924Board.org

[SecaBlue]

Hi, here is my first post I recently bought here in Europe a 1984 924 with only 9000km. Yes, you read correctly. Verified not only by ownership papers, overall condition, but also the original tyres date stamped 1984 with very little wear.

I travelled from Sweden to Luxembourg to drive the car, with a list of what to look out for. The previous owner (selling to me) had the car fully serviced in 2016, renewing brakes, fuel system including new pump, K-Jetronic pressure testing and cleaning, and a few other things (I have verified this via the original invoice which they gave me). The owner claimed it has always started and run perfectly over the last 6yrs of ownership.

When I drove it, it started cold without any throttle input, and ran a little rough until warming up. Then idled fine around 750rpm indicated. I drove it for 20mins at various speeds. Never missed a beat, and restarted wam with no issues idling or throttle application.

So now two weeks later I have the car in Sweden, delivered on a truck from continental Europe. The day before the truck was picking up the car, the dealer there advised that the car would start but not stay running, hot or cold. This puzzled them and the previous owner.

Now it is here I started it and confirmed what the dealer said... it starts with some help from a little right foot, but will not stay running, warm or cold. Immediately stalls out when no throttle is applied. And both warm and cold (especially cold), it runs rough, almost like it is only on 3cyl sometimes, until warm, and the exhaust smells very rich.

While I am awaiting the Swedish registration to be processed, I need to get it sorted for the initial inspection after the plates arrive. So what can go wrong in two weeks where it no longer wants to run?

The car is currently at a friend's dealership, but they don't have the pressure test kit needed. Anything else basic they can check without that? I have also ordered a new air filter and new spark plugs, as I imagine both items are original from 1984 but can't see them as causing this issue.

Just trying to get the car where it will idle before I take it to Porsche here who seem to be the only workshop with a pressure test kit and good knowledge of K-Jetronic.

Thanks!

[jacobroufa]

Congratulations on your purchase! That sounds like quite a find!!

Recently we had another member have a similar issue and it turned out to need new/fresh fuel and injector cleaning. We recommend for these cars a cleaner called Chevron Techron which these K-jet fuel systems seem to like. Possibly this is your issue.

https://www.924board.org/viewtopic.php?t=45442
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1980 Porsche 931
1981 Porsche 924 Weissach

[SecaBlue]

[jacobroufa]

If the car has had fresh fuel then maybe that is not the case.. Strange.

Another thought I have is it could possibly be the AAV (idle valve) or WUR (warm up regulator) as both of these have sensitive pieces which may be out of tune after only 9,000km in 40 years.. Also possibly the CSV (cold start injector) has failed?

I believe the AAV can be tested by measuring the interior diaphragm opening at freezing, ambient, and hot temperatures (tested by putting in a freezer, leaving out on a table, putting in an oven respectively) and it should see the largest opening at very cold temperatures, and when fully hot it should be closed.

If this diaphragm doesn't respond properly, the idle can be drastically affected. This is just a diaphragm exposed to air, but without regular exercise possibly it malfunctioned?

As to the WUR, I am less informed, but it has sensitivity to pressure in the fuel system. This might be worth exploring also.
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1980 Porsche 931
1981 Porsche 924 Weissach

[SecaBlue]

This is the fuel additive that the dealer in Luxembourg tried, but didn't have time to run a full tank. https://www.misteroil.eu/en-eu/shop/product/865/bardahl-injector-cleaner-petrol-1198?gclid=CjwKCAjwkaSaBhA4EiwALBgQaO693TzlhnsZOfoCPuJ2L_xbJ9-w17eKwjeZaJ2qhf5fqv1Pr6tt1xoCVMcQAvD_BwE

[Cedric]

Where in sweden are you located?
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1980 924 Turbo
www.instagram.com/garagecedric/

[kondzi]

I had very similar issue not that long ago. Had to strip down the WUR, clean it and reassemble it. Something clogged it and the fuel pressure was not right. There is also a sieve (not sure if it's correct term) on the WUR inlet that corrodes and stops the fuel flow. I eventually always delete it.
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)

[SecaBlue]

[SecaBlue]

Thanks for the input so far... I'll run through some of the suggestions and see where I end up.

In the meantime if anyone else has some suggestions, please fire away

[SecaBlue]

UPDATE: The car is now running I assume I still have a slight WUR issue, as the cold start is rough for a second or two and then quickly levels out at 800rpm with no issues.

Warm starts are instant, and idle sits perfectly at just above 800. Although also may have a slight vacuum leak, as sometimes the idle sits just above 1000rpm as well?

Well, I am happy it is running and passed roadworthy inspection once we sorted out some issues. Simply replaced the spark plugs and ignition leads to get it passable.

Here is warm start video: https://drive.google.com/file/d/1oXFRV0Pov9FzxfCbvi7xIzbWb-ecxRdB/view?usp=sharing

Now it is parked up for the winter, I will have a chance in the early new year to go over the vacuum lines, WUR, and general clean of all connectors etc.

If you are curious, I have another thread in general discussion area with pics