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Author Topic: Very little boost on my mTDI ALH Vanagon install  (Read 1086 times)

Reply #15March 30, 2018, 01:38:44 pm

libbydiesel

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Re: Very little boost on my mTDI ALH Vanagon install
« Reply #15 on: March 30, 2018, 01:38:44 pm »
I imagine you can make it smoke and have high EGTs with the LR pump.  If it smokes/has high egts before the turbo is producing decent boost, swapping pumps is not going to fix that situation.
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #16March 30, 2018, 06:39:55 pm

Zeitgeist

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Re: Very little boost on my mTDI ALH Vanagon install
« Reply #16 on: March 30, 2018, 06:39:55 pm »
I was just referring to swapping the 4BT head over to the LR pump.  But, that's for another time. 

I'm now thinking that those small automatic nozzles might be limiting the fueling needed to drive up boost with this pump.  Over in the MB IDI world, they're able to run huge Holset turbos by swapping in larger elements that vastly increase the amount of fuel available--larger nozzles don't really apply in that realm.  Since I was already planning to upgrade the nozzles, I guess I'll try that out. 
'87 300TD (OM603)-->(OM606)
'90 300D (OM602)
'89 Vanagon Bluestar (ALH)
'01 EV Weekender (AXK)
'94 100CSQ Avant (AAH)

Reply #17July 01, 2018, 04:32:16 pm

Zeitgeist

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Re: Very little boost on my mTDI ALH Vanagon install
« Reply #17 on: July 01, 2018, 04:32:16 pm »
Just to follow up on this topic, I found that the cardboard snorkel tube running up the pillar was collapsed and causing lots of boost issues.  I also found that my wastegate was opening prematurely, though I haven't fully diagnosed that yet, so I've been driving around with the actuator unplugged--no wastegate at all.  I can get about 13psi peak and the EGTs have never gone above 850F.  I have some PP764 nozzles coming my way, so I expect I'll need to dial back the fueling in order to keep EGTs low.  The engine produces good torque for around town driving, but the HP isn't quite there out on the freeway.   
'87 300TD (OM603)-->(OM606)
'90 300D (OM602)
'89 Vanagon Bluestar (ALH)
'01 EV Weekender (AXK)
'94 100CSQ Avant (AAH)

Reply #18July 02, 2018, 11:08:21 pm

libbydiesel

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Re: Very little boost on my mTDI ALH Vanagon install
« Reply #18 on: July 02, 2018, 11:08:21 pm »
Thanks for the update.  If the EGTs have never gotten above 850, then you can certainly increase the fuel a fair amount from where it currently is.  I look forward to hearing about the new nozzles.
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #19October 13, 2018, 03:33:54 pm

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Re: Very little boost on my mTDI ALH Vanagon install
« Reply #19 on: October 13, 2018, 03:33:54 pm »
Re-posted from the Samba:

My question: Can I remove the upper injection pump cover in situ, and are there any gotchas I should be concerned about prior to executing this task?  I guess it might be less problematic to just remove the head from the pump, but I don't want to assume anything.

Background: The engine in question is an ALH with a LR manual pump, though I assume this may apply to all VAG manual diesel pumps .

I went to start my van this morning and it started and stumbled (which it's never done since springing to life many moons ago), so I kept attempting to start. It would fire and die...until it wouldn't.

I checked for voltage at the solenoid with key on; yes.

I removed the electrical connector and then checked to see if the solenoid clicked when the connector was manually applied; yes.

I check to see if voltage stayed constant during engine cranking; yes.

I removed the incoming fuel banjo to see if there was fuel in the pump; yes.

I observed that when cranking after the previous test, the translucent fuel line refilled and the air bubbles disappeared; internal pump works.

Diagnosis: The fuel shutoff solenoid is bad.

The problem:
I cannot get a good purchase on the solenoid with the top cover in situ, hence the primary questions. 
'87 300TD (OM603)-->(OM606)
'90 300D (OM602)
'89 Vanagon Bluestar (ALH)
'01 EV Weekender (AXK)
'94 100CSQ Avant (AAH)

Reply #20October 13, 2018, 09:32:24 pm

libbydiesel

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Re: Very little boost on my mTDI ALH Vanagon install
« Reply #20 on: October 13, 2018, 09:32:24 pm »
Yes, you can remove the pump cover with the pump in place.  Mark accelerator lever to shaft orientation.  Mark accelerator rest and full stop bolts if they're in the way .  It's then 4 m6 bolts holding the cover on. 
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #21October 19, 2018, 06:14:38 pm

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Re: Very little boost on my mTDI ALH Vanagon install
« Reply #21 on: October 19, 2018, 06:14:38 pm »
Thanks, I used that info to practice on an old NA pump, and then realized that none of my sockets or box end wrenches would fit in there anyway.  I eventually got the solenoid out (it was ugly), but the one I replaced it with did not solve the issue. 

I then  replaced the fuel filter and filled it with ATF.  Despite cranking many times, I can't get any of the ATF to appear in the translucent tube to the pump.  Can you confirm that the solenoid just cuts off fuel to the plunger, but the pump should still be drawing in and expelling fuel (through the tank return line) when the engine is cranked?  This is a real puzzler.   
'87 300TD (OM603)-->(OM606)
'90 300D (OM602)
'89 Vanagon Bluestar (ALH)
'01 EV Weekender (AXK)
'94 100CSQ Avant (AAH)

Reply #22October 19, 2018, 09:38:52 pm

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Re: Very little boost on my mTDI ALH Vanagon install
« Reply #22 on: October 19, 2018, 09:38:52 pm »
I just installed the solenoid without the plunger, and it still won't fire.  I think this pump has completely failed internally. 
'87 300TD (OM603)-->(OM606)
'90 300D (OM602)
'89 Vanagon Bluestar (ALH)
'01 EV Weekender (AXK)
'94 100CSQ Avant (AAH)

Reply #23October 19, 2018, 10:20:21 pm

libbydiesel

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Re: Very little boost on my mTDI ALH Vanagon install
« Reply #23 on: October 19, 2018, 10:20:21 pm »
The vane pump should move fuel through the pump when the engine is cranking even if the stop solenoid is not energized.  The stop solenoid only affects the high pressure portion of the pump. 

The 'fuel pressure regulator' sends fuel back to the pump inlet.  If that is stuck in the open position it could prevent the fuel from circulating.  I don't think that would prevent the high pressure side from operating, though.

Any chance the hub slipped on the shaft resulting in wrong timing?  That wouldn't prevent the fuel from circulating or spraying but would could cause it to sputter, die, and not restart like you initially described.   
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #24October 20, 2018, 03:07:38 pm

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Re: Very little boost on my mTDI ALH Vanagon install
« Reply #24 on: October 20, 2018, 03:07:38 pm »
I think you're on to something with the hub suggestion.  It appears that it's slipped from the position I set initially.  I'm still confused about the lack of fuel cycling through the pump, but I'll re-time the hub and deal with that issue when I'm back to baseline settings.  I've forgotten the lift measurement for these LR pumps; is it 1.40?

'87 300TD (OM603)-->(OM606)
'90 300D (OM602)
'89 Vanagon Bluestar (ALH)
'01 EV Weekender (AXK)
'94 100CSQ Avant (AAH)

Reply #25October 22, 2018, 08:37:42 pm

libbydiesel

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Re: Very little boost on my mTDI ALH Vanagon install
« Reply #25 on: October 22, 2018, 08:37:42 pm »
1.40mm is a good starting point.
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

 

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