Help me get home this weekend!

[Jay87]

Hey guys,

Drove my E30 350 ('87 325is) miles home this weekend for the holiday. About 100 miles into the drive, it started to buck and hesitate intermittently. Each time it would do this, I would play with the throttle and it would pick back up again. At one point it ran perfectly for almost 100 miles in between episodes. Near the end of the drive it got so bad I didnt think I would make it.

Most times it would clear up with some throttle almost immediately. Other times it would completey refuse to fire until I lost about 10 mph in speed, and spontaneously pick up again, then smelling like unburnt fuel.

Now it has a bad idle issue. It will idle intermittenly fine, and then nearly die. The car will compensate, and rev the engine to prevent stalling. Sometimes it will stall.

First I will do my best to find vac leaks... what else should I check? Please give me your ideas, I need to get home Monday!

Thanks,
Jay

[StereoInstaller1]

Next time it happens shove the clutch to the floor, let it die.

Watch the tach, the check engine light (NOT the "CHECK" light for the DIC), and the other lights on the dash. Pay attention to whether or not the radio has power, too.

Report here.

But, before you head out, grab a foot or so of 18ga wire, 3 1/4" male non-insulated spade lugs and a pair of crimpers. Make yourself a daisy chain of the 3 terminals.

Have this ready to use to bypass your main relay AFTER the car dies. Simply pop the hood, pull the main relay and connect pin 30 with the 2 pin 87s. If the car starts and runs, replace your main relay.

Oh: you will not be able to shut the car off with the jumper in place.

[jlevie]

Next time it happens shove the clutch to the floor, let it die.

Don't do that! Instead watch the tach and econometer when the engine is trying to die. If the tach falls with the decrease in speed, but the econometer drives towards zero, you have a fuel issue (bad fuel pump relay, clogged filter, or dying pump). If the tach drives towards or to zero while the car is moving and in gear, the DME is loosing timing data or shutting down. That could be a bad CPS, bad main relay, bad ignition switch, flaky fusible link, or bad power/ground connection.

[Jay87]

Hey guys, thanks for the educated replies. Much better suggestions over here than on other forums. I found the cause of the misfire - the nut on the neg. terminal of the coil backed off, causing it to lose contact intermittently.

I have also had the intermittent problem where the tach will dive to zero as the car momentarily stalls... assumed I had a bad main relay. Can you tell me more about the other possible causes for this problem?

EDIT: Specifically the fusible link?

Thanks,
Jay

[StereoInstaller1]

If the car will restart afterwards, it is the main relay. That is the thing: the contacts heat up and make you have a crappy day, but 10 minutes later the car will start again.

Good catch on that loose wire.

[jlevie]

I have also had the intermittent problem where the tach will dive to zero as the car momentarily stalls... assumed I had a bad main relay. Can you tell me more about the other possible causes for this problem?

EDIT: Specifically the fusible link?

The fusible link in in the small cable, close to the battery, that connects to the positive post. Acid vapors can get under the shrink wrap and damage the fuse, which can cause the DME to "brown out" at higher rpm.