Porsche 924 Scheiße - knackered fuel accumulator?

[Fabergé Greggs]

Congrats on getting it running! It’s been some great live spannering.
 

I’m not a football man, but I imagine this is what it feels like winning the World Cup or something 

[inconsistant]

OK maybe not sorted yet but a step in the right direction, well done! This has been a fab thread to follow so far, just like the AS of old I learned so much from! 

Can I pls just check at TDC your rotor arm looks like this lined up with that tiny nick, not like the photo you posted.

 

[N Dentressangle]

28 minutes ago, inconsistant said:

OK maybe not sorted yet but a step in the right direction, well done! This has been a fab thread to follow so far, just like the AS of old I learned so much from! 

Can I pls just check at TDC your rotor arm looks like this liked up with that tiny nick, not like the photo you posted.

 

Cheers, I'll check that tomorrow as I go through the whole thing 👍

In my defence, this car has been immensely dicked around with, as the PO's YT vids show 🙄

[Westbay]

Well done ! and thanks for sharing the 'process' (so far  )

[N Dentressangle]

Here's the Warm Up Regulator (WUR) that was fitted to the car:

 

It's basically the wrong unit - it has a vacuum take-off on the back below the electrical plug (apparently to enrich mixture on acceleration) and I suspect it's off a 911 or something.

The car came with a very clean looking WUR of the right kind. Here's what the back of the correct unit looks like:

I took it apart and cleaned anyway, just in case:

and here it is fitted into the car:

Of course the fuel flow and pressure at the injectors is now different from what it was, so the frigging thing won't run again until I've played around with the mixture enough to stop it flooding. Especially as I fitted a spare Auxiliary Air Valve whichactually closes properly into the bargain.

🤣

[N Dentressangle]

Well, I think I'm going to throw in the towel. It will now start, but dies straight away:

I'll probably tow it round the corner to the 928 guys and get them to sort it out.

Had enough now. I've reached the limits of what I can realistically do, and don't have the appetite for yet more to and fro on the Porsche forum. Someone who actually knows what they're doing - rather than learning as they go along - could probably get this running properly in an hour or two, which seems like the best way to go.

[Talbot]

has the timing belt skipped back immediately?  You may well have a duff tensioner wheel somewhere.

[N Dentressangle]

Just now, Talbot said:

has the timing belt skipped back immediately?  You may well have a duff tensioner wheel somewhere.

No, it's fine - checked it again today.

Ignition timing is OK too.

[Volksy]

Probably a wise idea to seek professional help, before you need the psychological kind. 

Similar for me with the Merc, People immediately think (as I did) that running problems WILL be from the sorcery that is K & KE Jet. Given you've said that the previous owner had done loads to it - obviously not with the correct parts either - it would be prudent to assume that it'll need setting up from scratch. At least you found the main route cause, which the previous owner either missed or caused, or caused then missed, who knows what else they've tinkered with.

At least you have someone local who understands these. They can probably have it set up in a hour if they've the proper kit. 

There is no one around my that will touch mine. 

 

 

[Matty]

44 minutes ago, N Dentressangle said:

Well, I think I'm going to throw in the towel. It will now start, but dies straight away:

I'll probably tow it round the corner to the 928 guys and get them to sort it out.

Had enough now. I've reached the limits of what I can realistically do, and don't have the appetite for yet more to and fro on the Porsche forum. Someone who actually knows what they're doing - rather than learning as they go along - could probably get this running properly in an hour or two, which seems like the best way to go.

Absolutely no shame in that. Personally as a carbs, points and chains man you've got much further than I would. 

All will be erased when you're driving it bud!

[Peter C]

50 minutes ago, N Dentressangle said:

Well, I think I'm going to throw in the towel.

Good for you. That's what I did when my MGB was testing me and I stopped enjoying the experience. 

 

[N Dentressangle]

2 hours ago, Volksy said:

Probably a wise idea to seek professional help, before you need the psychological kind. 

Similar for me with the Merc, People immediately think (as I did) that running problems WILL be from the sorcery that is K & KE Jet. Given you've said that the previous owner had done loads to it - obviously not with the correct parts either - it would be prudent to assume that it'll need setting up from scratch. At least you found the main route cause, which the previous owner either missed or caused, or caused then missed, who knows what else they've tinkered with.

At least you have someone local who understands these. They can probably have it set up in a hour if they've the proper kit. 

There is no one around my that will touch mine. 

 

 

It was definitely the right idea.

I popped round to see the 928 guy - really nice chap - who watched the little video and told me it was basically running off the 5th injector. The mixture needs adjusting at the metering unit until you can just start to hear the injectors scream when you're jumping the fuel pump to make it run all the time. Further fine tuning can then be done with someone else in the car (ie my daughter) trying to start it whilst you fiddle with the metering flap height and adjust with the allen key.

Taking all that on board, I've just had a fiddle along those lines and got it running. So onwards...

[N Dentressangle]

So, that method of tuning the mixture gets the car in the right ballpark. Which for K Jet is stupidly narrow, as far as I can tell.

I'm an SU kind of guy. That big mixture nut under the jet can be twirled quite happily and the thing will generally still start. The right mixture is, in my experience, found in a window of anywhere from 2-5 turns of the nut. You can't really fuck them up.

K Jet is mix-tuned by a few different elements - the WUR, the aux air valve and probably other gizmos I don't know about. Plus the 3mm Allen key hole on the metering unit. Once you're in the ballpark it seems that just a twitch (literally) on the Allen key will alter the mixture noticeably, so adjustments are an Allen key flat at a time, if that. And to set it properly you really need a gas analyser. Although I might still try it on the Colourtune tomorrow 🤣

After a good deal of trial and error, this is where we are now anyway:

Idle is about 1100rpm - too high, and I've wound the idle speed screw fully in already so I need to fix that. More research needed, unless any of you resident experts know?

Dash is apart to sort the radio wiring, which is now done so that can go back tomorrow too. And maybe a drive around the block, high idle be damned? We'll see 😎

[Christine]

A  Lemons 924  did just that! 

 

[N Dentressangle]

8 minutes ago, Christine said:

A  Lemons 924  did just that! 

 

That is BRILLIANT

Can't pretend it hasn't crossed my mind, either, although I was thinking how nicely a pair of HIF44's would make it go.

[Christine]

 

[MrBig]

1 hour ago, Christine said:

A  Lemons 924  did just that! 

 

I contemplated that when I had mine. Eventually I gave up and sold the fucking thing. Great system when it works. Horrible when it doesn't. I think the final straw was getting the proper manual for it (Bentley I think? not the featherweight book of lies) and realising it was thicker than the yellow pages. At least taking the number plate off and selling that covered my costs.

I really hope you manage to get this sorted @N Dentressangle you absolutely deserve some payback from the ungrateful bastard!

[Christine]

I had a mk1 Caddy Sport  k reg . 1800 jh engine with k jet and an ecu .    It ran like a sack of shit,  but only sometimes . Other times it was fine .  The local independant VW garage told me to pull out the fuse box and twist it this way and that till it crackled , but not broke , and replace it  .  Apparently the copper tracks in the fuse box  , get verdigis  on them   creating high resistance , and twisting  till it goes crack , cleans the contact up .  Did it work ?  Yes !  

Indies know more than the dealerships sometimes !

 

 

 

 

[N Dentressangle]

21 minutes ago, Christine said:

I had a mk1 Caddy Sport  k reg . 1800 jh engine with k jet and an ecu .    It ran like a sack of shit,  but only sometimes . Other times it was fine .  The local independant VW garage told me to pull out the fuse box and twist it this way and that till it crackled , but not broke , and replace it  .  Apparently the copper tracks in the fuse box  , get verdigis  on them   creating high resistance , and twisting  till it goes crack , cleans the contact up .  Did it work ?  Yes !  

Indies know more than the dealerships sometimes !

 

 

 

 

5 min with the 928 guy round the corner was worth 3 days of 924OC forum advice.

He sparked up a Rothmans and spoke the word of the Lord.

[grogee]

Can't tell from the video but 1100rpm isn't too high if it's stone cold, in fact I reckon that's about right.

I used to drive a very very low miles LHD 924 around a yard and it was an absolute fucker when cold. It would just stall on any hint of throttle so you had to just drive it by lugging it until it was warmed up. 

It lived in a plastic bubble and hadn't even covered 10,000km.

[N Dentressangle]

It's warm enough for the fan to kick in, so should be lower.

Must be an air leak somewhere - I've checked the AAV and brake servo hoses and it's not those, plus had a good spray of carb clean around all the other hoses with no effect. Will probably try a clean of the throttle body and replacement of the idle screw O ring as my next gambit.

[N Dentressangle]

Replaced the missing wind deflector for the sunroof today. Some tosser had swiped the lot - hinges, deflector, everything - plus the front catches were missing and broken. A bundle of S/H bits arrived last Friday, so I thought I'd better get them fitted just to be sure the roof wasn't going to detach and blow off somewhere down the road.

All pretty straightforward, apart from the M3 screws in the front clips shearing off. I drilled and re-tapped the holes:

Weirdly, the deflector slots into that gap you can see between the roof and the lining, only deploying when you actually remove the whole roof and chuck it in the boot. Nope, me neither.

There was then nothing else for it but to risk a drive and see what happened 🤯

I checked everything I could think of and pulled it out of the garage for the first time since I bought it 6 weeks ago:

Doesn't really show so well, but it's absolutely filthy. Never mind, better have a drive anyway...

She drives really well. This is my first drive with the car running on all 4 cylinders and actually having working brakes and a properly bolted together rear axle. It's plenty quick enough - I can believe the 9.5 secs to 60 figure - and the engine pulls strongly and smoothly with a good noise. Gearbox is slick and sporty with a little stubby lever and great ratios. Handling seems good as far as I pushed it, which wasn't very far.

Main snags are a really odd clonking noise from the NSR suspension. I don't think it's the exhaust, but mindful that the wheel fell off that corner in the previous owner's collection video - yes, really - I did stop and check I'd actually torqued the wheel bolts up as well as pulling the wheel for a good look and tug and everything. Couldn't see anything obviously dangerous so I cracked on. I'll get it in the air again and find out what's going on.

Decided it had earned a wash before it went back in the garage:

Time to fix the suspension knocks and the high idle - I've booked it in for an MoT in a week's time! 🤣

[N Dentressangle]

Suspension noise was just a shock absorber I hadn't torqued up with enough oomph. Sorted.

Time to fix the idle.

[inconsistant]

Nice one! Glad you enjoyed the drive. They’re not fast but also not as slow as people would have you believe. Same performance in 1975 as a Mk1 Golf GTi, but for nearly twice the price.

[N Dentressangle]

Simply timing her up properly has sorted the high idle - I suspected it might.

Had to use the idle screw to bring it up a tad, so no wonder I couldn't find any air leaks. It's because there aren't any 😎

Got a week now to bomb around in it, fettle any last bits and get it ready for an MoT next Wednesday lunchtime...

[N Dentressangle]

13 minutes ago, inconsistant said:

Nice one! Glad you enjoyed the drive. They’re not fast but also not as slow as people would have you believe. Same performance in 1975 as a Mk1 Golf GTi, but for nearly twice the price.

and now worth less than half of what a Mk1 GTI would go for. Weird.

I've often thought as I've been working on it that had it been badged as an Audi - which let's face it, it's more of than a Porsche - it would now be worth heaps more than the £1800 I paid for it.

[inconsistant]

Yup.  And everyone would love them and think we were cool with great taste in cars. Sounds awful. 

[stuboy]

On 06/10/2025 at 15:17, N Dentressangle said:

Of course the fuel flow and pressure at the injectors is now different from what it was, so the frigging thing won't run again until I've played around with the mixture enough to stop it flooding. Especially as I fitted a spare Auxiliary Air Valve whichactually closes properly into the bargain.

🤣

just wondering if that wiring plug is broken or is just a single wire one as looks melted?

[N Dentressangle]

6 minutes ago, stuboy said:

just wondering if that wiring plug is broken or is just a single wire one as looks melted?

It's two wires and actually OK, although I know what you mean. Someone has used that self-amalgamating tape on it at some point 🙄

[stuboy]

1 minute ago, N Dentressangle said:

It's two wires and actually OK, although I know what you mean. Someone has used that self-amalgamating tape on it at some point 🙄

yeah it look broken