Erratic idle, stalling and the odd kangaroo (vr6).

[.Rich. 0]

The corrado's has developed a pretty bad idle problem. When you start the car you have to throttle it gently for 2-3minutes. If you dont gently caress the peddle at all it simple stalls and if you dont do it for long enough it will hunt for a while until it settles.

 

Once you get going you are generally ok, but 2/10 times it will stall as you put your foot on the clutch at junctions. Today i could feel a very strange but slight pulsation of power as i coast along at fairly low speeds (30odd) and it even went through a wierd kangaroo stage of what felt like short stalls which lasted around 5seconds (4-6 mini stalls in total).

 

I got home and plugged in vag-com and got the following readings:

 

00543 - Maximum Engine Speed Exceeded

00553 Mass Air Flow Sensor - G70

01257 Idle Air Control Valve -N71

00533 Idle Air Control Regulation

 

00513 which could be:

 

P0506 Engine Speed Sensor - G28 - Idle RPM Too Low B

P0507 Engine Speed Sensor - G28 - Idle RPM Too High B

Engine Speed Sensor - G28 - Signal Malfunction

 

 

I then cleared the codes and took it for a short trip around the block where it stalled once at a junction, but no codes came up on vag-com when i got back.

 

The car seems to be running rich, as the exhaust tip is very black and on startup the fumes smell like petrol. I changed the plugs/leads three months ago and checked them tonight:

 

Plug 1 - Very very bad, coated in burn and totally black.

 

Plug 2 - Electrodes darkish gray but rim below them had burn on it.

Plug 3 - Same as 2

 

Plug 4 - Electrodes lighter gray than 2-3 but rim below them had burn on it.

Plug 5 - same as 4

 

Plug 6 - Electrodes nice shade of gray and only a small amount of burn around the rim.

 

Any advice greatly recieved.

[.Rich. 0]

Forgot to mention that cleaned the MAF connector with electronic connection cleaner but it hasn't improved things. I also unplugged it while the car was running so that might have caused one of the fault codes?

 

fyi once unplugged the car gasped for air but kept running and only stalled when i tried to give it some throttle.

[Roger Blassberg 0]

Sounds like running rich, as you say, but it seems to vary from cylinder to cylinder which is a bit odd. How's your fuel consumption?

 

How about replacing the blue temperature sensor which controls cold start enrichment (cheap)? Next up, look at the lambda probe and its wiring (moderately affordable) Then you might look at the MAF which also controls air/fuel mixture (expensive).

 

Some one else will no doubt be along shortly to decode your VAGCOM readings, which may take the guesswork out of the process.

 

Mine had some misfiring issues recently which seem to have disappeared since I cleaned the MAF electrical connector block contacts and sprayed them with WD40.

 

Best wishes

 

RB

[dr_mat 0]

Sounds like the lambda to me.

[Lippy 0]

sounds a bit like a TPS (throttle position sensor) this may explain the coasting when changing gear as its letting too much air(??) through which is causing revs to drop and the engine cut out?

 

anyone else any advice?

[.Rich. 0]

Thanks for the idea, i will check the plug/wiring tonight but is there any way of checking if its dud without replacing it? Perhaps with a current/continuety tester?

[Lippy 0]

.Rich., don't know mate, think mine is on the blink as mine cut out on a roundabout this morning. No PAS, on a roundabout, with a freelander bearing down on me.

 

i papped myself big time!

[Chris VR6nos 0]

All what have been mentioned can cause problems but you need to understand what the codes mean before further guess work really.

If the MAF or Lambda were acting up i'd expect all the plugs to be the same condition, other thoughts are the injectors may be fouled to varying degrees on each one or the kcock sensors are doing funny things which leads to late burn retarding and giving black plugs but you would notice one bank black and the other bank different-ish in colour.

Like i say though it's all guess work, that's what VAG-COM's there for.

 

 

Chris

[.Rich. 0]

I have updated the vag-com codes with the descriptions, i was thinking the dirty plugs are a seperate issue (cylinder 1 burning oil) and might not be linked to this problem.

 

When i cleaned the MAF connections it ran like a dream for the rest of the day then was shit again the next morning :/

[Chris VR6nos 0]

One thing i would suggest is to vent the rocker breather(PCV) to atmosphere, this will stop oil/sludge deposits from clogging the MAF and will probably help if you have a lot of emissions from the rocker breather.

Pull the pipe off and run the engine to see what emissions and blow-by there is from there.

 

 

Chris