325es acceleration and idle problems

[325es86]

I own an 86 325es. Only have had a couple of months. The car idles rough in warm/hot weather. Has a definite, almost pulsating hesitation when accelerating. Most notable when engine is cold or air temperature is hot. Best driving so far has been when air temperature was 55 degrees and engine was warm.

Is it possible that the problem is the O2 sensor? Is there a separate air temperature sensor or is that part of the mass flow sensor?

Help appreciated.

[BimmerKris]

if it is a chugging feeling under acceleration, like it moves then feels like your hammereing on the brakes, and back on the throttle, chances are the o2 sensoer is shot, thats what was wrong with mine. other wise give your air intake system a good cleaning, and same with the ICV.

[{NTM}]

I Have the same car and the same problem.
I have seach the ICV and does'nt find it...its the at the same place that I model..
My O2 is new...so i think is more the mass air flow that have a problem.

2k to 3k RPM its like they does'nt have the gaz or the air that they need, but when you go more that 3500rmp its oki..so i think that the mass air flow does'nt suck the air that they need...

Anywais, i change my engine for a I and 3 week so i don't put $$ on this problem...

[onerchprk]

Check the throttle posistion sensor...

[BimmerKris]

the cat converter could be totally plugged to. chances are if it is still the original

[325es86]

Thanks. All good suggestions. The car has 147000 miles on it. I change the plugs and they looked excellent. Also changed the fuel filter. Both just because I didn't know how long it had been since they had been changed. The car mostly sat for a couple of years. Owner drove it around the block occasionally to keep the battery charged.

The hesitation does appear to be in that lower rpm range. It seems to pulse or chug. The car continues to accelerate but it is like it is accelerating in spurts.

I will look into all the items you discussed.

Thanks again for the great suggestions.

[300k 325e]

i have the same problem, it may be the Motronic Control Unit (ecu located in dash above glove box latch) i took readings on my AFM harness and found them to be reading correctly, possibly harness or coolant temp sensor causing car to run rich. where can you get throttle position sensors? AFMs are on ebay all over the place, i think they may be adjustable i just dont know how to adjust them. I would like to replace the MCU and see what happens but i would like some feedback as well. My car seems to be running really really rich, and from what i have learned through experience, the O2 sensor only "trims" the fuel, it doesnt have total control over fuel enrichment. i feel it may be a clogged cat, as my car has over 252K on it, probably original cat, too. keep posting ideas.

[onerchprk]

You can purchase a new tps from most auto supply stores such as autozone, Murphys and i believe napas...

[Fox]

have you tried using something to clean the fuel injectors? Sometimes at low speeds the diaphragms can get sticky but at higher rpms they warm up. Other than that nothing comes to mind right now....

[first5ny]

Some redline SI-1 fuel sytem clener wouldn't hurt and could be a cheap fix if your injectors are clogged.

[Old_School_Bimmer]

I am not sure how to check which injector is messed so what would be the easyest way and what is the easiest way to clean them out