924Board.org

[amoreton]

Bought my 924 back in November 23 with blissful naivety about what I’d gotten into! But I still love it. Just giving some back story which I believe is relevant.

I didn’t get a chance to drive the car for a few weeks after buying it, and after that time the car needed a jump to help start up but it started well and ran very smoothly. Took it out for a few drives over the next couple days which was a joy. In hindsight I’m pretty sure my car hasn’t escaped the usual hot start problems as it did fail to start a couple times after a drive.

The car was then stored outside under cover from mid December to the start of march with no starting or driving (in hindsight a silly mistake). I came back to the car in march and it wouldn’t start. I figured it would need a new battery after leaving it (previous battery was also on the small side) so I went out and got one along with doing a few jobs such as a fuel filter, air filter and spark plugs. After this I couldn’t get it started, so also changed the dis cap and rotor arm and the beauty woke up! But it was not running as it did back when I first drove it. It was very lumpy and struggled to idle. It would just choke out without a bit of acceleration. (Could the fuel filter have messed with the flow? I didn’t try to start it before changing the filter and wish I had given it a go before changing it) eventually, It did warm up and idled, but clearly was not running okay. There would be the odd blast of air out of the air box from time to time too. I read on this forum about fuel/air mix and played with the screw on the throttle body to make it run richer, which did bring the idle revs up slightly but still, running lumpy. I turned the fuel mix shut and played with between 2 to 4 full rotations but unfortunately didn’t solve the issues and it was left then for another month. Hindsight wish I didn’t touch the fuel mix.

After this month takes us to this past weekend. I did more research and things pointed again to the fuel/air mix being the issue. I was sure the car would start up, and hoped I’d play around with the mix to get it running smooth, but I had a totally flat battery which threw me off. With some jump leads, we managed to get it turning over, and after some battling got it running in its previously lumpy state. I was letting it warm up with a slight press on the accelerator. After around 5mins I thought I’d see if it would idle, and it choked out. Since it had just started, I thought it wouldn’t be an issue and we’d just start it right back up, but we simply could not get it back running. It turned over really smooth but didn’t sound like it was really trying to start (if that makes sense?).

So, in short - got a 924, left it a month before driving properly, needed a jump start but ran super smooth. Left another 3 months, I didn’t even try it start it, but first changed fuel filter, air filter, spark plugs, dis cap and rotor arms and got a new battery. It started, but very lumpy, played with fuel adjustment on throttle body, didn’t help. Then left another month. After the month (this weekend), totally dead battery, got started after a good few tries for around 5 mins, but was very lumpy, did not idle, choked out and did not start again. Even charged battery overnight and tried the next day but couldn’t get it going. Did play around with richness of fuel when trying to start. Only time it started this weekend was with 3 full rotations on the screw.

Sorry for the short story, just wanted to share as much details as possible.

So that’s where I’m at. I’m hoping to get back to it next week and spend whatever time I need to get it running properly and would like some advice on where to start.

My thoughts… Would it be a pump issue? I figured not since it has started? Maybe changing the fuel filter has messed with the flow? The old filter had some sort of glue holding the bottom washer onto it which points to some sealing problems. I did replace this with new washers and currently have no leaks. I plan to clean up terminals and connectors for the battery and starter circuit as per FAQs. Also have o-rings on order for fuel injectors to replace as no evidence of replacements in history.

Although I have no experience with engines, or cars for that matter, other than a real love for them, I feel that I should be able to get this running fine based on the fact that it ran really well not long ago, but maybe I am silly thinking this and need someone to come out to get it running for me..!

P.s. All spark plugs are sparking!
Since reading the “welcome noobs” post, particularly the fuel system (wish I saw this months ago!!!) this could possibly be a fuel pump relay issue? I might start here. Could this also explain battery drainage? I have also taken the fuse out for the clock/radio etc as suspected this may be drainage culprit. Have history of wiring being adjusted to fit a “regular relay as existing one was incorrect”. Any clues as to what the hell this means??

Aware I've rambled but any help would be massively appreciated.

Many thanks,
A helpless 924 owner.

[scm924s]

Portsmouth UK or USA?
_________________
1984 n/a Ruby Red Metallic
1988 924S Guards red- sold
1986 924S Guards Red - sold
1984 n/a Black - sold
1980 n/a Le Mans#1 - sold
1980 n/a Le Mans#2- sold
1977 Martini - sold

[amoreton]

Portsmouth UK, car is up on the Wirral at the moment though. I’m here for a week in the hope of getting it started and driving it back down to Portsmouth… so far no luck.

We have spark, and fuel entering the engine, but no start. Going to try some starter fluid tomorrow to see if it will just get running.

[Raize]

Do you have a K-jet pressure tester? They're easy to make and are essential for troubleshooting.

Wideband O2 sensor in the exhaust helps a lot for fine tuning but is only useful if the car will actually run.

Were you able to rev it at all when you had it running most recently? If you can rev it, it's not Stuck Plunger which then points to WUR.

WUR can make or break a 924. Mine is in good condition but due to my WUR being slightly mal-adjusted it takes about 15 seconds of cranking to start cold, won't start hot at all, idles like shit, and misfires horribly when trying to accelerate from idle - this is from ONE out of spec component that I didn't get round to sorting! The saving grace is that they're very easily adjustable and rebuildable.

[amoreton]

Thanks for the suggestion, but things are pointing to a dead fuel pump relay. Contacts were a bit worse for wear, and had oil on to help conduction? Held the fuel pump when cranking and felt nothing which lead to us trying the relay. Mad it is likely so simple! However, finding impossible to source one. The current is a KAE 3.300.300 so not OE, any suggestions on a replacement that I’ll be able to source soonish?

[scm924s]

You can bypass the FPR temporarily, by removing the FPR and bridging 87 and 30 in the socket, Be warned doing this puts the pumps in a permanent live situation and they won't shut off, OK for testing but dangerous in use as it defeats the FPR function of shutting the fuel supply off in the event of an unplanned stop. a switch in the line is a sensible approach ,see elsewhere here for what happens if you get this wrong

FPR's are becoming hen's teeth at the moment, there are some workarounds about, recommend you visit here for details and further help https://porsche924.co.uk/
_________________
1984 n/a Ruby Red Metallic
1988 924S Guards red- sold
1986 924S Guards Red - sold
1984 n/a Black - sold
1980 n/a Le Mans#1 - sold
1980 n/a Le Mans#2- sold
1977 Martini - sold

[amoreton]

Further update…

It’s the fuel pump. Relay is in working condition. Will be getting one on order tomorrow.

[scm924s]

If your car is post 79 it will have 2 pumps, one in tank and one in line, will usually work on 1 as long as the in line pump is up to it.

Have you checked the fuel pump fuse, No 2 in the aux fusepanel Counting from bulkhead end.
_________________
1984 n/a Ruby Red Metallic
1988 924S Guards red- sold
1986 924S Guards Red - sold
1984 n/a Black - sold
1980 n/a Le Mans#1 - sold
1980 n/a Le Mans#2- sold
1977 Martini - sold

[amoreton]

So it did actually get up and running a couple of times, so I’m guessing the in tank pump must have done enough to get it started. It was incredibly lumpy when it was running though.

The out of tank pump doesn’t make any sound or make any sort of movement when cranking the engine (have held it when someone turns the ignition). I also remember that I could hear an electrical buzz inside the car, to the rear right, back in November when I first got the car. I have not heard that since November which is again pointing to the pump not working. What do you think?

[scm924s]

The initial start is assisted by the Cold Start Valve (essentially a 5th injector) which gives a timed (about 10sec) injection of fuel into the system to ensure prompt starting, when the fuel pumps will take over supply. In addition to being timed, the CSV also has a temperature sensor which reduces the effect if the engine is warm. I would expect your car to start and run initially if the CSV is working.

The only real way of checking if the pump is at fault is either bridging the FPR as previously suggested, or applying 12v directly to the pump.

Being in the UK, you may find more help here https://porsche924.co.uk/
_________________
1984 n/a Ruby Red Metallic
1988 924S Guards red- sold
1986 924S Guards Red - sold
1984 n/a Black - sold
1980 n/a Le Mans#1 - sold
1980 n/a Le Mans#2- sold
1977 Martini - sold

[amoreton]

Thanks for that. We properly tested the FPR by jumping it and could clearly hear it activating, whilst the pump made no sound nor could I feel any sort of movement in the fuel itself whilst holding it.

I have no record of it ever being replaced (and I have an F tonne of history on this car) so it feels worth replacing at this point anyway, along with the hose that goes into the tank. Two out of three of the rubber mountings are totally shot, and the clips are heavily corroded which are again pointing that it has not been touched. Wonder if anyone can suggest some rubber mounting replacements? I'm not concerned about them being OE as they seem to be £10+ a go...

I've been meaning to join porsche924OC so I think it is time to do so!

[924RACR]

Those rubber bumper mounts, aka vibration isolators, with studs at each end, are pretty generic metric auto parts; there should be good sources over there for such.

Here in the states I'd get 'em from Bel-Metric:
https://belmetric.com/screws/vibration-isolators/

Those are probably M6 from what I recall...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[amoreton]

Ah brill yeah managed to find some in UK on eBay at much more reasonable price. Thank you.

[924RACR]

Good deal.

One last bit, have you verified power and ground at the pump? Not disputing your assessment of the likely state of the pump itself, but would be wise to check those as well before getting too excited with a new pump...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype