AHU swap into 93 Eurovan Weekender

njt1rider said:

Hmmm...To do the alh pump conversion I did chop the three wires to the n108 and n109 and resoldered them. How would I check if I did this properly? I know the wires are in the right spot and have continuity, but I'm guessing this would be a resistance issue? Thank you for the quick responses guys!

Edit: what would the check engine bulb affect? I'm reading the codes through vagcom...

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Sorry, missed that you were checking with vcds....assumed you were taking the no CEL as a sign of no codes.

SINCE you actually have no codes then I would do as Aaron suggests and take a look at your IQ. Sounds like it could be very low.

Is there anything I could have screwed up by soldering the n108 wires or is it as long as there's continuity its good?

If you had screwed something up with the wiring you'd get a code

Ok Im pretty sure its overfueling. Getting black smoke and can smell the fuel. I tried changing the IQ but I'm not getting any results. I think something isn't right as the inj quantity is reading 0.0 no matter what I do...

at 32784:


at 32850:


at 32650:


What do I do next?

I was able to do an N75 output test and it appears the computer is controlling the turbo as it should. I wont know if its working 100% correctly until I get her on the road and log some data but at the moment its looking good. Now to figure out this idle problem....

EDIT: Now that the tach is working and I have the oil press/temp and boost/egt gauges hooked up, I had the balls to mess with the pento again. If I move it at all, the engine automatically winds up to 4k then backs off to 3k then back to 4k back to 3k and keeps doing that until i shut down the engine. Possible all this is being caused by the pento? it worked fine prior to being pulled. I dont have an extra on hand to swap out with...lets see if i can find trouble shooting procedures for the pento...

I believe the pedal pento is fine. Looking in group 000 bank 3 and operating the pedal the number corresponds properly 0-100. Then again group 02 "load" corresponds correctly as well 0-100% depending on throttle position. Would this be the correct way to check through vagcom?

Gonna try hammer mod next to bring IQ down...

Shot in the dark: Have you checked timing? (Be sure to be set to the right engine type in VCDS)

Timing is at 65; right in the middle of blue and green line, but that is with the engine idling at 1200 RPMs. Does that make a difference? I'm not having much luck with the hammer mod but will keep trying...

njt1rider said:

I'm not having much luck with the hammer mod but will keep trying...

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Are you able to make any changes to the IQ value? Keep trying to increase and if you really aren't seeing any changes then you need to pull the QA housing to make sure the nub is inserted into the collar.

I tried to lower it by moving the housing toward the passenger side. At the moment I have it as far to the pass side as it will go AND still start. It can go much furthur but then it wont start. If I kick it to far to the driver side the engine revved super high and I killed it before it got above 4k. Where it is at right now is where I saw the most improvement: when i first start it, the idle is rough jumping between 800-1100 BUT when I am looking at it in adaption, I'll actually see numbers in the inj quantity ranging from 0-22. When the idle finally smooths out at 1200 RPM, it goes back to saying 0.0. Group 5 inj quantity is at a steady 22. The RPMS are still jumping between 3k-4k when I try to mess with TPS. Calling it a night but will be back at it tomorrow if there's anything else I can try...????

as Nick said, it sounds like you need to verify that the nub is in the collar under the Quantity adjuster housing on the injection pump. check out the pump reseal video thread to get a good idea what to look for.

basically there is a ball at the end of the quantity adjuster shaft that goes into a hole in a collar that slides back & forth on the pump shaft behind the pump head. if the nub is not in the hole, all heck can break loose and cause running like you have described. I think you are lucky you got it to run at all if it is not seated in the collar properly.

has the pmp ever been apart that far? has it been resealed recently?

Pump history is unknown. I will verify the nub as next step; although with this weather, it might have to wait a day or two. Thank you for the advice again and I will report back the results...

mtdi for life not really though because I have a mk4 too..

maybe this has already been mentioned but you can remove the top cover from the QA and move the sweeper arm by hand ... it should move full travel and snap back with zero resistance .... if the fuel control ring or pump plunger is gummy it can cause strange idle issues

jimbote said:

maybe this has already been mentioned but you can remove the top cover from the QA and move the sweeper arm by hand ... it should move full travel and snap back with zero resistance .... if the fuel control ring or pump plunger is gummy it can cause strange idle issues

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^^This. should only take 5-10 minutes, and will spill some fuel and cause you to have to reprime the injection pump, but will also let you know how smoothly the ring is sliding if it is installed properly.. any resistance other than even spring resistance is cause for at the minimum a Diesel purge enema..

Ask Paramedick if you can borrow his DDD to do this procedure and tell him I sent ya.

Pump condition was unknown, and sat for several years...

What kind of tdi owner would I be if I didn't have a can of diesel purge layin around? Anyway, I will verify QA pieces are installed correctly and free moving then run a can of diesel purge through her....

just picked up a 98' beetle organ donor that sat for six years misdiagnosed ... dealer said injectors were bad ... so the pump sat for that that time unsealed... once i figured out the real problem(s) of timing off one tooth and that the ten pin connector for the engine harness was nothing but goo inside it fired right up....it ran like crap though, surging idle would not rev above 2500 etc. ... pump was completely gummed up from sitting ... every last little teeny piece inside the pump had to be soaked and scrubbed in carb cleaner to remove the offending varnish, lift pump, pressure control valves, rollers, cam plate, plunger etc. etc... runs sweet now ... may not be your issue but a little goo goes a long way
.... and i did try diesel purge first with no effect

Got a couple hours out in the garage. I pulled the QA housing. The lever seemed to be in the plunger piece but I did notice the plunger was not sliding smoothly on the rod. It would even get stuck when pushed all the way toward the passenger side. I vacced all the fuel out and sprayed it down with throttle body cleaner and played with it until it moved freely. I then sucked all that out and washed fuel through there a couple times. I got it all back together and got it running. This is what it is doing:


The only difference I could tell is the engine doesnt have a mind of its own when I play with the pedal pento now. If I try to accelerate, I can hear the engine sounding like its trying a little harder but the RPMS do not change. Vagcom is still registering the pedal properly.

I played with the QA housing a little bit more and tried playing with adaption but I couldnt discern any huge differences. Then I decided to diesel purge. It actually seemed like it was helping slightly until the engine stalled out; the DP can tipped over while I was in the van playing with vagcom ::slaps self:: I re-primed pump and now I can't get it to start. To top it off I think the starter is about to go. I'm sure it being 20 degrees outside with no heater doesn't help either. So I'm gonna defrost a little bit and hope to hear some advice from yall.

I do have a viton seal kit on the way...

any photos of the gunk you cleaned out before you cleaned it?

I didn't really clean out any gunk. The fuel inside the pump seemed to be clean and I did not notice any buildup on the rod that the plunger moves on. Only thing I could tell was that it did not move freely until after I used the throttle body cleaner. Even the throttle body cleaner that I sucked out looked to be clean as well.

EDIT: I adjusted the QA housing and gave her another go and she started right up. Played with pedal pento and took off like a bat out of hell. Had to shut her down. Got her idling at 1200 and running the rest of the DP I have through her...

EDIT: After running a quart of DP through this is what the in line fuel filters looked like....HMMMMMM

the deposits in the pump may not be affected at all by diesel purge as was the case with the pump i mentioned above ... it actually had zero effect and i had to disassemble and scrub each part with carb cleaner and scotchbrite ... you may still have another problem but the sweeper arm sticking is a strong indicator of a gummed pump ... next i would remove the entire quantity adjuster and get a good look inside

Ok before I go too crazy with all this let me stop and think for a second. What are the actual troubleshooting steps for this issue?...i guess it would fall under idle speed incorrect rough or irregular. The bentley touches on troubleshooting but doesnt really give any procedures of what to do. for instance "probable cause": faulty injection pump; "corrective action": replace pump. Really? I would have never guessed that. So how do I get to that point. I'm still not 100% certain the the throttle position sensor has nothing to do with it either. I need some definitive troubleshooting guides and steps before I start throwing too much time and $ at the problem at hand.
Per Bentley:



A. pedal isnt attached to anything so its not binding
B./C. All fuel lines including hard lines and fuel filter are brand new and were carefully installed
D. Kerma just rebuilt these injectors
E. timing is as close as i can get it while checking vagcom and engine idling at 1200 RPMS
F. Have not done a compression test but I could. complete engine is fresh build from Frank
G. We know about the plunger sticking and I probably need to investigate some more. I have tried searching the forums, is there a write up anywhere of how to tear down and rebuild this pump or is this something I should leave to the "professionals". (i have a viton seal kit should be here before the weekend)

Then under "engine runs at a high constant idle and speed does not vary"
A. no faults in vagcom; how do I verify the pento is not causing this?

I hate just swapping out parts as a "troubleshooting" step but I do have access to another pump. I do not have access to another pedal. If I can not figure out how to actually troubleshoot the pump, I may swap it out to see the results.

Is what I observed so far proof enough that the pump needs rebuild?

How do I rule out a wonky ECM/Tune?

jimbote, growler, and greengeeker, I really appreciate all the advice so far. This van needs to be on the road!

EDIT: http://forums.tdiclub.com/showthread.php?t=245955 <==Very interesting read. Still no clue whats going on with mine hehe

Another thing you might check while you are at it is the case pressure relief valve.

take an open ended 10mm wrench, and take out that funky bolt thing next to the inlet nipple on the injection pump.

you will want to make sure that the area around this bolt is clean first.

once you remove it, see if the black cap is fully seated in the end of the bolt. if it is sticking out of the bolt, or has completely fallen out, carefully tap it back in flush with the end of the bolt. open end down.( I believe it is hat shaped with a flat top, but it also could be like a split ring, its been a while since I have opened one of these)

I am not sure that this being out will cause high idle, but if the internal case pressure is messed up or low, its def not good for things.

Another thing you might check while you are at it is the case pressure relief valve.

take an open ended 10mm wrench, and take out that funky bolt thing next to the inlet nipple on the injection pump.

you will want to make sure that the area around this bolt is clean first.

once you remove it, see if the black cap is fully seated in the end of the bolt. if it is sticking out of the bolt, or has completely fallen out, carefully tap it back in flush with the end of the bolt. open end down.( I believe it is hat shaped with a flat top, but it also could be like a split ring, its been a while since I have opened one of these)

I am not sure that this being out will cause high idle, but if the internal case pressure is messed up or low, its def not good for things.

what growler said and also remove and check the case pressure control valve, which is the what the return banjo slips over and the banjo nut threads onto ...when removed and shaken it should give a little "click" "click" back and forth .. it has a free plunger inside with i think a spring at one end ... i've never had one apart but i know ones that don't click are stuck and must be freed up or replaced ... what leans me toward a pump fault is the erratic nature of the rpm's ... pedal faults will cause a stable increase in idle, injector faults will cause a steady skip or knock ... just my dos pesos and im pulling from my own pool of experience ... others may vary

Ok, took the pump apart and cleaned it. It honestly looked pretty clean to me. It was also a lot simpler to disassemble/assemble than I imagined. Growler, the o rings on the pressure relief valve were shredded. Now that I am re-reading your post, I think that cap was not seated all the way and I need to go back and seat it. jimbote, the pressure control valve "click clicked." I got everything back together. Pump seems to hold prime and bled injector lines. Couldn't get it to start. Advanced timing and still wouldnt start. Seemed like starter was grinding worse so pulled it out and threw the old gasser one in. Come to find out, the shaft of the gasser starter slides into the trans housing where as the diesel starter I have is just stub nosed and doesn't slide in. I'm guessing this is causing it to skip teeth because there is nothing to hold the starter gear onto the flywheel on the engine side. Unfortunately, the gasser starter spins much slower; then the battery died. So, I have no new answers really. I will charge battery and try starting some more and if that gets me nowhere, I am going to swap QA's before I pull the whole pump out again.

Question: Is there a difference between gas and diesel starters? RPMs? The new starter I was using that is grinding is euro only where as the gasser one can be bought at autozone...

Pics for the day:

wow!..you really went for it ....ok just want to double check you got the camplate back in the correct orientation...it can go in two ways and only one is correct...the dowel pin drive lug that the plunger foot fits into should have been assembled to point to about 2 oclock if you are facing the rear of the pump with the pump lock pin in place...if it's assemble 180* out you will have a no start ...as for the starter itself do you have a picture of the euro starter? and the number of teeth on the pinion? part number? ...there may be a match somewhere in the american parts bin ...

All I have to say is wow. I am impressed you tore into it that deeply. You are way out of my comfort level now. Listen to Jimbote.

O man I'm really learning things the hard way eh? Well I had no idea about the orientation of the camplate so it looks like its coming back out...ill get pics of the starter next time I'm in the garage. ..