Re: idle revisited

["David Teitelbaum" <jtrealty@xxxx>]

If the car is running rich at idle then you have vacuum leaks and/or
your mixture adjustment is off. You might also have dirty fuel
injectors. Check the plug over the mixture screw to make sure it is
still there and is sealing the opening. If the car's behaviour changes
like throwing a switch then I am still thinking that something is not
right in the advance circuit, maybe some hoses are not connected
correctly and when the themostatic valve heats up it is advancing the
timing. Vacuum leaks can be hard to find and can make the car act
weird. On 1 car I worked on it cycled like it was hunting. I didn't
completely correct it but it behaved a lot better after getting the
"O" ring on the air tube for the idle motor sealed right! I really
thought it WAS the idle ECU till I tried it with a known good one and
it didn't make ANY difference! In most cases to REALLY make the motor
run like it was meant to means taking the top off and fixing something
left behind by a previous mechanic. Even with the best mechanic
sometimes an "O" ring can slip out of place when reassembling the
intake. It is not easy to put it back and if you slide it in an "O"
ring can move without noticeing it. 
David Teitelbaum
vin 10757


--- In dmcnews@xxxxxxxxxxxxxxx, Louie Golden <louie@xxxx> wrote:
> Of course I remember my last DeLorean ran on a manual idle speed
circuit Bill. The car actually ran much better that way. I am going to
go and buy some vacuum caps and cap off the idle speed motor and see
if my idle problem goes away when the idle speed motor is
non-functional. However the idle speed motor does buzz with the
ignition on, so I think it's OK. I can try running a manual idle
circuit for a while, but don't want to keep the car that way
permanently. The more things I change from stock on the car, the less
someone down the road who works on the car will understand how it
operates. I don't plan on ever selling the car, but I may have someone
else work on it eventually, and I'm also not going to be around
permanently either. Someone will inherit the car one day. I try to
look to the future with these cars...
> 
> I've been told before that the DeLorean O2 sensor does nothing until
about 300 degrees. Why then is it so common for people to diagnose a
car that hunts at idle to have a defective O2 sensor? Or is it only
when the car hunts when *WARM* that the O2 sensor is bad? So would a
vacuum leak cause hunting when cold, and high idle when warm then?
> 
> Just to reiterate my car's behavior, when the engine is VERY cold
(when it has been sitting overnight), it does hunt for about a minute,
then the idle smoothes out to about 800 rpms and stays that way for
several minutes until the engine gets warmer. Then something changes
the idle speed- the car jumps from idling perfectly at 800 rpms to
idling at 1500 rpms. It's literally like the flipping a switch. If I
go out and drive the car after this, the idle will get stuck at about
2000 rpms now. The idle speed has progressively gotten higher since
I've owned the car. These symptoms don't sound like a vacuum leak to
me... it sounds like something electronic... though I could be wrong. I'm