Hi! I'm pretty sure my cts is taking a dump as I have periodic no fast idle cold starts or other starts. Have to keep fast idle with throttle then after couple mins. everythings good, idle at 550rpm.My mechanic and 85 service manual are out of town. So how do i take it off? I have
a bad back & bad knees so 15 mins of bending and leaning is torture! The Haynes manual that came with the car says"remove the bracket bolts & slide the air control valve assembly forward til you have room"
Whaaat? Also, I would assume I'd do this on a cold engine. How much coolant would leak out? Finally I get temp. readings that can go from
93c to 88c and back in 10 sec. That's also why I think the cts is toast.
sorry for the long post Thanks!

 

The temp. reading on the dash is not related to the CTS.

It would be best to ohm the CTS to test it.

On my '88 changing it would probably take 15 min. Unplug it, unscrew it, catch a bunch of antifreeze, screw the new one in, plug it in, pour the coolant back in. Done.

Is there any way you can sit on the tire or something instead of the bad leaning over?

There are other causes of the problems listed, so changing the CTS would be a guess without further testing. Good luck.

 

Thanks for the reply, I know about the proper tests (thanks RRT Vette)
but it would be a lot easier in my mechanics(3 houses down) garage.and not my driveway. I'll probably end up waiting for him. What would I have to take off to get at it? If I'm that crazy!

 

On my car, nothing, it's easy to get to. I don't have an '85 thought so can't speak for that year, also I have done the TB bypass. With those coolant hoses there it might be a tight fit. Take a look. It'll take a lot to break it loose, because of the gummy pip sealant.

 

You don't have to remove the CTS to test it. You can test it at any time. I assume you remember how to test it? You will need to know what the outside temp or engine temp is when cold. The CTS resistance varies with engine temp. Cold the reisitance is high and hot the resistance is low. Ohm the sensor cold and write the number and temp of the engine down. Start the engine and get the temperature up (~200F) and ohm the CTS again. Write that number down and temp of the engine. If you don't have you FSM handy just post what you wrote down and I or someone can help.

The CTS in the front of the intake manifold sends resistance signals to the ECM (one black wire and one yellow wire). The 85 is different from the other L98 in guage temperature location and aux fan sensor location. On my 86 the guage temp sender is between #6 and #8 spark plugs in the right head. On your 85 it is in the left head I believe between #1 and #3 spark plugs. It should have one green wire going to it.

EDIT: The CTS can be ohmed by removing the air duct between the TB and MAF and just disconnect the senor connector and reaching down with the ohm meter leads. There are two terminals in the CTS. Make sure you have a good solid connection when done.

 

Thanks again RRT!!! Of course today the 4 starts I did today the car performed perfectly! I will print out your response to me and hand it to my mechanic when he gets back! Thank you so much for your help

 

I changed mine last week,not bad at all. A deep 3/4" socket if I remember correctly. I didn't have to remove the 'U' hose either. There was just enough clearance. Bought the part at Napa $28. Good luck, Larry