The old hesitation after remap problem

[bjorn]

Well up until today it still wasn't sorted (pulsing/hesitation) and was planning to go up and get the car live mapped next month - in the meantime I thought I'd try the simple 'Bypass N249' mod as it's something that has been discussed a fair bit on the SEAT and Audi forums and seemed to be successful for them (with similar symptoms to me)

I didn't remove the valve completely (as I thought I might need to re plumb it in) so I just re-routed the vaccum line from DV to inlet (excluding the whole N249 set up) and all I can say is it's 90% better - I would go as far as to say it's gone completely! Part throttle there is no hesitation/pulsing of boost, full chat it's great I do get a slight boost drop but I put that down to turbo/actuator being worn or the car is actually controlling boost as it should.

I'm well chuffed - and thing is it's only a 15 min job that is reversible if it doesn't work out!!

[Lex Dysia]

Any chance of some pics as to where you plumbed it in. I take it you used a T-piece to connect it? Been thinking about this but don't know where to feed the line from :confused:

[martziniuk]

Glad you eventually got it sorted Bjorn, it certainly been a long drawn out problem.

Lex have you got problems too?

[Lex Dysia]

Sometimes on part throttle I have heard what sounds like the DV dumping at about 3500 rpm accompanied by what I can only describe as a blip in power. I figured bypassing N249 might cure this. Done a scan and no DTC's present, was expecting the dreaded 17705.

[martziniuk]

Try it and let us know, mine dumps on part throttle too although it has no side effects. I have not heard mine since taking the CAI off though.

I know of a few others that have heard theirs dumping on part throttle too, i thought it was just the way the car was supposed to work. After all the excess boost has to go somewhere even if you aren't flooring it.

There are plenty of threads on Scn about the n249 bypass.

[gmaster]

I have this problem too on a standard map! been getting worse lately, ran vag-com no fault codes where found! I've replaced the dv and N75, though just recently now and again (mostly when cold) say in 3rd gear at low revs it wont pick up and stutters and what might be a misfire, could this be early sign of coil packs?

[martziniuk]

Or secondary air pump. Mine occasionally sounded like a misfire but when cold only.

[Fezboy]

Sometimes on part throttle I have heard what sounds like the DV dumping at about 3500 rpm accompanied by what I can only describe as a blip in power. I figured bypassing N249 might cure this. Done a scan and no DTC's present, was expecting the dreaded 17705.

I have done the N249 bypass and it's still the same :thumbdwn:

The car ran smooth for 1 day after but then it's the same as.

New DV

New N75

New Coil Pack(A few months back)

New MAF

I guess it's just the way the car is and I have to live with it

No fault codes on the car.

Only thing is my secondary air pump coming on every 5 mins :confused:

Edited 19 October, 2008 by Fezboy

[bjorn]

To bypass the N249, you run some vacuum hose from the top of the DV to a nipple under the right hand side of the Inlet manifold.

Under the Inlet manifold (right hand side), you find two nipples (oo er) if you trace them both one connects to the FPR (which you can see - leave this one) and the other dissapears down into the hose nest that is the N249 set up - this is the one you need to disconnect and replace with your vacuum to DV line. At this point the N249 is not connected to any active vacuum lines and so is having no affect on the DV operation.

Like I said it's a quick job, and if it's the problem you should pretty much know straight away. I've driven 20 miles to work this morning, and the overall driveability is massively improved - most noticeably on part throttle acceleration

[Bodge]

I went as far as replacing the N249, DV, Air Temp sensor in inlet manifold, 1 vac hose, 1 breather hose, 2 pressure hoses, air filter.....

All had no effect on 17705, and occasional reduced boost days!

So I cleaned the TB after all this, and now it runs good as gold! It's faultless now. I must have done about 5k miles since, and it's still fine. Smooth persistent power.

I've since fitted a boost gauge to monitor the inlet pressure, which should help me keep track of things. I've even trialled the APR stage 1 map, which hit a lovely 17psi peak, and things are still fine.

My advice would be to clean the TB before you spend any more cash on guesstimate solutions like I did.

[gmaster]

I went as far as replacing the N249, DV, Air Temp sensor in inlet manifold, 1 vac hose, 1 breather hose, 2 pressure hoses, air filter.....

All had no effect on 17705, and occasional reduced boost days!

So I cleaned the TB after all this, and now it runs good as gold! It's faultless now. I must have done about 5k miles since, and it's still fine. Smooth persistent power.

I've since fitted a boost gauge to monitor the inlet pressure, which should help me keep track of things. I've even trialled the APR stage 1 map, which hit a lovely 17psi peak, and things are still fine.

My advice would be to clean the TB before you spend any more cash on guesstimate solutions like I did.

Yep this is next on my list, hope it works for me too!

[Fezboy]

I went as far as replacing the N249, DV, Air Temp sensor in inlet manifold, 1 vac hose, 1 breather hose, 2 pressure hoses, air filter.....

All had no effect on 17705, and occasional reduced boost days!

So I cleaned the TB after all this, and now it runs good as gold! It's faultless now. I must have done about 5k miles since, and it's still fine. Smooth persistent power.

I've since fitted a boost gauge to monitor the inlet pressure, which should help me keep track of things. I've even trialled the APR stage 1 map, which hit a lovely 17psi peak, and things are still fine.

My advice would be to clean the TB before you spend any more cash on guesstimate solutions like I did.

I have done all of this and more :eek:

I don't have any error codes only low down stutter/boost dumping :thumbdwn:

I can see my car going back to standard very soon

[Bodge]

I have done all of this and more :eek:

I don't have any error codes only low down stutter/boost dumping :thumbdwn:

I can see my car going back to standard very soon

When you pull away off the lights sometimes, does the boost suddenly dump, and almost break your neck? Can you hear the pressure dumping when ur just driving along sometimes aswell (not lifting off the throttle)?

I've had this, and it's a strange one. I no longer get it when leaving the lights, but occasionally while driving along from cold.

My wise old Dad recons it's something to do with limiting boost on a cold engine to protect it. I just think it's the N249 or N75 being a smart ****......

[Fezboy]

When you pull away off the lights sometimes, does the boost suddenly dump, and almost break your neck? Can you hear the pressure dumping when ur just driving along sometimes aswell (not lifting off the throttle)?

I've had this, and it's a strange one. I no longer get it when leaving the lights, but occasionally while driving along from cold.

My wise old Dad recons it's something to do with limiting boost on a cold engine to protect it. I just think it's the N249 or N75 being a smart ****......

Yes thats the one.

I have changed the N75 and bypassed the N249 and it's still the same

I do think it happens more when the engine is cold like you say.

As I said before I just think it's there to stay and there is nothing that can be done to cure it :(

[yellotaxi]

The SEAT forum have done this on Ibiza's mostly, but once done if your engine decides to over boost i believe you have then taken away a safety device to stop detonation as boost is not governed.

Live with it or buy another car

[Fezboy]

The SEAT forum have done this on Ibiza's mostly, but once done if your engine decides to over boost i believe you have then taken away a safety device to stop detonation as boost is not governed.

That's why you fit a boost gauge

[Lex Dysia]

The SEAT forum have done this on Ibiza's mostly, but once done if your engine decides to over boost i believe you have then taken away a safety device to stop detonation as boost is not governed.

Live with it or buy another car

I thought the N75 prevented overboost by rerouting exhaust gasses around the turbo :confused:

[martziniuk]

N75' can cause over boosts which send the car into limp mode, an example of this can be the N75J

I would think the wastegate would open up first before any major damage was done though wouldn't it?

[David 8]

I thought the N75 prevented overboost by rerouting exhaust gasses around the turbo :confused:

The wastegate control the amout of exhaust gas that drives the turbo by re-routing it around the turbo...........I think

[Bodge]

Yeah, we have 'Active wastegate control' on our cars, rather than the basic 'passive wastegate control'. Which means the actuator pressure can be controlled independently from the boost pressure.

The point at which the wastegate opens is modified by means of a solenoid valve (N75), which sets actuator capsule pressure.

The wastegate valve itself is just a bypass valve, allowing some of the exhaust gases to skip the turbine stage. Which obviously reduces turbine speed, and boost pressure. Protecting the turbo from overspeeding, and protecting the engine from overboosting.

[vrs180]

Its been about 11 months since I last posted in this thread so just thought I'd give a quick update, as to how my jabba, custom remapped octy vrs has been performing.

The (post remap) hestitation I was getting in 4th and 5th gear has gone.... the car runs so smooth in any gear hot or cold and in any weather conditions.

I had tried all the usual stuff like N75 and changed the dump valve for a 007P but had no luck. I even tried some unusual stuff like limiting the max working pressure supplied to the N249 and N75 to OEM max boost pressure but again no luck. My reasoning for doing this was, i thought the problem might be caused by the N249, N75 and waste gate actuator not being able to operate correctly at approx twice OEM max boost pressure.

The cure for mine was the cage mod.... only I'm not sure which connector was at fault, cos I did every electrical connector, sensor and solenoid on or around the engine at the same time. It took me two days to do, first day was undo connectors and clean with "electra dry" leave to dry, next day treat with silicone grease.

As I posted at the time, I not saying this is the answere to all the hesitation problems, cos I'm not convinced we all have/had the same problem, but if all else fails, its got to be worth a try.

[Lex Dysia]

Did the N249 bypass today and all seems well. Really easy to do and took about 10 minutes all in. DV makes a louder and very abrupt noise as it works now and car seems to hold boost a little better but this could be in my mind, I will give a more rounded opinion in a week or so after I driven it a bit more. Certainly seems improved though

[Bodge]

Did the N249 bypass today and all seems well. Really easy to do and took about 10 minutes all in. DV makes a louder and very abrupt noise as it works now and car seems to hold boost a little better but this could be in my mind, I will give a more rounded opinion in a week or so after I driven it a bit more. Certainly seems improved though

Did you leave the N249 on the car, with the connector connected after you bypassed it? Or did you completely remove it?

[Lex Dysia]

Yes everything is in situ just unplugged the vac line to N249 and capped off the line and the original DV hose connection point to stop crap getting in and ran a vac hose from DV to inlet manifold where the N249 originally went

[Lex Dysia]

Right having covered a couple of hundred miles I can say......It's an improvement but not a cure. Still getting odd stutters but not quite as bad. Now though the revs climb abit when I change so might try a weaker spring in the DV to cure this.

I have a Revo sps and reverted to stock map and car runs smooth as anything am back on performance map though as I prefer the power even with the stutter.

I have had a thought about this because I still am sure that I have heard what sounds similar to dv sound on part throttle accompanied by the momentary loss of boost and think maybe the problem is exhaust side specifically the turbo actuator.

I figure that increasing the boost may be to much for the old componant and like a dv with a weak spring bleeds boost this could be bleeding exhaust gas through the wastegate.

Had a look at this and was thinking of trying it with a slightly harder spring Forge Motorsport | Alloy Fabrication . Will contact forge and ask them if it fits first.