vr6 still stalling on new ISV

[jjgg125 0]

Sorry to post yet another boring VR6 stalling thread. Ive tried searching but cant find anything the same as this and would really appreciate some help or advice.

 

I was having the normal stalling at junction issues even after the ISV and throttle body had been given a good clean. my local VW specialist, who generally seem to know what they're doing, fixed a couple of leaky pipes (air and fuel) and told me the ISV was intermittently faulty and needed replacing.

 

The car runs ok when its properly warmed up, but initially it wont start properly without some help from my right foot and for the first 5/10 minutes when its cold it stalls unless i keep the revs up manually. Now, having replaced the ISV with a brand new one at an extortionate cost there is no change from what the car was doing before. Obviously this is pretty annoying given the garage were adamant that the ISV was causing the problems.

 

anyone able to shed any light?

[Reggit 0]

I'd suspect the blue temp sender has failed - it tells the ECU what the coolant temp is - and the fuel/air mix isn't richening for cold running.

 

Anyone got VAgcom near you to check it out?

[CazzaVR 0]

As above, or check all the ISV pipework and make sure the sponge from the black plastic ISV damper box hasn't been sucked into a hose. Happened on mine and I had identical symptoms to you.

[jjgg125 0]

Ill check the sponge thing tomorrow, thanks.

 

Is there anyone in the bristol area with a vag com?

[CazzaVR 0]

Not as far as I know :(

[VR-OOM 0]

Keep us informed as I'm having a similar problem.

 

Cheers

[Kevin Bacon 5]

In my experience, if VAG COM shows the all clear and you've replaced / checked everything else, 9 times in 10 it's MAF sensor related. There's 3 ways to diagnose them. 1) On a scope, but with all due respect, most garages haven't got a clue how to do that or what they're looking for. 2) Read the measured air flow in VAG-COM, but the caveat there being OBD1 does not report the MAF's output! and 3) gut instinct / butt dyno.

 

I've seen quite a few VR6 stalling issues solved with a new MAF sensor, but they're not cheap, which is why they seldom get replaced and they seldom get checked due to the above issues. It's one of those biting a bullet scenarios.

[CazzaVR 0]

Do you know anyone with a working MAF? You could swap over and see if it makes a difference. Also worth checking the MAF connections and giving the pins a clean with an emery board + contact cleaner.

[jjgg125 0]

So im STILL having problems with my vr6, despite new ISV and MAF! Sorry to bore everyone with yet another thread like this, but any help or advice anyone can give would be much appreciated.

 

Firstly i was having the classic 'vr6 stalling at junctions' problem. Cleaned throttle body and ISV; didnt really make a huge difference - but it was hard to tell as it was such a temperamental problem.

 

So back to the garage where the fuel return piped and intake breather pipe were found to be split - both replaced.

 

I was advised that the ISV was 'intermittantly sicking' - So replaced ISV. No change - car still had lumpy idle and frequently stalled, particularly when cold.

 

Drove the car for a month or two anyway, and found the issue developed into lack of power or engine choking itself, even when thoroughly warmed up. for example on motorway if i applied a little extra throttle, car would slow, sort of choking itself as though i had completely removed my foot from the throttle. somtimes it would correct, and sometimes i would end up on the side of the road with no power available at all. idle would be erratic and it would be near impossible to get revs up to 2/3k. mostly it would sort itself out (temporarily) after a few minutes of patiently trying to coax revs up on hte side of the road.

 

So i bit the bullet and took it to a proper VW garage, who checked it over and replaced the spark plugs. Seemed to run fine for the few days they had it in - their only comment was occasionally the lamda sensor gave a spiked reading for no obvious reason. Further investigation was going to cost me a fair amount, apparently.

 

They suggested i tried removing the connection to the MAF next time it did its choking game; it worked wonders - although it still tended to stall rather than idle when cold, as soon as it warmed up it was pretty much fine; for a month or two, including 2 return trips from bristol to edinburgh.

 

So given it was working ok (albeit with a crappy mpg) without the MAF connected, i assumed the MAF must be buggered and the source of my problems. Bought a new one, installed it and it was back to its usual issues, worse, if anything, than before. So the new MAF is unplugged again and the car runs ok when its warm (quite lumpy idle but drivable) but now when its cold it stalls every time revs drop.

 

this is driving me mental and i cant afford to just keep throwing money at it! anyone have any suggestions??

 

cheers guys

[andy 0]

Drove the car for a month or two anyway, and found the issue developed into lack of power or engine choking itself, even when thoroughly warmed up. for example on motorway if i applied a little extra throttle, car would slow, sort of choking itself as though i had completely removed my foot from the throttle. somtimes it would correct, and sometimes i would end up on the side of the road with no power available at all. idle would be erratic and it would be near impossible to get revs up to 2/3k. mostly it would sort itself out (temporarily) after a few minutes of patiently trying to coax revs up on hte side of the road.

These are classic lambda probe fault symptoms.

[volksworld13 0]

vag com it, check wahat codes you have set, this will be a good indiaction where the fault lies, and try carrying out basic setting, after you have cleaned throttle body.

[VR6 0]

Threads merged - can you stick to one thread per problem please?

 

Ta

[hodaz 0]

My 2p would be Lambda Probe issues, well worth replacing as there only circa £80 from ECP for an OE Bosch one. A knackered Lambda will make the car run very rich which would explain the bad MPG and lumpy/slow running issues, then by disconnecting the MAF your making the ECU learn to run without it, so its probably cutting petrol and providing more air to compensate.

 

When I read the instructions that came with the new Lambda they are actually supossed to be changed every 60k, I'm sure mine was the original 15 year/150k old one as when I took it out was all sooted up.

 

Leaving the MAF connected is a bad idea though, must be costing you a fortune in petrol.

[wazza 0]

I have similar symptoms, although stalling happens both hot and cold!

 

Starting isn't normally a problem and its been fine for a few weeks, but every now and then it'll turn over and over but won't fire...

 

MAF on mine is relatively new (2 years i think, if that) and as soon as unplugged it dies. A few weeks ago it was diagnosed as a poor connector to the MAF, which following cleaning has improved things no end, but its still stalling every now and then.

 

It should be popping into the DG Autotech car-spa soon as i've asked them to have a fiddle (and look at the car :tongue: ) so hopefully they'll work their magic!

 

Waz