I have a 1987 automatic Porsche 944 NA

It's giving me no start trouble. I've been working through the instructions at
http://www.clarks-garage.com/shop-manual/fuel-16.htm

I can tell you that the tach does indeed bounce when it's turned over
That with the jumper you can hear the fuel pump run and it'll fire right up

I checked the fuse #34 it's fine
The DME/fuel pump relay checks out and appears to function properly when voltage is applied according to my multimeter

The Voltage from terminal 30 is roughly 12v
I couldn't check 86 because I didn't have a small enough spade

On the DME plug...the big one Terminals 18 and 35 are again approx 12v
From terminal 4 when you crank it it reads approx 12v

I don't have a spare computer to test with...
and I actually can't find the plugs for the reference sensors...I'm likely looking in the wrong spot but are they not in the same area as the computer?

I haven't had a chance to jack the car up and check the sensors physically

I'd read that the bouncing tach was an indication that those were functioning anyway...

I have yet to take apart the computer...I'm still hoping it's easier than that

Is there anything that I'm missing?

 

Have you checked to see if you have a spark at the spark plugs?

It could be the distributor cap, rotor arm, ignition coil, leads, etc.....

 

When I replace the relay with the jumper it runs...like it fires up and the engine functions
I didn't hear it missing?

I thought that meant the spark and ignition bits were essentially fine...I had popped the distributor cap off before and it looked fine (this problem started after I washed the car...water in the distributor seemed an obvious suspect)

Also since the DME relay was the first thing I checked...I popped it out and checked it on the bench...it checked out...
when I put it in and tried to start...it fired right up...I was shocked...I haven't been able to do that since
Is it possible for the relay to still check out but not work?

And where are those plugs for the sensors? Even if it's not that the curiousity is going to eat me

 

I think that your first point of call is getting a new DME relay. They are quite temperamental and can work one minute, then fail the next, then work again. They are quite cheap to buy & it's always recommended to have a spare handy.... because if the thing isn't faulty, one day it will be!

When mine failed this year, I could get the engine started with one lead removed, but not when all four were fitted!?

 

Yeah I've heard that. I was actually hoping it was the DME relay because it's relatively simple.
I was disappointed when it seemed to check out (disappointed with something working?)

You you're saying it might seem to work on the bench and not work when it's in the car?

 

Yes mate and it's always worth having a spare!

 

So I might still be lucky and it's not something else that's wrong

Well I'll see if I can find one today then
Here's hoping that's all that it is

 

Well...I popped it apart and reflowed the solder
and it now fires right up like nothing ever happened...

That's crazy...it passed all the tests on my workbench
Thanks for the help

Oh....and where did they hide the reference sensor connectors?

 

I'm glad you sorted it! I'm not sure where the reference sensors are....when I get a chance I'll have to have a look in my Haynes manual.

I'd still recommend you get yourself a spare D.M.E. relay. Ready for the next time it goes! (It will eventually!)

All the best, CTP.

P.S. have you any photos of your 944 for the forum gallery?

 

Hi,
Your speed and reference sensors are at the back of the engine next to the inspection hole, and the two plugs should have two marks on them BG and DG.Not sure which is which.
Hope it helps