually requires special equipment. You can splice in a Bosch Ford Mustang V8 sensor much cheaper than OEM. Just go to Pep Boys and ask for the cheapest one, shouldn't be more than $25. Here's my logic...your car runs well cold in open-loop mode, but as soon as it heats up it switches to closed-loop mode, using the O2 sensor. You fixed the temp sensor; maybe the car never ran in closed-loop at all...now all of a sudden it's trying to run closed-loop and it's choking on the bad sensor readings. You should see a code for that though.

It's running rich and it has trouble revving up. Those symptoms are usually due to vacuum leaks but you've already covered that. So I'll bet on the O2.

I don't think flattening the battery is a problem. If it's not the O2 sensor I'd look at the fuel pressure off the pump or the FPR if you think it's running rich.

e3002is · « **Reply #3 on:** June 25, 2009, 10:59:46 PM »

I recently replaced the o2 sensor, but it could be fouled by the rich conditions. It came out tough and went in even tougher. LOL And it wont come off idle at at all. 750 max. really bizarre. Its concievable I missing a vac leak. but Ive double checked all the hoses. The really strange thing was, it made no differance to the idle when I introduced a massive air leak by removing the breather hose. If I disconect the 02 sensor should'nt it resort to a slightly rich condition? Limp mode verses the silly overly rich condition
Im experiencing. Also I should add. this condition is uneffected by engine temp. cold or hot, it runs the same. idle only. POS. Its has to be FPR or ecu what a PITA. lol
Thanks for your input.

doitover · « **Reply #4 on:** June 26, 2009, 10:22:56 AM »

I'm sure you would not have done this but if the AFM is facing the wrong direction it will do just what you describe.

DesktopDave · « **Reply #5 on:** June 26, 2009, 11:10:08 AM »

Disconnect the AFM and see if that changes anything. I did that once accidentally and it wouldn't rev at all, just idle. Oddly, it would also 'catch' at WOT on the TPS since that seems to override the AFM and O2 readings.

Deftones · « **Reply #6 on:** June 26, 2009, 04:54:18 PM »

how's your air filter? did you clean it recently or is it dirt?
however if it's a vacuum leak sure you will be lean not rich, making the engine dies when accelerating, not avoiding it!
o2 sensors if damaged can be disconnected and you can run without it, but i recommend you to leave the car without battery for few hours to reset the ECU before cranking again. You can eventually see if the car is really rich or lean by watching the plugs, what colour are them?

e3002is · « **Reply #7 on:** June 26, 2009, 05:20:03 PM »

D,
The air filter is new, It was very rich, "black exhaust and stinky" but was semi drivable before I replaced AFM. Ive tried resetting the ecu several times. Hoping it would fix it self, but noooo. LOL I'm going to try to get a fuel pressure reading, but Im not sure were the heck I can pull that from yet. What still bothers me is the fact I can create a massive vac leak by removing the breather hose and it doesnt change the idle.....#^*@!!!! I'm going to try disconnecting the AFM,the 02 sensor and check continuity on the ECU harness. Thanks guys for yor input.

e3002is · « **Reply #8 on:** June 26, 2009, 07:07:49 PM »

I just pulled voltages off the AFM connector. Clockways from missing pin. with extension connector. 4.92, 3.39, 3.150, 4.87, .008. Without extension conector, 5.10, 4.90, .300, 4.91, .008,

TPS ohms, top pin/bottom pin 2085 closed. 6.53 WFO Mid pin/bottom pin 1772 closed. 6.56 WFO. Going to try to check fuel P and continuity on the harness. AFM/ECU

e3002is · « **Reply #9 on:** June 26, 2009, 07:15:35 PM »

Oppssy, addendum
I also disconnected the AFM and it was very rich. Very similar to initial symptoms.
I connect the AFM and it almost seems like its very lean and the RPM's strugle to reach 1k its not poping back thru the intake, but kind sounds like it's knocking alittle at very low rpm dips, when playing with the pedal

?

e3002is · « **Reply #10 on:** June 26, 2009, 09:05:48 PM »

Did the contiinuity test on the AFM harness to ECU 1st pin clockwise, 1pin .0000 ohms 1pin 460ohms, 2nd .000 ohms (3rd nothing!), 4th .000, 5th .000 ohms. I need to find a schematic for these. Damnina
Update.. 3rd pin is the wire that is suppose to be disconected at the fire wall. Non cat cars.

e3002is · « **Reply #11 on:** June 26, 2009, 09:55:19 PM »

Does anyone know of an active down load for a e36 fuel system wiring schematic? The e30 Bently is usless for the fuel. I tried some other links , but I suspect that they were fouled and are now un-usable. Does anyone know how to place a T bettween the FPR and the injector rail? The FPR in attached directly to the fuel rail unlike the earlier style.
Can I "T" into the supply side before the rail to read system pressure? Thanks

Deftones · « **Reply #12 on:** June 27, 2009, 02:08:56 AM »

you should put the pressure gauge directly on the rail directly or between the rail and the fuel filter. but i think you won't find nothing cause i am suspecting a leaking injector...

e3002is · « **Reply #13 on:** June 27, 2009, 08:24:44 AM »

Fuel pressure 40 lbs. If it was a leaky injector, wouldnt the idle be rough. It accually seems to idle relativley normal after a little pedal play. Does anyone have a ECU for rent or for sale. Im getting to the WTF point. Thanks.

e3002is · « **Reply #14 on:** June 27, 2009, 09:06:56 AM »

I tried the stomp test with no result. Key in second position, and stomp the pedal 5 times. I tried atleast 10 times, incrimentaly reseting the ignition and stomping a little slower each time and still nothing.