I have a 1995 Volvo 940. The engine idle roughly even when the engine is warm up. Randomly the engine would die even when it's already warm up. The temperature gauge needle would bounce up and down. After doing research on the Net, some suggest that it could be a faulty temperature sensor. Need second opinion. If it is the temperature sensor, need help on how to replace it. Thanks.

 

The two are not related. The temp gauge sensor is in the head, driver side, under the #1 intake manifold runner. Make sure it's connected securely. To get it off you have to break it.
The stalling is hard to diagnose without more info, like last "tune up", engine misfires, things like that.

 

I would like to give your suggestion a try. Do you know where I can get an engine diagram so that I can see where all the items are located? I'm a visually oriented person.

 

the #1 cylinder is the one closest to the front of the car. the intake runners are the 4 silver tubes going into the engine on the left (american drivers) side. so directly under that #1 cylinder.

btw, the reason Lev said its not related, there are two seperate temp sensors, the one for the gauge in the dashboard, and a completely different one used by the ignition and injection control units

 

Finally resolved my problems. Replaced the temperature sensor (the one for the gauge in the dashboard). Tried to clean the idle air control valve. But it still wouldn't open. Replaced it. Now it's running fine.

 

Good day. New to forum. Thanks for all the advise. I've got a 1992 940 2.3 wagon. Recently started to idle rough. As well as a rough acceleration. Replaced cap and rotor, spark plugs, plug wires. Cleaned throttle body, air intake and hoses, fuel injectors, as well as the flame/pcv valve. On plugged the maf( died instantly). Waiting to replace o2 sensor, and fuel filter(on order from part store). Been researching online and have discovered this to be a common problem. Haven't heard too many success post with exception of. Faulty distributor, bad plug wire, bad bosh plugs, or switching out radio relay suppressor, radiator thermal switch. Summary: next step is to replace 02 sensor, fuel filter, temp sensor. Beyon that any other ideas would be appreciated.

 

if its not throwing any OBD codes, your O2 sensor is probably fine.

fuel filters are rarely a problem, they last a long long time. if the filter was partially obstructed, you'd be having high RPM high throttle power loss problems, not idling.

 

Just in from the garage with an unfavorable update with the rough idle/low compression issue with my 92 940 non turbo.
Symptom: rough idle/miss. Low compression at acceleration.
Cleaned: throttle body, flame trap/pcv( I think that's what it's called. Very dirty, and may need to be replaced. But don't know where to find one).
Replaced: plugs, plug wires,cap and rotor, air idle control valve, temp sensor, temp switch. Fuel pressure reg.
Checked: injectors by unplugging injector while car running to see if changed. #1&#4 from front to back. Shut vehicle off. #2&#3 from front to back no change.
I'm at a loss, and pass frustrated. Been looking on line for similar situation and fixes. While each remedy seems to be different. Any ideas would be much appreciated.

 

flame trap and the oil seperator box can be had from any Volvo dealer, or any of the discount dealer websites like TascaParts.com or Volvo Parts - Authentic OEM Volvo Parts direct from Volvo Parts Webstore | VolvoPartsWebstore.com, or from the various Volvo-centric independent parts resellers, like Volvo Parts, Accessories and Performance Specialist Since 1963 or FCP Euro

what do you mean by 'low compression on acceleration' ? compression is something you test with a compression gauge that you screw into each spark plug hole, and crank the engine over with the ignition and injection disabled.

did you clean the idle air control valve when you were in there cleaning the throttle body? are all the rubber hoses in the MAF to intake path and idle air control valve path, and vacuum hoses in good condition?

if unplugging the #2 and #3 injectors didn't cause an immediate change in engine running, then something is wrong.

 

Thanks for your input. No master mechanic by any means coming from this end. Couldn't locate the maf. This is a Regina system if that means anything. Unplugged battery in hopes of resetting the car( read that on an earlier post). I replaced the idle air control valve with new. Checked and cleaned hoses while I was in there. Checked for leaks by spraying carb cleaner to see of any change in idle. And what I meant by low compression. When doing road test. N
Little to no power after first gear/ first acceleration. And total loss of power on any incline what so ever. Pulled all injectors off for cleaning and inspection last night. Noticed no difference in condition between one or the other.
Looking forward to replies to add to this weekends project. Thank you for your input. And wish me luck. Not scoring many points with the wife!!!!!!

 

oh. regina has no MAF, hah. it has a air temp sensor in the airpath, but air leaks aren't nearly as critical. I know a LOT less about Regina than I do LH (never seen a regina system up close).