3-Series (E21, E30)Chat relating to the BMW 3-Series from 1975-1983 and 1984-1991 line. Specific models: BMW 315, BMW 316, BMW 318, BMW 318i, BMW 320/4, BMW 320i, BMW 320/6, BMW 323i, BMW 320i. E30 Family models include: BMW 325e, BMW 325i, BMW 325is, BMW 325ix.
My boyfriend and I are at our wits' end over this.
I have a 92 318ic. I started it up one day, and I drove it about 5 feet, then it completely failed. It started up fine, and I was driving off a curb. One wheel was off the curb, then it completely failed to respond.
The car would crank, but it would not turn over. We thought it could be an inertia shut off switch, given that it happened as soon as it went over a curb, but all of our research pointed to no - we read that my model doesn't have that feature.
We determined that the fuel pump works, but is not getting power. A lot of electrical tracing showed nothing out of the ordinary. We replaced the fuel pump relay, which we thought was bad, but still nothing - crank crank crank, but no start.
Any ideas on what could be going wrong? We're both stumped!
but did the pump come on and run continually is what I'm asking? as far as just coming down off a curb and have it happen, I have a 90 325i. Being the age they are they tend to get kind of set in the way things are plugged in, meaning they get corrosion or build up in the plugs. A slight jarring could have just unset a plug(just about anywhere) and made it so it's not getting good connection. I would start by getting dialectic grease and start pulling relays and plugs corresponding to its getting fuel and put grease on them..ie...main relay (which is usually next to the fuel pump relay, ecu plug. Even as simple as pulling the fuel pump fuse, greasing it up and putting it back in. Did you replace the relay with a new one or swap one out? It may have even jarred the plug on your pump. I know the plug on my fuel pump was pretty corroded.
By bypassing the fuse and relay, jumpering battery to fuse socket, we got the pump to run fine.... so downstream of the fuse socket, all is well. We did grease the connector to the fuel pump itself a while back. We will use your suggestion and pull, grease, and reseat the main relay. We have purchased new relays for pump and O2, as both appeared to be dead (no "click" when powered 85/86). Just plugging in the new relays didn't work... we still need to test them. The fuel pump relay was flaky when we bought the car, and we replaced it with a used, working one. There could be a shared cause of failure there, but we don't know what that could be.
make sure to check the plug into the ECU not sure on your 318 it is. You may want to download the manuals at the top of our bmw class specific forum too, I got them all, and it has helped with some of my problems.
We did more troubleshooting on it today, and we're almost certain the problem is upstream of the relay. I didn't know there were manuals on here - that will most certainly be helpful. Thank you again, I'll grab those, and thank you for your help in general.
I do what I can your welcome. I noticed on one of your threads you said you "By bypassing the fuse and relay, jumpering battery to fuse socket, we got the pump to run fine...." to bypass without relay you put a jumper wire between to contacts where the relay plugs in, not from the battery. it shows a diagram in one of those manuals. I could tell you what pins, but then again, not sure your setup is the same as mine as location and pin placement. So hopefully the manuals help, the one is a fairly big download. (bently) but it seems to be the most help.
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