A sad day for my 325es

[325esvt]

So recently bought my first e30 see thread

http://www.r3vlimited.com/board/showthread.php?p=3887249&posted=1#post3887249

...and she died after 3 days.
Driving home to put the car on the lift and finally get to do the once-over; look at the underside closely for what maintenance should be done for car upkeep and whats already been done and I never made it. The fuel system died en-route.

The car is currently in the garage and the troubleshooting has began. The pumps (pre and under the car) work fine. The relays (main and fuel) seem to work most of the time, although the connection is spotty and needs to be rewired.

The fuel system has pressure, although I haven't hooked a fuel pressure tester to it yet.

The problem seems to be electrical. I say this because it does weird things with the electrical part of the system. Voltages seem to come and go, (they are fine when they are there) and at one point the fuel pumps wouldn't shut off after the fuel line was pressurized. The car starts with starter fluid and runs fine, no problem with spark or fuel injectors it seems.

There was a mouse problem in the past, so knowing that should I start looking for blown/ damaged wires going to the DME? I haven't pulled the C107 apart yet to look at it, but that and looking inside the motronic for cracked soldering is probably the next step.

I will keep posting about the fix and look forward to getting the car back on the road.
Any other ideas where I should look for an electrical problem with the fuel system?

[603Racing]

Some e30 fuel basics:

• fuel pumps will only kick on while cranking the car to start it, or when the car is running
• fuel pumps will not kick off when up to pressure, they will continue to run
• It takes accurate pressure to get an e30 to run, simply having some pressure and volume is not adequate
• If the in-tank (low pressure) pump fails, the car will likely still run as long as there is a significant volume of fuel in the tank
• To test fuel pumps, you can jumper the fuel pump relay to get the fuel pumps to kick on
• Key failure items on fuel system - pump(s), filter, fuel pressure regulator, crank sensor(s), dme, relay, wiring (usually ground).

Save yourself some time and possibly money. Test fuel pressure with a gauge, test injector functionality with noid lights, check crank sensor(s).

All of this information can be found on this site. If you already know this stuff, then you're better off than I was when I picked up my first e30.

[LateFan]

Great answer, 603. Your list is exactly the stuff we are testing on our project ES. Lift pump replaced, hoses / filter / all sensors / relay replaced, injectors rebuilt, VDO pressure gauge arriving this week. This site is invaluable to those of us learning this car. Thanks -

[325esvt]

Working on the car right now... posting a couple updates.
The car had a surging idle before the problem, not the ICV, figured it might be AFM or ICM, but I'm pulling the TPS off and cleaning it now, as well as the throttle body.

I cleaned the ground connection from the engine to the frame, then the car started right up. I didn't think this was the g103 ground connection, which is supposed to be above the starter, but maybe my electrical diagram has the location wrong.

Still has the surging idle problem, going to test fuel pressure later as well. (with a boost gauge that goes up to 40 psi lol)

I did bridge the relay earlier to test it, it worked intermittently, which lead me to look for a bad connection within the main/ fuel/ o2 wiring harness.

[dnguyen1963]

Do yourself a big favor and perform a smoke test on your engine. Any idling problem can almost be traced back to vacuum leaks.

[325esvt]

So fuel pressure is good. The reason for no smoke test is all the vacuum lines are new and tight... It still might be worth a smoke test, but its a lot of work for something I don't think is the problem. TPS works great :)

I'll mark the critical engine failing to start to a bad ground connection, the car is running (other than the surging idle) great now and starts up no problem.

Two funny things I found while working on the car. The throttle cable is incredibly loose, and I wonder if there are actually two cruise cables on the car. The sleeve looks fine, just way too much slack, like 2-3 inches. I'll look into that later. Already fixed the gas peddle being off the track, so thats not the issue either.

Also when putting the throttle body back on, I dropped a nut. It ended up in one of the holes in the engine frame, completely unreachable and now forever part of the car. No worries, I got another the same size, and planned on getting a oem off a doaner car later. Well I dropped that nut, and while trying to fish it out from the manifold, found another oem nut tucked in there dropped by the previous mechanic. Problem solved! Four original nuts thanks to one thats been riding under the throttle body the last 1k miles.

Going to look into the electrical issue more the next couple days and make sure all grounds are groundy.

[325esvt]

So I just wanted to follow up and close out this thread...
The final verdict on the fuel problem was a bad ground coupled with a seemingly functional, but actually broken pre-pump. At the moment I'm keeping it above half a tank and its running fine.

The idle problem seemed to go away when I switched out the ICV, but it comes back occasionally when the car is warm, although nowhere near as violent, and blipping the throttle makes it go away.

Other interesting notes, found a donor car, actually just a 325, at a local junkyard that I plan on ripping many parts from... starting with the seats, AFM, cold start valve, ICV (I now will have 3), ICM, blower resistor, and whatever else looks good on the car. Black interior, so now I have an excuse to start swapping from the pasty tan interior to a black on black e30. :twisted:

Just replaced the transmission fluid, the tranny is now much smoother, and cold shifting isn't a challenge. No bits of metal in the old oil, but it was pretty sludgy and needed to be replaced. Green tag so 75w90, synthetic.

Also did a valve adjustment. Went well, they definatley needed to be adjusted, but I messed up one of the 12 (I blame it on getting dark at 6:30) so I'm going back to do it all over again tomorrow. The flat spots in acceleration seem to be gone, and the car sounds much better other than one valve making a little racket.

Last, I got my hands on an actual camera, so nice pictures of the car and projects will be in the works.

[AndrewBird]

Idle problem when warm could be a bad ECU temp sensor. If it isn't working correctly, the car will run rich when warm.