924Board.org

[555mk555]

Hey fans, so... I had this problem a few months back when my 3rd cylinder was not firing. I threw some valve and injector cleaning fluid in with my petrol and it seemed to clear up.

The problem had recently occurred again and has since not gone away.
I've got spark, spray, and good airflow.

I just had a few days in the countryside, enjoying every moment of driving. The car seemed to be tuned just right.. starts first time.. every time.

I'm wondering if it's a possible broken valve spring.... can anyone confirm or help scratch my head a little more?

Thanks,

Mick
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Cape Town - 1982 - 924

[Fifty50Plus]

Do a compression check (easy) or a leak down (more difficult) on the 4 cylinders. If much different on # 3 you MIGHT have a valve/spring problem after a compression test.
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1979 924 NA race car H-Prod SCCA
1982 924 NA race car - Sold
1981 924 Turbo sold
1982 924 Turbo sold
1972 911 E race car - traded for Cayenne Diesel
1975 914 1.8 Building for H-Prod SCCA

[555mk555]

I read somewhere, that a broken valve spring would pass a compression check.

Will take her to my buddy next week to take a better look at it...

Obviously I'd rather not have to remove the head, open it up etc.
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Cape Town - 1982 - 924

[555mk555]

Ok... so get this, I've been plowing the web for the past 48hrs desperately trying to find solutions to the issue I had... I was checking German Porsche 924 forums as well (being half German).

A lot of people were pointing towards VALVE issue... I was really hoping this was not the case... but it seemed really plausible.

I had good spark
good compression
and consistent spray
BUT NO FIRE on cylinder 3

Finally... I read a post by a German 924 owner who said something similar along the lines of: "My mechanic took the blunt end of a screwdriver and tapped the cylinder corresponding fuel injector. Fixed the issue right-away"

So... I thought to myself, before spending time money, stress, and looking at the biggest and worst faults again, let me go try that nifty little German Meister Mechanic trick.

I went out, tapped lightly on the injector jets and fired her up... still rough... went back under the bonnet and tapped them lightly again (using a piece of soft wood) BOOOOOM she started firing on ALL 4 cylinders!

Wow... I love it when a plan comes together

Cheers for feedback, hope this helps ppl in the future... no need tearing the engine top off at this stage, although future plans of course are to have it done over and reconditioned etc.

I love these cars and the engines are robust as anything... I keep forgetting that Ferdinand Porsche developed tanks once upon a time

x
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Cape Town - 1982 - 924

[SlayerSST]

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[555mk555]

Yea.. deep down.. I know it's a quick fix.
BUT.. at least the probs not with a valve. I'm going to track down prev. owner to ask if he ever had the engine done over, valves replaced etc.

What;s the best method you can recommend to keeping the fuel lines clean?

I'm gna get a new filter, that;s for sure.. and I know my tank is not in shabby condition, as I drained by fuel and checked a few months back.

Cheers for the input.. just stoked about the way it turned out today
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Cape Town - 1982 - 924

[555mk555]

Ok, so finally I decided to address this problem again, as it occurred on a few occasions, that the car ended up firing on 3 cylinders again..

I could basically move the one injector with my hand (it was lose and I could hear the spray.)

I decided to let the engine cool down and then removed the air intake boot to grant me access to the injectors. I pulled the culprit and out popped half a broken o-ring. There was another one fitted on the injector, but this was as hard as a rock, so I replaced the o-ring, fitted the injector, AIB and she fired up on all 4 right away. Easy fix.. happy days..

MK
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Cape Town - 1982 - 924