Real Time Help - thermostat issues...

Joshua993 · 11-06-09, 05:08 PM

I just changed out the thermostat in my 88 FJ62. Everything is hooked back up - plenty of coolant (I did not drain it like the FSM says to do for EVERYTHING). I jsut started the truck, and it revved to 2k rpm and would not come down. The old Thermostat was stuck open...

Anyone had this problem - or have any thoughts on what it might be?

I am supposed to be takeing the truck to Oklahoma in the early am...I need some help!!

Thanks in advance!
J

miker · 11-06-09, 05:36 PM

I don't think a thermostat change would cause the engine to rev up.

Check the "Throttle Control" on the dash and make sure its not pulled out.

Joshua993 · 11-06-09, 05:53 PM

That was the first thing I checked - maybe the cold start connector? Maybe the water pump isn't priming?

Joshua993 · 11-06-09, 06:24 PM

I think I found the issue - there is a green connector on the driver' side of the water housing - it is busted, not completely off, but enough for it to swivel around loosely. I am trying to identify now...

Anyone who knows what that is off the top of thier head please feel free to educate me...

rchalmers3 · 11-06-09, 08:29 PM

Can you describe the part better or post a photo?

If it is a temp sender connector, I don't think it would affect the engine RPM as dramatically as you indicated. It sounds like something is affecting the throttle operation or if you have a EFI motor, possibly a vacuum leak.

Take another look at the area where you were working and see if you disturbed any vacuum hose connections. It would be advisable to inspect the throttle body to see if the butterfly shaft is contacting the idle stop as well.

Hope this helps,

Rick

77cruiser · 11-07-09, 04:50 AM

have you looked at all your vaccum hoses to make sure they are all intact and connected? how about the accelerator linkages to make sure nothing is stuck.

Joshua993 · 11-07-09, 03:53 PM

Quote:

Originally Posted by rchalmers3

Can you describe the part better or post a photo?

I will try to post a pic soon. For now...

If you look at your water pump and water housing, there are three electrical connecters and on connector with 2 vacuum lines on it. The vacuum lines are top left, one connector is top left, and two connectors are low on the right, on the pump housing under the hoses.

Well, the top left electrical connector is bad; I was just looking at the truck and making sure things were where they should be, and the wire was so frayed that it just feel off the connector when I touched it. On the bottom right, the green connector closest to the engine just spins on the sensor, and I can see wires frayed in there too. I did not disconnect any vacuum lines other than 2 on the water housing to do the job, so those are all fine. But, the sensors, which I believe are part of the cold start system, are toast.

Should have just left well enough alone, and done with marginal heat again this winter...

Joshua993 · 11-16-09, 02:48 PM

This part, if it looks like the one on the bottom, will indeed make your truck run rough. It is the water temp sensor for the cold start system, and mine was FUBAR, as you can see.

cruiser88 · 11-16-09, 03:01 PM

They and the wire itself goes bad often

miker · 11-17-09, 06:15 PM

Quote:

Originally Posted by Joshua993

This part, if it looks like the one on the bottom, will indeed make your truck run rough. It is the water temp sensor for the cold start system, and mine was FUBAR, as you can see.

This is good to know. Thanks!

Can you clariy if this sensor, if bad, will it make the engine idle fast, or rough, or both?