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[Omegatoy]

Hmm, Im still trying hard to understand why when chipped certain cars including mine suffer a "missfire" at around 1500rpm on a very light throttle
now i found this which would seem to be the fault? its number 8 highlighted in red and called
 Solenoid valve for injection adjuster, have read a fair old bit about it and it seems the prime candidate
to me? oops pic would help here
http://www.realoem.com/bmw/showparts.do?model=CC32&mospid=47446&btnr=13_0436&hg=13&fg=15&hl=15

so anyone got opinions on this?

 if nothing else it shows exactly whats in the injection pump!
also found one that had been converted to a throttle cable system!!! rather than the fbw!

takes some searching but there is a fair amount of information out there on this vp37 pump!!

[TheBoy]

Easy cure is to not try to drive at 46.5mph in top gear

[Omegatoy]

Easy cure is to not try to drive at 46.5mph in top gear

lol true!!!
however on the main roads here the limit is often 80kph, =50mph its fine if there is no traffic i do 52/53 car drives perfect! but follow a spaniard who always do 45/46/47/48 and the damn thing starts playing around!! overtake said spaniard and another appears a mile down the road!!!
so i stick in 4th but its driving me nuts trying to sort it!!! lol

[Seth]

Never got to the bottom of this 'stutter' at 1500 rpm on our previous TD either

If you overcome it G; please keep us informed!

[Omegatoy]

Never got to the bottom of this 'stutter' at 1500 rpm on our previous TD either

If you overcome it G; please keep us informed!

will do mate

[Elite Pete]

Mine seems to be between 45 and 50 mph, i've got used to changing down at 40 and back to top at just after 50mph

[hoofing it]

Hmm, Im still trying hard to understand why when chipped certain cars including mine suffer a "missfire" at around 1500rpm on a very light throttle
now i found this which would seem to be the fault? its number 8 highlighted in red and called
 Solenoid valve for injection adjuster, have read a fair old bit about it and it seems the prime candidate
to me? oops pic would help here
http://www.realoem.com/bmw/showparts.do?model=CC32&mospid=47446&btnr=13_0436&hg=13&fg=15&hl=15

so anyone got opinions on this?

 if nothing else it shows exactly whats in the injection pump!
also found one that had been converted to a throttle cable system!!! rather than the fbw!

takes some searching but there is a fair amount of information out there on this vp37 pump!!

This also is the culprit for code 34

[Kevin Wood]

Surely if the chip is causing the issue, it will be a problem with the mapping of the chip rather than an unrelated component? Unless it's a difference in some component between the BMW spec engines and the GM spec?

[Andy H]

Is this only a problem on chipped vehicles? or common across all?

There was a time when noise and emissions regulations for motorbikes resulted in the manufacturers programming a flat spot to reduce noise output under one particular test (IIRC it was full throttle at 60 kph in top gear?) maybe BMW/GM did the same with the traktor?

Maybe it also explains why the auto gearbox in my 2.6 V6 is so keen to hunt between 3rd & 4th at around 48mph 

[Marks DTM Calib]

Surely if the chip is causing the issue, it will be a problem with the mapping of the chip rather than an unrelated component? Unless it's a difference in some component between the BMW spec engines and the GM spec?

Agreed

All to often the new maps are developed using a minimal set of test conditions and dont allow for the fact that the origianl map may well have some operating points which are compromised in order to overcome or counter known difficult operating points on the mechanical setup.

It might be as simple as the speed at which the control solenoid is operating at that rpm happens to be the same as the resonant point of one of the springs for example.

The Vp37 is a pretty standard rotary pump design with a controlled spill valve so not rocket science.

Has anybody found an overhaul pdf for one as the repair kits are normaly under 100 pounds including new cylinder liner and seals.

[Shackeng]

Doesn't occur on mine.......Oh, I forgot mines auto

[Omegatoy]

Surely if the chip is causing the issue, it will be a problem with the mapping of the chip rather than an unrelated component? Unless it's a difference in some component between the BMW spec engines and the GM spec?

Agreed

All to often the new maps are developed using a minimal set of test conditions and dont allow for the fact that the origianl map may well have some operating points which are compromised in order to overcome or counter known difficult operating points on the mechanical setup.

It might be as simple as the speed at which the control solenoid is operating at that rpm happens to be the same as the resonant point of one of the springs for example.

The Vp37 is a pretty standard rotary pump design with a controlled spill valve so not rocket science.

Has anybody found an overhaul pdf for one as the repair kits are normaly under 100 pounds including new cylinder liner and seals.

did find one but its in dutch or portugese or somehting!!! however its all well and good overhauling it, but the vp37 becaus its used in so many applications has to adjusted for the particular engine its on? and that is rather difficult at home!! worst part is if you get the top hat set wrong it can lead to full throttle being appolied as soon as you start it!1 boooom, damn fbw of course it can go the otherway and have no tickover but sods law and all that!!

[Seth]

Is this only a problem on chipped vehicles? or common across all?

There was a time when noise and emissions regulations for motorbikes resulted in the manufacturers programming a flat spot to reduce noise output under one particular test (IIRC it was full throttle at 60 kph in top gear?) maybe BMW/GM did the same with the traktor?

Maybe it also explains why the auto gearbox in my 2.6 V6 is so keen to hunt between 3rd & 4th at around 48mph 

Yes indeed, it would seem so.
And, going by Shackeng's experiences, it only seems to affect manual-boxed TDs.

The chip that TB and MDTM fitted into my former TD was the 'plus 5' jobbie!

[Marks DTM Calib]

Surely if the chip is causing the issue, it will be a problem with the mapping of the chip rather than an unrelated component? Unless it's a difference in some component between the BMW spec engines and the GM spec?

Agreed

All to often the new maps are developed using a minimal set of test conditions and dont allow for the fact that the origianl map may well have some operating points which are compromised in order to overcome or counter known difficult operating points on the mechanical setup.

It might be as simple as the speed at which the control solenoid is operating at that rpm happens to be the same as the resonant point of one of the springs for example.

The Vp37 is a pretty standard rotary pump design with a controlled spill valve so not rocket science.

Has anybody found an overhaul pdf for one as the repair kits are normaly under 100 pounds including new cylinder liner and seals.

did find one but its in dutch or portugese or somehting!!! however its all well and good overhauling it, but the vp37 becaus its used in so many applications has to adjusted for the particular engine its on? and that is rather difficult at home!! worst part is if you get the top hat set wrong it can lead to full throttle being appolied as soon as you start it!1 boooom, damn fbw of course it can go the otherway and have no tickover but sods law and all that!!

That would be fine, its the diagrams that are key.

It would give us an insight as to what the various electronic inputs are doing and may help shed some light on the route cause of the issue.

I suspect you will find (infering from working on other pumps) that the variations on settings on a per application basis are pretty basic.

[Omegatoy]

LOL you kow how you find somehting then dont bookmark it and cant find it again?

so far came across this on a vp37 which is pretty clear on how to strip and rebuild
http://gnarlodious.com/Vanagon/Bosch_Pump/-Rebuild
will keep searching!

damn forgot to say some other stuff on the site to!!