924Board.org

[Levans]

i am very curious to know what was at fault with your 924 to cause you a hot start problem.

it is still a problem with my 924 and has been for a long time now, i have changed everything i can think of with a new or working part. i am now looking at changing the fuel lines that come off of the fuel distributor to the injectors as i believe it is a vapor lock problem.
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78 Dark met Green "THE 924"

[5150]

Bigger (more oomph!) battery on mine sorted out all my hot and cold starting issues. Well, that combined with the replacement engine
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Mars Red '78 Euro 924 n/a
http://www.cardomain.com/id/5150_uk

Graphite? Grey Metallic '85 (late model) 944 2.5

There are two kinds of pedestrians: the quick and the dead.

[-nick]

You forgot the fuel pump check valve and the fuel dizzy check valve (often overlooked).

Just pick up the CIS gauge and figure out where the leak is, if you don't have a leakage then it's a tuning/warm-up reg problem. Pretty easy to diagose.

-nick

[Levans]

nick, what check valve is in the fuel dizzy or more to the point where is it and can it be replaced. i am thinking that the pressure problem is between the fuel dizzy and the injectors.do you think having low pressure between these two points would lead to a vapor lock situation?
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78 Dark met Green "THE 924"

[Levans]

i only suspect this because i had my mechanic do a fuel pressure test at certain shutdown stages and the results were all above the required levels but i am thinking that he did the test prior to the fuel dizzy(eg at the filter?) so i am sure that the problem is from the fuel dizzy on.

i have replaced ALL fuel system components that are prior to the fuel distributor, aswell as the cold start valve and also the WUR
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78 Dark met Green "THE 924"

[Chrenan]

I changed the following (fuel related) items and my hot start problem is no more:

WUR
Injectors
Accumulator
Check valve
Frequency valve
Hose from tank to pump (leaking)
Hose from pump to accumulator (leaking)
Hose from fuel filter to distributor (leaking)
Fuel filter

Who knows which one was the problem or cure, but my car starts much better now, no matter the situation. Of course, there were also a few non-fuel items replaced:

Plugs
Wires
Rotor
Cap
Oxygen Sensor
Battery-Starter-Alternator wiring
All vacuum lines

In any case, I wonder if it is ever one "fix" that solves the problem, or if it is a number of things...
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1987 951 - M193 Version for Japan

[D Hook]

Hows your wiring between the battery and the starter?

I've never had a hot start problem but I've replaced all those things Chrenan has, plus the boots going from the fuel distributor to the manifold and I've never had a hot no start occurence. Also have that naca duct on the hood...helps get the heat out of the engine bay. But probably the most signicant difference was the battery and wiring to the alternator/starter.

[Porchenewbe]

Hi there.

I posted a thread a while back after i cured my hot start problem, not sure if this was the problem i.e. electrical or something which thich this just overcomes but it worked for me and has continued to work for the last 5 months.

Hi all.
I have a '83 924. Since i've had the car i've always had problems with its starting, both hot and cold. This was an intermitant problem which would sometimes occur but othertimes would not. From cold when the car was turned over it would take quite some time to fire and when it did it would run 'lumpally' (excuse the english!). From hot, the car would fire immediately but then cut out and take about a minute of cranking before it would refire, often then only running on 3 cylinders for a minute or so.
Anyway, to get to the point, what i did was to run an ignition controled fused power supply to the fuel pump relay via a switch. I use this every time i start the car. What i do is switch on the ignition and allow the pump to run automaticaly for about 10 seconds untill it cuts out, then i switch on my switch and allow the pump to run untill it slows down because of back pressure. i then switch off the switch, (the pump runs for a further few seconds because of the relay). I now start the car as normal with just a small amount of throttle. This little dodge has made mine start like a new car and is still safe because it is only opperated at start up and not continuously, so in the event of a stall, the fuel pump still cuts out.

Hope this helps someone, its probably something other people have tried.

Take care.
John.
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Riding a steep learning curve about all that is 924.

My first porsche ... I'm only 19..But loving it (except the insurance) ... quite some car.

[Diesel]

Making sure every single fuel line was not touching the engine and heating the fuel inside is what cured mine.
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Dan Flanagan--2002 VW Jetta TDI, 83 Mercedes 300D,83 Mercedes Euro-240D

[Chrenan]

In response to D Hook,

Hows your wiring between the battery and the starter?

Wiring is good now. It was one of those things I noticed while I had the car raised over the winter and figured I might as well fix it when I have the chance. The old wires were in bad shape, missing a lot of insulation, covered in road grime, and partially burned through from contact with the exhaust. Now they are new, with extra heat shrink insulation applied, and held as far away from the exhaust as possible. If nothing else they are nicer to look at while I change the oil filter!
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1987 951 - M193 Version for Japan

[AGD931]

Basic things, idle adjustement and mixture. Starts good now when hot.
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1981 931 S2
1990 E30 320i Cabrio
1979 Ford Capri Ghia