Anouther idle issue!!! Help!!

[holcan]

My idle is way to high. I've looked for a vacuum leak without success. The idle screw on the Ecu does not make any difference. The idle screw on the throttle body is turned all the way down. If i plug in the temp sensor the idle bounces and just about stalls . The aux air valve is working correctly and closes off. I'm running it now with the temp sensor in the manifold unplugged and the idle is at 2000 and won't go down. I tried pinching each vacuum hose with vise grips to find a leak. what i did find was that when I clamped the decal valve end port or side port hose the idle went down to 1000 rpm idle with no bounce. I clamped both ends of the vacuum hose from the manifold to the decal valve to make sure it as not leaking. no change. I have installed all new vacuum hoses .
Putting suction on the control port opens the decal valve and allows air to be blown through . So i guess that it works.

Why does closing the air flow to the decal valve by clamping the hose closed give me correct idle ???

Why does plugging in the air temp sensor cause the idle to bounce an stall if I don't feather the gas pedal?

I drove the car for 15 minutes with the hose to the sideport on the decal valve pinched closed and it ran perfect.

Any thoughts???

[Dave at Pelican Parts]

The decel valve should not let air through it under normal running. Sounds like yours is leaking pretty badly. I suggest plugging all of the lines that go to it until you get a good replacement. The car will run pretty well without the DV.

Unplugging the air temp sensor will make the mixture a bit richer. When the VD lines are plugged, turn the idle mixture knob on the ECU clockwise to richen the idle mixture, then try plugging the sensor in.

Double-check the fuel pressure; should be 29 PSI.

You can find the expected resistance range for the temp sensor on Brad Anders' D-jet pages. And tons of other info too.

--DD

[holcan]

Thanks Dave !!!!!
I searched around on the net after posting last night looking for a new DV and realize that they are very hard to find. Looks like used will be the only option.
There is an adjustment on the DV valve and judging by the way mine is setup it could totally wrong. I will see if brad has the correct settings.
The temp sensor ( not the one in the head) is new and i hope that it is not defective.

I will try your suggestions and see if I can get this car running correctly.
I am considering pulling out all the FI system and going carbs.

Brads d-jet page has been a great help!!!

[Morganr81]

Check the vacuum advance line. Well not the line but the actual vacuum unit on the side of the distributor. Because thats where mine was leaking from badly.