I have a '93 940 Turbo. Was having a stalling issue on first start up in the morning. After that would run ok. But would not fast idle on start up and idle rpm was a little low. I cleaned the IAC valve and also sprayed the MAF with MAF cleaner. Car has new air filter, plugs, rotor, wires. I adjusted the small idle screw so that it now idles at about 750 rpm. Car still does not fast idle at first start up. Just stays at 750.
The other issue I'm having is if I'm driving on a flat road and let my foot off the gas, the car will not slow below 14 mph. Just keeps going at that speed.

Did some extensive searches, no success. Any input would be greatly appreciated.
Thank you.

 

Your slowing down issue might be your kick down cable getting stuck. Find a lite weight all purpose oil (3 in 1 works great) and send a few drops down the cable housing...see if that works.

Is the low idle tripping a code yet? Sounds like the ECU thinks the car is already warm on start up. You'd think that'd trip a code. Otherwise, does the 940 have an Idle Position Sensor? Or is it just the screw and valve?

 

Thanks for your response cbevis. I will try the oil on the kick down cable.

Yes, the check engine light is on. I took it to Advance Auto and they couldn't find the diagnostics port. I have a Chiltons and still couldn't find it. I'll have to spend more time with it this weekend. I'll also check for the idle position screw. When I adjusted the idle I just loosened a small nut, turneda smallscrewslightly, then retightened the small nut.

Thanks again. Will post after I check things out.

 

I've found the tachs to be somewhat inaccurate on these cars. Use a separate gauge to verify the RPMs. Creeping along and not coming to a complete stop is something automatics will do especially if the idle speed is a little high.
These cars don't have a diagnostic port as they are OBD1. There is a small black box under the hood clise to the driver's side fenderwell and it uses flashing lites to show codes. To reset the CE light disconnect the neg. battery cable for a couple of minutes.

 

Thanks tedv. Your'e right. We finally figured it out last night at Advance Auto. I took my Chiltons along and we found the black box w/the flashing lights. Got a 2-3-1 code - adaptive fuel trim too lean or too rich in part load range. Not sure what to check next.

Interesting that you mentioned the automatic trans. Just had it rebuilt late April. Will ask them about it. Have a year warranty. Didn't notice until recently that the car will creep along and not roll to a stop. Could have been doing it for awhile, however the CEL only came on about 5-6 weeks ago.

Ron

 

What I meant was that automatic cars will creep along and not come to a complete stop especially if the idle speed is a little high which yours might be. There is nothing to make you suspect anything's wrong with the trans.

 

2-3-1 is a popular code that comes up on these old birds and (as with most OBD1 codes) it calls out more than one possibility. The one that has always confused me (until just recently) is: Lambda adjustment. It means the fuel trim (lambda control) is too lean or too rich at idle (Idle screw). Another: adaptive fuel trim too lean or too rich in part load range. I think that's the one you mentioned. It sounds the same as the first definition but it's not, it's an O2 sensor deal. But here's the catch. It says it's only for '94 and up. But, given you're in a '93 I guess I'd still start there. Replace the O2 sensor and re-adjust the idle screw accordingly...see what happens.

Tech and I were trouble shooting this once back in '06 and he mentioned that "231 is a vaccum leak. But alot of times on the 4 cylinder it comes up when no leaks are found." That's where I'd go next. Vacuum leaks are a PITA.

 

Thanks tedv and cbevis:

Still working on it. Will keep you posted.