944S Start up trouble after rebuild

[ballysdad]

This is a list I started a while ago something here may help narrow it down.
Hmmmm.... that could be alot! you really have to go step by step and check the ecu harness and voltages to each area as you go. Here is a list of some test you should do one by one and eliminate problems.
Air/fuel/spark/compression
start by making sure we have a battery that is in spec.
all fluids topped off
no obvious broken wires and all vaccum hoses intact on visual inspection.
OK we have 12v at the battery with adequated cranking voltage we get in and turn the key.
12v from battery to ignition switch
12v from pin 50 on switch to pin 4 on dme plug (start signal)
12v on pins 1 (ignition pulse to ign. coil) and 18 (to G5 dme relay power supply)
12v pin 30 at dme relay (fuel pump power supply)
12v to pin 86 at dme relay in the run position (primary coil voltage)
12v to coil + black wire to ground 12v to - (green wire) to ground
12v to one side of the injectors
All ground contacts are clean
Fuel pump will run if dme relay is jumpered 30/87/87b
Fuel pressure at the rail is 29psig +/- 3 (jumpered 36 psig)
20 minute leakdown not under 14.5 psig
Fuel flow rate is 28oz after 30 seconds
Ignition coil primary resistance across + and - is between .4 and .6 ohms
Secondary resistance is between 5000 and 7200 ohms
Ignition wires are good no cracks or splits including coil wire and seated
Plugs are properly gapped
Ignition rotor is seated correctly with the set screw
Timing belt is installed correctly
Firing order is correct
Reference sensors are gapped correctly with .8mm clearance off the flywheel
Reference and speed sensors resistance checks in spec pins 8 and 27 speed 600-1600 ohms and pins 8 and 23 >1m ohm
Reference and speed sensors voltage checks 2.5 and 2v on oscilliscope (good luck)
Reference and speed sensor wiring is not broken at connector to sensor or to dme
Ok Im tired anyone else want to add or be more specific?

[mhariush]

And I checked terminal 30 (for the dme relay) with a spade plug into it with the red wire on the volt meter and the black on the - battery and it came up with 11.86 volts, so close enough i think. So at least the DME relay has power...

I went under to change my fuel filter, gotta change that anyway, and I also looked at the pump. I disconnected the green wire on the pump and used a test lead from + on battery to the fuel pump where the green goes, no action.
I disconnected the brown wire and used my volt meter, with the battery to the car connected, and check the two wires with the ignition in "on", all the way to the right, before it cranks, and i got no reading at all. Will it only show a reading when the car cranks? Or should it still show voltage?

[kfray]

When you jumper 12 vdc to the fuel pump (green wire) it should run.

[mhariush]

It should right? I pulled the green wire off the pump and then put the 12V lead from the battery (out of the car) directly onto the pump.

If, for some reason the pump is bad, would that cause all these issues? like no spark etc?

[kfray]

A bad fuel pump will not cause no spark.

[mhariush]

Update on this nightmare, the fuel pump is good, works when i put 12v straight to it.

[mhariush]

I tried test point 15 on page 136 of the 16V manual.
I connected a test lead with a spade on each end to the two pins it says. But nothing happened. Then i turned the key to "on", still nothing. I tried Cranking the engine and i heard the fuel pump start for a short burst, but then everything went dead. The clock went dead, the engine didn't crank either. And i think i took the key out, and put it back in but still nothing. Then I disconnected the battery and connected it again and the clock, lights etc started working again and the car cranks.

[Truckin4life]

I quickly read through this, but have you checked fuses?

If so sorry i missed it.

Possibility that the ground cable from bell housing to block gave out or body to block?

Maybe that's why the starter didn't want to work?

[mhariush]

checked all the fuses, all good, all relays are good too.

There might something about a ground, but i changed the starter and the starter works.

This all happened after driving through a car wash. The car was running before this. Turned it off in the car wash, started right up after, drove about 2 minutes tops to my house, then parked and tried to turn the car off. The engine turned off but the starter was still engaged. It went like that for maybe 5-8 minutes, then a semi loud metallic clank and the engine sound changed. I assume the clank was the starter disengaging and the engine sound changing being that the starter was no longer running.
The battery was dead the next day, starter was dead. Replaced battery, replaced starter and now it only cranks.

[mhariush]

I ended up towing it to a shop, G-Man Automotive in Culver City. He diagnosed it and got it running.

The Ignition Module was dead, I had tried with a new module but never heat sinked it to the fender so it didnt get grounded and thus didnt work.

Also he said the white relay (i only spoke to him on the phone so not sure which relay he refers to) was also dead.

So now the car runs! Lesson learned, always pull and install Ignition Module with heat sink even if the old one might still be good (which it wasn't in this case).