High Idle, but only when driving or warm., Cold, and sitting... 1000 RPM. Driving...1400 ?? Options

[MikeInMunich]

Greetings from Munich gentlemen!

As seen in the title, my car (1973 1.7 converted to 2 liter, D-Jettronic F.I.) idles at 1000 after starting and letting it sit. When I take it out in the road it quickly changes to 1400. It still idles at 1400 when stopped after the car is warm.

1) I think my AAR (auxiliary air regulator) valve isn't working at all. Disconnecting the vacuum hose, the idle shot up to about 3000 and covering it with my finger 100% it went back down to where it was before I had detached it from the AAR. So the AAR should have been OPEN as the car wasn't warm yet, but it seems to be closed 100%.

Strangely, the idle only goes up after the car is out on the road / is warm...but not even yet near normal operating temperature.

I'm thinking the AFR is leaning out under load and after the car is fully warmed up. (IMG:style_emoticons/default/idea.gif) I currently don't have AFR or CO values. I will have the CO measured cold and after warming up in a few days.

Here's another issue and question fer y'all. While looking into the bay yesterday I noticed a substantial leak at one of the fuel injectors. I didn't mess with it much (checking the seating of the seal) but after I drove the car and it was warm, I looked again and it had stopped leaking. I thought it could have something to do with temp and fuel pressure (IMG:style_emoticons/default/confused24.gif) Starting up the car cold this morning however, I checked again, and there was still no leak. Does anyone have any idea what could cause an apparently intermittent leak like this? Perhaps just fudging with it gently got a seal to sit better, but I'm skeptical about that.

Thanks for your feedback! (IMG:style_emoticons/default/beerchug.gif)

By the way, I do know about this thread on Rennlist, which is a tremendous resource:
http://members.rennlist.com/pbanders/djetparts.htm

Mike in Munich

[Dave_Darling]

The injectors generally leak from three places. One is a leak of the short hose connecting the injector to the fuel rail. The original injectors had crimped-on clamps holding the hose to the injectors; to replace the hose you cut the clamp off to remove the hose, and use a new fuel-injection hose clamp to attach the new hose. There are formed curved hoses specifically for this, but ordinary straight hose can be made to work.

The next place they leak is between the plastic and metal parts of the injector body. Some of the rebuilders can cure some of those, but often enough the real fix is to replace the injector.

The third place they can leak is around the rubber O-ring that goes around the tip and holds it in place in the intake runner. The O-rings can be replaced fairly easily.

The fuel pressure regulator in a D-jet system has no vacuum connections, so spraying it should not affect the idle at all. Double-check that. The screw on the end can be moved after the jam-nut on it is loosened, but you're not nearly at that point.

--DD

[MikeInMunich]

Thanks again Dave.

I am sure that spraying the cleaning fluid onto the end of the fuel regulator cause the idle to drop significantly. Very odd, no?

Question: Any idea why the fuel leak could be intermittent? Again, sometimes BAD, like two drops a second and most of the time not at all. (IMG:style_emoticons/default/confused24.gif)

M.i.M.