Cold start issues

[kevinbowe2000 10]

I fitted a new maf, to fix the issue of stalling when braking at roundabouts etc. That problems is now solved but every time I turn on the ignition now its hard to start when cold, then the revs keep dropping, jumping up and back down again. Stalls most times unless I hold revs at about 750. Once I'm driving for a couple mins, everything is fine.

Battery was disconnected so I did half an ecu reset as I only have vcds lite unregistered so couldn't do the basic settings part.

Wondering if a full ecu reset would solve this issue or is it likely to be something else?

Its an 1994 vr6 btw.

Thanks in advance

[MoonlightVR6 10]

MINE DOES EXACTLY THE SAME, DOES YOURS DO THIS FOR THE FIRST MINUTE SAY OF RUNNING?

 

[kevinbowe2000 10]

Yeah similar but mine normally drops down to about 200rpm then up to 1500 and back down until it stalls. Keeps doing this until I drive her for about a min. Then she's perfect. Still can't figure it out. Really hoping its just an ecu reset thing.

[kevinbowe2000 10]

Did you remove the battery or anything that would wipe you ecu?

[MoonlightVR6 10]

Yes actually, I noticed it shortly after one of my battery terminals worked itself loose.

 

However I noticed what you said about stalling while putting it in neutral as I'm coming upto roundabouts etc. Before this came loose. Not a lot but it does do it occasionally.

Basically if I am coming upto a roudabout, and I put it in neutral it sometimes stalls itself the same way it nearly stalls itself in my vid, kind of de-revving itself. If its in gear its fine though, but then will actually stall as I'm going toop slow... Hmmm

[kevinbowe2000 10]

The reason my engine was stalling at roundabouts was due to a broken MAF. Got one on the cheap from the EuroCarParts ebay store.

Not 100% sure if your issue with the roundabouts would be the same. It is very easy to clean the MAF with contact cleaner. Got mine from Maplins.

Did clean the MAF and ISV a couple of times and was about to clean my throttle body before I found the cheap MAF.

 

Will check my battery connections after work to make sure I put it on correctly and then hopefully find someone that has full VCDS to do a full ecu reset.

I really do think that the reason for the bad starting is due to the ECU not knowing all the correct information. Then once I start driving, it learns them all and runs fine. Crossing my fingers naturally.

If anyone near Glasgow might be able to help with the full VCDS front, it would be most appreciated.

[MoonlightVR6 10]

what is a MAF?

[kevinbowe2000 10]

Its the Mass Air Flow sensor. Measures the amount of air going into the engine (if I understand correctly, a newbie myself).

This might help for cleaning:

http://the-corrado.net/showthread.php?t=28621

 

This is what it looks like and where it is located:

http://www.corrado-club.ca/forum/viewtopic.php?t=9564

image in step 3

 

very easy to remove and clean.

[kevinbowe2000 10]

The corrado MAF can be an expensive part (seen it priced at over £300).

Did read something about using a passat or golf or galaxy vr6 MAF, but I wouldn't trust my memory right now.

That cleaning thread is worth a good read. Alot of very useful information on it all.

[MoonlightVR6 10]

I cleaned my MAF with some air intake cleaner from allparts, I cained the whole can on it and it seems to have sorted my issue of pressing the clutch, and then as the revs drop, rather than leveling/choking itself off, they just continue to drop almost to the point of stalling, then bounces back up to normalish idle speed. Sometimes this stalled the car completley, stopping the brakes and steering from working (which is dangerous). Other times it just almost stalled and the battery light comes on for like 1/3rd of a second then it speeds back up to idle speed, narrowly jus missing stalling itself.

That seems to have been sorted by cleaning my MAF, although I only drove it today so time will tell.

 

The other thing I have noticed its doing which the MAF clean hasn't changed, is pulling away at low revs, normally it pulls away fine as long as I am above 1000 rpm( or the line below it), but below that, depending on gear it will go jolty/bumpy as if its going to stall, which it is. I noticed this pulling away from like 1-2mph in 2nd, I think thats normal. After you go past the 1000rpm speed its fine.

Last week say, its been doing this upto about 25000 revs which isn't normal. Any idea as to what that could be? I saw someone post about loosing power upto 25000rpm and they mentioned they had idle issues, could his be the same thing starting to break/happen?

[kevinbowe2000 10]

I still have not got to the bottom if this issue. I removed the plastic silencer at the back if the isv as I thought if might have a leak. Checked everywhere for any leaks. Changed the blue temperature sensor. Done a full ecu reset. Issue has gotten even worse.

I read on a different forum that if you disconnect the tps sensor, the engine should still run if your maf is okay. If your engine cuts out, then you know you have an issue with your maf, and visa versa. Anyone know if this is true as my engine cuts out if I disconnect the tps. Have occasionally got a maf grounding vag error and also a lambda vag error, 00537 - Lambda (Oxygen Sensor) Regulation

11-00 - Control Limit Not Reached.

Did a multimeter test on the maf and it seems okay. Not 100% with the values but close enough. I did install a BMC CDA so might remove this first before going any further as I have been told it can cause issues.

All in all, I want to make sure that all this is my maf still, and as the unit is new, I think it is the cables, so will rewire. Any thoughts/ideas would be most appreciated. Thanks

Edited October 23, 2014 by kevinbowe2000

[easypops 8]

How many pins is your MAF, I have a spare here you can try if it's the same

[kevinbowe2000 10]

That would be great martin thanks. Its a 6 pin for a 1994 vr6. Potentially could be the lambda but still need to multimeter test that.