VR6 Stalling help

[Christoph 0]

Hi All,

 

I'm having a problem with my Corrado, where it will sometimes stall coming up to a junction.

 

I've noticed that when it happens, the battery warning light on the dash comes on as I press the clutch pedal. It seems to happen more when I'm steering, as I aproach the junction.

 

Also, when I was testing my new light switch, I noticed that with the engine off, turning the lights on made the radio loose power for a second. I'm sure that's not normal.

 

The battery is a Basch Silver that I've had about 6 or 7 years, so I wouldn't be surprised if it was dead.

 

Would a dying battery cause these problems?

 

With the engine running my voltmeter is steady at about 14v, which I think means the alternator is OK?

 

Any help or suggestions welcome, before I go out and blow 60 beer tokens on a new battery.

 

Cheers

 

Chris

[plateletboy 0]

i think this can be caused by dirty sticky throttle bodies, or a dodgy/failing ECU power relay (109 i think)..

 

also a more 'retro' classic would be a leaking hose to the brake servo - if it occurs mainly when breaking

 

pb

[dr_mat 0]

Use the search, there's a number of threads discussing this problem out there already.

[Christoph 0]

Use the search, there's a number of threads discussing this problem out there already.

 

Thanks Mat. What insight!

 

I'm not a noob dude. I know how to use the forum, but I can't find any posts that link stalling problems and power problems when the ignition is off.

 

So this morning, when I dip the clutch, the car wasn't stalling, but the power was still dropping enough that the radio would switch itself off.

 

Then I'm sitting in the car park with the key at position 1, so I can listen to the radio as I sort my life out and there's not even enough power to run the radio. Everytime it switches on, the display fades and it goes straight off again.

 

I'm almost convinced it's the battery, but I'm just not sure how it's starting the car every morning if it really is that dead.

 

At the same time it's not the MAF / CPS / ISV / lamda etc, because the engine isn't even running.

 

cheers

 

Chris

[dr_mat 0]

Thanks Mat. What insight!

 

I'm not a noob dude. I know how to use the forum, but I can't find any posts that link stalling problems and power problems when the ignition is off.

 

Which is possibly because they may not be linked ... ?

 

Your original post said "vr6 stalling help".. You also mentioned, as an aside, that with the engine off the radio goes dead for a moment if you turn the lights on. Therefore you most likely have the "generic vr6 stalling problem", which is why I suggested looking around in the search because other people have had the same problem, and you probably also have either an ignition switch, a relay or even an alternator problem.

 

If you think you have a battery problem I suggest you test the battery - it's really not hard to do (voltmeters cost £5 from maplins) and once again it's been discussed before and I've personally written up instructions several times. Speculating over whether a weak battery can start the car when it can't run the lights and the radio at the same time is a little pointless without facts backing it up, because batteries can fail in different ways (as can ignition switches and relays...).

[Christoph 0]

2 problems? On a Corrado? Are you mad?

 

You may be right.

 

The thing that made me think they were linked is that before, when I've had stalling problems, the engine has stalled as I've dipped the clutch, and both the oil pressure light and the "battery" warning light have come on as a result.

 

The difference now is that the battery light comes on before the engine has stalled. Sometimes the engine even picks up again and recovers to a steady idle, but the warning light seems to be a precursor to a stall rather than the other way around.

 

If I can find my multimeter, I'll try testing the battery. As you say testing the voltage across the terminals is easy.

 

Do you know if the ECU relay that PB mentioned is the one that cuts power to the lights etc. when you start the engine? I thought that was called the "X" relay, but that might have been in my Golf?

 

Cheers

 

Chris

[dr_mat 0]

2 problems? On a Corrado? Are you mad?

 

You may be right.

 

The thing that made me think they were linked is that before, when I've had stalling problems, the engine has stalled as I've dipped the clutch, and both the oil pressure light and the "battery" warning light have come on as a result.

 

The difference now is that the battery light comes on before the engine has stalled. Sometimes the engine even picks up again and recovers to a steady idle, but the warning light seems to be a precursor to a stall rather than the other way around.

 

This is not unusual - clearly if the engine stops (which it tends to do), OR if the revs drop really low, the output from the alternator drops and the dash light warns you that the alternator isn't charging the battery - it is nothing to do with the condition of the battery.

 

If I can find my multimeter, I'll try testing the battery. As you say testing the voltage across the terminals is easy.

 

Leave the battery to settle for 30 minutes after running the engine before you test this. Measure the volts, then start the engine and measure again. The battery alone should put out 12.2V or more if it's > 50% charged, the alternator should put out around 13.5-14.5 volts.

 

Do you know if the ECU relay that PB mentioned is the one that cuts power to the lights etc. when you start the engine? I thought that was called the "X" relay, but that might have been in my Golf?

 

I think on the Corrado VR6 the ECU relay is labelled "109" but don't quote me on that. There is a separate relay for load reduction during start, but I don't know what it's called...

[Christoph 0]

Leave the battery to settle for 30 minutes after running the engine before you test this. Measure the volts, then start the engine and measure again. The battery alone should put out 12.2V or more if it's > 50% charged, the alternator should put out around 13.5-14.5 volts.

 

OK, so I left the car for about an hour after I got home from work, found my digital multimeter, and... 14.4V across the terminals. 16.4V across the terminals with the engine running. WTF?

 

Now, with the engine running, the (VW) voltmeter in my centre console reads 13.5V (drops to 13V with the lights on). I think this used to read 14 with the lights on not so long ago.

 

Also, I found a part number for relay 109 (ECU), and it was in stock at my local dealership, so I swaped it over to see if that would help. It didn't, but at leaset it's ruled out.

 

Chris

[Christoph 0]

On a separte note (because it might be a separate issue),

 

After a 50 min drive home, the radio wouldn't even stay on, with the egine at idle. At the first sign of having to drive the speakers, it turned itself off.

 

I'm guseeing that if the current drops below a certain value, a circuit in the radio turns it off. Does that sound right?

 

However, after a short trip back home from the horses tonight, the radio was more than happy without the engine even running.

 

I'm more confused about this than ever now.

[dr_mat 0]

OK, so I left the car for about an hour after I got home from work, found my digital multimeter, and... 14.4V across the terminals. 16.4V across the terminals with the engine running. WTF?

 

Now, with the engine running, the (VW) voltmeter in my centre console reads 13.5V (drops to 13V with the lights on). I think this used to read 14 with the lights on not so long ago.

 

Also, I found a part number for relay 109 (ECU), and it was in stock at my local dealership, so I swaped it over to see if that would help. It didn't, but at leaset it's ruled out.

 

Chris

 

I think your digital voltmeter is out of whack by +2v, that's what I think ... ;)

 

You may have a voltage regulator problem on the alternator if the voltage is dropping under load more than normal, but tbh that doesn't sound out of range by much if at all.

 

I think, overall, that your battery is probably fine, as is your alternator. I suspect the ignition switch or some other component in the radio's circuit is causing that problem (perhaps even a speaker is shorting somewhere?), and as for the stalling .. well that can be the ignition switch too, or the crank sensor, or as said, one of a large number of problems. But more and more I'm convinced they're not related.

[Christoph 0]

I think your digital voltmeter is out of whack by +2v, that's what I think ... ;)

 

Yeah, me too.

 

But more and more I'm convinced they're not related.

 

Yeah, me too.

 

I am normally on the brakes when it stalls, so I guess the next thing to check is the (vacuum?) hose to the servo.

 

Thanks for your help so far Mat.

 

Chris

[chriscorrado 0]

this could be your idle control unit it can fail intermitently and cause

exactly the symptons you describe as you brake it won't hold idle and cuts out the engine

does idle go up and down?

I may be wrong but worth thinkinking about

otherwise go to Stealth near Warwick

[dr_mat 0]

I am normally on the brakes when it stalls, so I guess the next thing to check is the (vacuum?) hose to the servo.

 

Could be, but start on the rest of the "common VR6 stalling problem" fixes too. The "brakes" coincidence is highly likely to be because that's the most common time when you dip the clutch and let the revs drop to idle from the engine being on overrun. It's just as likely to be the MAF sensor though, so it might be time to start trawling around and getting hold of some used parts to try out: ISV, MAF etc ..

[Christoph 0]

Progress!

 

I was (ahem) working from home on Monday, so I decided to see if my local VAG independant could take a look.

 

They replaced the hose from the MAF to the throttle body, because it had a split (how much £££!), cleaned the throttle body, tested the battery and the alternator, and did the ECU reset procedure.

 

Touch wood (still early days), it seems a lot better. I picked it up Tuesday PM, and it hasn't stalled since.

 

The "Radio" issue is still there though. Infact, it's not the radio at all, that's just the most obvious symptom.

 

If I turn the radio off (listen to the window rattle), I still get a drop in power when I hit the brakes and dip the clutch coming up to a junction. The revs drop a bit lower than usual, the dashboard lights dim, momentarily, and sometimes the "battery" light comes on.

 

It seems to be worse the harder I brake. If I'm not pressing on, it's fine, the revs don't drop past the idle, no drama.

 

Chris