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ic932
Joined: 11 Feb 2005
Posts: 1104
Location: UK
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 Posted: Tue Apr 07, 2009 8:43 am Post subject: |
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Hmmm...It would sure make life easier if this suspect wiring variable was taken out of the equation.
Well good luck with that wiring anyway. Personally I would look for a complete harness.
Don't be shy with the "starter fluid", I just dump in raw gas and lots of it. Like I said I blew the AFM off on the last 944 motor in a non-start situation! That was an S2 lump, god knows how long it had been sitting. I did all the usual tests/checks, I had fuel (probably not enough), had spark but no go. I dumped fuel into the inlet manifold with the DME relay terminals bridged and after numerous attempts the injectors cleared themselves ( i pressume). Within an hour she was running up to temp and purring like a kitten. As it turned ou,t it is a very sweet motor indeed.
Certainly not a methodical approach I admit.
While I think about it, you have tried bridging the DME relay terminals? |
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legoist
Joined: 03 Apr 2009
Posts: 30
Location: Eugene OR
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| Posted: Tue Apr 07, 2009 9:26 am Post subject: |
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I haven't done that yet, but I can hear the fuel pump running.
| ic932 wrote: |
While I think about it, you have tried bridging the DME relay terminals? |
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924s - 1987 Not running |
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ic932
Joined: 11 Feb 2005
Posts: 1104
Location: UK
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| Posted: Tue Apr 07, 2009 9:57 am Post subject: |
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The thing is, the pump is being energized when you are cranking the motor over but is dying when you release the key?
Classic DME relay failure. Dump fuel in the intake, bridge the DME relay and if you hear the pump running and hear things going on within the fuel-rail...try and start her.
If the car starts but will not run thats the time to look at the injector wiring (amonst other things)
Jumping the DME relay is the first thing on the list...you have spark yes? Now is the time to add a SUFFICIENT amount of fuel. Even getting it to run for a few seconds will rule out a lot of variables. |
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legoist
Joined: 03 Apr 2009
Posts: 30
Location: Eugene OR
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| Posted: Wed Apr 08, 2009 1:09 am Post subject: |
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I'll give it a try tonight. I was going to work on it last night but my wife had other plans for me.
I did pull the DME relay and it looked brand new. I am 90% sure the PO replaced it.
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924s - 1987 Not running |
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ideola
Joined: 01 Oct 2004
Posts: 15550
Location: Spring Lake MI
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| Posted: Wed Apr 08, 2009 1:35 am Post subject: |
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| legoist wrote: | | I am 90% sure the PO replaced it. |
Not good enough. Never ever ever trust what you think the PO has done. Never.
You need to go back to here:
http://www.clarks-garage.com/shop-manual/eng-15.htm
Make yourself a testing matrix with squares to record what you've done and what the results were based on that troubleshooting guide. Follow the trouble shooting guide methodically from square one, regardless of what you think you've already done. If you're not methodical, and don't record the results, and don't start at the beginning, you'll be here for another week trying to isolate the problem.
Having said that, one additional thing that is worth checking is the battery connections. Make absolutely certain that the starter connections, alternator connections, and the connection at the battery themselves are all good, clean, and properly grounded. On a 924S I recently got rid of, I failed to properly tighten the negative battery post after replacing the starter. Weirdly enough, the car started fine for me, and ran for two days for the new owner. Then it refused to start. Would crank over just fine, but would not start. Turns out, the loose nut on the negative battery post vibrated further out, apparently enough that the DME or something wasn't happy about it during starting attempts.
As I said, NEVER trust the PO.
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erstwhile owner of just about every 924 variant ever made |
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legoist
Joined: 03 Apr 2009
Posts: 30
Location: Eugene OR
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| Posted: Wed Apr 08, 2009 2:53 am Post subject: |
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| ideola wrote: |
As I said, NEVER trust the PO. |
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924s - 1987 Not running |
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legoist
Joined: 03 Apr 2009
Posts: 30
Location: Eugene OR
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| Posted: Thu Apr 09, 2009 12:45 am Post subject: |
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So last night I verified the wiring on the Fuel injectors was correct then jumped the DME relay. Still no start. However when I put the relay back in I noticed the fuel pump wasn't running. AH HA! I say then I figured out that the fuse block had a few loose connections and if I held the wires behind it it would do what it was supposed to.
Then The car stopped getting spark.
Gremlins.
Tonight I guess I'll be pulling the fuse block out and trying to make sure all the connections are clean and secure.
but hopefully not 
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924s - 1987 Not running |
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legoist
Joined: 03 Apr 2009
Posts: 30
Location: Eugene OR
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| Posted: Fri Apr 17, 2009 12:01 am Post subject: |
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OK. I tested the coil. It was way out of spec. I posted about it here: http://www.924board.org/viewtopic.php?t=28846
That explains why the spark test seemed intermittent. I had power and spark at the coil, but it was very irregular.
New coil shows up today. I hope to know more soon.
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924s - 1987 Not running |
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legoist
Joined: 03 Apr 2009
Posts: 30
Location: Eugene OR
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| Posted: Tue Apr 21, 2009 3:41 am Post subject: Intake and injectors |
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OK. Here's where I am at on the getting the car running process.
I managed to get the car running after blocking open the MAF with a piece of hose. the car idled and ran at 2700-3500 and sat there surging.
'AH Ha', I thought. the maf is bad. I removed it and tested it via the write up at clarks. The meter said it was good and no flat spots.
I decided to take a look at the idle control valve. When I pulled the intake it wasn't super tight. I think air was getting in. Also 2 of my injectors had cracks on the plastic around the tip. I have a reseal kit on order.
Questions:
* How do you test the idle stabilizer?
* would a slightly loose intake cause starting issues?
* the plastic hats on the injectors - if they are cracked or broken what will it do to the running of the car?
Thanks,
Chris
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924s - 1987 Not running |
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legoist
Joined: 03 Apr 2009
Posts: 30
Location: Eugene OR
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| Posted: Mon Apr 27, 2009 9:13 am Post subject: Car running |
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Finally got the car to start and run. Apparently the intake was not seated properly and the drivers side was about an inch higher than it should be. Once I reseated everything and put the new injector seals on it fired right up.
Tons of other little issues to address now.
Sigh of relief.
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924s - 1987 Not running |
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bcblase
Joined: 23 Oct 2007
Posts: 574
Location: Winchester, VA
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| Posted: Wed Apr 29, 2009 12:09 am Post subject: |
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Good job Leg!
Welcome to the wonderful world of 20+ year old Porsches!
BC
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1987 Porsche 924S - track toy
1986 Mercedes 190E 2.3-16v - autocross
2007 F-150 5.4L Lariat Supercrew - tow beast
1994 Volvo 850 Race Wagon - 24 Hours of Lemons Car
2001 BMW 325xi - daily driver |
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924 FAQ (Technical)
