Porsche 924 Scheiße - understanding why people fit carbs...

[juular]

7 minutes ago, N Dentressangle said:

Yep, I think I agree. But then the spark is shit even directly from the king lead, so I'm not convinced the dizzy is guilty.

Test Three is warm engine "operating pressure", which for obvious reasons I can't do.

Fucksticks

If you run a + and - 12v to the pins on the plug socket on the WUR, it will run the internal heater which simulates a hot engine.  If it works you'll see the gauge start to creep up as long as the pump is running.

[N Dentressangle]

20 minutes ago, juular said:

If you run a + and - 12v to the pins on the plug socket on the WUR, it will run the internal heater which simulates a hot engine.  If it works you'll see the gauge start to creep up as long as the pump is running.

I can give it a go, but I suppose it's of no relevance in determining why this fucking thing wan't start / run

[inconsistant]

I feel your pain, having been in this situation a couple of times and just wanting the chod fairy to come and make it work.  I really appreciate your methodical approach, and can’t believe you haven’t won yet.  I wish I was closer so I could pop in for a look, not because I know what I’m doing but just to be an extra set of eyes who at least knows what it should look like.

I know you keep saying the timing is all fine but for the sake of double checking could you pls post up photos at TDC showing the window at the back of the engine on 0 degs:

the notch on the timing belt pulley lining up with the pointy casting on the front of the block:

The dimple on the back of the cam pulley above the E of Germany  lining up with the pointy casting on the rocker cover:

And the distributor rotor arm  lining up with the tiny notch on the edge of the distributor casting. 

and then the ht lead directly above the rotor arm going to cylinder 1 (front of engine) followed clockwise by 3, then 4 then 2. 

 

[N Dentressangle]

5 minutes ago, inconsistant said:

I feel your pain, having been in this situation a couple of time and just wanting the chod fairy to come and make it work. 
I really appreciate your methodical approach, and can’t believe you haven’t won yet. 
 

I wish I was closer so I could pop in for a look, not because I know what I’m doing but just to be an extra set of eyes who at least knows what it should look like.

I know you keep saying the timing is  all fine but for the sake of double checking could you pls post up photos at TDC showing the  window at the back of the engine:

the notch on the timing belt pulley lining up with the pointy casting on the front of the block:

The dimple on the back of the cam pulley above the E of Germany  lining up with the pointy casting on the rocker cover:

 

 

cheers - sympathy much appreciated 🤣

That's exactly the check we did yesterday. Found the timing marks and made sure everything was timed up exactly right.

[scdan4]

It ran for a bit having been stood, sounded shit then stopped and we're now playing back to basics...

How's it's compression?

[N Dentressangle]

5 minutes ago, scdan4 said:

It ran for a bit having been stood, sounded shit then stopped and we're now playing back to basics...

How's it's compression?

It sounded pretty good for about a month. Then stopped suddenly. Compression felt like there was plenty there, and it certainly ran like there was.

[rusty_vw_man]

it’s really fighting you. 

Is it worth getting an adjustable spark tester (if you don’t already have one) to quantify how weak the spark is? 

I l ike the idea above to of building the system back up in blocks until in theory you get to the point of failure. 

In my experience if it won’t have a good go starting on something suitable whanged down the inlet it’s been spark related. 

[rusty_vw_man]

11 minutes ago, rusty_vw_man said:

it’s really fighting you. 

Is it worth getting an adjustable spark tester (if you don’t already have one) to quantify how weak the spark is? 

I l ike the idea above to of building the system back up in blocks until in theory you get to the point of failure. 

In my experience if it won’t have a good go starting on something suitable whanged down the inlet it’s been spark related. 

Or just get two decent sized nails or similar spaced about 5mm apart and see if it will jump - should do…. 

[N Dentressangle]

The only part I haven't changed is the distributor, or more precisely the Hall sensor in it. The pn for the dizzy is 0237002054 / 477905206, but the obviously replaceable sensor screwed to the side of it seems elusive.

Anyone with better Google-fu than me track one down?

[Westbay]

5 minutes ago, N Dentressangle said:

The only part I haven't changed is the distributor, or more precisely the Hall sensor in it. The pn for the dizzy is 0237002054 / 477905206, but the obviously replaceable sensor screwed to the side of it seems elusive.

Anyone with better Google-fu than me track one down?

LINKY

[N Dentressangle]

13 minutes ago, Westbay said:

LINKY

I wonder if this is the part I need:

https://www.ignitioncarparts.com/PopoverProductsDetails/PPU2662

I'll give them a bell tomorrow.

[rusty_vw_man]

If you’re bored* today and don’t want to wait for a new sender you could:

pull dizzy from engine, and leave the cap off. You should have a mark for number 1 cylinder in the dizzy body, and the king lead should give  a spark each it passes. So pop a plug or suitable earth gap on king lead, and give the dizzy a spin. Everytime it passes the notch you should get a nice clean spark, if not it suggests the sender is not sending quite right  

You can also pop the cap back in and rig up a display of all the plugs to check the dizzy is actually distributing sparks reliably.

I found this helpful when tracing down a fault on one I had, which due to some corrosion and spring issues effectively had given itself random timing on each rotation as sometimes it would spark, sometimes it would not.

Also highlights if there is excess play, or it’s notchy or something similarly mechanical.

 

[rusty_vw_man]

That ignition car parts lot you link to are great - they still have an old school dizzy test rig (or they did a few years back at least) so you could send them yours for a refurb, as they can actually test it. 

[N Dentressangle]

2 minutes ago, rusty_vw_man said:

That ignition car parts lot you link to are great - they still have an old school dizzy test rig (or they did a few years back at least) so you could send them yours for a refurb, as they can actually test it. 

Thanks for the vote of confidence. I'll give them a call, unless I can find somewhere more local - not impossible round here, where there still seem to be those kind of businesses

[N Dentressangle]

1 hour ago, rusty_vw_man said:

If you’re bored* today and don’t want to wait for a new sender you could:

pull dizzy from engine, and leave the cap off. You should have a mark for number 1 cylinder in the dizzy body, and the king lead should give  a spark each it passes. So pop a plug or suitable earth gap on king lead, and give the dizzy a spin. Everytime it passes the notch you should get a nice clean spark, if not it suggests the sender is not sending quite right  

You can also pop the cap back in and rig up a display of all the plugs to check the dizzy is actually distributing sparks reliably.

I found this helpful when tracing down a fault on one I had, which due to some corrosion and spring issues effectively had given itself random timing on each rotation as sometimes it would spark, sometimes it would not.

Also highlights if there is excess play, or it’s notchy or something similarly mechanical.

 

Your wish is my command 😄

Brand new plug, brand new lead. To me, that spark looks weaker than it should be, but appears to be happening at the right time.

Any thoughts?

[Westbay]

eerrrmmm , have you checked the coil is wired correctly ? 😇

[N Dentressangle]

15 minutes ago, Westbay said:

eerrrmmm , have you checked the coil is wired correctly ? 😇

I haven't changed anything from when it ran, so I presume it is, and the wiring colours check out.

[N Dentressangle]

16 hours ago, inconsistant said:

I feel your pain, having been in this situation a couple of times and just wanting the chod fairy to come and make it work.  I really appreciate your methodical approach, and can’t believe you haven’t won yet.  I wish I was closer so I could pop in for a look, not because I know what I’m doing but just to be an extra set of eyes who at least knows what it should look like.

I know you keep saying the timing is all fine but for the sake of double checking could you pls post up photos at TDC showing the window at the back of the engine on 0 degs:

the notch on the timing belt pulley lining up with the pointy casting on the front of the block:

The dimple on the back of the cam pulley above the E of Germany  lining up with the pointy casting on the rocker cover:

And the distributor rotor arm  lining up with the tiny notch on the edge of the distributor casting. 

and then the ht lead directly above the rotor arm going to cylinder 1 (front of engine) followed clockwise by 3, then 4 then 2. 

 

I thought I'd try this check too, as you've been good enough to give such great pics and instructions.

Here's the cam pulley and rocker cover:

Here's the distributor:

Here's the crank pulley:

Here's the flywheel:

Something's wrong, isn't it?

[N Dentressangle]

Now had another play and set the flywheel marking and crank pulley marking to TDC. Re-fitted the dizzy so the rotor is pointing eactly at the mark on the casing.

Here's the camshaft pulley now:

A tooth out, perhaps?

[captain_70s]

Certainly looks a tooth out. Could you have gone from rough running with a slack belt to a non-starter with a skipped tooth?

My Acclaim spent most of my ownership a tooth out, ran alright but you could feel the engine fighting the starter motor on startup.

[N Dentressangle]

Just now, captain_70s said:

Certainly looks a tooth out. Could you have gone from rough running with a slack belt to a non-starter with a skipped tooth?

My Acclaim spent most of my ownership a tooth out, ran alright but you could feel the engine fighting the starter motor on startup.

That's my experience too. It doesn't fit with the symptoms.

But it is something wrong at least.

[comfortablynumb]

Bit late to the party, but I've had results by going back to square one, starting with compression and timing, then electrics, then fuel.

I'd agree that looks like the timing is out.

Does it even attempt to start with brake cleaner etc sprayed down the inlet?

[N Dentressangle]

SHE RUNS!!!!!

I loosened the tensioner, moved the cam to the right position on the belt and she starts and runs fine!!

I have never known one tooth make that much difference, but there you go.

Here's the proof:

Timing's still out, as it's fighting the starter, but it's a move in the right direction!

@inconsistant I think you have the best claim to the virtual 🍺🍺🍺

[barefoot]

38 minutes ago, N Dentressangle said:

Timing's still out, as it's fighting the starter,

I know nothing about anything, and my 944 is completely different to a 924, but a man who knew something once told me that, 'they all crank slowly'.

[N Dentressangle]

Now warmed up, she's died again and doesn't want to re-start. Hey ho.

It was obviously running very rich, and ran rougher and rougher at it warmed up, so I suspect the WUR it has fitted is rubbish. Will have another pressure test of it tomorrow and maybe swap the spare on I have in.

[Matty]

1 hour ago, N Dentressangle said:

SHE RUNS!!!!!

I loosened the tensioner, moved the cam to the right position on the belt and she starts and runs fine!!

I have never known one tooth make that much difference, but there you go.

Here's the proof:

Timing's still out, as it's fighting the starter, but it's a move in the right direction!

@inconsistant I think you have the best claim to the virtual 🍺🍺🍺

Thank god for that. You were fair ruining my holiday what with the constant dramatic tension 🤣

 

 

(Excellent result pal 👍)

[Matty]

3 minutes ago, N Dentressangle said:

Now warmed up, she's died again and doesn't want to re-start. Hey ho.

It was obviously running very rich, and ran rougher and rougher at it warmed up, so I suspect the WUR it has fitted is rubbish. Will have another pressure test of it tomorrow and maybe swap the spare on I have in.

Fuck. Too soon. Best of luck, you're definatly getting closer.

[juular]

3 hours ago, N Dentressangle said:

Now warmed up, she's died again and doesn't want to re-start. Hey ho.

It was obviously running very rich, and ran rougher and rougher at it warmed up, so I suspect the WUR it has fitted is rubbish. Will have another pressure test of it tomorrow and maybe swap the spare on I have in.

Worth checking the pressure hot before you go at the WUR.  

Given the richness is (I assume) at idle, it could be as simple as the Allen screw between the metering head and the rubber air sock, which sets the idle mix.  This can be off enough to make it splutter and die once warmed up.

Also, the system pressure being a tad low would make it rich across the board, which is adjusted with shim washers on the main pressure regulator.

TLDR; avoid touching the WUR until you have to.

[N Dentressangle]

Just now, juular said:

Worth checking the pressure hot before you go at the WUR.  

Given the richness is (I assume) at idle, it could be as simple as the Allen screw between the metering head and the rubber air sock, which sets the idle mix.  This can be off enough to make it splutter and die once warmed up.

Also, the system pressure being a tad low would make it rich across the board, which is adjusted with shim washers on the main pressure regulator.

TLDR; avoid touching the WUR until you have to.

Ta. It was so rich I did try some adjustment of the Allen screw, but pretty sure there's something else in play, ie. the WUR.

Before this whole bollocks started, it did run worse when warm anyway. All needs returning to good standard base settings - valve & ignition timing, mixture, WUR etc - so that's tomorrow's job.

[N Dentressangle]

and just to say thanks again to everyone on this thread for the spot-on advice and help. Very much obliged 🍻