New project 924S - if only it would start

[MrTibbs]

Hi Pelicans,

Just wanted to share my excitement at a new project with someone who knows how I feel.

Just bought a 924S from Ebay for the equivalent of 575 dollars, plus another 160 dollars to get it delivered. Arrived today (my birthday - I'd taken the day off), and spent the day looking it over and playing with it. It doesn't run at the moment, and is kinda on the point between being a parts car and a 'fixer upper'. Am going to see if I can get it running and sell it on for a few beer tokens more than I paid. If I can't I'll use a load of parts for 'my' 924S, sell the rest and hopefully make a smaller number of extra beer tokens.

It's been sat around for a while - was last on the road 2 or 3 years ago. Like a good boy I changed the cam belt for a spare new one I had lying around before trying to start it (took me about 3 hours I think). Then put the battery from 'my' car onto the new one (the one in the new car was reading 4V so not quite enough to turn it over!), and tried cranking it. Turns over but won't start. The guy I bought it from said it was running for a few seconds then cutting out (I figured fuel pressure damper). So far I've tried disconnecting one injector and cranking it (no luck) and changing the DME relay (no luck). I was doing slightly random things as I was running out of time before the light faded.

Then I reminded myself that even when short of time it's best to be systematic. I pulled the no1 plug lead and put a screwdriver into it and laid it on the intake to check for spark. No spark. I measured the resistance of the coil between the two terminals (didn't measure the resistance to the lead that goes to the dist cap). it read about 0.2. I think I might have found the problem. When I get a chance I'll swap in the coil from my other car, but do you guys reckon this is the culprit? When I crank it I get a small amount of tach bounce so I think the DME and ref sensor are working OK.

Be good to get it running and save a Porsche from the great racetrack in the sky.

Will keep you all updated on progress if I do get it started.

Mike

[MrTibbs]

[Brozoar]

Wish I knew enough to be of any use mate, but I don't.

Just wanted to say - great deal! She'll be a nice ride as soon as you crack her.

[kfray]

Ignition information:
http://www.clarks-garage.com/pdf-manual/ign-04.pdf

[Brozoar]

Actually, could be the Fuel Pressure Regulator (not to be confused with the Fuel Damper):
Fuel Pressure Regulator - General Information and Replacement

Also, a good place to look (just because someone just posted it to another Thread):
Let start a NO START checklist

Go with your gut, it's probably not your DME. Hopefully that's some help..

[MrTibbs]

Thanks for the suggestions.

I've been working through a bit more methodically. Found it's not getting spark (have just bought a handy thing that looks like a pen but you hold against the plug lead to check for spark).

Using Clarks ignition and fuel trouble-shooting lists I've checked out the power to the DME relay, that the fuel pump runs, resistance on speed and ref sensors, resistance of coil (checked it again and it seems fine - not sure what I was doing before), 12V to both coil primary posts, 12V to relevant terminals on DME plug.

I'm fairly sure I have the no spark issue narrowed down to:

1. DME
2. rotor and cap

The rotor and cap didn't look too bad when I changed the timing belt, but I might have another look as I was focusing on getting the belt done before.

My bet is on the DME though - It's been pretty wet. The batt tray is obviously leaking as both footwells are very damp and the DME had a few drips from it when I disconnected it. Need to go to work now, but if I get a chance this evening I'll swap in the DME from my other car (lucky to have a fully working spare) and see if it starts up.

Fingers crossed it was the DME causing the car to run for a few seconds then cut out. My first thought on this was fuel pressure regulator so may still need to swap this in from the working car.

Have set myself the challenge of getting it started by the end of Saturday.

Mike

[kfray]

It might help to move to a dry climate!

[MrTibbs]

Update:

It runs! Cleaned up the rotor and distributor cap, no start. Swapped in the DME from my running car and it fired right up. Sounds pretty good too. Idling about 1500 rpm but might be the ICV stuck open or something else slightly out of whack. Will try to fix the DME that was soaked but might need to track down a good used one.

I am a very happy man.

Mike

[romad]

Car looks so much better without that cheesy rear panel side reflection that was required in the states

[Brozoar]

Huzzah! Congrats.

[The Glademister]

I've got a known good DME from an '88 924S or 944 that I'm probably going to sell. Not sure that's compatible with your Euro model though. Somebody here will chime in I'm sure.

[MrTibbs]

Thanks Glademeister,

Might take you up on that offer - though with shipping from the states it might be cheaper to get one from closer to here.

I think the DME's changed around '88. If I recall correctly you can't mix and match DMEs and AFMs. The one I need is part number 944.618.121.04.

Am hoping mine might start working once dry, but might try re-soldering if that doesn't work. Basically it's dead at the moment so no harm in trying something to bring it back to life.

If anyone knows of a successful method of reviving a water damaged DME do let me know.

The white car I'm trying to fix up and sell so no immediate problem only having one DME between both cars, though I'll need to either fix the dead one or get a new one before I sell the white car (or else I'm walking for a while).

Mike