I recently installed a rebuilt 6-port into my '91. I started it up and it idles around 1500 rpm until it warms up. Once its warm the idle jumps to 2000 rpm and then swings between the 2000 and ~1500 marks constantly. Is this part of the normal re-learning mode of the ecu or is something wrong? I also have a connector that i couldn't find a place for.....could this be part of the idle problem? It didn't seem right to me so i turned the engine off. Any help would be greatly appreciated. I'm going to try and attach a picture of the connection below.

- Pat

 

that plug is for the CAS....crank agnle sensor. Your car wouldnt have even ran if it wasnt plugged in..your problem sounds like your TPS is out of spec..is the idle going vrrommm..drop.....vrrooomm...drop..bouncing from the 2k to 1500 RPM?

 

wait are you reffering to the white connector or the black one?

 

im pretty sure you mean the black one..im lookin through manual for ya...not seeing what it is...dont remember it from putting my motor in either..maybe its for p/s-a/c if your car used to have it or something??

 

That is exactlly what the idle was doing. I'm gonna start the car tomorrow and see if it still does it. Thanks for the help!! I still can't figure out that plug...

 

I have my motor laying in my garage right now. Tomorrow Ill go check where that thing goes.

 

that connector is not hooked up on any of my sevens...and I've had four.

This idling issue is interesting to me as well...for my only running seven idles very high as well...mine started out like stated earlier and continued to, over a little bit of time, increase until now, where it idles no less than 4K.

My suggestions would be to spray carb cleaner or B12 around all of the vacuum hoses and around the intake manifold to make sure there are no leaks. Also the TPS may need to be adjusted as well.

 

As far as I remember, that is the 02 sensor. The place where it branches out from the rest of the harness should be over near the UIM, and it should be going in the other way, but you put it in wrong. If thats what it is, it won't cause any idle problems like that.

And I am having the same idle deal with my car. I recently put a rebuilt in, and it will rev between say 1800 and 2200, or sometimes between 800 and 1400. Its got about 150 miles on it, and probly 4 hours run time in addition to those miles. It is getting progressively better, but I am unsure of what the cause is.

 

If you reuse the housing, it will have little grooves in it leaking compression. As you break the motor in the apex seal will wear into those grooves. Im not sure why that would cause a high idle, if it would at all.

 

Yep, O2 sensor. The wire shown branches off just in front of the thermostat housing. Route that wire around the passeneger side of the engine, and connect it to the single wire connector coming out of the exhaust header.

 

i dont know about yalls car, but on the supra, that is the Knock sensor wire. if that is that it is, it would not mess your idle up.


ben

 

I really don't know about what you guys FC are set up with but in each and every one of mine the O2 sensor is on the other side of the engine...unless this particular has accidently cut and spliced in about 2 feet of coax onto the O2 sensor connector (which is yellow on my cars, also) I doubt that is what this plug is. I have this plug on all of my cars and not one has had it plugged to anything.