How can you die on the freeway....

[m3recon]

Ive got an issue that I haven't been able to pin down. Ive checked the forums and tried a few things. So that being said......
I'm having an issue with my e30 dying after about 30 minutes of driving. It seems heat related to me because it takes about that long to fail. I cant get the blink sequence to work to help me in the right direction.
Every time I get the car to start after failing my MPG gauge as well as my RPM gauge starts working again then eventually they fail. That's the only visual commonality Ive noticed.
On the freeway the car hesitated like it was missing and then it died... all dash lights come on and I'm coasting. It didn't feel like it was running out of gas. Depending on how hot the car is determines how long I wait until it will start again.
I don't have my Bentley yet and No money for a code reader... yet! If my damn check engine light would stay on I would go that route.
I'm new to the BMW scene so I appreciate any assistance.

[Sagaris]

If both the tach and econometer lose signal at the same time, then the ECU (also known as the DME for Digital Motor Electronics) is losing power. A somewhat common cause of this is a bad DME Relay. Start there, replace it with a known good one.



The DME relay is the white one on the left side in that pack of 3 on the drivers side strut tower area.


Also check to make sure your battery cables are in good shape and connected snugly to the battery.

Hopefully it is just the relay, otherwise you will be in for some electrical troubleshooting.

[Sagaris]

sorry for the huge pic

EDIT: Re-sized

[Stephen]

check ALL your connections after that. i had a similar iussue and where the harness connects to the battery cables was loose, causing vibration to kill the car

[Sagaris]

Just for your information:
Reading the DME fault codes http://e30world.com/fuel/BMW-E30-DME...ic-fault-codes

If you are unable to get the "stomp test" to work then it is most likely because the full throttle switch of your throttle position sensor is toast. Not a huge deal. It is easy enough to diagnose and replace. Let me know if you need further information on it.

[416stroker]

whats the year of your car?
It could be the C191 connection.

the tack and econometer could be a dead SI board?

[jlevie]

If the tach goes to zero and the econometer goes to max when the engine looses power while the car is moving and in gear, the DME is losing timing data, losing power or ground, or faulting. However while the car is still moving only the CEL light could or should be on. If the other warning lights are coming on during the event, a main power problem is likely.

[nando]

I'd start with the main relay and checking to see if your CPS is rubbing on the waterpump pulley.

seriously, even if you think your main relay is working now - if it's original, replace it. this should be one of the first item replacements for any E30. I chased ghosts for 2 years that turned out to be the stupid $20 relay.

[m3recon]

1988...325is

[m3recon]

whats the c191 connection

[Sagaris]

The C191 is a round twist-lock wire harness under the intake manifold that delivers electricity to the fuel injectors. Follow an imaginary line from your throttle body to your oil pan and you will be able to see the C191 connector. Just like the oxygen sensor , you have to unscrew the connector 90 degrees for it to release and pull apart.

The connectors can become corroded like this:

[m3recon]

Thanks for the help. I will be checking all of these items. I'm tired of being the best looking bimmer on the side of the road. Hahahahahaha

[Sagaris]

:pimp:

[m3recon]

If the dme relay is bad will the car even start?

[Sagaris]

They work when they want to when they go bad.