Suddenly won't start after recent tandem pump change

Hmm let me see, on my thread project black mambo, I did tandem pump, maybe I put pictures, doesn't look right at first glance. I also took shots like you have so see if I can find them

Edit, only got these ...
 

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Hmm let me see, on my thread project black mambo, I did tandem pump, maybe I put pictures, doesn't look right at first glance. I also took shots like you have so see if I can find them

Edit, only got these ...
Thanks Edd.
Looking at your photos they both do indeed look like mine.
 
Thats the coolant pipe lower head feed, not a nut isnt it? In which case loosen and rotate around.
From what I remember it looked like a spigot that is screwed into the head which the coolant pipe is attached to using a clip. The spigot is the problem not the clip. At the time I decided that there was no way I was going to try and move this as the risk of a leak or breakage on a 20 year old fitting was just too great, bearing in mind also that the whole thing is completely inaccessible once the pump is fitted. Hence I filed a small amount of aluminium off the pump and everything worked. There may well be other workarounds. I think part of the problem may also be that the tooling for the pump body is now probably quite old and worn resulting in more flash and moulding inaccuracies.
 
I've taken loads of photos of both pumps and will upload them Asap.
Complete with measurements.but. Here is one side by side.
PXL_20230220_123220263.jpg


You can clearly see the difference between the two.
Bosch on the left
 
What was wrong with the Luk pump? I’d be tempted to stick it back on, I would use a used gasket and see if that air disappears from the fuel lines. If an old Luk with a wrecked gasket pumps fuel without air the the problem is the Bosch.
Edit, my Bosch replacement for my leaky Luk fit and ran very well
 
It was getting to the point where the car was taking an age to fire up, especially when facing uphill.
If left on the flat for a couple of days it would do the same.
So the conclusion was that the internals of the pump somewhere was fubar.

There was no leakage around the old pump what so ever, perfectly bone dry.








update..........................................................Ive managed to get the pump on without any leakage (I think)
The leakage was oil not fuel as I first thought and it was at the bottom of the pump just above the plastic water pipe where the temp sensor lives...............massive lesson learned here guys, use a good quality torque wrench. my old one must have be out of calibration so I must have tightened the allan bolts to tight, this time with the new one, 20Nm top two, 10Nm bottom two.

fresh starter motor put on as well this afternoon so no squeal hopefully.

I've yet to try and turn it over as it was getting to dark so tomorrow will be test time.
 
Another update chaps..............
So this morning I had a go at starting the car with the help of a mate who turned the key in short bursts resting in-between, no joy.
Then I thought that if I put the long original fuel pipe back on, the one with the fuel temp sensor lets see what happens.
low and behold , she burst into life on the 5 th crank, nice tick over and revving nicely.

But........................................look at the video.
Tell me what you think.
I'm wondering if thats what normally happens when the engine is running because normally you would not see the fuel passing through the pipes.

 
This is with the bosch unit on there yes?
Does it drive and pull smooth now? If so must be okay then in that it has the fuel it needs.
The only way that air would get in would be from split in pipes from the filter, or filter itself.
May find bubbles disappear after some driving around?
 
It drives great now and the brakes seem a bit more responsive.
Yip, Bosch pump.
It's parked up now and tomorrow I will crack it up again but before I do I will check the short clear hose to see if any bubbles have appeared
 
Another update chaps..............
So this morning I had a go at starting the car with the help of a mate who turned the key in short bursts resting in-between, no joy.
Then I thought that if I put the long original fuel pipe back on, the one with the fuel temp sensor lets see what happens.
low and behold , she burst into life on the 5 th crank, nice tick over and revving nicely.

But........................................look at the video.
Tell me what you think.
I'm wondering if thats what normally happens when the engine is running because normally you would not see the fuel passing through the pipes.

Cool, I like the clear hoses 😉 looks like you've done a thorough clean up too. Top Jon
 
Tell me what you think.
I'm wondering if thats what normally happens when the engine is running because normally you would not see the fuel passing through the pipes.
I’ve never seen a clear fuel pipe either but I would say there should be no bubbles.
The pickup in the tank is under the surface of the fuel so it should be air free. Unless
- You have a leak and the tandem pump draws air in with fuel. But then you would probably find fuel leaks on the drive.
- The tandem pump is pulling vacuum and the air it draws gets into the fuel. Not sure how but this was my favourite theory. Interesting your brakes are now more responsive.
Air in fuel will compress so you would be unlikely to get correct pressure in the rail. Also the injectors would be short on pressure.
Sounds like you have fixed it though. Well done.
 
I’ve never seen a clear fuel pipe either but I would say there should be no bubbles.
The pickup in the tank is under the surface of the fuel so it should be air free. Unless
- You have a leak and the tandem pump draws air in with fuel. But then you would probably find fuel leaks on the drive.
- The tandem pump is pulling vacuum and the air it draws gets into the fuel. Not sure how but this was my favourite theory. Interesting your brakes are now more responsive.
Air in fuel will compress so you would be unlikely to get correct pressure in the rail. Also the injectors would be short on pressure.
Sounds like you have fixed it though. Well done.
Not so sure about the fixed it bit .
Been stood now a couple of days while I sort out the rear left side door lock cycling, now sorted (thanks timmus).
Took around 15 seconds to kick in.....:(
I can't see any fuel leaks whatsoever,
I've got a replacement cover for the bottom of the fuel filter cartridge, the new type canister so will clamp the appropriate fuel pipes and swap it over.
Im at a bit of a loss now to be honest.
 
Not so sure about the fixed it bit .
Been stood now a couple of days while I sort out the rear left side door lock cycling, now sorted (thanks timmus).
Took around 15 seconds to kick in.....:(
I can't see any fuel leaks whatsoever,
I've got a replacement cover for the bottom of the fuel filter cartridge, the new type canister so will clamp the appropriate fuel pipes and swap it over.
Im at a bit of a loss now to be honest.
I think you need somebody to loan you a known good pump.
Edit: this is a known bad one, it has a slight fuel leak from the front cover. Other than that the engine ran fine. If that pump works you have a problem with your Bosch. If it fills you fuel lines with air your Bosch is good and you need to find the air leak. Interested?

44A1C06A-4146-4996-940B-402F61BE006E.jpeg
 
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I've got two here on two A2s that are fine but I'm loathed to start taking them apart.
Can anyone advise if its worth running a good (Archoil or similar) injector cleaner through? I couldn’t get mine started (AMF Bosch) after replacing the tandem. My A2 specialist ran some through and it fired up fine. It sounds like you’ve tried everything else bar a new tandem again. For the sake of £25 ish, can anyone rule this step out as pointless? I think ultimately the gasket or pump itself could be the culprit.
 
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