Limp mode - Pressure issue

[shazzydoosh]

Hi all.

Im a total newbie on this site, but have posted this question on other forums.

My 1999 (Mk2) Toledo TDI (110) SE has occasionally gone into Limp mode when flooring it up hills etc. Usual engine off / on fixes it. I had someone look at with Vagcom and it was a pressure related fault - but the part number was for a pressure sensor, and the mechanic said it didn't realy tell us much.

I want to go down eliminating the obvious first. I have seen a lot of people (mainly with petrol engines) replacing the N75 valve, and in some cases fitting the N75J from the Audi A2. Apparently this holds boost smoother and slightly higher than Seat stock fitted ones.

I have one of these N75J valves from Vagparts - but can it be fitted to replace my standard one on a TDI. It does the same thing in essence, but it does look quite different - even if I get around connecting the hose's - im not sure if it is designed for a TDI and if it will Kill my turbo etc.

Can someone tell me if It can be fitted, and anyone ever done it? I dont care if I get no gains, but it will eliminate my existing N75 or Pin point it as the fault if it works.

cheers

Daz

 

[sssstew]

no, you have a N75 for a petrol car if your talking about J's etc, this is not the same as the TDI N75s, you cannot use this. You need a standard replacement N75 for it.

do you know what the exact fault error was that was recorded?

 

[shazzydoosh]

I can't remember the exact code now, and the mechanic has cleared it. But it said something relating to the pressure, and he checked his book and the part code was for a sensor he said, and that it didn't point to where the problem was.

As it is intermittent, and tends to happen if i've been doing a lot of city miles, then move to motorways etc, i thought maybe the VNT vanes were sticking - but would this be a pressure fault in VagCom????

So this N75 J is totally incompattible (it has the same conectors, just arranged differently - i guess i was hoping for too much) ?

Ive also read about the EGR valve sticking etc, but he does not agree, and when I point out the experience of others, and why the EGR caused this, he is not very receptive (understandably as i know nothing about cars, and he is quite a good mechanic). any advice is much appreciated.

I dont want to take it to Seat as I hear theyre not always the best, but are always the most expensive. Not sure what other options I have in Plymouth

 

[sssstew]

yep, im thinking sticky vanes, this would cause the pressure deviation error messages, overboost as it cant crank the vanes back intime to reduce the boost.

A sticky EGR would not cause boost pressure problems.

 

[shazzydoosh]

what can be done about that? Im not noweledgable to take it apart myself, and the mechanic seemed unkeen on the idea (not sure if he knew how).... any ideas?

Is this N75 J I have totally useless to me then

 

[sssstew]

yep, sell the J on.

the strip and clean of a turbo is not a difficult job, very commonly done, theres even guides on how to do it on tdiclub.com. i would find a turbo specialist if i were you.

 

[shazzydoosh]

Cheers. I have seen the guide, but definately not something I could do myself (well, I probably could, but id knacker something in the process and it would take me 4 times longer than a mechanic). Any idea how much someone would charge for this sort of thing.

Also, anyone out there on the forum know of anyone in or near Plymouth that can do this (any decent garges etc)

cheers

 

[sssstew]

ask Devonmikeyboy on here, he might know somewhere.

 

[shazzydoosh]

Thanks. But next question, how do i ask him???

Found his profile, but there was no "send msg" button etc... can't find a way to pm him? Im new to this site, what am i missing

 

[devonutopia]

Are you sure it's not a dicky pressure sensor (thrust sensor) ? I had to replace mine which sorted out pressure deviation fault codes I was getting.

 

[shazzydoosh]

Devonutopia,

Thanks for the info. Im not sure. I figured if it was the sensor then it would be more frequent. The fact that I only get it when I boot it on the Motorway up a hill, after weeks of city driving was making me think sticky vanes in the VNT.

How much are they to replace on the AHF TDI (110)? Any ideas where I could source one from?

If it is the Turbo, is there anyone in Plymouth, or just South devon in general that you could reccomend for cleaning it and at what cost.

Sorry for all the questions, and thanks for the original reply

Daz

 

[devonutopia]

If it is the Turbo, is there anyone in Plymouth, or just South devon in general that you could reccomend for cleaning it and at what cost.

Sorry for all the questions, and thanks for the original reply

Daz

Not sure, but if you need the car scanning again to see what fault codes pop up, then I'll do it. I'm based up Dawlish way though.

 

[shazzydoosh]

devonutopia,

I was just sorting out some paperwork and found a copy of my fault code list. The code is as follows:

17958 Charge Pressure: Controll Deviation
p1550 -35 - 0 (or D, cant read it)
Intermittent

What you think? Could it still be the Turbo Vanes, or could it be the pressure sensor? Could it even be the N75 or something else?

Even if I knew what it was, I wouldn't know what to do about it

Daz

p.s. was playing around with a copy of VagCom myself a while back and logged the following (unfortunately the fault did not occur at that point)

Group B: '011
Engine speed Specified MAP Actual MAP Duty cycle
Group C: '020
RPM Inj. Quantity Voltage Load

I was hoping I could match the time stamp with when I noticed it go Limp, but it never went limp. Would they be any use to anyone though in identifying a potential fault? I have the file

 

[devonutopia]

Sounds like a similar fault to what I had. If you can get a new boost sensor, you could try swapping them over and seeing what happens. If it does nothing, well, you have a new spare sensor then.

 

[shazzydoosh]

So you don't think it's the vanes or N75?

Any idea where I can look for one of these (apart from the stealers) and estimate of price?

 

[sssstew]

i would get the new sensor from vagparts.com i bought my N75 from them some time ago and they were good.

still could be a vanes but swapping the sensor is a start