Hello,

I've scanned through most of the threads and found numerous possibilities to check for under the hood of my 1995 945T. But I thought I would send a little story in case anyone has other suggestions.

Last winter (in Montreal, Canada) I drove my car most days and we had many -30 degree Celsius days (about -20 Fahrenheit). I have a heated garage so starting is not a problem. Near the end of winter I noticed the car idled high on really cold days. This was particularly problematic when stopping on icy roads. A few times I had to pop the car in neutral to take the torque off the back tires because I'm braking but the car wants to keep moving. I thought the extreme cold was causing the problem (although not sure what). As spring came and warmer weather appeared the high idling stopped. Note to self to get that fixed before winter. About two weeks ago the car began to idle at about 2600 rpms after it reached temperature. So, not a cold weather problem as it has been hovering around 30 Celsius (about 85 Fahrenheit) here in Montreal.

I had some cooling/coolant issues earlier in summer. Heater control valve was leaking; replaced it, then the turbo coolant lines sprung leaks so replaced those; then the radiator cracked at the top nozzle so I replaced that. However, when the radiator went I didn't smell coolant cooking and the car overheated. I noticed the temp gauge pinned and pulled over. As I did, the engine revved and the turbo kicked in as if it was overheating too.

I solved all the coolant problems and replaced the radiator with a new Nissans as well as thermostat while I was at it. Now I'm having high idle issues as if it was winter again. So, I thought maybe I had sustained some damage to my turbo during the overheat. I've found a few threads on checking turbo boost and seeing when the turbo kicks in. However, my car does not have a turbo boost gauge on the dashboard. So when the car is at temperature and idling at 2600-2800 rpms I can't determine if the turbo is spinning and boosting or if it is just engine revving.

I'm the second owner of the car. It has 360,000 kms (about 220,000 miles). I have the complete service record of the car right from the bill of sale and I can't find any indication that the instrument cluster was changed. Could it have come from the factory without the turbo boost gauge?

The car lacks the power I recall it previous had although not in limp home state. I finally decided to check the codes. I went out today and to my dismay the cable end for the OBD box was snipped off. I'm sure I can manufacture something to check the codes as it's not that complicated but I didn't want to stick the bare end of the wire into slot #2.

I purchased vacuum lines today however they are only sold in imperial measurements here at my auto stores. Everything is metric in Canada (so i thought) so I walk into the auto parts store and ask for 4.2mm vacuum lines. The guy gives me a blank look and says he needs it in fractions of an inch. Anyway, I figure that out and have to opt for the 5/32 (just under 3.9mm). I get home and begin to have a look. The vacuum lines are a mixture of OEM 4.2mm and various other types including windshield washer lines. The plastic Tee connector - turbo to manifold to something else is 1/4". The hoses are stretched over the Tee. I pull it apart and the Tee connector cracks. I stop and suddenly recall Volvoforums member Pierce warning against those aged plastic parts cracking from brittleness. I bodge the lines back together in the Tee and decide to let sleeping dogs lie for now.

Last week a slight squeak/mild squeal sound showed up which has me thinking the water pump is next to go. The sound seems to disappear as the car warms.


So, here is my plan: remove and clean the Throttle body, replace all the vacuum lines. But first, I'll check the codes (after I fix the wire).

Any other ideas? And where can I order 4.2 mm vacuum lines and proper connectors, Tee or otherwise?

I posted a picture of my car that I drove to Saskatchewan and back 7000 kms round trip last summer.

Thanks again.

Roy

 

the circuit in the diag box is really simple.

+12 goes to a resistor to an LED to the jumper wire. also the jumper wire goes to the pushbutton which goes to ground.

the same circuit works on my mercedes 300E and E320 which have diag connections but no LED-button.

so when you push the button, the diag output that the jumper is plugged into gets grounded. when you release the button, the ECU/ICU/ABSCU/whatever at the other end blinks the LED by grounding the diag output.

re: the boost gauge, I think they dropped those from the 1995's, they were putting turbo engines in cars that weren't labeled turbo nor had the sport features associated with the turbo label (most 940 turbos had fog lamps, nicer alloys, stiffer shocks, bigger swaybars).

yeah, finding 4.2mm vacuum line is hard. the 5/32 stuff works OK. i've used those 5/32 t's too. its all good.

 

Thanks Pierce. I was puzzled when I went to look at the car and noticed the lack of signs that the car was a turbo. It only had "940" across the back tailgate, no fog lamps. The PO didn't know it was a turbo when I asked over the phone and until I popped the hood I didn't know either. I'll get that jumper plug replaced (i have old audio connectors called banana plugs that will work nicely). Thanks for your response. Cheers.

 

Ran codes:
On socket #2:
1-2-3 wiring faulty in/to ECT sensor
2-3-2 Fuel Trim (lambda control)

on socket #6
2-2-4 ECT faulty wiring or faulty ECT

then I ran the Diagnostic test mode 2 for System Sensor Signals
on socket 6; I only got a flashing LED which according to OBD codes page at swedishbricks suggest a faulty TPS.
Then I started the car to check the rest of the codes. The flashing LED went out but did not give me any other code nor did it begin flashing again. I ran the remaining tests in socket 2 (fuel injection related test) but could not get any flashing nor any codes.

So, I removed the intake hose to the throttle body to have a quick look. It had a coating of 'wet soot' on the inside. I put the hose back on with plans to remove and clean once I get a gasket.

Thinking the TPS connection might be corroded I grabbed a bottle of electrical contact cleaner and pulled of the connector. The inside of the connector was wet with an oily substance, it was actually collecting inside the cap! I cleaned the connector and the contact points on the TPS, sprayed it and re-attached.

I rest the codes. 1-1-1 all around.

I started the car. Engine revs at around 4000 rpms. I slipped my foot under the gas pedal and pulled it back and the idle dropped slightly to about 3700. I turned on the AC and the load of the compressor on the engine dropped the rpms to 3000. I shut the car off. After supper I started the car, idled at about 3500 rpm and drove it into my garage.

I checked the codes and get only the 2-3-2.

I'll clean the Throttle Body and maybe the Idle Control Valve. I'll replace the TPS. As for the 2-3-2 code, I'll finished replacing the vacuum lines once I find some tee connectors before jumping to other conclusions about lambda issues.

 

that sounds seriously gummed up. there's no way it should be idling nywhere near that high, I'm betting your throttle is so gummed up its not closing.

a worn out turbo can spray oil into the intake path. also, the crankcase ventilation goes to that 1" hose that crosses over the valve cover and connects to the air intake pipe between the MAF and the turbo intake, if your engine has a lot of blowby, thats where it all ends up.

 

while yall are on the subject, where is the OBD port on 1995 940's? I've searched for mine but have been unable to locate it.

 

its OBD-1, not OBD-II. its on the left strut tower under teh hood, near the power steering reservoir, a black box with a plastic cover and a jumper wire, pushbutton, and LED. some cars have two of them next to each other.

 

Awesome, thank you.

 

Replaced vacuum lines and connectors.
Replaced TPS
Removed and cleaned Throttle Body
Removed and cleaned idle control valve. (idle control valve hose to intake was cracked. patch job until dealer opens on Monday)

reinstalled everything. Car started. idled at approx 1400 rpms. went for a quick 5 km highway ride. car to temperature.car idled at 1900 rpm in Park.

shut off car and ran codes. 1-1-1 .

I checked the adjustment instructions at swedishbricks for the TPS but was not able to achieve the click sound or feel.

Engine: Fuel Injection


car performs very nicely on the autoroute, lots of power and response.

Ran Diag #2, System Sensor signal test. Faulty TPS indicated by continuous flashing LED after throttle wheel turned.
started car and code 1-4-1 flashed indicating RPM sensor is OK.
None of the fuel injection tests in socket 2 produced any "no-fault" codes.

Worried my old TPS may have been fine and I have to check voltage at the TPS connection?

other ideas?

Roy

 

if the throttle position idle switch isn't closing (said click, which is not really a definitive test unless you verify the switch operation with a ohm meter), then your throttle isn't closing all the way. I'd take the throttle body and idle switch assembly off the car and clean it thoroughly and investigate its mechanical behavior on the bench.

a warmed up engine, with the idle air control valve disconnected, should idle somewhere around or under 500rpm. a cold engine probably won't idle at all without the IAC. the IAC only comes into play when the idle switch is closed.

 

yeah, I thought something was up when I fit the TPS on the TB and it didn't seem to matter how I remounted the TPS with the screws. I'll pull it off again and check the shaft that runs through the TB to the TPS and see what is happening. >Pierce: to what are you referring when you mention the: "idle switch assembly"? Thanks. posting a pic of the TB before cleaning for everyone's reference of a gummed up TB.

Roy

 

yeah, the throttle position switch. the idle switch is the important part of it, the full throttle switch is less important. this is NOT a throttle position sensor in the sense of a potentiometer or whatever like some other vehicles use.

 

10-4. Got it. Thanks.

R.

 

Pulled the TB.
Inspected. Noodled with the TPS. Heard the famous click.
Reinstalled. Warmed car.
Idledat 1700 rpms.
Loosened TPS set screws and adjusted until idle dropped to about 1500 rpm. Couldn't get any better than that.
removed linkage arm from TB spring and adjusted set screw that stops the spring. Idle dropped to 1100 rpms. Reinstalled linkage arm and the idle jumped to 1700.
removed idle arm and adjusted to accommodate the new setting screw on the TB.
reinstalled the linkage arm.
Idled at 1100 rpms in neutral, 900 rpms in drive with brakes applied.
went for an autoroute drive and came off and car idled at 1100 and 900 respectively.
not quite to the instructions at swedishbricks for throttle position adjustments.

found a good link for throttle linkage etc adjustments here: http://www.volvotips.com/index.php/9...repair-manual/