2.0L 16v 9a - need help asap - very low idle

[Bazmcc 0]

I need some help with this one.

 

I can start the car no problem and it will run flawlessly for 20 - 25 seconds and then the idle will suddenly drop right down to 4 or 500 rpm and splutters and chugs and even with the throttle open it won't pick up the idles again. But it will continue to run. It does not cut out.

 

If I turn the ignition off and turn the car back on again it will start easily again and run as normal for another 20 seconds or so before doing the same thing.

 

The car has recorded no faults at all, not even a misfire, no sensors out of range etc.

 

All vac lines are plugged in where they should be and the isv appears to be perfectly functional. Throttle body is perfectly clean. Airbox and plate is spot on, clean and moving freely.

 

My first suspicion was that it might be a faulty cam sensor or something which might be adjusting the timing or somthing but I would have assumed it would show a fault of some kind.

 

Any ideas of what to check or how to test some bits would be good.

[Bazmcc 0]

It's all gone quiet.......

 

Has anyone got any ideas?

[swiftkid 1]

Could possibly be a fuelling problem, is the fuel pump making any funny noises? Is the fuel pump relay in position properly?

 

So when you lift the throttle it just stays at the same RPM? or does it try and raise but struggles?

[pumbaa 0]

Does it run any better if you pull the electrical plug on the right hand side of the metering head out?

[Bazmcc 0]

I'll check the fuel pump and relay when I get home. I had kind of ruled them out though as the car can be driven at full tilt as normal for the 20 or 25 seconds that it's running correctly.

 

When it's running badly I can put the throttle to the floor and it'll splutter and chug for a bit and eventually make it's way up to about 2.5Krpm but still runs like crap. When I take my foot off it returns to the very low revs and spluttering.

 

---------- Post added at 03:25 PM ---------- Previous post was at 03:21 PM ----------

 

Does it run any better if you pull the electrical plug on the right hand side of the metering head out?

 

I haven't tried that yet but will have a look when I get home. I cleaned out the metering head a few months back when I was cleaning the throttle body. It appeared to be fine but i'll unplug it and check later.

[Bazmcc 0]

Tried unplugging the metering head and it ran probably worse.

 

I have noticed that the 167 relay is heating up though. I think this might be the source of the problem. I'm going to try and find another relay somewhere today and test it out later.

[Bazmcc 0]

Tried a new 167 relay and the car seems to idle normally when it's left alone but the revs are still varying and hunting a bit. Then when it was warmed up a bit I checked it out by slowly giving it a few revs up and down and the rev hunting got worse and there was a fair bit of spluttering and chugging but it does seem to be improved slightly. However, the problem isn't solved and still very much a problem.

 

Any ideas?

[Bazmcc 0]

I still need some help with this.

 

Should this valve be ticking in time with the engine revs?

 

And when this is unplugged the car seems to run fine. Can someone confirm what this is?

[aide 0]

I've a book at home on the 9a injection system, I'll have a look when i get home, but I thought the sensors around that take off were temp related, could be a thermotime of some sort rated at 20secs, hence why it runs fine for that length of time before affecting the fueling.

[Bazmcc 0]

But it's now more inconsistant. A couple of times it's idled bad from the start yesterday. There's no doubt that unplugging the white plug shown above sorts it out. Can anyone confirm what sensor it is?

[odub 0]

I'm pretty sure that one is the ecu temp sensor. I am on a boat in Spain reading this off my phone though. If that is this case it will effect the ignition map

[Bazmcc 0]

Nice one. I'll try and do some searching online and see what I can find. Sounds about right though.

[pumbaa 0]

Its defo a temp sensor.

 

I'll have a look round as i might have a spare you can have for postage cost. They're only a few £'s new though anyway.

[Bazmcc 0]

I need to pick up stuff from vw this week anyway so if it's cheap enough i'll just order one. I'll try and find out.

[Bazmcc 0]

Changed the temp sensor.

 

Problem is still there.

 

I'm going to have a good dig around the wiring later. I found one part of the ISV plug wiring which was slightly rubbed through and exposed so i'm going to rewire it with fresh wire and cut the bad bit out. I think i'll also strip off the main earth at the battery and try to clean it up and see if it helps.

[Big'G' 0]

Keep us up-to-date with this, I have a very similar prob, but nearly as bad as what you have, good luck finding out

how to fix it .

[Bazmcc 0]

What have you tried to sort it out?

[easypops 8]

Have a look in here...............i posted links to a few other related topics in the last post of this thread..............i know where my money would be going :)

 

http://the-corrado.net/showthread.php?52775-Idle-Problems.......&highlight=2.0+16v+idle

[Bazmcc 0]

ISV is cleaned and is functioning normally. When I nip the pipe at the manifold I can change the idle and cut the car out if I close it completely. If I unplug it, the car will cut out.

 

I've already tried a new fuel pump relay.

 

The links you posted don't seem to work. I just get error pages.

 

Should this valve be ticking in time with the engine revs?

[Big'G' 0]

What have you tried to sort it out?

 

Nothing as yet, My car randomly jumps to 1200-1600revs and sometimes drops to 400 and stall.

would like to get the fuel filter changed, got one but need to change it, cleaned throttle body and surrounding

bits, but still the same.

[Bazmcc 0]

I got this fixed. I thought I had updated the thread but obviously not.

 

I removed all the earths, cleaned then up and bolted them all back on and the car is running perfect again.

Thanks

Baz