upgrades, now code 1550

MacAndrew_Jack

Well-known member
Joined
Oct 21, 2005
Location
Colorado, United States
TDI
Vanagon Syncro Weekender
So I dove in with a bunch of air system upgrades to my TDI vanagon. It was working well before the upgrades, though I wanted the boost to be sustainable over 10k ft mountain passes and see lower IATs, so I plan to keep the same boost levels, but remove the boost valve from backing off the engine when I go over the passes, since I was at the limit for the old turbo.
Was:
1998 ALH, 11mm pump, 3 Bar map, .216 nozzles, Malone custom tune, stock VNT-15 turbo, cone-style air intake, stock pancake pipe on way to intercooler, stock intercooler

Now:
1998 ALH, 11mm pump, 3 Bar map, .216 nozzles, Malone custom tune (same as from before), tacotaco intercooler, donaldson airbox, new VNT-17 turbo, new 2 inch piping to intercooler (removed pancake pipe), replaced all vacuum hoses, new n75 valve

Verdict:
Everything works great, with nice boost, good airflow, lower EGTs, a bit more lag with the increased volume of intercooler piping, bigger intercooler, and bigger turbo. I live at 5500 feet of elevation, and the tune is set for that.

Problem:
in 4th gear, when I accelerate, I get a 1550 code and limp mode. This happened even more as I went to higher altitudes. Bummer!

Question:
Is this indicating that I really need Mark to update my tune (it is in the works) or might there be something else that I have not thought of?

Thanks in advance,
-macjack
 

MacAndrew_Jack

Well-known member
Joined
Oct 21, 2005
Location
Colorado, United States
TDI
Vanagon Syncro Weekender
So I haven't had a chance to test it out yet, but I did find that the vacuum hose I used for between the n75 and turbo actuator might have been slightly too big. At the n75 end it was good, but the nipple on the actuator is much smaller than the on the n75, and the hose just pulled off easily. I had used some vacuum hose from the hardware store that was not metric and it looked like the right size, but perhaps the lesson is that it really needs to be pretty exact when dealing with vacuum hose, especially at higher altitudes where the air is less dense and can leak easily.
I will report later if replacing it has gotten rid of the code 1550-throwing.
-macjack
 

MacAndrew_Jack

Well-known member
Joined
Oct 21, 2005
Location
Colorado, United States
TDI
Vanagon Syncro Weekender
pumps, nipples, oh my!

For those who might stumble across this thread (even though no one else is replying, SOMEone will need to learn from my experience), I am posting the ongoing story of this one.
After replacing all the vacuum hoses after the vacuum pump and still getting the 1550 code, I finally actually put a mityvac on the system. Well, right near the vacuum pump I was getting 15 in hg, where I believe I should be getting 25+. Then I wiggled the nipple coming out of the pump and yes it was very loose and it would change the vacuum readings. I read on this fine forum about people having problems with this nipple, but usually there are some accompanying break problems. I have not noticed the brake problems, partly because I am not driving aggressively since the code is showing up. And perhaps 15 in hg is enough to drive the brake booster but not the turbo actuator to the pleasure of the ECU, hence the code. I read about people JB welding the nipple and also about using black RTV silicone maker. I think I misunderstood how people are using the RTV, since after smearing it on the outside, I see that people actually put inside the seam between the nipple and the pump housing. The nipple, at least for an ALH, is designed to rotate in the housing, but this seal can eventually fail. It is not officially serviceable, and the pump is $200+.
At any rate, I will let the RTV set overnight, hoping that it will get me by until my new pump comes from Kerma. $*gulp*$.
I sure hope this does the trick.
One lesson I am learning is actually use diagnostics, in addition to using common sense. I was reluctant to start checking vacuum pressure, but I think it is much more pinpointed identification of the problem this way. BFO, I suppose. Mityvac is your friend with vacuum systems.
I hope this helps someone else, and I'll post the updates.
-macjack
 

MacAndrew_Jack

Well-known member
Joined
Oct 21, 2005
Location
Colorado, United States
TDI
Vanagon Syncro Weekender
RTV helped. I now get 25 in hg in the line, but the nipple still moves (I only let it cure for 18 hours in 40 degree temps), and I still don't think that it is really "repaired" sufficiently. I can drive it without getting the code, but if I repeatedly give it WOT, eventually the 1550 code returns.
I await a package from Kermatdi.
-macjack
 
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