The Infamous No Fuel - No Spark

[SpecM]

Put my ECU in Tara's car and it starts her car right up.

I would say the problem's in the m50 harness

[RobertK]

I would say the problem's in the m50 harness

Do you mean the engine harness or the harness adapter?

[SpecM]

Do you mean the engine harness or the harness adapter?

I say engine harness, maybe you damaged it on the install

but that's a guess

[atomic]

Put 'ole smokey back in???



:D

[Stevie30]

Put 'ole smokey back in???

Please....No (gasp, gasp) Get er done!

[rs4pro3]

Found another ground I over looked on the ecu connector for you to check out it's pin 28.

Also I found that there is an automatic tranny switch that could possibly be on your harness, it goes to pin 65 on the ecu connector, check and make sure you have 12volt on that wire. The diagram dosn't show how the manual cars deal with that wire.

[golde30]

i had an e36 auto harness for my 24v swap, i just cut out all the wires that went to the tranny dme plug, diag port, and connector(looks like o2 plug) out of the harness with no ill effects.

[318isbmw]

Even though they never were disconnected, I would check the crank and cam sensors. Common problem is those go bad so the ecu won't turn on spark. I'd hate to see those be the problem with all of the work being done, and their both a simple test, the only issue is getting to the connectors.

[JGood]

You can test the crank sensor via pin 16 and 43 (IIRC) at the DME. You are usually looking for 540 ohms at the sensor, so figure a little less at the DME. I had 537 at the sensor and ~520 at the DME.

[RobertK]

If the cam or CPS was bad wouldn't the fuel pump still turn on?

Also, this harness came from a manual E36 so would that automatic pin still apply?

[rs4pro3]

no as the ecu has to see that the engine is actually cranking to kick on both the pumps and send spark. So a bad crank sensor could cause your problems.
I'm not sure about the park switch thing, usually on the diagrams it shows a separate diagram for manual and automatic cars, this diagram doesn't show that. So just check for 12-volts on pin #65 of the ecu connector

[FredK]

I know that the ECU has to see cranking before it sends a signal to the fuel pump for the earlier Motronic systems, but is this true for the 413 DME? I hear a buzzing right when I turn the key to the ON position, but it is a short buzz.

[jakeb]

Isn't the buzz the ICV?

[RobertK]

Yeah, usually the buzzing is the ICV adjusting itself.

So next on the agenda this afternoon is test power to the fuel injectors, check those pins on the DME plug and then check the CPS.

[RobertK]

Also, would a bad Cam sensor also cause the fuel pump not to turn on?