1986.5 with high idle after warm up.

porshapower · 07-20-2009, 06:45 PM

Hello Guys, My 1986 automatic will start up and idle around 650 or so but within a couple of minutes it is at 1200 or so rpms. I have checked the idle screw on the throttle body and it is completely in the closed position as tight as it can go. When I loosen this screw(counterclockwise) the idle goes higher but it wont go any lower than 1200 rpms with screw all the way in. Linkage is not binding and gas pedal is free and nothing in the way. It smells like it is burning a little rich too. I had a ford f150 a few years back that did the same thing and it was a temperature sensor for the computer. Dont know if this car works the same? Thanks in Advance

Nel

zoltan944 · 07-20-2009, 07:40 PM

check both pins on your Temp2 sensor in Ohms to ground both cold and warm and report the resistance.
Temp2 has the blue connector going to it.

porshapower · 07-20-2009, 10:08 PM

I just bought a meter from Sears yesterday but not familiar with how to use it. What I am interpreting from your directions is to pull the blue plug off. Take the red probe and touch one side of the pin cold (get reading) and then hot (get reading) and then do the same on the other pin correct? What do I turn my selector to on my meter. Sorry for sounding like an idiot

but I never used one of these things before. Thanks again for the help

Nel

zoltan944 · 07-20-2009, 10:26 PM

Take the meter and set it to ohm reading (the symbol looks like the Omega sign or like a horseshoe), google it to find an image if you need.
the temp2 sensor is 2 sensors in one and each prong is giving a reading.
Take your meter and put the black one on a good ground and the red on each sensor and mark down the readings. Warm the car up and take these same readings with a warmed up car.
report those figures back to us.

Danglerb · 07-21-2009, 07:21 AM

The normal connection on the sensor to the cars wiring harness needs to come off for a ohm measurement doesn't it?

Could also be a vacuum leak or ISV issue.

porshapower · 07-21-2009, 03:08 PM

Thanks guys for the help! I unplugged the sensor and got 1153 on the left pin and 1153 on the right pin and this was with the car cold after sitting overnight. I then tried to start it and get some values but with the sensor unplugged the car would not start(I cranked it 5 times) so the sensor is doing something. Plugged the plug back in and probed the wires and got 854 on each side with the car cold. Started the car and let it run for 30 minutes and watched the values drop until they finally came to a stop at 638 on one side and 596 on the other side. I was probing over the passenger fender and can smell gas coming from above the front tire in the wheel well area but dont see leaks...maybe fuel leak causing this? Thanks again

Nel

Danglerb · 07-21-2009, 10:04 PM

There is a plastic Y that goes to the carbon canister that often breaks, any of the normal 928 vendors will know what you need.

Gas smell not something to let go.

porshapower · 07-22-2009, 01:07 PM

I have done some research and it appears this Y piece is in the passenger side wheel well and I have to take tire off to get to it? Is this the same thing you mentioned? Thanks again

Dozman · 07-23-2009, 06:18 AM

BTW the temp 2 sensor, many times there is corrosion in the two spade connections. Ensure if any corrosion is present that you clean up the corrosion.