'94 VR6 keeps stalling

[Scotties 0]

When coming up to a situation that requires me to slow right down or stop, with my right foot on the brake (i.e. no throttle) and clutch depressed, the revs drop right down and the engine stalls. Idling speed at rest is fine, it's only happening when I slow down from speed. A quick turn of the key and it fires up again immediately, but is annoying and embarassing! Any ideas chaps? I have read somewhere there is a specific ECU reset procedure to be carried out after diconnecting the battery - could this be my problem, and if so, what is the procedure?

[Toohottotrot 10]

94 VR6? ;) I'll go for throttle damper.....

[Storm Guy 0]

Mine did exactly the same back in 2006 - changed the damper - 021133429A, smoothe ver since. Yes its embarassing.

[Critical_Mass 10]

More common than you think. Mine does it and have never got to the bottom of it. Luckily doesnt do it very often.

[Storm Guy 0]

See here also...http://the-corrado.net/showthread.php?58046-Strange-stalling-problem

[Scotties 0]

Thanks for the replies guys. Now my ignorance and rank amateur status will become apparent! Is the throttle damper the metal cone-shaped thing with a plunger sticking out the top that contacts a small metal roller? I ask this because it looks to me like some sort of damper mechanism, but the part number 021133429A seems to be a small plastic box with two pipes attached, which sits next to the damper thing.

[Yandards 0]

You running the factory airbox or a cone filter?

 

The MAF needs a smooth airflow to work correctly and aside from the BMC carbon cans cone filters tend to induce the behaviour you have described.

[Scotties 0]

Aha! That could be my problem then! The guy I bought it from had fitted a cone filter but supplied me with the factory airbox, so I could just put that back on. I thought cone filters were meant to IMPROVE performance by allowing better airflow, or am I wrong?

[nrc 0]

A split crankcase breather hose is what caused this problem on mine. Patched it with self-amalgamating tape until I got a new one.

[floppyman 0]

What fuel do you use? Premium?

[boost monkey 0]

84 sounds like an ultra prototype! :D

[Scotties 0]

Yes I try to use premium whenever possible. An engineer guy once told me he'd only use regular in his lawnmower!

 

---------- Post added at 02:42 PM ---------- Previous post was at 02:41 PM ----------

 

84 sounds like an ultra prototype! :D

 

Told you I was an amateur! And when you're my age, the odd 10 years is neither here nor there!

[floppyman 0]

Ok... Then give the original air filter box a try, adjust the pot on the throttle and a full ecu reset. Need vagcom following RW1 method. That should do it... Of course if theres no leaks on the intake

[Scotties 0]

Refitting the airbox, no problem. What adjustment needs to be made to the damper? The ecu reset with vagcom will defeat me though as I don't have a spare 300 quid to buy one at the moment!

[nrc 0]

Where are you located? There might be someone nearby with the cable and software who can help you. Otherwise the cable is about £15 and the software about £65 to register to allow you to use the basic settings function.

[Scotties 0]

Really?! That's manageable. Tell me more! Where do I go?

(I live in Bridgwater, Somerset)

[Critical_Mass 10]

Dont think you need vagcom to do the ECU reset. Never used it myself when doing an ECU reset. Just disconnect the battery for 10 mins. Then go for a 20 min drive using various speeds/revs.

[nrc 0]

Really?! That's manageable. Tell me more! Where do I go?

(I live in Bridgwater, Somerset)

Have a read of this thread: http://the-corrado.net/showthread.php?4948-VAG-COM-scanning-amp-help

If you're doing it yourself you'll need a 16 pin OBD2 cable and optionally a 2x2 adapter depending on the connector beneath the gearstick surround.

 

Dont think you need vagcom to do the ECU reset. Never used it myself when doing an ECU reset. Just disconnect the battery for 10 mins. Then go for a 20 min drive using various speeds/revs.

I think the point of doing the basic settings is to calibrate the throttle position sensor, which is probably quite important if messing with the dashpot :)

[Scotties 0]

Brilliant, thanks chaps. Ebay has the cables in plentiful supply, some complete with software. Looks like a job for next weekend as this one seems to be nearly over. Appreciate all your assistance.

[floppyman 0]

It comes with vagcom allright, but it wont do adaptations untill you register. Best thing is download vcds light from ross tech, when the cable arrives install the drivers only. And then try it on the car with the vcds, if all works good go back to ross tech to buy the license.

[pbradley98 0]

Hi, this sounds suspicously like what I'm having at the moment!

 

Only problem is working out what's causing it! Could be the breather tube, as I've though for a while that there looks to be a very slight oil leak from the corrugated bit, although could also be the battery thing, as recently had to change the battery due to the car not moving for too long and the battery dying! Don't think that I went for a decent drive straight after doing it though - just checked the battery started the car ok, so may well need to go through the disconnecting for ten mins then a great excuse for a 20 min drive at various speeds and revs!

 

Cheers

 

Phil

[pbradley98 0]

Tried the ECU reset procedure last night and it has improved the idle speed up from 500 rpm previously to about 600rpm now, but that still seems a bit low - oil temp may have been a bit low for the ECU reset procedure though so may try this again tomorrow, as I'm still getting stalls when allowing the car to drop to idle at roundabouts (haven't got VAG.com so couldn't check the settings after I'd done the 20 min drive). Hopefully this will sort it, as the car only stalled very occasionally in this manner before the old battery died! Strangely the idle seems much better when the engine's cold and sits more towards 750rpm - it's only once the car's warmed up that the stalls occur. Presume that this is something to do with fuel management for a cold engine?

[pbradley98 0]

Did the ECU reset again, this time making sure that the oil temp was as per the Wiki guide, much better now but still stalls occasionally. Thinking about it, it's been doing this to a greater or lesser extent since I had the MAF replaced with a reconditioned unit about a year ago, as the original MAF was dying.... just didn't really bother me as at the time it was just a weekend car and didn't happen regularly enough to work out the conditions under which it happened, whereas has now become my daily drive so a lot more aware of the occasional blips!

[pbradley98 0]

Just thought I'd post a progress update! Looked like the breather tube had a small oil leak onto the exhaust manifold heat shield, so though that could also be an air leak, so stripped down the breather tube and cleaned all the pipework, as it looked like it was leaking from the connector with the dummy electrical socket on it rather than from the breather valve. I don’t think there’s any evidence of the oil leak onto the exhaust manifold heat shield cover since, however it didn’t seem to make any difference to the stalling.

 

Next step was I managed to get hold of a second hand ISV on the forum to try (thanks Speedysmartypants), which I gave a good clean then tried and at first I thought had made an improvement, but I think it was more me avoiding the conditions that seem to be most conducive to stalling as more recently it’s been worse again! Whilst changing the ISV, thought I could hear a bit of a hiss from the damper box just behind the ISV so ordered new hoses from the ISV to damper, from damper to intake manifold and also a new damper, which I’ve fitted this evening and look to have made a significant difference, as have been out for a quick run and seems to be significantly smoother when dropping to idle speed and doesn’t overshoot the idle speed (i.e. drops smoothly to 650rpm rather than carrying on to 500rpm or less and then recovering / stalling).

 

One strange thing did happen the first time that I started the engine after fitting the new damper though, as the engine was idling at a much higher speed (around 1200 rpm) and surging up to approx 1500rpm before then dropping back to 1200rpm and continuing to do this until I opened the throttle a couple of times and allowed it to then drop back down to idle, at which point it started to idle at a more normal speed of 650-700rpm. Only guess as to why this happened would be that the old damper was significantly reducing the air flow through the ISV, so with the new damper there was a much increased flow through the ISV and hence with the new damper was idling at a much higher rate, which the ECU would then try to regulate down before opening again when it saw the revs dropping, which presumably was resolved through the ECU learning once the throttle was opened and closed?

 

Fingers crossed it’s now back in good shape!

Edited October 17, 2012 by pbradley98

[floppyman 0]

Thats good you found the problem... Yes your guess is spot on. A isv adaption with vagcom would be good but if your happy with the result then you can leave it