My 91 1275cc single point fuel injection motor is having idle issues. It starts no problem idles at 1200rpm till slightly warm then settles to 900rpm. Normal right? Here is when the problem starts after a few more min of driving and the motor gets warmer the idle begins to climb as the temp goes up. eventually at stop lights the engine will rev up to 2300rpm and then fall to 1500rpm then up and down and so on. any suggestions would be helpful thanks!

 

sounds like it might be a compression issue, make sure non of the air hoses are kinking, or disconected......does it sound like the car is breathing (like a constant inhale exhale type thingy..)

 

Thanks I should have mentioned i have a red vac tube that connects to my air filter case. but is not connected at the other end. I think it goes to the trottle body i will try to find its home today maby that is all the problem is.

 

Does it go back to idle if you rev it a little when this happens? Also do you have additional steam out the pipe on a colder day as if its running way too rich when this happens?

Check on the oxygen sensor if you have one. I assume it does since its injected. It may have a loose wire or the sensor could be real carboned up. I wouldn't go out and order a new one right away though since they are pretty expensive.

 

If I blip the gas it setteles to about 2000rpm for 3-4 sec then back to its climbing and falling thing. I do have quite a bit of steam from the tail pipe when cold but I have no basis for comparison due to my other mini being new it dosent have any at all on cold days. I will pull my O2 and attempt to clean it. I believe yuo can soak the end in carb cleaner to remove some of the carbon. thanks for the Ideas!

 

Problem solved I think. The red vacume hose connected to the throttle body it is very tight between the fire wall and the throttle. Temporarly plugging the throttle body inlet has resulted in no more high idle issues, however it now idles a little low at times.

 

Is your problem still fixed ? I am having the same issues with my '93 1275cc single point fuel injection motor. I have had two mechanics look at it and no solution yet. It is a real mystery, some days it runs perfect and other times the whole trip will be the engine ocilating between 1800 and 2200 rpms.

 

Lots of mysterious problems with later model injected Minis.
I much prefer my carb.