Rough Idle on Cold Start

  • Thread starter Thread starter KLB
  • Start date Start date
K

KLB

I have a 1994 940 turbo Wagon

Working very well but has quite a rough idle on cold start, almost chokes
out.

On a warm start all is well.

Where would anyone suggest that I start looking?

Plugs and air filter are new

Thank you
 
KLB said:
I have a 1994 940 turbo Wagon

Working very well but has quite a rough idle on cold start, almost chokes
out.

On a warm start all is well.

Where would anyone suggest that I start looking?

Plugs and air filter are new

Thank you
Click to expand...
A good place to start is by cleaning the throttle body and idle air control
valve (the cylindrical air valve under the throttle body. They tend to get
fouled with deposits, especially the idle passage from either side of the
throttle plate to the thumbscrew underneath. Cold stalling is a typical
symptom for dirty throttle bodies.

I remove my throttle body for thorough cleaning (takes about half a can of
carb cleaner!) but it can be done on the engine.

Mike
 
Thanks Mike

This cleaning was or is on my to-do list and although it can be done on the
engine I was sort of thinking of doing the whole works, hence yanking it
off. Car is new to me and I would like to get an idea of just how dirty
everything is.

Any idea about my other post (replacing air intake) as it relates to this as
well.

Thank You
 
Took the car out to my mechanic last weekend and he removed and cleaned the
throttle body (somewhat dirty, smaller of the two ports was plugged)

Rough idle is better but not gone away.

What should a fellow look at next?
 
KLB said:
Took the car out to my mechanic last weekend and he removed and cleaned the
throttle body (somewhat dirty, smaller of the two ports was plugged)

Rough idle is better but not gone away.

What should a fellow look at next?
Click to expand...

Gwen Stefani, Catherine Zeta-Jones, or Angelina Jolie would smooth most
things out IMHO :)

---might help if you told us what kinda car, what year, have you done the
obvious fuel and ignition system maintance and how many miles are on the
car.
 
Sorry, Sorry

For a minute there I thought you were all mind readers.

Car is 94 940 turbo wagon, 110,000 miles, is not the Regina System.

Replaced plugs, wires, air filter, removed and cleaned TB so far. Volvo
just popped in new crank sensor via recall.

Runs great when warmed up, just a rough idle on a cold start. Idle stays
below 1000 during cold start, I would guess some where around 750 rpms.
 
Try cleaning the Idle Air Control Valve and checking the MAF for
cleanliness. Some air filter housings collect a large amount of plastic foam
dust which can affect the MAF.

All the best, Peter.

700/900/90 Register Keeper,
Volvo Owners Club (UK).
 
Steve said:
Gwen Stefani, Catherine Zeta-Jones, or Angelina Jolie would smooth most
things out IMHO :)
Click to expand...
The mark of a seasoned shadetree mechanic!

Mike
 
Michael Pardee said:
The mark of a seasoned shadetree mechanic!

Mike
Click to expand...

From their new commercial I think some Heineken light would also help
immeasurably... :)
(you have to drink imported beer to fix an imported car, no?)

--Steve (who has yet to find a brew to exceed the unique wonder of
Dortmunder Union Dark, although Becks will work in a pinch (started drinking
those when I had VW's - Do I need to change to one of these?
http://ohhh.myhead.org/list/2c-swe.html )
 
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