Newby with limp mode issue

[GrapplingDMC]

Ok I put this in the wrong section & was told this is where it goes so hopefully someone here is familiar with this issue:
I bought a 1997 Passat TDI wagon for $600. Test drove it & no issues but on the way home it went into limp mode. When I started the next day, issue was gone then came back on. I believe it has happened 3 times & all at freeway speeds. No check engine lights. The motor has 267k on it. Power on it when not acting up I am more than impressed with. I took my Edge 2 controller and plugged it into the TDI but it does not seem to read the boost and was no VW to select, just had to click "other". Not sure if there is an update that can do more, I will look. The car had some motor work a little over 30k ago: Crankshaft, rod bearing set, crackshaft gear, front & rear seal, main bearing set, lower timing cover, clutch disc, release bearing, oil pan gasket, boot, connecting rod bolt, seal/flange, timing cover. There was some screws, bolts & lube too. The other thing is 5th gear is out. Where do I start on troubleshooting? I will buy a code reader if it helps. If so what would be a good one with out breaking the bank?

 

[Steve Addy]

Since we don't really know what other things are going on the first thing I would check would be the small hose inside the ECU connecting to the MAP sensor. They are known to develop holes after a while. At the same time you can verify which ECU you have...it should be silver cased FA since the car is 97 but you never know what you'll find depending on who touched this car over the years.

Your best tool for this will be VCDS by Ross-tech, you will get limited info from the other devices. If you can find someone local with one you can save yourself the initial need to purchase.

I've never known a 02A trans to lose 5th but I suppose you could, but before I declared it dead I'd be checking to see if the linkage was setup properly. Since all that came out for a clutch not that long ago I would want to verify before dumping in another CTN transmission.

Steve

 

[GrapplingDMC]

Since we don't really know what other things are going on the first thing I would check would be the small hose inside the ECU connecting to the MAP sensor. They are known to develop holes after a while. At the same time you can verify which ECU you have...it should be silver cased FA since the car is 97 but you never know what you'll find depending on who touched this car over the years.

Your best tool for this will be VCDS by Ross-tech, you will get limited info from the other devices. If you can find someone local with one you can save yourself the initial need to purchase.

I've never known a 02A trans to lose 5th but I suppose you could, but before I declared it dead I'd be checking to see if the linkage was setup properly. Since all that came out for a clutch not that long ago I would want to verify before dumping in another CTN transmission.

Steve

I will verify that stuff tomorrow since I have to leave soon. I can jack the car up & check linkage but I only bought the car for a motor conversion. I just want to make sure the motor is correct before I do the conversion. Having a good transmission would be great to sell though. I decided to see if I could make the issue repeat. Under usually 80-100% acceleration load it happens but not always right away. I will do more acceleration tests on the way to town here in a minute. No smoke when it happens. My thoughts are a pre turbo leak maybe but I am about 4 days into TDI stuff. Any thoughts?????

 

[GrapplingDMC]

I just ordered a Foxwell NT510 Elite. I hope this will do the trick. After it comes in I will run the diagnostic & come post what I find

 

[Steve Addy]

If you're honestly doing a conversion IDK why you're bothering with any of this. The limp mode condition is unlikely to have anything to do with the engine internals. It's more likely to be a fault in the pressure lines or boost control lines, and all this will likely be changed for the conversion.

Steve

 

[GrapplingDMC]

If you're honestly doing a conversion IDK why you're bothering with any of this. The limp mode condition is unlikely to have anything to do with the engine internals. It's more likely to be a fault in the pressure lines or boost control lines, and all this will likely be changed for the conversion.

Steve

Ok if you think it will be a good idea to change those lines I will & just start the conversion. I just want to do things right. I did order a Foxwell 510vt elite or something like that to check for codes. I will check codes on Tuesday when it is here then just start the conversion. Still need to order the conversion kit though but the company is not too far away

 

[GrapplingDMC]

I ran the test & code ID: 00575 Status: sporadic Regulating difference Description: Intake Manifold Pressure - sporadic - Regulating difference
popped up. Cleared it, drove around no codes put my foot vin a little until about 60 & nothing, hit about 70 & limp mode came on & code popped. Anyone have experience with this?

 

[DivineChaos]

Being that's not a vw specific code. Brant the requested and actual boost is off. So it could be n75 actuator, a sensor, the vanes. Maybe the maf, boost leak.

 

[GrapplingDMC]

Being that's not a vw specific code. Brant the requested and actual boost is off. So it could be n75 actuator, a sensor, the vanes. Maybe the maf, boost leak.

I will start with the n75 actuator since I hear it is a common part to go out & should carry a spare (soon as I figure out where it is LoL), then vacuum lines since I planned on replacing them with the motor conversion anyway....unless it is suggested I start somewhere else by someone who actually knows what they are doing which is probably everyone here except me

 

[ToddA1]

We don’t have vanes, in this forum!!!

Look at the firewall and look for something with red, black and blue vacuum lines. That’s the n75. Theres a low power sticky, that’s gets into 00575. if you’re lazy and don’t want to read it or go though the steps, with VCDS (me), here’s my quick checks…

Do a visual for boost leaks.… greasy connections.
Then start with the vacuum lines, including the one in the ECU.
If that doesn’t fix it, try cleaning out the n75 with brake clean and air.
If that doesn’t fix it, get under the car and exercise the wastegate lever and hose it down with lube.

At this point, I’d bet it’s fixed, and it only cost you free time and a fast food meal. The link below has 2 posts where I recently did the above steps, and fixed my limp mode.

The "What did you do to your B4 today" thread...

Rotbox, you served me well, good friend. You’ll be able to peacefully rust away at the big scrapyard, in the sky... Well, someone came out for the IP and tail lights, yesterday. It started flawlessly, in front of the buyer. It’s officially a part out, now. Seems it’s always the top dp...

forums.tdiclub.com

-Todd

 

[DivineChaos]

We don’t have vanes, in this forum!!!

Look at the firewall and look for something with red, black and blue vacuum lines. That’s the n75. Theres a low power sticky, that’s gets into 00575. if you’re lazy and don’t want to read it or go though the steps, with VCDS (me), here’s my quick checks…

Do a visual for boost leaks.… greasy connections.
Then start with the vacuum lines, including the one in the ECU.
If that doesn’t fix it, try cleaning out the n75 with brake clean and air.
If that doesn’t fix it, get under the car and exercise the wastegate lever and hose it down with lube.

At this point, I’d bet it’s fixed, and it only cost you free time and a fast food meal. The link below has 2 posts where I recently did the above steps, and fixed my limp mode.

The "What did you do to your B4 today" thread...

Rotbox, you served me well, good friend. You’ll be able to peacefully rust away at the big scrapyard, in the sky... Well, someone came out for the IP and tail lights, yesterday. It started flawlessly, in front of the buyer. It’s officially a part out, now. Seems it’s always the top dp...

forums.tdiclub.com

-Todd

Ah, wastegate not vanes. Still an n75 so part right. Still wrong though. Eh, it's how I learn.