1988 944
Car history setting for a year, running when parked (they said)
Drained all fluids, new battery. Had to remove engine before first start, see https://www.germanautoforums.com/m_8160/tm.htm

Current state
1. Fuel is at the rail my gauge only goes to ten psi( I am going in the morning to get another gauge, and try again.)
2. Plugs Dry
3.Tach Not bouncing
4. No spark (some was noticed but very very seldom)

Tried:
Checked the speed sensors and adjustment
Bypassed DME relay as described in clarks

Is there anything that can cause no spark and no fuel?
I had read in this forum to remove #1 then #3 injector connector, what would they tell?

Thanks
Lowell

 

Bad dme possibly. Have you checked the timing belt?

 

I checked the belt and it looks ok (no cracks) I plan on changing it later, just want to hear it run once before doing anything extra.

So is the dme the only thing that will cause both?

Tested fuel 39 lbs while cranking over 90 when return pinched

I pulled the speed sensors to triple check them. One is fine 1098 ohm and one appears to have a loose connection 1098 and drops to nothing by just tapping on the side of the sensor.
I guess I 'll be going to ebay for a new one.

I marked the wirring harness and plugs when they were originally removed. But I am not real sure if I have them back in the correct hole in the bell housing. (I did swap once just to see if it helped, nope)

How do I make sure the harnes, plug, and correct hole is used?

Also are the injectors firing dependant on spark?
Thanks

 

Fuel is not your problem at this point. If the tach is not bouncing at all, it means you are not getting any spark. There are 3 things that typically kill the tach bounce, bad DME relay, bad reference sensor, and bad DME itself. The reference sensor is the sensor on the bellhousing towards the front of the car, the speed sensor is the rear most sensor. There should be a small tag on the wiring harness where the sensors plug in, one says BG and one says DG. The BG plugs into your reference sensor, and the DG plugs into the speed sensor.

 

One has a tag , Yepeeee Thanks a bunch PorscheDoc!!!!!!!!!!!!

Looked at my notes and I had the BG in the back. On top of it having a loose connection.

I just ordered a new sensor from houstoneuropean.com for $39.00

When I go to install, clarks says .8 mm clearance how critical is that?

When the sensor comes in I'll let you know if that fixes it ,,,,, I hope,,,,,

This Forum ROCKS!

 

The .8mm needs to be pretty close. You can probably be off a hair one way or another and be ok. I took my micrometer to the hardware store, found a washer the right size, and glued it to the bottom of the old sensor to use as a special tool, just as clark shows. Works like a charm.

 

Considering Auto Destruct Button!!!!!!!!!!!!!!!!!!!!!!!!!!

Recap
No spark no fuel (fuel is at rail)
No tach bounce

List of tried things ,

Bypass DME relay (checked volts at socket per clarks)
Changed Ref sensor to NEW OEM (made sure it was in right location, and setting)
Swaped Ref and speed sensor
Changed DME to one from running 944 (same model # on DME , 086)

Additionaly
Dist Cap and rotor
New Battery and cables (double checked grounds)

Motor has been out and put back in to replace dampner https://www.germanautoforums.com/m_8160/tm.htm

I must be over looking something,

Any Ideas?
HELP

 

Hi,

I just did a lot of work on my first porsche, a 1987 944 N/A.

It stopped running on a test drive after changing lifters, cam gasket and a bad vacuum hose, (I also changed out the prom). Ran great for 2 days and died. I bypassed the DME/Fuel pump relay (30 and 87b) and the fuel pump does work (fuel comes out of the disconnected hose). So I am thinking it is the relay. I pulled #1 plug wire and there is spark.

The tach also bounces when cranking. (I read that if the tach bounces, the DME computer is still good(?). I put the original chip back in and no change. Timing and balance belt are practically brand new, as is the cap rotor and wires. Cranks strong and hard.

Looking for some advice. I just purchased a DME relay from a guy on ebay and he recommended this site. should be here in a few days.
TIA
Henry
1987 Porsche 944
1970 Camaro RS 350
2000 Audi A4 1.8T Quattro
1996 Chevy Suburban LT

 

Does the car start with the jumper wire installed in place of the DME relay? If not, then your issue is elsewhere.

 

You sat that the issue is e;sewhere, where else should I look?