Idle speed - Hope for the best deathtrap.

[harrisvr6 0]

My Corrado has been suffering from this weird idol problem for some time now and I really want to get it sorted. I have seen a few posts about this so maybe it is a common issue,

 

The only time this is a problem seems to be when I am slowing down and push the clutch at the actual "stopped" point. As the RPM needle falls it doesn't stop at the usual idol spot, almost stalls (oil lights briefly flash) and then bounces up to the usual spot. On occasion it'll stall, and in turn I'll **** myself.

The problem comes and goes, sometimes it's completely fine and there is nothing wrong, sometimes it will drop slightly but has no real effect ofr fear of stall, others it is nearly every time.

It seems to be worse when it is at running temp. When it's cold it tends to be ok.

 

Also when at temp.

It seems to nearly always happen if I have been in the same gear for a while ie crawling along in gridlock at about 20RPM.

I have noticed that each time it does it, it'll find a slightly different idol spot, usually a little lower than the norm (just below the 1st thin marker) but sometimes very low (2nd thick marker) and almost shaking.

 

The other thing I have noticed when it does nearly stall it takes a good full second to bounce up. Say I anticipate this and as its still falling pump the gas to keep it at say 10+ RPM and keep pumping, no matter how long I am pumping it will always drop after I stop and nearly stall or stall. Its like the nearly stall speed jolts something and makes it run a little higher.

That's the best I can describe it, the weirdest thing is sometimes it's just completely fine.

 

I have cleaned the ISV out with cleaner a few times, and on both occasions it helped a little, I think, but didn't completely fix the issue and it has gotten worse again.

How do I test if the ISV is faulty exactly? If I unplugged the sender should the engine behave any differently, indicating this?

Could it be that wire? How would I test that?

 

Fuel pump maybe?

 

 

 

 

 

 

 

 

 

 

A guy in the pub mentioned that it could be a vacumme problem, is this applicable for the VR6 as I also believe that I have a problem with thecentral locking pump in the boot (the idol thing has been going on much longer than the boot noise)

[Jim Bowen 1]

I went through loads of trying to test my isv, swapped it for a used genuine one and still had issues, but i dismissed the isv. I ended up buying an ebay non-genuine one for under £40 and it fixed my issues. All the tests i did on the other two i had suggested nothing was wrong with them.

[It's not a Scirocco 10]

This used to happen to me a lot in exact same scenarios. I found that a clean of the isv followed by unplugging the battery for a day to reset the ecu. Then taking it for a drive as per the wiki ecu reset guide fixed it.

[harrisvr6 0]

Thanks for te help, both of you.

 

This issue is soo frustrating.

The ECU reset sounds like something I deffo need to try before forking out for new parts.

 

Jim thats really interesting, kind of weird, but interesting. Do you have a link or part number for the one you went for?

I was thinking about getting a new one but its a lot of money for something I do not know 100% that it'll fix the issue.

 

Since it comes and goes, today it was fine. It was dry here though. Could it be affected by the wet?

[Tigerfish 10]

Have you had it vagcom'd for any faults?

 

Both times I've had similar issues it turned out to be a failing lambda once, and a air leak after the maf the second time.

 

 

Sent from my iPhone using Tapatalk Pro

[harrisvr6 0]

After ages, cleaning things multiple times for a barely noticeable improvement, I think I found the problem with this. Fuel.

I swapped to super unleaded strictly. After a couple of full tanks it has gone, completely, its been a few months now and back to how Ive known it to be.

 

The weird thing is I have been using regular unleaded for years without a problem.

[sandman3082 0]

Oddly I had this problem chronically when I first bought my vr6. When i fitted a performance fuel pressure regulator it never happened since.