Difficult start TDI 90 with MYP 6-speed conversion

Dont give up ! sounds expensive
Either there is a one way valve in the rubber pipe next to the pump that is leaking or your pump is still defective. (Vanes not sealing but able to produce pressure at speed)
Google tandem pump non return valve, then read the first US TDI club blurb.
I have a not good but works Luk pump, that did not suffer with your problem you could use to eliminate yours or find cost of the the rubber hoses from Audi.

PS Oil pressure is often similar to fuel pressure if engine in good condition. I assume cold oil pressure would be about 75psi ? from memory tandem press the same at 1500rpm ?
Martin
 
I’m wondering if the injectors could be leaking.

This sounds very plausible. These PD engine injectors are only clamped down on one side with a M4/5 bolt and block. It is a known issue with some higher mileage vehicles that the injector has been able to move causing the seals to leak and damage to the injector bore. I would be looking at just popping the injectors out and replacing the seals to start with.

Edit: pictures added showing some bore damage from a PD injector.
IMG_0318.jpg
IMG_0319.jpg

The side with the threaded hole is where the injector is clamped and shows no wear. The opposing side has 2 additional lines which have been worn into the aluminium head from the harder (steel?) injector.
 
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Today’s progress: I temporarily replaced the rubber fuel-pipes between the stainless pipes on top of the cam cover and the tandem pump with clear 8mm I.D. PVC hose so I could see the fuel and supposed de-priming happening after engine turn off. I removed the 2 sections of pipe including the fuel temperature sender in the return line, but left the electrical connector attached so as not to generate an error. There appears to be no NRV in either hose. The car starts and runs exactly the same with the clear hose. More importantly, after turning off, there is no de-priming, no sign of air in the clear pipes. Yet it still needs sustained cranking. Even turning it off and IMMEDIATELY re-cranking doesn’t result in immediate starting. One thing I failed to mention before: When I stripped the pump to replace the seals and gaskets I noticed that you could see where the rotor and vanes had polished the pump plate (the diamond shaped part held with 3 screws), but there was no detectable wear to feel, certainly no scoring so I reckoned it was OK. Since the pump is able to prime itself I guess it must be able to pump air and this suggests it is not worn.


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If there was "black goo" in the filter originally, could there not be goo in the line between the fuel tank and filter or even in the tank itself, which might be causing an obstruction?

RAB
 
FIXED IT !!!
Today I finally got around to taking the (original Bosch) starter out, inspecting the flywheel ring gear and the starter pinion and comparing it to the used CAYC engine Valeo starter I bought on eBay back in November. (The MYP gearbox was originally fitted to the CAYC 1.6TDI engine in the 2011 Passat, possibly the Leon too). It was immediately clear from inspecting through the bellhousing hole that not only was the original starter pinion not meshing far enough in its direction of throw, but also the teeth of the pinion and ring gear were not engaging close enough in the radial direction. Please take a look at the pictures. You can see the bright spots where the teeth are touching and the brown dust / rust where they're not.
I tried to take some measurements but decided I didn't have the right gear to do it with sufficient accuracy in 3 dimensions.
The ring gear on the new DMF has been damaged, I am hoping not too badly.
Putting the new and old starter side by side, it was obvious that the old starter has a smaller diameter pinion than the CAYC starter.
Not so obvious, the centre of the pinion shaft seemed to be in a slightly different position vs. the imaginary line between the 2 mounting bolt holes in the casting.
I tested both starters on the bench. Although the direction of rotation was the same, t seemed as if the throw-mesh would only be 2-3mm more with the CAYC starter. I decided to try it anyway. The solenoid connection was different and I had to improvise a spade connector and tape it up to hold it together, also the solenoid sleeve didn't fit properly so I used several cable ties to hold it in place.
The engine started on the second compression, just like it used to before I fitted the MYP. Several more start-ups were just the same. And the cranking noise was really sweet, just like it used to be. Some air was punched!!

So, after so many blind alleys and so much thought and support in posts from so many members, I'm a happy man.
I wonder if the damage clearly done to the ring gear will be OK. Maybe the throw-mesh is still too small, maybe I will have to change the DMF again (shudder). Also I wonder if a starter from an AMF would have just slotted straight in and meshed really properly....
To anyone who has done the MYP conversion on their 90bhp TDI with ATL engine (at least OKO-Martin): if you didn't change the starter and cranking sounds a bit ropey or is becoming difficult, I strongly suggest that you consider sorting it out. I think your ring gear is getting shredded and you need a different starter (maybe one from a CAYC or maybe AMF).
To those who have done the MYP conversion on a AMF or BHC: which starter did you use, how does it sound and is starting fine?

All the best, and thanks again to everyone.

Matt

IMG_3888.JPG
IMG_3889.JPG
IMG_3891.JPG
IMG_3894.JPG
 
Blimey, what a story. Chapeau, for your persistence, and thanks for the gold-dust information about the right starter to use. I suspect my DMF is getting a bit rattly, so when the time comes, I'm intending to upgrade to the MYP option, and without your hard work, no doubt there would have been tears before bed-time.
 
Hopefully now that the starter pinion is moved further into the ring gear the damage caused won't get any worse and the flywheel can be saved.

This is now vital information for anyone considering doing the myp to a 90. Do you think you could add this to the original myp gearbox thread?

Well done for your perseverance.
 
Hopefully now that the starter pinion is moved further into the ring gear the damage caused won't get any worse and the flywheel can be saved.

This is now vital information for anyone considering doing the myp to a 90. Do you think you could add this to the original myp gearbox thread?

Well done for your perseverance.

Thanks Steve, I've added a few lines to this thread, hope it's the one you meant:
https://www.a2oc.net/community/inde...od-passat-11-onwards-myp-gearbox.25919/page-7
 
Well done Bigg Dog for your perseverance and thank you for your advice.
I was not expecting that and will have to check when I can.
Mine starts ok but certainly not as sweet as it used to be pre MYP (oddly sounds as rough as my XJ 3.6 was !)
I am surprised it has not been picked up on before, as 13 teeth to 10 is a substantial difference. Would the teeth mesh better or worse
if the starter is fitted 180 degrees out; or is it not possible ?
Brilliant stuff, thank you
Martin
 
Martin, thanks, I don't think that fitting the starter rotated 180 degrees out is possible as the solenoid clashes with the gearbox. I've thought about drilling a hole in the bell housing so I can see the mesh I'm getting but decided against it, at least for the time being. Guess what today my CEL has come back on and the turn-off shudder is back... if it's not one thing it's another.
 
Well done Bigg Dog for your perseverance and thank you for your advice.
I am surprised it has not been picked up on before, as 13 teeth to 10 is a substantial difference.
Martin
Theoretically, it can even be worse... if the two sets of flywheel ring gear and starter pinion are made to different module, tooth profile will not match either...
is it a good idea to clean and blueprint ?
 
FIXED IT !!!
Today I finally got around to taking the (original Bosch) starter out, inspecting the flywheel ring gear and the starter pinion and comparing it to the used CAYC engine Valeo starter I bought on eBay back in November. (The MYP gearbox was originally fitted to the CAYC 1.6TDI engine in the 2011 Passat, possibly the Leon too). It was immediately clear from inspecting through the bellhousing hole that not only was the original starter pinion not meshing far enough in its direction of throw, but also the teeth of the pinion and ring gear were not engaging close enough in the radial direction. Please take a look at the pictures. You can see the bright spots where the teeth are touching and the brown dust / rust where they're not.
I tried to take some measurements but decided I didn't have the right gear to do it with sufficient accuracy in 3 dimensions.
The ring gear on the new DMF has been damaged, I am hoping not too badly.
Putting the new and old starter side by side, it was obvious that the old starter has a smaller diameter pinion than the CAYC starter.
Not so obvious, the centre of the pinion shaft seemed to be in a slightly different position vs. the imaginary line between the 2 mounting bolt holes in the casting.
I tested both starters on the bench. Although the direction of rotation was the same, t seemed as if the throw-mesh would only be 2-3mm more with the CAYC starter. I decided to try it anyway. The solenoid connection was different and I had to improvise a spade connector and tape it up to hold it together, also the solenoid sleeve didn't fit properly so I used several cable ties to hold it in place.
The engine started on the second compression, just like it used to before I fitted the MYP. Several more start-ups were just the same. And the cranking noise was really sweet, just like it used to be. Some air was punched!!

So, after so many blind alleys and so much thought and support in posts from so many members, I'm a happy man.
I wonder if the damage clearly done to the ring gear will be OK. Maybe the throw-mesh is still too small, maybe I will have to change the DMF again (shudder). Also I wonder if a starter from an AMF would have just slotted straight in and meshed really properly....
To anyone who has done the MYP conversion on their 90bhp TDI with ATL engine (at least OKO-Martin): if you didn't change the starter and cranking sounds a bit ropey or is becoming difficult, I strongly suggest that you consider sorting it out. I think your ring gear is getting shredded and you need a different starter (maybe one from a CAYC or maybe AMF).
To those who have done the MYP conversion on a AMF or BHC: which starter did you use, how does it sound and is starting fine?

All the best, and thanks again to everyone.

Matt

View attachment 36361View attachment 36362View attachment 36363View attachment 36364
Biggdog

Did you use the DMF for the Passat or for the a2 I have the same problem I have 2 x cayc starters and they don’t fit using the a2 DMF
 
I used the A2 DMF from LuK, but note that I kept the spacer that goes between the ATL engine and the GRJ gearbox. Others have removed this when doing the MYP conversion.
Matt


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I used the A2 DMF from LuK, but note that I kept the spacer that goes between the ATL engine and the GRJ gearbox. Others have removed this when doing the MYP conversion.
Matt


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That’s that is interesting, the gearbox has to come off anyway, as the refurb unit as thrown an input bearing after the first few miles :/


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That’s that is interesting, the gearbox has to come off anyway, as the refurb unit as thrown an input bearing after the first few miles :/


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I also have the spacer, the cayc starter just doesn’t fit, it just hits the fly wheel


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I also have the spacer, the cayc starter just doesn’t fit, it just hits the fly wheel
I'm running the ATL DMF and CAYC starter combo without the spacer with no issues (so far).
However, last time I spoke to Rob at WOM about this he thought that removing the spacer and using the standard ATL starter (and DMF) was the correct setup, based on measurements they had taken.
Are you able to try with the original starter and no spacer fitted?
 
I'm running the ATL DMF and CAYC starter combo without the spacer with no issues (so far).
However, last time I spoke to Rob at WOM about this he thought that removing the spacer and using the standard ATL starter (and DMF) was the correct setup, based on measurements they had taken.
Are you able to try with the original starter and no spacer fitted?

This is super useful, the gearbox has to come off as there is an issue with on of the bearing when it goes back together we will drop the spacer. Thank you.


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