Bizzare Icv Issues On Gti6

[gti-si 0]

Yet again another cry for help, so sorry for that, but again, another puzzle that I need to solve!

 

When I'd got her sorted and fired up, the idle was very high. I would estimate it was idling around 2,500 rpm but as soon as I'd touch the throttle, the revs would rocket and not drop at all on release of the throttle.

 

I had a look for air leaks and found that air was completely bypassing the ICV. I have put a small filter on the ICV hose and on idle the noise is tremendous. You can feel it sucking air through if you put your hand on it.

 

I then blocked the pipe, started her and it was struggling, but with some feathering of the throttle was behaving normal (well, as it should with no ICV). The revs would drop easily etc.

 

On finding this I've got another stepper motor, not new but known good. Put that on today and symptoms are exactly the same! I then unplugged the ICV, and plugged it into my old one, started it up and there was no movement whatsoever with the motor. Seeing this I figured the wiring must be broke but I've since stripped the loom back and all 4 wires are in good condition right to the ECU plug

 

Help! Anyone any ideas what is causing this? Like I say, it's like the motor is at it's most open setting and not being told to move by the ECU?

 

Any other sensors that could cause this type of problem?

 

Many thanks in advance,

 

Si

[whizzer71 0]

Are the three wire going to the TPS ok ?,If so remove the ICV and push the plunger all the way back into the motor,once youve done this refit it.

Do not start the car but turn the ign on and off 30 times or so (To the 2nd position before start)and this should motor the ICV plunger back into the correct position,start the car and see how it idles,If its still too high then repeat the ign on/off sequence and that should be it.

 

let me know how you get on !

 

[gti-si 0]

Are the three wire going to the TPS ok ?,If so remove the ICV and push the plunger all the way back into the motor,once youve done this refit it.

Do not start the car but turn the ign on and off 30 times or so (To the 2nd position before start)and this should motor the ICV plunger back into the correct position,start the car and see how it idles,If its still too high then repeat the ign on/off sequence and that should be it.

 

let me know how you get on !

 

 

Whizzer, is this some kind of calibration method? I was wondering if there was one! Thanks alot for that though, if it manages to stop pissing down, I'll go outside and give that a go.

 

The wires to the throttle position sensor looked fine as far as I can remember. Once I'd got the loom off, the only problems I found were that the oil level sensor (the green plug much like the knock sensor) was completely knackered, the insulation had come away and the plug had twisted joining the two wires shorting it, I just removed this. The knock sensor plug did seem a bit dodgy, what kind of symptoms do they show?

 

I'm also abit worried about the amount of plug's I've deemed unnecessary and removed, but I'll find out later on. I think I removed:

 

Oil Level sensor

Brown plug that goes to thermostat (aircon?)

Blue power steering plug

White plug dangling low (not the TPS, aircon again?)

Brown purge solenoid

Oil temp (was knackered and I need to fit a 205 one)

 

Think there might of been a couple more, I'll check when it brightens up. Those plugs right?

[gti-si 0]

Right, I tried the calibration method you described and it had no effect. I tried both motors with the engine off, ignition on, and engine on, no movement with either of them. I then took my old idle motor and pulled thestop out as far as it would go, then put it back on the manifold, this obviously restricted the airflow and once warm it idles solid and low.

 

So the ICV is definatly the problem and there arn't any other air leaks.

 

I've isolated the wires to the ICV right back to the ECU plug and there's no problems with it. It's got me stumped, what on earth can cause it not to move at all? Theres nothing from the wires

 

Topped now with another problem, which seems abit more on the serious side. There is smoke (like exhaust smoke) coming from the lefthand breather hose, I've currently got it vented to air while I source a new pipe... So yeah, smoke out of the breather, what's happened?

 

I can't understand that one atall, it's on the inlet side, not even exhaust?

 

Edit: Theres abit of "white" according to my dad's mate, but I think it's got a slight blue tint to it, smoke coming from the exhaust too...Piston rings?

 

I am very unhappy with the engine condiiton tbh, I bought it under the impression it had a suspect headgasket gone and everything was fine. On inspection of the head it was very warped and and been very very hot at some point. Ended up having to have new stem seals and reseating of the valves

Edited July 5, 2008 by gti-si

[Toddy 7]

For the ICV:

 

1) Disconnect the battery for 15 mins or so then reconnect.

2) The ECU then needs to relearn the ICV settings so that it can idle @ c.850rpm

3) With the engine running either go for a drive or rev and allow the engine to return to idle ( what ever this rpm is) in short burst and it should eventually learn the new parameters of the ICV in order to idle at the normal speed of 850rpm. Just be patient as it can take some time.

[gti-si 0]

With it connected up, if I touch the throttle the revs rise rediculously and will not fall. I'll plug the motor back in and try again, see if it changes. I don't think there is a signal from the ecu though, the motor doesn't do ANYTHING atall. Could the ecu be knackered in that respect but still start the car? That would be 2 haha

[CaptainK 11]

On a different car (Mitsi FTO) I had a similar problem to you were my ICV had died, but also "kindly" decided to burnout the part of the ECU that drives the ICV. I replaced my ICV and still had the problems. We only discovered the ECU problem later on and it meant we had to send the ECU off to be reconditioned. Unfortunately, I can't remember how we found out it was the ECU. I think its a case of putting a voltmeter on the ICV outputs from the ECU and see what they are doing. Mine was random and just sending out silly signals to the ICV.

[gti-si 0]

Cheers Captain! I'll check the read outs. I've only just got this ECU to get the engine going! The one I got with it was duff and wouldn't start, really hope I don't need another

[welshpug 1,657]

not sure what outputs you should get from the ECU, this is the only info I could find for the ICV itself

 

[gti-si 0]

Same mate, I'd checked autodata aswell, there's no output voltage listed :s

 

Looking at that, I'd check voltage in 2 loops A,D and B,C yeah? Forward and reverse loop?

Edited July 7, 2008 by gti-si

[gti-si 0]

 

Had a good gander through Autodata and came across this, might be handy to know so I thought I'd post it up

Edited July 7, 2008 by gti-si

[gti-si 0]

Figured out my problem with the ICV today. Got my new loom through. Decided to test my ECU as the first port of call so I made a little rig in the kitchen.

 

I stripped off the big multiplug and found CC2 which goes to pin 14 on the relay. I then went and got my battery, connected this and the permanent live (which weirdly attaches to the alternator positive on this loom, rather than the terminal on my other) to the positive side and connected the earth and the -/ive on the multimeter to the negative.

 

 

Soon as I did that, the relay clicked and the ECU powered up. Got my positive multimeter prodder and found the voltages over Pin 1 and over Pin 3 of the ICV plug were reading a nice 12v. Went a undid my ICV, plugged it in and it calibrated, excellent news, my ECU is fine

 

 

I then hoped that it was a dodgy ICV plug on my loom, so I cut that off and took the voltages again. 0v and 4v respectively. Things are starting look more lengthy at this point. I cut the wires about 2 inches from the plug and again saw 0v and 4v.

 

I set the multimeter to it's buzz mode, which basically does a circuit test. Put one prong on the correct pin on the ECU plug and then one on the end of the ICV wire and it buzzes through clearly. Repeated that for all four wires and there was a circuit on all. Rather than checking the resistance (multimeters a bit dodgy on resistance readings) I fed 12v to the pin on the ecu and then tested the voltage across the wire and it came back at 4v. So it's definitely the ECU plug that's shot

 

I did have a go at removing the ICV pins from the ECU plug on my spare loom, but I only got this far:

 

 

I tried using GLPoo's guide, managed fine on a test with smaller connectors but couldn't remove one damn terminal from the ECU plug. So I put it all backl and left it

 

Just need to decide now, do I...Swap the whole loom, massacaring 2 hours or soldering and crimping efforts. Cut the ECU plug off and swap the whole thing or have another go at removing and replacing the terminals?

[welshpug 1,657]

to remove a pin from the ecu plug you need to pull out the purple bit from the side of it, you'll then be able to push the terminal out (may even be able to get it out with a gentle tug of the wire)

[gti-si 0]

to remove a pin from the ecu plug you need to pull out the purple bit from the side of it, you'll then be able to push the terminal out (may even be able to get it out with a gentle tug of the wire)

 

DOH!