mtdi, vnt17, no power with boost

[deepmud]

Loooong story - I have an MTDI in my Suzuki Samurai, bolted up to a Toyota drivetrain. I used to have a 1.9td AAZ/Suzuki drivetrain combo, and loved it - should have kept it as it was - but anyway, I'm a beta tester sometimes - I cut the rig in half, stretched it, lifted it - I had ACME's beta vw-toyota adapter - had some issues, ACME resolved them - and finally after much much much modification my Suzi is up and ready to actually NEED some power.

I find that if I boost the motor, it just slows down (I've got the VNT under manual control). I can get to about 45 mph offroad in deep snow without boost - then I pulled the cable to close up the vnt, run it to 15psi of boost, and it just drags power to make the boost - no extra fueling. I've done all the mods to my pump that worked GREAT on my old AAZ - it made great power/spoke at 12 psi boost.

I think the fuel pin that follows the bevel on the boost diaphragm  is stuck. The pump was to be a hybrid, built from an AAZ pump and a TDI pump. When I first started the motor (5 years ago? Something like that) it would barely run, with unburnt/white smoke. I advanced the timing (not with a dial indicator -just "some" - the pump pulley is one of those that has oblong slots to let it adjust easily) and it ran much better - starts right up and idles, and it has a lot of idle power - much of the time I don't bother with the throttle -it idles over rocks/stumps great.

The other issue - it has a heck of a time shutting off. When I turn the key, the idle drops to about 500 rpm (by ear) and shudders/ and bucks, but wont' shut off. I have to drop the clutch in gear to kill it. I can turn the power screw down, which brings idle down (and power) and it will usually shut off.

Is the top of the pump removable or should I grit my teeth and take it off for tear-down. I'm not a VW tech, but I was a Ford tech for 5 years, and have a degree in automotive tech  - so I'm above average in ability - but not experienced inside a Bosch pump.

Erik
pics of the beast for the curious
http://www.supermotors.net/registry/7029

[410]

That is a very cool rig.  What kind of pump are you running?

[deepmud]

looks like an AAZ type pump - hopefully has the 10mm TDI internals...I have a pic, somewhere.....

I guess I'm hoping someone will say "oh yeah, that's the follower getting stuck, pull the top off of the pump, make sure it's clear, put it back together".......  .....I'm thinking of taking a peek in there soon.....

[745 turbogreasel]

I had one in a pump that  had sat, the follower pin was stuck for the first day, and the car was miserable.
after that, it would hang for a minute, then enrich with a  cloud.

You can get to there by removing the pump top, even on the car if you can keep it clean (tinfoil hat)
Before that, you can pull the lid off the spaceship, and verify the LDA doesn't leak, and can move.
There is a tiny o ring around the follower pin, and you need to pull one of the lower  bolt looking plugs to get to it.

[Syncroincity]

Sweet rig, and beautiful shot.

Did you put a different engine in it, or did you use the AAZ block and convert it to mTDI?
Something I'm interested in doing at some point...

Cheers!

[theman53]

how are you controlling the vnt manually?

As for fueling issue I would maybe try running some diesel purge through the pump as well as what the others have suggested.

BTW, if that is stock drivetrain how does it like the boggers? Are those the 35x16 size? I have some 38.5x16 TSL on my bronco and the stock ford stuff doesn't like it.

[RabbitJockey]

I would guess the issues are pump related the turbo problem might just be that it sounds like it operating it by hand with a cable or something

[libbydiesel]

I think you have multiple issues with the pump.  If it doesn't shut off immediately, then either current is reaching the stop solenoid or the solenoid itself is at issue.  Could be crud buildup causing it to not seal totally.  Anyway, remove it, clean it up and reinstall it.  As far as the poor performance, it's hard to say.  There's a lot that can hang up inside the pump.  Could also be timing related.  I've found that timing to 1.35-1.4 on my pumps works really well but yours isn't one of mine so I can't say for sure.  I'd jump the belt one tooth to advance it and see how it does.  Diesel purge is a great idea.  Pulling the top of the spaceship and making sure the pin can move would also be wise.

As far as the turbo control is concerned it sounds like you have a cable to control the vanes by hand.  If you just close the vanes fully at higher rpms it acts like an engine brake. 

[Henk]

i was thinking the same ^ with the vanes pulled shut it restricts the exhaust quite a bit i imagine
Try putting a boost actuator inline with the cable, that way as soon as it hits the set boost level it puts the vanes back out(?) again to relieve pressure

[libbydiesel]

i was thinking the same ^ with the vanes pulled shut it restricts the exhaust quite a bit i imagine
Try putting a boost actuator inline with the cable, that way as soon as it hits the set boost level it puts the vanes back out(?) again to relieve pressure

Yup, and then attach the end to the accelerator lever so you don't have to mess with it by hand...     

[8v-of-fury]

Pulling the top of the spaceship and making sure the pin can move would also be wise.

I have seen them where the pin will move, but the pin that actually comes out to interact with the boost pin has been stuck. So the whole lid may need to come off to get it resolved.

[libbydiesel]

You can pull the lid, pull the boost pin and then rotate the accelerator lever to the max and the feeler pin should pop out and be visible in the channel of the boost pin.  I'd certainly check that out prior to pulling the lid.

[8v-of-fury]

If it is stuck in the out position, like I have experienced personally, no amount of fooling with the boost pin will get it out past the lip on the bottom of it.

So, if you cannot remove your boost pin chances are the feeler pin is stuck in its bore and not allowing boost enrichment.

[410]

looks like an AAZ type pump - hopefully has the 10mm TDI internals...I have a pic, somewhere.....

I guess I'm hoping someone will say "oh yeah, that's the follower getting stuck, pull the top off of the pump, make sure it's clear, put it back together".......  .....I'm thinking of taking a peek in there soon.....

If it has an aaz top, there's a lever on the side of the pump that will shut the engine off if moved.  If you have this lever, I would pull the top of the pump off and cut the end off it.  This lever can limit max fuel delivery.  I would also put a test light on the stop solenoid to check for power when shutting the engine off.  If you're getting some power to the stop solenoid after shutting the ignition off, use a relay to isolate the circuit.  If the power is cut off completely when the ignition is cut then do as libby says and remove, clean or replace the stop solenoid.

I'm doing a Jeep liberty turbo on a TDI right now with a wastegate off a K03.  I've never tried this simple vane control but I'll let you know how it works out.  For the vnt I would run it wherever it feels the best.  Don't worry about what the gauge says.

[R.O.R-2.0]

looks like an AAZ type pump - hopefully has the 10mm TDI internals...I have a pic, somewhere.....

I guess I'm hoping someone will say "oh yeah, that's the follower getting stuck, pull the top off of the pump, make sure it's clear, put it back together".......  .....I'm thinking of taking a peek in there soon.....

If it has an aaz top, there's a lever on the side of the pump that will shut the engine off if moved.  If you have this lever, I would pull the top of the pump off and cut the end off it.  This lever can limit max fuel delivery.  I would also put a test light on the stop solenoid to check for power when shutting the engine off.  If you're getting some power to the stop solenoid after shutting the ignition off, use a relay to isolate the circuit.  If the power is cut off completely when the ignition is cut then do as libby says and remove, clean or replace the stop solenoid.

I'm doing a Jeep liberty turbo on a TDI right now with a wastegate off a K03.  I've never tried this simple vane control but I'll let you know how it works out.  For the vnt I would run it wherever it feels the best.  Don't worry about what the gauge says.

you will need a stronger can than a K03 unit.. mine opens WAY too soon..

you want something that is open by ~25psi, if you are running a VNT20 or VNT22/23