960 '94 - idle problem

[nimeya]

I have a '94 960 with idling problem (no idle, very high idle 2000 rpm).
The car runs on LGP and petrol and I have the issue in both mode
I have changed the idle control valve and the air mass meter (second
hand parts) without result

For now I have replaced the control valve with a manual one and it is
working "fine" in LGP mode, but it is still unusable in petrol mode (the
engine speed is fluctuating, and stops, even when I accelerate).

It seems that the idle control valve is receiving some bad signals but I
don't know which sensors are involved (temperature, AC, pollution, ...).

Any help is welcome.
Thanks in advance,
Stephane

 

[John Robertson]

Hi we are in the same boat with our idle on a 1988 turbo volvo even the
Volvo guys are stumped .I cleaned the throttle body idle control and still
it will go for a while then play up .Its a safety issue too as it goes up
down when it feels like it with no warning .

 

[Peter Adler]

And the same here with my '90 765T, B230FI. It's resting at the moment
because I'm tired of chasing down every last little thing that could be
wrong with it and still not finding a solution. The idle problem got
steadily worse and the car is now undriveable. It's also running extremely
rich. Here's what I've done so far:
New air filter/fuel filter. Cleaned out IAC. Checked and adjusted
throttle & switch. Cleaned inlet galleries etc. Checked AMM. Checked all
vacuum lines etc. for leaks. Replaced inlet manifold gasket. Pulled all
possible relays, cleaned points, checked continuity of coils, checked
circuit boards. Replaced coolant temp sensor under inlet runner 3. Replaced
O2 sensor. Pulled all related connectors, cleaned with contact cleaner,
reassembled with silicone grease (except O2 sensor leads -- they're best
left bare). Replaced spark plugs and leads. Cleaned injectors, tested for
leaks and spray pattern, reassembled with new seals. Cleaned and reassembled
all ground contacts. Bench tested fuel pressure control unit and checked
fuel line pressures. Replaced rusty section of fuel return line and checked
for unrestricted return flow. Checked rpm sensor for continuity (couldn't
get the thing out but it looks okay). Tore out hair. Said rude words.
And I've probably done other stuff that I don't remember now.

Is there anything I've overlooked? Is there anything you guys have done
that's made the slightest difference?

I'd be really, really interested ...

Pete (fP)

 

[Michael Pardee]

And the same here with my '90 765T, B230FI. It's resting at the moment
because I'm tired of chasing down every last little thing that could be
wrong with it and still not finding a solution. The idle problem got
steadily worse and the car is now undriveable. It's also running extremely
rich. Here's what I've done so far:
New air filter/fuel filter. Cleaned out IAC. Checked and adjusted
throttle & switch. Cleaned inlet galleries etc. Checked AMM. Checked all
vacuum lines etc. for leaks. Replaced inlet manifold gasket. Pulled all
possible relays, cleaned points, checked continuity of coils, checked
circuit boards. Replaced coolant temp sensor under inlet runner 3.
Replaced O2 sensor. Pulled all related connectors, cleaned with contact
cleaner, reassembled with silicone grease (except O2 sensor leads --
they're best left bare). Replaced spark plugs and leads. Cleaned
injectors, tested for leaks and spray pattern, reassembled with new seals.
Cleaned and reassembled all ground contacts. Bench tested fuel pressure
control unit and checked fuel line pressures. Replaced rusty section of
fuel return line and checked for unrestricted return flow. Checked rpm
sensor for continuity (couldn't get the thing out but it looks okay). Tore
out hair. Said rude words.
And I've probably done other stuff that I don't remember now.

Is there anything I've overlooked? Is there anything you guys have done
that's made the slightest difference?

I'd be really, really interested ...

Pete (fP)

How have you checked the AMM? The connector on mine has become intermittent
in recent years; I pull the connector off and clean it with isopropyl
alcohol then reconnect it for another several months' use. When bad the idle
becomes low and lumpy and the engine power is terrible. During the lumpy
idle I can lift up on the AMM connector and it will surge then smooth out.

Mike