Ok, this is really two questions in one. The first question is just for clarification. On a 1987 L98 Iroc-z, the two sensors in the heads are the knock sensor and temp gague sensor....correct? Temp on driver's side and knock on passesnger's side. Now, are there any differences between the 87 L98 and the 85 LB9 in this respect? Also (I guess this three questions), what would happen if the knock sensor wasn't plugged in? Can you guys post some pics of the electrical connectors for these sensors too? Thanks in advance.

 

Actualy the sensor on the passenger head is the fan switch and the sensor on the drivers side is the coolant sensor the knock sensor is usually in the block.

 

yeah, just had a revelation. What would the knock sensor be doing in the heads! Apply my questions to only the temp gauge sensor then on the driver's side.

 

temp sensor on the driverside and fan switch is on the passenger side. lol

 

I agree, if the temp sensor is unplugged, you won't get a reading on your dash, if the fan switch is unplugged your fan won't turn on

 

Not true. The fan switch is not hooked up and the fan does turn on. It must be bypassed somehow. But back to the temp sensor. Was there a difference between 85 and 87? And does anyone have a picture of the electrical connector, or even a good shot of the thing hooked up?

 

Is it possible that If the Fan switch isnt hooked up that the fan will always run? That's my problem. My fan runs all the time. From the moment i turn the key to on it comes on. Regardless of coolent temp and a/c.

 

Maybe, I don't thinks its a problem as much as a blessing. Of course I don't drive the car in winter either so the colder the engine the better . If you have to drive the car in the cold you definitely do not want your fan on all the time.

 

See the problem is.....ITS WINTER!!! And Im on my second fan motor because the first one already burned out. Id like to take it to a shop and have them tell me but electrical diagnostics can be $$$ intensive. And at the moment $$ is tight. Im wondering if I'm the only person with this problem.....

 

I just noticed last week, when installing my headers, that there is NO fan switch sensor installed in my pass side cylinder head. This is a '87 L98 installed in a '85 TPI IROC ( originally a LB9 car ) and my fan works just fine. GRANTED, I have the single fan, and I'll be swapping to dual fans here shortly, but I thought it was weird nonetheless.

I'm too lazy right now to look thru my '85 Helms to see how the '85 TPI electric fan is SUPPOSED to work.......Anybody know?


And NO, my fan doesn't run all the time, only when it hits 210 degrees F or so does it even cut on.


Later

 

if the fan is running all the time then the fan switch is bypassed, like mine. all it takes to do this is ground the wire. if don't want the fan to run all the time, you could hook up a switch in the car and manually turn it on,
the wire that runs to the fan switch should be a black wire just below the manifold on the passenger side, yours is probably grounded somewhere around there or even the wire melted and grounded to something. hope this helps a little

 

I'll take a look tomorrow while I'm at lunch. Thanks a lot. Also does anybody have a pic of the fan switch ON the head so I know what exactly it is that I'm looking for?

 

I tried to get a couple pics tonight but I really couldn't see w/o searchin for my flashlight, but it should be between the 6th and 8th plug on the head, I'll try to get some pics in the mornin.

 

Ok, back to the pre-jacked post, does anyone have a shot of the temp sensor and connector?

 

I don't have a pic... Just go to the auto parts store and ask for one and look at it, that would be a whole lot easier than trying to get a pic.

The connector for the temp gauge sending unit is a "mushroom" style slide; the one for the fan is a single-contact round Weatherpak; the coolant temp sensor for the ECM (not in the head, it's in the water outlet usually) is a 2-contact mini Weatherpak; the knock sensor is in the side of the block about 1" above the oil pan rail, pass side, halfway from front to rear, has a single round Weatherpak.

The hole in the head in the same place on the head, whether the head is on the right or the left bank of the engine: comes out to being in between the #1 & #3 spark plugs if it's a left head, or in between the #6 & #8 spark plugs if it's a right head.

 

I did even better. I went to the bone yard and got one for myself . Thanks for the info though.