924Board.org

LostAngel · Joined: 25 Apr 2008 Posts: 5 Location: Meadville, PA

Hi guys, I have a 1987 924S, automatic. All throughout the cold winter here in NW pa, the car never stalled. Once spring came, and the weather warmed up..it seems to randomly stall once the temp gets up a bit. What would be causing this? Sometimes, it completely stalls (and the volt meter drops, tach drops to 0), and sometimes when driving when its warm when you gas it, it just backfires some...no acceleration...then it will either fix itself or stall. It USUALLY starts right back up after a few cranks, but a couple times it didn't start for about 20 minutes. Anyone know what might be the problem? It will range from stalling once...letting me drive 5 minutes...stalling again....to stalling...I drive 2 feet...stalling...drive 2 feet...stalling. The other day, I couldn't take off from a stop 'casually', I literally had to blip the throttle when in neutral, then put it in gear and squack my tires to go without stalling.
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1987 Porsche 924S Red

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

Welcome.

The most common reason for the symptoms that you describe are: a defective DME relay (most of us carry a spare known good part) in the car for emergencies), or failing solder connections inside of the Motronic brain box (next time you have a problem, whack the box to see if the condition improves), It's located under the carpet on the right side under the dashboard, or failing (or misadjusted) flywheel sensors.

The place to start looking for the problem is the DME relay. Buy a new one (NOT USED), and try installing it. In the meantime, when you have the problem, whack the Motronic box, and see if the engine starts to behave. If this is the problem, and you can solder well, you could remove the box and resolder the board. Otherwise, you are going to need to buy a replacement Motronic brain box. (not cheap).

LostAngel · Joined: 25 Apr 2008 Posts: 5 Location: Meadville, PA

Thank you, do you know anywhere where I can buy one of those relays?
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1987 Porsche 924S Red

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

I suggest that you buy a copy of Excellence magazine and scan the ads for aurthorized Porsche Dealers who advertise toll free phone numbers and discounts from PCNA (Porsche Cars North America) suggested retail. There are also lots of aftermarket companies who advertise in there.

Then, before you order, post a message here and ask about the reputation of the companies you are thinking about ordering from. The sad truth is, lots of shady or flakey companies run big ads in the magazine. Some of the biggest ads are from companies that don't ship what they advertise, and are located in garages behind their owners houses. One example of this: Vertex, big ads, good prices, but they make mistakes, and are slow shipping. Someone dropped in at their advertised location, and found a small garage behind a house with a guy rebuilding a component by spray painting it from a can. NEVER order rebuilt parts from Vertex. Their name brand products (Bosch, Hella, etc.) are okay if you can get them to ship after you pay them. And never order from AA (Automobile Atlanta). Excessive shipping charges, extremely poor condition on used parts, slow shipping, no refund and no apology for their frequent screwups. Another company to stay away from GPR (German Parts & Restoration).

Some good reliable companies beside the larger Porsche Dealers: Performance Products/Automotion, Zimms, EBS (Engine Builders Supply).

skytrooper · Joined: 29 Aug 2007 Posts: 461 Location: Canandaigua, NY

EBS has been a real life saver for me with my turbo rebuild. Parts that no one else had ...they had, or got real quick. I have used Zimms also.
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Matt

1987 - 924S "Black Pearl"
1982 - BMW 633CSi
1984 - BMW 528e
1983 - 944 N/A "Blue Max" (Gone)
1981 - 931 "Scarlet Harlot" (Gone)
1976 911S Targa (Gone)

bcblase · Joined: 23 Oct 2007 Posts: 574 Location: Winchester, VA

I have been happy with the stuff I have ordered form Vertex so far - wheel bearings and other off-the-shelf packaged parts. I have not ordered any re-built stuff from them. I was thinking of ordering some brake components from them, but not ready yet.

Paragon Products has good prices, and the owner (Jason Burkett) seems to be a really knowledgable guy - (plus he owns one of the few 968 RS Turbos!). Some of the stuff I have ordered from them has been the real Porsche part in factory packaging.

If you have a 924S, then 944online.com has a great selection, but prices are not the lowest.

I'll have to try some of the other vendors mentioned.

Just my 2 cents,
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

JSilverman · Joined: 16 May 2006 Posts: 93 Location: Burke, VA

Paragon Products are great to deal with, and they have great prices. Pelican Parts has good service but tends to be expensive, espeically with shipping. They do have some stuff that no one else carries though. I use paragon when they ahve what I need and Pelican for everything else.

LostAngel · Joined: 25 Apr 2008 Posts: 5 Location: Meadville, PA

Thanks, I ordered one from paragon products. Hopefully that is my problem. Aside from the relay and the ecu...what else might cause this?
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1987 Porsche 924S Red

bcblase · Joined: 23 Oct 2007 Posts: 574 Location: Winchester, VA

I have a spare DME/ECU on the garage shelf, and I keep a spare fuel pump relay in the glove box.

I still have an occasional problem with my 924S faltering/stalling when the engine is lukewarm. It only seems to happen in cold weather for a minute until the engine reaches a warmer temp.

I have tried several fixes, including replacing the engine temp sensor, the throttle position switch, and the fuel pump relay.

I have a thread from a few months ago addressing this problem.

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

LostAngel · Joined: 25 Apr 2008 Posts: 5 Location: Meadville, PA

Well I bought a new DME relay and that wasn't the problem....still stalling. Guess i'll move onto looking into the computer and the flywheel sensor.
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1987 Porsche 924S Red

LostAngel · Joined: 25 Apr 2008 Posts: 5 Location: Meadville, PA

I replaced the fuse...same thing happened. I believe I found the problem. Under the hood, center of the car...right up near the fire wall is two sets of connectors for wires. They were attached with a bracket...the bracket was bent slightly causing them to connect/disconnect under certain conditions. I fixed the problem and no stalling so far.

I do have one problem though, since the weather has started getting cool/humid in the mornings...my car doesnt like to start. I have to have someone pull on my throttle cable all the way...then it starts right up when I try the key...otherwise...nothing...what would cause this?
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1987 Porsche 924S Red

bcblase · Joined: 23 Oct 2007 Posts: 574 Location: Winchester, VA

Those connectors in the bracket are for the reference sensor and speed sensor from the top of the flywheel, I believe.

The other problem might be related to the throttle position sensor (TPS) located under the throttle body.

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