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Car runs rough, cuts out.

November 21, 2012 10:52AM
Hey guys, so I have a sort of interesting problem going on with my 88 325i. It ran and drove pretty fine before, but I recently crashed into a deer going about 50.. Bent things in up front pretty well. I've replaced the engine fan and clutch, and straightened out the radiator fins so it works fine. Disconnected the belt to the A/C.

The car hardly runs with the airflow sensor plugged in, it fouls plugs and covers them with a thick black soot. It surges at idle but I'm sure there's not an intake vac leak, i've checked with carb cleaner, as well as water. Smells rich too. doesn't drive. If I unplug the airflow sensor it will idle better, and accelerate fine if I give it 1/4-3/4 throttle, then if I stomp the pedal it cuts out, and spits and sputters. It will also jerk if I'm just barely giving it gas in a high gear to maintain speed. This all leads me to think it's the TPS, but I don't see how an accident could have changed how it works.

I should also note that the deer bent the actual engine fan pulley, so that it was rubbing the gear which the crank sensor uses. I corrected for this by spacing the fan outwards, since it was hardly angled. It barely, and I mean BARELY touches that gear now, and the car runs no different.

I've already replaced the crank sensor, and tried a couple different airflow sensors to no avail.

Any help would be appreciated, I've been at this for a couple days now. Anything else the deer could have damaged?
November 21, 2012 06:20PM
Wow, that is a tough one. So it looks like the fuel mixture is very rich and is not reacting to the oxygen sensor at all. The impact might have damaged the air flow sensor and knocked it out of calibration. Might locate another and try it to see if there is a difference.

Bob in Everett
November 21, 2012 06:31PM
Thanks bob I agree that she's running very rich. I've located one other sensor. It's off a 1986 325e. When I plug that one in she just dies right after it starts up. Today I noticed that the ground cable was pretty frayed in the center, so I replaced it with a battery cable.. still runs like ****. :furious: I'll see if I can crack the sensor that I currently have on it (the one that was in the impact) open and possibly calibrate it. I just ordered the bently, but I won't have it till monday so it's up to me and the interwebs to figure out how so I can tinker on turkey day. haha.
November 21, 2012 06:57PM
I have read some stuff on the air sensor and there is not much recommendation to be opening it as calibration is apparently something that requires special equipment.

I would recommend a replacement, even a used one instead of trying to repair without some idea of what the settings are supposed to be. There might be someone nearby who has some spare parts or salvaged a car. Even a salvage yard probably would not charge much.

Bob in Everett
November 25, 2012 06:54PM
Before opening up the airflow meter sensor, read this article.

November 25, 2012 11:00PM
The link Ferdinand provided should either discourage or help.

Bob in Everett
November 26, 2012 12:45AM
Before tearing anything apart; check to see if the AFM flap is free and moves unobstructed. Also check to see that the intake tube to the air cleaner is not blocked with deer meat or something else.

Once on the throttle; the ICV is no longer active so if it idles correctly then that item is probably working fine.

Check for obstructions to air flow as mentioned.
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