240 General: "poof" no fuel or spark..... Long.....

Put a new alternator (previous one went bad) in my 82' 244 yesterday and all was well. Started it up after getting everything back together and checked to see that the alternator was charging, let the car idle for about 10 minutes then shut it off.

Came back about an hour later started it, ran for about 10 seconds and just died.

Turned the starter over for about 1 minute straight and no start. Noticed I didn't smell any fuel, so I pulled an injector and turned the starter over and nothing. Fuel pump turns on and primes as normal when the key is turned on, but no fuel when cranking.

Decided to check for spark, nothing there also. No spark from the coil, but the coil IS getting power and the primary resistance is right at 1.0ohms where it should be.

Not sure where to go from here. If it was just fuel or spark missing it would make a little more sense to me, but both just going "poof" at once
has me confused.

My guesses are ignition control unit? If I understand correctly, the relay that turns the fuel pump off when the motor is running but the ignition is on gets it's signal from the coil pulsing telling it that the motor is running and to power the pump. Could a dead ICU cause the coil not to pulse, thus indirectly cutting fuel?

Fuel pump relay? Don't see how a bad PF relay can cut spark too.

I have ruled out the obvious, timing belt is good, fuses are all fine. Fuel in the tank ect...

Any opinions would be greatly appreciated.

[Mike_Brace]

The ICU certainly would be favourite to try first. Had one of mine go in similair circumstances. Switched off and it wouldn't spark. Didn't check fuel though.

Mike

[Peter D]

The system relay on this model shuts down the fuel pump relay via the Control Unit and the the pulsed output to the coil so you could loose both. Chack you have power at pin 30 of the System relay and when on at pin 9 of the Control module. Also ensure with ign on there is power at pin 18 of the Control Unit. Regards Peter

[Andrew (UK)]

Originally Posted by Hiesman

My guesses are ignition control unit? If I understand correctly, the relay that turns the fuel pump off when the motor is running but the ignition is on gets it's signal from the coil pulsing telling it that the motor is running and to power the pump. Could a dead ICU cause the coil not to pulse, thus indirectly cutting fuel?

In short yes. But so could a bad hall effect sensor in the distributor. The Haynes manual has a procedure for testing both but you need a multimeter. A logic probe is not good enough.

I had the ignition amplifier die on me one morning on the way to work. The car just died. Diagnosed it at home with Haynes, got a new one from my local car parts shop and all was fine once fitted which is easy. Do clean up the old heat sink compound and apply the new stuff which should be supplied to make sure you don't get any hot spots that could prematurely kill the new one.

Andrew

[Peter D]

Good point I forgot about the Hall effect sensor on this model. It should measure between 950 and 1250 ohms so you need a meter. However if you connect one end of a 9volt battery to the hall effect sensor and the the other HES terminal to a length of wite and stick it on your tongue along with the other battery terminal it should 'fizz' noticabley. No 'fizz' then the HES coil could be open cct. Regards Peter

Thanks Peter and Andrew...

One more quick question. I may have missed it, but I can't find the location of the control relay listed anywhere in the Hanes or Chiltons manuals.

I will get to do more diagnosis this weekend. I have a good multi so I should be able to get to the bottom of this pretty quick. Will post back the results.