radiator temp sensor

[muzzaspike]

Hi all. In the throes of chasing the cursed over rich rough idle gremlin after warming up on a 95 318i. Discovered something weird today. After disconecting the battery and earthing the terminals and leaving for 2 days the old girl started fine (as usual) and idled just beautifully at traffic lights, driveway etc, until I turned the A/C on. Instant evil again! Rich idle (petrol smell), hunting till it stalls. Put the foot into it and it goes fine, just don"t idle. Also, if sitting on set speed, eg 60kph, plays up till you accelerate again.
So.... the question is: Does/can the radiator temp sensor for the A/C fan cause computer problems as regards to idle mixture?
Believe me any help would be soooo greatly appreciated
Am hoping that this might explain why it plays up after sitting in hot sun for a while. First thing you do is turn the A/C on!!!

Thanks, Muzza

[shogun]

Do NOT post in the E36 DIY forum questions, this is for DIY fixes/instructions.
Questions post in the E36 main forum, I will move it to there, more people read and you will get a reply there.

[muzzaspike]

Sorry, thanks

[Eric93se]

Find your vacuum leaks (smoke test it, watch youtube to make your own smoke tester). Replace you oxygen sensor (pre-cat). Remove and clean the inside of your IACV, make sure the weight inside moves freely. Test that your MAFS is properly functioning. Make sure you alternator is putting out good voltage, should regulate at 14.4V while idling (some regulate at 13.8V).

[muzzaspike]

Thanks for the reply. Have done some of that but will do the rest over the weekend. Starting to worry about the HG. HG was done 2 years ago and cracked head welded up. Was not impressed at the time by quality of the job, dipstick not fixed back on and a few little things like that. I'll post how I go.

[muzzaspike]

Well, did a smoke test with fluid transfer pump and a cigar from utube. absolutely brilliant! Is so cheap and so effective, have to use a longer cigar next time. One minor leak at rocker cover hose. took oil cap off and pressure of smoke pouring out was amazing. Did it again and pulled the dipstick, same thing happened, amazing. Fixed the leak and now Peake is throwing a O2 sensor which I will replace next week.
While engine was hot I did a compression test, from the front it was 180, 180, 185, 185. All PSI. Manual says 140-160 is on the low side so where does place? Also all plugs not very old (1000klm) but very very black sooty.
ICV seemed to be moving freely and OK.
Oh well, see what next week brings......

[Eric93se]

Good engine compression. If you wan to re-use the spark plugs you heat heat them with a propane torch till the carbon burns off, will turn white soot. Definitely do the oxygen sensor.

[zachdude1100]

I believe the IACV opens up more with the AC on to compensate for the increased load. Check for vac leaks between the intake boot and the iacv.