De Lorean EuroTec

You could try stopping the intake vacuum getting to the charcoal canister from the cold start pipe. This is how I did it on mine, and it lowered the idle back to normal. Pretty easy too!

I did try that about a month ago when I found that the plug on the charcoal carnister was almost perished.
Pluged it like you did but no luck on my car. It still was at 1000 rpm when hot.
As for the dirty valves I probably need to change the valve stem seals.
Has that been done on a Delorean without pulling the heads?
Will a standerd valve spring compression tool do the job on a pvr head?

Does your idlespeed control idle OK when cold? Does it "hunt"'at all i.e. rev up and down?

I'm struggling to think of any other big obvious air/vacuum leaks that you haven't already got at.....you have a plug over the mixture screw?

Yes it runs very good when cold, nu hunting and around 750 rpm. When i got the car it did not have a plug over the mixture screw. Did a lot of reading on this forum and dmc talk and found out it needs to have one. So i made something to plug it, but nothing changed . Sprayed with starting flued on all the places where i could get to, but no leak was found. Was not happy with how loose the pipe from the idle speed motor goes into the mixture unit so made a temporary solution using some sealant. Again no luck.

Hmmmm....well unless you adjusted your mixture after plugging the CO hole you are now running about 2% CO richer than you were before. Although I can't see that affecting the idlespeed too much.

The manual quotes the oil dipstick tube and oil filler cap as sources of vacuum leak...maybe look there (o-ring on oil filler?), otherwise I'm running out of ideas for you.

No chance your sealant fix on the idle pipe has melted? FWIW I have the stock pipe and fitting and it still idles on spec when warm so it can be made to work, even though it looks and feels like it will leak.

Check for a stuck valve in the idle speed control valve.

Horsebox wrote:Hmmmm....well unless you adjusted your mixture after plugging the CO hole you are now running about 2% CO richer than you were before. Although I can't see that affecting the idlespeed too much.

The manual quotes the oil dipstick tube and oil filler cap as sources of vacuum leak...maybe look there (o-ring on oil filler?), otherwise I'm running out of ideas for you.

No chance your sealant fix on the idle pipe has melted? FWIW I have the stock pipe and fitting and it still idles on spec when warm so it can be made to work, even though it looks and feels like it will leak.

Thanks for your ideas Horsebox. I have not adjusted the mixture. After plugging it I went to get the title on the car and it was tested ok. Don't know how much it was and what the maximum limit is in Holland.
I know the dipstick is tight. Newer checked the oil filler cap. I will check it tomorow.
Did notice there was no gasket between the cold start valve and the pipe, so I will order one. But nothing happend when this was sprayed with starting flued.
I will replace the o ring in the idle pipe, it has gotten a flat side.
Thanks for your help!

Admin-bloke wrote:Check for a stuck valve in the idle speed control valve.

I have cleaned the inside with brake cleaner and compressed air about a month ago.
But i have never checked if the thing actualy works! Car is in pieces now, i will check it once everthing is back together.
Is there a way to trigger the valve to see if it moves? Just run the car and let it warm up?

Did you get a printed emissions report when you went for the test? If you did then that should have the CO value.

Mine doesn't have a gasket between the cold start valve and the brass tube either, but there is a little o-ring there. Mines a bit flat on one side too, but my idle is OK so I haven't done anything about it.

Bitsyncmaster on DMCTalk has written quite a bit about the way the idle valve works. I think it should move to half open when you put the ignition to Run, and then slowly close after a while if you don't start the car. I can't see how you'd be able to eyeball the valve with the engine running, as all the pipe work would have to be open and that really would be a bit of a vacuum leak Unless you've got an endoscope and can plumb it in to a closed system?

Delta Delorean wrote:

Admin-bloke wrote:Check for a stuck valve in the idle speed control valve.

I have cleaned the inside with brake cleaner and compressed air about a month ago.
But i have never checked if the thing actualy works! Car is in pieces now, i will check it once everthing is back together.
Is there a way to trigger the valve to see if it moves? Just run the car and let it warm up?

Use a test car battery and fused wires.
Disconnect the idle valve if not done already.
Apply 12v to the centre pin of the idle control valve.

Apply the 0v briefly (less than 1 second) to one of the outer pins, the valve should fully move in one direction ie move fully opened or fully closed.

Apply the 0v briefly (less than 1 second) to the other outer pin, the valve should fully move in the opposite direction ie move fully opened or fully closed.

The valve should move freely, as in if you had the control valve in your hand, you could flick the valve open and closed if you quickly flicked the case around.

A quick check if the ecu is controlling the valve is to connect it to the wiring but still have it off the car. With the valve in the closed position, turn the ignition key to position 2, the ecu will slowly move the valve open in a controlled manner.

One thing to note is that the air flow is directional, the air should flow in one direction, there should be a small arrow on the casing. This should point to the direction of the brass pipe that is a push fitment under the inlet manifold.

I think you're better off isolating the systems that can cause the engine to hunt, one of which is a contaminated oxygen sensor giving poor/ slow switching feedback. You can electrically disconnect this at the back of the drivers seat under the wooden board, behind the grey rubber bung in the fire wall. Disconnect this and tape over the bare electrical spade connection at the blue wire that goes to the lambda (fuel) computer.