Post Remap Issues

[johnnyj]

Hi guys,

As per the title of the thread, I've been having some issues following getting a generic remap from Jabbasport the other week. It wasn't till I was most of the way home I started getting quite a few little symptoms which include stuttering/jerky in 30-70% throttle positions and jerky on lift-off. Strangely at full throttle positions there's no issue, but I can't drive like that everywhere!

So I got in contact with Jabba and they stuggested a few things it could be:

1. Boost leak

2. DV

I guess it could possibly be the N75 also.

In terms of the checking of option 1 a boost leak they suggested doing a smoke pressure test. Anyone ever done one or have an idea of the best way to do one? Also anyone suffered similar symptons and managed to solve them with a certain fix?

Thanks

[Chris B]

I had this issue with a Apr remap ,I went through the list of changing the maf ,n75,D.V.and cleaning the throttle body the only thing that I found really helped was the replacement of the N249 even though it tested OK hope this helps

[Guest westallc]

i would suggest you drive it for a few days first and let the ecu find its feet ( self adapting ecu ) so give it a week if still the same then get vag com on it and do some logs to pinpoint the issue

DO NOT just start changing parts it will cost you money and they might all be okay

hope this helps

[johnnyj]

Thanks for the responses guys.

It's been nearly month since the remap and unfortunately it's only getting worse. What was just about noticeable is now at the point where the car isn't much fun to drive. As you said Westallc I'm really trying just to avoid changing loads of bits and racking up the bills. I was hoping perhaps there was a clear route to fixing the problem but the list is growing.

I've heard that the N249 was another possible culprit as I believe it controls the DV. I guess it's time to find someone with Vag-com or possibly pop down to JKM for some troubleshooting.

[Bogwoppit]

Assuming you are still running the standard DV (which is prone to failing if mapped). Take your DV off and try a leak test on it to see if the rubber diaphram is split.

Follow the intructions on the last page of this pdf : http://www.forgemotorsport.co.uk/valve_service.pdf

Edited 2 October, 2010 by Bogwoppit

[bettsy]

this thread has got me a little worried.

after considering all the options i had finally decided on a jabbasport stage 1 remap.

have i chosen the wrong company ??

has anyone else had issues with theirs ??

[Jonny5ive]

Thanks for the responses guys.

It's been nearly month since the remap and unfortunately it's only getting worse. What was just about noticeable is now at the point where the car isn't much fun to drive. As you said Westallc I'm really trying just to avoid changing loads of bits and racking up the bills. I was hoping perhaps there was a clear route to fixing the problem but the list is growing.

I've heard that the N249 was another possible culprit as I believe it controls the DV. I guess it's time to find someone with Vag-com or possibly pop down to JKM for some troubleshooting.

Surely it's worth talking to Jabba in the first instance?

[johnnyj]

Thanks for the link Bogwoppit. I took the DV off today and turns out that's not the issue. The piston stays up - no leak there. Those one-off clips are a right pain to get off though!

I have spoken to Jabba and it was them that suggested it was either a boost leak or possibly the DV. The only problem is Jabba is 2.5 hrs drive away so not really preferable to have to go all the way there again. In an ideal world I would get them to look at it as they did the remap. Unfortunately, it just appears that as with many people who have remapped their cars, the extra boost has highlighted a weak spot that I now need to track down.

I did some research and found a how to guide on you tube to do with boost leak checks? Anyone done one on a 1.8T?

[peppyuk]

Alright Jonny,

I see you mention JKM, where are you based? I have access to VAGCOM, if your not to far away I can do a scan on your car.

[johnnyj]

Thanks for the offer peppy. I have a mate who has some OBDII software that an simply scan codes so that I can do. Westalllc earlier in the thread mentioned running data logs with vag-com. I'm not at all familiar with vag-com. Do you know what data can be logged with vag-com? And if you were willing to help with that I'd appreciate it.

Cheers.

[peppyuk]

Johny, I've never done anything more than read codes. The version I have access to is very old and not registered so I doubt it will do anything fancy.

[johnnyj]

Ok, thanks all the same.

A mate seems to think that what I might be experiencing is boost surge as a result of the N75. There don't seem too many conclusive threads about this. The search continues...

[karlbar2k]

What you are going to have to do is work through some things before you start spending money.

1. get is scanned with vag com and post your codes.

2. As Clive suggested you need to run some logging - even if it is just block 32 on the engine module

3. Bean Can Boost Leak tester not the best way but the cheapest fix any leaks (boost and vac leaks can show up if you use this method as it goes into the TIP)

4. Throttle Body Clean, cost of a gasket and some carb cleaner

5. Borrow a known good N75 for a trial run. only replace if it solves your issues.

6. N249 Bypass (can help to smooth surging issues) Why replace a valve when you can "Delete It" :D

7. your into checking plugs and coilpacks and other things if you still have issues, OR you need a different map?

I had some issues with my Generic stage 1 map and swapped various bits which improved things but the map needed tweeking to get rid completely so always keep that in mind before spending out. HTH

[paramaniac]

Mine did this immediatly after a jabba generic map, the boys at jabba traced it to a faulty coil pack.

The car was fine as standard & the remap highlighted a weakness.

After Jabba replaced the coils it was fine.

[johnnyj]

Thanks guys for the suggestions. Some data logging was next on my list anyway so we'll see how that goes. I'm intrigued by the "Bean Can Boost Leak Tester"... care to elaborate? I've been trying to find a cheap improvised way of doing a boost leak test so I'd be interested to hear exactly how that works?

[martziniuk]

For Jerking in the 30-70% load range I would be looking at cleaning the throttle body, this can make a big difference especially on a high mileage car.

[The Skud]

I'm surprised that no one has mentioned the MAF, try cleaning the sensor with Electrical cleaner if this improves it replace it.

[SideshowBob]

How are you getting on with this one?

I'm watching this thread with interest since my stg1 mapped vRS also has pretty much the same symptoms.

I've not had much time recently to do any troubleshooting, all I've had chance to do was a fault code scan but there are no faults logged.

At the moment it's starting to ruin my enjoyment of the car a bit, since it happens on a light throttle which is where you tend to be most often.

My MAF seems sound, it was analysed a couple of weeks ago when I had an emissions issue at MOT time, and was found to be ok. Hopefully I'll be able to do a logging run soon, but I could do with guidance on what measuring blocks to log?

[johnnyj]

Well, unfortunately I have not been able to do any data logging yet because I asked a few people locally who were listed for having vag-com, but no responses so far. I'll keep pestering and hopefully someone will be kind enough to let me steal some of their time (& vag-com!)

However in the meantime I scanned for codes and surprise, surprise nothing! So as I know the diverter valve is fine and I'm pretty sure it's not a boost leak as I would expect much more noise from anything that could have that much effect on my car, I started looking into the N75.

Firstly I did a check on the hoses going from the N75 to make sure there were no leaks there. I just did this by inflating the hose going from N75 to the wastegate until the wastegate piston moved and clamped it. This showed that the piston/diaphragm on the wastegate was working fine and there were no leaks. There were no leaks from the hose coming from the high pressure side of the turbo to the N75 so I moved onto the N75 itself.

The default position for this N75 valve is that air passes from the high pressure inlet down the output to the wastegate. By blowing on the appropriate ends of the N75 i confirmed this to be the case. I then noticed and had heard about a screw on the N75 that could adjust the position of it! So with nothing to lose I adjusted the screw by turning it 1/8 clockwise. This was jammed pretty hard and didn't really want to force it, but I managed to get a bit over an 1/8 of a turn out of it. Have a read of this thread on seat forum: N75 valve

And the result.... after a few days driving it's been better. Much less jerkiness and stuttering. The N75 valve is either open or shut and has no intermediate position so it regulates high pressure air going to the wastegate in some instances by quickly opening and shutting the valve which I believe may be the cause of the stuttering. If the N75 valve was being allowed to open to far and not able to react quick enough opening and closing this could very well be the cause, but because I cannot adjust the N75 anymore as I would be likely to break it my mate had an idea to prove the theory. I'm going to buy a flow control valve to put in series with the outlet from the N75 to air intake (low pressure). By restricing the vent to low pressure it would have the same effect as reducing the amount the N75 valve can open. Restrict the flow too much and I lose boost (wastegate opening early) but get it just right and stuttering should be eliminated but maintaining current peak boost.

I'll let you know how it goes....

[martziniuk]

Jeez I wouldn't mess with the N75 well not again in my case lol, gave less power and never felt right again, bought a new one in the end. I can't believe you haven't tried to clean the throttle body yet! it's practically free to do and may solve your issues rather than messing with the boost controller which is set at the factory.

Get some carb cleaner and give it a go.

[SideshowBob]

I cleaned my throttle body a couple of months back when I decided to try and cure the surging problem. To be honest it was very clean already, with only a small amount of gunk on the inside face of the butterfly.

In my case, it made no noticeable difference, still worth doing though so you can rule it out.

[peppyuk]

I cleaned mine a month or so ago, pretty quick and easy to do, and made a differnce to mine. If your local enough and need some pointers I can normally find a little free time on a weekend.

[johnnyj]

Yeah I suppose as it's free there's no harm in giving it a shot, but I'm pretty confident it's not related to that. When I have a moment I look into it. I'm sure the Haynes book of lies will guide me a long the way but thanks for the offer. If I have any issues I'll give you a message.

Cheers.

[johnnyj]

So I think I have tracked down the cause of the problem... as I mentioned in a previous post I said I was going to buy a flow control valve to put in series with the outlet from the N75 to air intake (low pressure). The hope was that by restricting the vent to low pressure it would have the same effect as reducing the amount the N75 valve can open which I believed to be the issue.

Well this weekend I modded the N75 fitting to put the flow control valve in and to my surprise it worked just as expected. With the valve fully shut the car drove around with min boost but most importantly it was as smooth as you like! With the valve fully open the car runs with max boost but with the stuttering back again.

So now I've been able to adjust the valve to allow the maximum peak boost possible without the stuttering. So I have the smooth power delivery back but I think I'm a bit down on peak boost. Now I just need to figure whether a new N75 valve will actually solve the problem whilst still allowing me to reach the peak boost of the remap.

I'll let you know what I find out.

[johnnyj]

So, after a lot of research and checking for this and that I have finally tracked down the cause of my stuttering woes.

In the end it turned out to be a very large split in one of the inlent manifold oil breather hoses. This large split was venting high pressure air and now replaced seems to have been the whole cause of the issue. I would have detected earlier if I had a smoke leak test done earlier on it. In the end it was Kevin at Jabbasport who tracked it down for me so big thanks to him.

The particular hose on my 2003 Mk 1 Vrs causing the issues is the 'S' shaped hose shown in the digram below which had a 2 inch long split in it. The part number on my car was 06A 103 221 AF which has now been replaced by 06A 103 221 BK (£13.10 from VW dealer). The pipe in connected to underside of the inlet manifold and hard to get to but there's a post in the following link that shows a good shot of where it is: Breather Hose Location

In addtion to this I also had a split on the 'Y' hose shown in the above diagram, but I believe this is on the lower pressure side (I think there's a one-way valve down stream to stop high pressure air getting to this pipe) and so wasn't a massive issue. For info this was 06A 103 221 AH and is replaced by 06A103 221 BH (£30.54 from VW dealer).

I strongly advise anyone who has similar problems as discussed at the beginning of this thread to check out these hoses. They're a common issue and well worth a check. Afterall they're cheap and pretty easy to replace. It's a confined place where they are and you'll probably lose a bit of skin off your knuckles but well worth the sacrifice!

Thanks to to all that helped along the way.