hi all, 1994 850 T5: when the car is warm, breaking or slowing makes engine rpm irregular and stall, recently changed torque bushing (upper engine mount) in situ and have tried: cleaning throttle body now clean, idle valve next to throttle body, (both filthy), dizzy cap and rotor, and replaced two split vacuum hoses to the vacuum tree under the throttle body plastic cover found by listening. idles fine when starting cold, rough once engine up to temp. not getting any response to obd1 fault finding and I mean none not even three flashes.Any ideas would be appreciated, heaps!

 

Maybe your OBD-I port is bad. Do you have a OBD-II port under the coin holder?

Maybe the IAC is bad and or the MAF. Do you have a CEL? Does the bulb work?

 

Yeah I would CRC the MAF, or disconnect it the let it run or idle as usual and see if it does the same thing.

 

thanks, got the obd1 to work: lots of wiggling: (A2) for the ignition, got codes 232 and 121 faulty signal from air mass meter (?MAF) and fuel trim too lean or too rich @ idle, no other codes still. I have cleaned the MAF sensor with the CRC cleaner. I have tried disconnecting the MAF sensor at idle and mokes no difference, therefore MAF cactus? or wiring. I have ordered a new MAF eta next week. The CEL light ? Lamda works and shines beautifully and has since starting the weird idle and rpm under breaking. I don't have the OBD2 under the coin tray like in the pictures on this site, however I do have the four switch blanks in the console next to the shifter, perhaps these are not all for accessories and one may be for obd2? Thank you Marvin and RSPi, is the IAC the idle control valve next to the throttle body? Thanks again, if all comes good I'll let you know. Love the car.

 

My guess is you may have more vacuum leaks. Try spraying carb cleaner around the intake manifold area; if the idle speed goes up, you've found your leak...

 

thanks gdog, guess what I'm doing tomorrow, alot of the vacuum hoses look old but no audible leak like the two split lines on the vacuum tree under the throttle cover.

 

thanks, found vacuum leak at top of vacuum tree tubing to idle control valve using the throttle body cleaning spray. not yet sorted.

 

ok, changed the PCV system, changed oil and filter, fitted new turbo return line seal, cleaned idle control valve, MAF sensor (with the CRC Maf cleaner), cleaned the PTC valve, found a small split in the top hose from Idle control to vacuum tree and trimmed hose to remove and refitted. I moved the throttle cable around when replacing the upper torque bush and am thinking maybe this has ?stretched so lowering the idle and causing the problem. when I took the car for a test post the work today, the CEL light was off even at idle initially, but came on whilst driving after a few minutes before the temp gauge started coming up. Stalling at no throttle ie at roundabouts and give way signs when braking but also as I come off the throttle. getting some noise left hand side engine ?possible alternator bearings or power steering .

 

The throttle has a switch that should click when the throttle is applied any at all. With the car off, move the throttle linkage and listen for that click. If you hear it, that should be good. If you don't hear the click, maybe your throttle cable is out of adjustment. Please keep in kind that parts do not correct themselves all because you clean them.

 

I bought mine with many troubles of which one was the "boyfriend slash mech-a-niK" used the throttle cable adjustment to open the throttle to try and get the thing to idle. Still died occasionally at stop sighs and after I replaced the offending MAF sensor I couldn't figure out why it would race so badly. I went to check the idle set screw and realized the throttle wasn't returning all the way.
Same thing with too much play, you will not reach WOT (wide open throttle). Or as some call it, "The Playground" You should make sure you have just enough play for the throttle to close all the way and sit on the set screw. That set screw is between the second and third finger on the lower left of the throttle body in the picture. The "tab" that parks on it is on the other side and you want to make sure at idle they are touching. This is when the IAC is doing the work. If it's off that set screw then you have the IAC fighting to control idle as just the vibration of the engine will tug a little on the throttle and you have the throttle plate going one way and the IAC going the other. It doesn't make for a smooth idle and may not idle at all.

The throttle body's throttle plate has a set screw that is adjusted at the factory and should not be touched under any normal circumstance. Normal being unless you replace the plate or try to bore out the throat. The cable does not control idle and should have a touch of slack to let the throttle plate sit down on that set screw and allow the IAC motor to do ALL, I repeat ALL the work of controlling the idle.

 

thanks all, I am waiting for a new MAF sensor to arrive, I'll pull the codes tomorrow off the OBD1 and see what's there. I think I may have a vacuum leak somewhere but cannot hear any even when manipulating the lines, I'll get some more throttle body spray and try testing that way around the inlet manifold again. Dear RSPi, the click should be heard at the end of the throttle cable on the spring loaded round 'wheel' that joins to the arms that opens the butterfly?

 

read the codes today: A1 (trans) 313, 223, 143
A2 (fuel/ignition) 325, 535, 121
A3 (ABS) 444
A7 (combined instrument) 122
there is no connection for the A6 so A2 is for ignition and fuel
your input would be much appreciated

 

hi, found the codes on MVS, what and where is the TC control valve and where is the throttle position sensor located? The MAF sensor has been ordered, the code A2 325 Memory Failure has me stumped. thanks again to those wiser than I.

 

Thank you, kiss4afrog and rspi, pulled the codes yesterday: A1 223 throttle position sensor signal too low, 313 faulty signal from gear position sensor
A2 121 MAF signal 325 memory failure and 535 TC control valve signal
A3 444 no power supply to valves in hydraulic unit
A7 122 temp sensor interval too long
I am waiting for a new MAF sensor to arrive and am not sure what to do with the rest, any help/advice would be welcome, thanks again

 

hi all, ordered a new TPS as well, ran the car with TPS disconnected by not remembering to reconnect; no stalling just waiting on post to arrive now. Thanks. No longer blowing oil out rear of car or block since changing PCV system, Yay! Temperature sender for engine temp sounds suspect: next.