[downhillboss]

OK, So I was driving out from phoenix yesterday to las vegas and a problem happend. After i was cruising along at about 80 or 90 or 100 for about an hour and a half i came to a steep grade. At this point the engine temp was still 190 and stayed the same forever. But when i came to this steep grade, i just starting lossing speed. Lots of speed. From 80 down to about 40 in 3rd gear with about 3k rpm. I then pulled over and checked oil levels and opened up the fill hole. The oil level was a little low, but some smoke came out of the fill hole, not a lot but enough to worry me. So i filled it with some oil i had in my trunk 5w-40 syn cumming oil. The same stuff i use for oil changes. We shut the car down and let it cool down for about 10 min keep going. When i turned it back on it sounded like there were no turbo noise, which would make sense if the turbo died, i would have no power. Anyways, we kept going, about 2 miles later the check engine light came on, We pulled over and let it cool down for about 40 min. We turned it back on: Turbo noise and Turbo power! We decided to turn around and not risk getting stranded in the desert. The whole way home it ran fine, we were just crusing with low trottle pressure. Once we got home the check engine light had gone away.
Tell me if i'm wrong this is one of the two things i think could be happening.

1. High temp oil induced excessive oil pressure. Which the ECU picked up on. Rather than risking distroying the turbo, the computer lowerd boost pressure to a min. Or turned the turbo off. When the Oil temp went town i recognized that the pressure was lower to and "restarted" The turbo.
2. High oil temp, and light weight oil at high temp caused a lack of lubrication between the turbo shaft and the bearing, it seized up and stopped working. The computer recognized that boost pressure was wrong and turned on the check engine light. After cooling down and restarting the turbo worked but the bearings were screwed up, so it basically limped home.
Its a 2000 TDI runs 5w40 oil in Phoenix AZ it runs fine for short trips like city driving. This problem only occured after running for hours and hours at a high speed in the desert. It has 75k on it too.
I would Vag com it, but don't have a vag com yet or else i could see why the check engine light came on. Since i got home it hasn't been run.

 

[GoFaster]

Re: TDI engine problem. HELP NEEDED (downhillboss)

You need to scan for codes ...

 

[downhillboss]

Re: TDI engine problem. HELP NEEDED (GoFaster)

ok i Got the code its p1556

 

[Mass. Wine Guy]

Re: TDI engine problem. HELP NEEDED (downhillboss)

I did a search on tdiclub.com and got this:
p1556 Charge Pressure Control Negative Deviation

I don't know what this means, but one person stated it involves the onboard computer not getting the amount of boost (turbo boost, I presume) it expected.
You may want to go to tdiclub.com one early evening and join the chat to get more information. That's usually when people are there.

 

[cooleremail]

Re: TDI engine problem. HELP NEEDED (downhillboss)

Quote, originally posted by downhillboss »

We shut the car down and let it cool down

Something seems wrong with this statement... Whenever I try to cool my car down, I let it idle for a while, keeps the vital engine oil flowing to hot components...

 

[downhillboss]

Re: TDI engine problem. HELP NEEDED (cooleremail)

Ya i already checked with TDIclub.com .Hopefully somebody replys with something that i should be able to check something so that it works and stuff. As for the engine cooling down, the only probelm with turning it off is that i starve the turbo for oil. But thats why you need a turbo timer and stuff. I really need to know what to check inorder to get my TDI working. Cause i need to get back to Las Vegas and stuff. Thanks

 

[downhillboss]

Re: TDI engine problem. HELP NEEDED (downhillboss)

OK so i checked out everthing today. The N-75 valve seems to be operating OK. It moved freely and didn't bind anywhere in its stroke. The linkage that connected it to the turbo seem to be ok as well.
But, i did notice when i pulled off the piping that goes to the little EGR throttle linkage that connects into the intake manifold, that there was a noiticable amount of "oil" in the piping. So does that mean that my turbo is leaking oil passed the bearings and into the intake side of the compressor?

 

[DEZLJET]

Re: TDI engine problem. HELP NEEDED (downhillboss)

It's tough to diagnose cars not present but this is totally dejavu to me and a converstion I had with a VW tech last week. He had a 02 TDI with 40K miles that was being a headache to him. It had come in with lost power intermiitent and threw a code of a bad MAP sensor.
He replaced the MAP and problem still occured, it would run fine for awhile but then would pop back up. Next, he tried replacing the ECU but the problem popped back up again. So he makes a call to me and I ask him if he's tried the N-75.
He says no, and then asks me why I would think that? So I explain it to him and he reluctantly tries it and guess what?
It fixes it.
The leson learned there is the ECU brains/processor and it will like a computer send out orders as it sees fit but the problem is garbage in and garbage out. If the ECU is getting bad poop from one solenoid that doesn't readilly show it's bad, it can throw the whole operation into a canundrum. Verstehen?
Turbo's are expensive, a N-75 costs about $50.
Try changing it, if it doesn't fix it, you can sell it in the classifieds, I'm sure someone in need of one will swoop it up.
My guess is, when you went to make that long hill you sent the system ops over the top from high demand and a N-75 that is no longer doing it's job. A bad N-75 can get along just fine in the system for awhile but sooner or later it will show it's ugly head, the challenge is to see it when it camoflauges itself so well within the sytem.
From the sound of it, you probably could use a good intake-EGR cleaning, I hope this is not the source of your problem but it could be. Worst case for that is your going to spend one messy day in the garage cleaning it as most techs won't touch that job and they prefer to order all new components and hand you one helluva bill for them changing some parts out and getting hands dirty.
These cars are called oil burners for a reason, a well used TDI will have oil all through it, particularly if you haven't done things like CCV mods or EGRectomy's etc...
I may be wrong but I think you might be getting a little frantic about the turbo that's not warranted.

 

[genau]

Re: TDI engine problem. HELP NEEDED (downhillboss)

Quote, originally posted by downhillboss »

But, i did notice when i pulled off the piping that goes to the little EGR throttle linkage that connects into the intake manifold, that there was a noiticable amount of "oil" in the piping. So does that mean that my turbo is leaking oil passed the bearings and into the intake side of the compressor?

I believe that DIZLEJET already said this but just to clarify further, there should be a small amount of oil in your intake. It's not coming from the turbo it's coming from the CCV (crank case vent). That oil in the intake is how the car is supposed to run when stock and the only negative side effect is that, that oil when baked by the heat of EGR it tends to cake up and eventually lead to intake manifold restriction. One last bit for posterity, while a small quantity of oil in the intake is normal - too much is far from it and can lead to what is referred to as a "runaway" condition, when the engine is literally feeding on that oil and it goes nuts (if you're experiencing this condition - you'll know it, that is if you can get your motor to shut off before it kills itself). just FYI.

 

[downhillboss]

Re: TDI engine problem. HELP NEEDED (genau)

thanks for your help.

 

[rorabeck]

Re: TDI engine problem. HELP NEEDED (downhillboss)

this might be interesting http://forums.tdiclub.com/show...art=1

 

[KERMA]

Re: TDI engine problem. HELP NEEDED (DEZLJET)

Before you spend the bucks on a new N75, try swapping it with the N18 to see if that fixes the problem. These are the two solenoid valves on the firewall, one has a black cap, the other has a white one. Can't remember which is which, but ne ontrols the turbo and the other is the EGR control. There are some diferences between them that some will point out, but they are functionally interchangeable. just be sure to mark the vacuum lines. Fairly quick and easy and cheap test.

 

[downhillboss]

Re: TDI engine problem. HELP NEEDED (KERMA)

good point maybe i'll try that today.

 

[T700mech]

Re: TDI engine problem. HELP NEEDED (downhillboss)

Hope you didn't spend any money yet... I had a similar thing happen to me, on mine the turbo noise would kick off in the middle of going up a hill, and lose all kinds of power, almost an unsafe condition if your'e trying to pass someone. Anyway, I researched on TDIclub (awesome site) and decided I needed a new MAF, waited a week for it to come in from Germany and was so happy when I put it on, I was sure it fixed it, well no joy, it did the same thing 5 min. later. Anyway, I ended up cleaning the intercooler and it works much better now, I pulled the top rubber hose off as close to the engine as I could, and the bottom rubber hose off the back side so the water would drain, poured some boiling hot water down there, the first time it would barely drip out, after four or five times I couldn't pour fast enough. use HOT water and give it time to drain and dry out a little bit, if it doesn't work you're out an hour of workand some water. Good luck.

 

[downhillboss]

Re: TDI engine problem. HELP NEEDED (T700mech)

thanks for the advice, i'll check that out. im suprized that your problem was solved by a simple cleaning of the intercooler....... But i would take that over buying new parts

 

[Godlike]

Re: TDI engine problem. HELP NEEDED (downhillboss)

this may be a dumb question, but if the engine is being flogged this hard, wouldn't the oil in the i/c be blown clear by the heated are that is moving pretty rapidly?
if so, i can't see that causing the problem...

good luck, man.

 

[downhillboss]

Re: TDI engine problem. HELP NEEDED (Godlike)

oil doesn't like burning, so i would think that the heat in the intake wouldn't be enough to "melt" it away. Also the intercooler would also cause it too cool to the point that nothing would happen, i would think.
THE PROBLEM GETS WORSE!!!!!!!!!!!!!!
My room mate was driving it today and told me that the car wouldn't go over 2k at all for about a minuete..... I think it might be related. Because this is what it did right before i pulled over when i had the intial problem.

 

[weedeater1]

Re: TDI engine problem. HELP NEEDED (downhillboss)

There IS such a thing as fuel starvation.
When was the last time you changed the filter?

 

[downhillboss]

Re: TDI engine problem. HELP NEEDED (weedeater1)

its not the fuel filter.....
I fooled around with it tonight..... The problem was fixxed until i unfixxed the N-75 valve. I broke it while trying to take off my manual boost regulator...
Heres a link
http://forums.vwvortex.com/zerothread?id=1207138

 

[rorabeck]

Re: TDI engine problem. HELP NEEDED (downhillboss)

I know I get the same problem when the temp get really cold! when it is -5 to -10 it works great! Anything cooler and it will go instantly into limp after about 5 mins of 3000 rpm and then constantly after that its about 20 sec of 3000 rpm. I think its the intercooler clogging since there are no leaks in the vac lines.