87 325i Idle Problems

I AM HAVING IDLE CONTROL PROBLEMS. I REPLACED ICV AND ENGINE STILL JUMPS UP AND DOW. I HAV ETHE mOTRONIC 1.1 WITH 3 WIRES. I KNOW ICV IS GOOD, I SWITCHED IT WITH MY 86 735I AND EVERTHING WORKS. ANY IDEAS

Originally Posted by rickburby

I AM HAVING IDLE CONTROL PROBLEMS. I REPLACED ICV AND ENGINE STILL JUMPS UP AND DOW. I HAV ETHE mOTRONIC 1.1 WITH 3 WIRES. I KNOW ICV IS GOOD, I SWITCHED IT WITH MY 86 735I AND EVERTHING WORKS. ANY IDEAS

#1 Please stop yelling (CAPS)

#2 Is your idle problem at start up (cold) or at normal oper. temp?

Originally Posted by misterlance

#1 Please stop yelling (CAPS)

#2 Is your idle problem at start up (cold) or at normal oper. temp?

At start up and as I drive. Of course I only notice it at stop lights.

Originally Posted by rickburby

At start up

Cold start valve. Do you have a manual?

Originally Posted by misterlance

Cold start valve. Do you have a manual?

I have a Haynes 3 & 5 repair manual. Is cold start injector expensive to replace?

Originally Posted by rickburby

I have a Haynes 3 & 5 repair manual. Is cold start injector expensive to replace?

If you go to the stealer, yes.

Its @100$ for the part, if you go aftermarket, Bosch only.

Its pretty easy to replace.

Originally Posted by misterlance

If you go to the stealer, yes.

Its @100$ for the part, if you go aftermarket, Bosch only.

Its pretty easy to replace.

Will it hurt the car to drive it? It is quite frustrating to drive. Is that a part I could get used? I get some at vinesauto.com sell only bmw parts

Originally Posted by rickburby

Will it hurt the car to drive it? It is quite frustrating to drive. Is that a part I could get used? I get some at vinesauto.com sell only bmw parts

IF the prob is only at cold start up, and it runs fine after its warmed up, I would say its ok to drive it. You might want to maintain the idle manually intil it is warmed up.

As far as buying that part used, I wouldnt recommend it. Its like buying a used lightbulb.

Originally Posted by misterlance

IF the prob is only at cold start up, and it runs fine after its warmed up, I would say its ok to drive it. You might want to maintain the idle manually intil it is warmed up.

As far as buying that part used, I wouldnt recommend it. Its like buying a used lightbulb.

Thanks for all your help. I will try to warm it up and see if problem goes away. If not any other ideas? Manual also mentions Thermo-time switch in same section???

Originally Posted by rickburby

Thanks for all your help. I will try to warm it up and see if problem goes away. If not any other ideas? Manual also mentions Thermo-time switch in same section???

IIRC the thermo time switch is a mechanical part, that "should" be o.k. From my experience with the Old E30's, corrosion is my #1 enemy. I would check all the points, connections and clean or replace them. Also fun little things that would be a factor after warm-up are the oxygen sensor and the air flow meter.

oxygen sensor is my guess.I had the same problem on my 85 eta.After new o2 sensor,it was gone.

Not sure we have the same problem though the symptoms sound close, but my '89 325I was having cold start/rough cold idle issues. Cure: New Cooleant Temperature Sensor, which tells the computer to leave the injectors open a little longer in cold weather; new Fuel Pressure Regulator, and new Fuel Pump Relay. Parts = $145, Labor = $160.

I still question the Coolant Temperature Sensor replacement, however, since Bentley says that when that goes the Check Engine light responds with a certain blinking pattern. Same with O2 sensor. Who knows.

The Motronic 1.1 did away with a separate Cold Start Valve, as I understand it.

Originally Posted by misterlance

IIRC the thermo time switch is a mechanical part, that "should" be o.k. From my experience with the Old E30's, corrosion is my #1 enemy. I would check all the points, connections and clean or replace them. Also fun little things that would be a factor after warm-up are the oxygen sensor and the air flow meter.

Hey misterlance, just reading your helpful replies here. I have a 92 318ic. The car runs beautifully except just recently during start ups. It seems a little rough at idle but only after it's been warmed up and only at the first stop light. I never drive it cold, always let it warm up. It idles at .8rpms and never waivers..that seems low to me. Back to the first issue though, the rough idle seems like it isn't getting air or gas would be my guess, but I'm not a mechanic. When I read your answer stating to check air flow meter or OS, could that be my problem too..(I realize diagnosis over posts isn't accurate)..but gives some point of direction. Thanks

Originally Posted by julz

Hey misterlance, just reading your helpful replies here. I have a 92 318ic. The car runs beautifully except just recently during start ups. It seems a little rough at idle but only after it's been warmed up and only at the first stop light. I never drive it cold, always let it warm up. It idles at .8rpms and never waivers..that seems low to me. Back to the first issue though, the rough idle seems like it isn't getting air or gas would be my guess, but I'm not a mechanic. When I read your answer stating to check air flow meter or OS, could that be my problem too..(I realize diagnosis over posts isn't accurate)..but gives some point of direction. Thanks

When was the last time you had a tune-up (cap, rotor, plugs)? Next I would check all filters (fuel, air, oil). After that, you'll need to narrow down the fluctuation. Is it at start-up (cold)? Or is it consistent even after warmed up?

Originally Posted by misterlance

When was the last time you had a tune-up (cap, rotor, plugs)? Next I would check all filters (fuel, air, oil). After that, you'll need to narrow down the fluctuation. Is it at start-up (cold)? Or is it consistent even after warmed up?

I have replaced the plugs (not the cap and rotor) in the last 1 year and 3 months. I have regularly replaced the oil and air filters. I have not replaced the fuel filter. If it isn't the OS or the FM, my guess would be the FF. It feels starved or choking for something but runs extremely smooth once we get going. It only does it at start up and only on my way "home" in the afternoon from work...not first thing in the morning. Our temps aren't that much different am/pm, maybe I warm it up longer in the am. If it isn't too much to ask you, could a person that is somewhat mech-inclined change the fuel filter? (me) Thank you so much for taking the time to answer.

Whoa, guys....have you checked the air intake's elbow pipe, the one that looks like an accordian? If it has any cracks, especially at the flex points, replace it immediately. It's like $15. These cars are getting up there in age, so the rubber tends to break down.

I've had that problem, as did my buddy, and in both cases, replacing it solved the surging idle.

Originally Posted by WileECoyote

Whoa, guys....have you checked the air intake's elbow pipe, the one that looks like an accordian? If it has any cracks, especially at the flex points, replace it immediately. It's like $15. These cars are getting up there in age, so the rubber tends to break down.

I've had that problem, as did my buddy, and in both cases, replacing it solved the surging idle.

Real good idea. Were you able to spot the cracks by looking closely?

Originally Posted by julz

I have replaced the plugs (not the cap and rotor) in the last 1 year and 3 months. I have regularly replaced the oil and air filters. I have not replaced the fuel filter. If it isn't the OS or the FM, my guess would be the FF. It feels starved or choking for something but runs extremely smooth once we get going. It only does it at start up and only on my way "home" in the afternoon from work...not first thing in the morning. Our temps aren't that much different am/pm, maybe I warm it up longer in the am. If it isn't too much to ask you, could a person that is somewhat mech-inclined change the fuel filter? (me) Thank you so much for taking the time to answer.

The FF is a slight pain to get to but it is straightforward ( I hope you have small hands).
It should be an inline type filter below the master cylinder.

Good luck!

Originally Posted by 89 325i

Real good idea. Were you able to spot the cracks by looking closely?

Yeah, it's pretty simple. Pinch it to cause it to flex.

Originally Posted by misterlance

The FF is a slight pain to get to but it is straightforward ( I hope you have small hands).
It should be an inline type filter below the master cylinder.

Good luck!

what type of plugs did u use? when was the last time you cleaned your throttle body? Also air flow meter flap is known to lose its ability to open flush to the housing and will actually start to make a groove after a while (long shot) but easy to R&R for both.

Originally Posted by misterlance

The FF is a slight pain to get to but it is straightforward ( I hope you have small hands).
It should be an inline type filter below the master cylinder.

Good luck!

Thank you for treating me nicely. I've been having a rough time just trying to ask honest questions in some other areas. I'll give it a go on the FF.
Take care.