924Board.org

[Chewtoy]

Ok, I've searched the boards and come to the end of my knowledge. So thought I would just ask.

My car starts great when cold, and if within about 5 minutes of shutting it off when warm. But if you wait about 10 - 15 minutes when the car is warm then it won't start. I've done some testing and believe it is starving for fuel. I say this becuase a quick squirt of gas into the intake and it starts right up. Rough but quickly goes to normal.

I have replaced the fuel filter and the pre-filter before the pump. The pump was replaced right before I got the car, so the guy tells me. I can't find any vacuum leaks. The engine was just swapped out in it along with the complete CIS system and it did this with both engines.

Any assistance would be greatly appreciated, this is getting quite embarrassing when I go for lunch and it won't start when I leave.

Thank you,
Wayne
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'77 Yellow 924

[Ozzie]

Do a search for hot start problem.

Common problem with these cars caused mainly from the fuel evaporating in the lines from the heat causing vapor lock.
Recommended way to start is with foot flat on floor and crank till it starts.

Later cars had the hot start solenoid fitted to the CIS and will start without touching the gas (or very little).
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[Rasta Monsta]

Fuel pump check valve, fuel accumulator, primary pressure regulator.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Chewtoy]

Ok, I just looked up in the repair manual that I have looking for this check valve. I hadn't seen anything in the line that I thought might be such an item.

Well when looking at the diagrams, I don't have an accumulator. From the best that I can see the line comes from the bottom of the tank to a pre-filter then to an electric pump. From there to the front of the car through a fuel filter and into the fuel distro.

Where is the check valve instaled at? There is a cut and splice in the line right after the pump that something could have been there. I don't know about the accumulator as I don't remember seeing any mounting brackets and the pump I have looks nothing like the one in the book. But I will inspect again tomorrow.

I did find the page to wire the cold start injector for manual operation. I am going to look into setting this up tomorrow for an interim measure.

Thanks for all the feedback, maybe this will help stop me sitting in the parking lot for a good 5 minutes with a car that won't start.

[Edit] Nevermind, just read a post saying that my style fuel pump has the check valve built into the neck of it.
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'77 Yellow 924

[Rasta Monsta]

It looks like you should have the accumulator (from what I can tell in PET). Someone may have decided it was to expensive to replace and tossed it. . .but it is there to counteract the problem you are having.

If it is set up like my car, you will need to hit the junkyard for hard fuel lines if they were tossed as well.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Mike924]

[Chewtoy]

Yep, just looked under the car again. The line coming from the fuel pump has been cut with a small piece of steel line clamped in. And nothing between the pump and where the line goes under the main body headed to the front.

Looks like I will have to wait on this one, no junkyards in my area with these cars in them. There are some around my dad's house so will put this on a to-do list for when I go visit him.
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'77 Yellow 924

[Smoothie]

In the meantime try what Ozzie said and hold the pedal to the floor while cranking. The problem is vapor lock, and flooring the pedal helps to clear it quicker.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[Vince Ponz]

Always buy new fuel accummulators. Eventually used will leak before a new one and your problem will start again.

My carbed car is hard starting cold. I pump it a lot to start. But it always starts. Hot, never a problem. I think that it needs to fill the bowl.
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"Never let them see you sweat"
77.5 924 modified track car
79 931 Euro stock
88 924S SE
87 911 Targa stock

[Ozzie]

IIRC the early models had 2 accumulators (20cc each) but later cars went for 1 larger 40cc. As yours is missing get the large one.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[Mike924]

+1 to buying new and +1 to the larger accumulator.

I've been running a Golf (Rabbit?) GTi accumulator on my car. They're a good deal easier to get hold of than a pukka 924 one (still quite pricey, though). It has a larger inlet connector than the 924 unit (same size as the outlat), but as you'll need to adapt the line from your pump anyway, this won't be a problem.

Good luck.
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1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org

[rkn]

Hi
I have the same problem, so I'll just add to this thread. The PO has removed the fuel accumulator = horrible hot starting
This really takes the pleasure out of the summer sunday drives - if you stop for ice cream, you know it's gonna take you at least 2 painful minutes to get going again.

Anyway this also means I don't have the fuel line connectors for the accumulator. Hard to find a 924 in the junkyards around where I live, but If I get a new accumulator, can I get the connectors from some other car that uses the same accumulator?? Perhaps a Golf/Rabbit?

thanks for helping
Rasmus
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1980 924NA ROW

[Mike924]

I don't the Golf fuel line will help, because they use a different pump, etc.

I had my line made up by a hydraulics specialist. Just tell them the length and the type/size of the unions (or take some examples along) and they can make one up on the spot. Warning - not cheap! I paid £35 (€50) for the job.
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1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org