Ok I recently bought my 89 and I was told it over heats. I ran it and the gauge has never left the "Lo" reading. I put in a brand new switch, the one to the front of the motor, and put some electrical tape on the wires because one had bare wire showing

I just let it sit in the driveway and still nothing? All the other gauges seem to be reading ok. I swapped out the thermostat while I was in there.

Just to check what should the oil temp run around? With the over heating issue and no gauge reading I flipped the oil pressure to oil temp and it read 198*.

Any more ideas?

 

Oil will stay around 200+-10 degrees unless you are driving it hard in stop and go. My 94 therm. stays under 210 for coolant most of the time. No overheating probs.

 

I thought the temp sensor on the front of the intake manifold just under the throttle body is the sensor for the e.c.m. Isn't the sensor for the dash temp guage screwed into the right cylinder head between cylinders 6 and 8? I have an '86 and I think that's how it is on mine. Another thing to check would be to hook up a scan tool and see what that shows the engine temp to be since that shows the e.c.m. temp reading not the dash guage one. Can you take that wire off the temp sensor between cylinders 6/8 and try grounding it out and see what the guage reads? That will show you if the guage is doing anything. Your oil temp seems about right for a drive on a warm day. Have you also made sure your coolant is properly bled? If the coolant is so low as to not be flowing over the sensor you won't get a good temp reading will you? With the engine cold take the cover off the radiator (not the overflow tank). Top up the coolant/water mix. Start up the engine and run it till warmed up at a fast idle. When the thermostat opens and the coolant starts running fast through the radiator if it's low it'll drop down now. Top it up and keep the rpm's up about 1200 or so. When you're sure it's circulating and topped up put the cap back on without letting the rpm's drop. The shut it off and let it cool down fully and pull the cap off and see if the fluid is still at the top. If not ad some and do it again. I might have something wrong here so I'm sure somebody else will correct me. Good luck.

 

Between 6 and 8 on the passenger side? I know there is a sensor there but I am not sure if its for the fans or not. There is another sensor on the drivers side that I replaced, although its a tad different style then what was there.

I think the previous owner grounded the fans so they run all the time, I need to correct that soon.

 

Seems to me the sensor on the left head between cylinders 1/3 is for the extra Z51 front cooling fan, isn't it?

 

It would be a lot easier if you posted the year of the car you are working on. There is no switch in the front of the engine. The ECT sensor, that feeds temp info to the ECM is in the front of the intake manifold on the L98s. 1984 and 1985 cars have the fan switch in the right head. Those same years have the IP temp gauge sending unit in the left head. In the 1986 through 1989 L98s the gauge sending unit went to the right side and the aux fan switch, if the car has the B4P auxiliary fan option, had the aux fan switch in the left head. 1985 and up, the main fan is controlled by the ECM based on the temps reported by the ECT sensor.

RACE ON!!!

 

I thought he said it was an '89?

 

I sure did thanks!

Also this extra fan, I do believe I have it. I took the fan shroud off today and what a mess...tons of stuff shop vac out of there! I have a large fan towards the motor and a smaller fan towards the front bumper...that may explain why I have been confused with what looks to be like a sensor on each side down near the spark plugs. The one I just replaced I believe runs the large fan and I believe it was grounded so it runs all the time (previous owner). That one is on the drivers side. The other one, that looks like the new one I just put in (the one I took out was a little different type of connector for the wire) is on the passenger side.

The other item I replaced has a two wire plug that goes to it just under the TB.

So the next step to get my gauge working is? I got a bit confused now.

 

OK, lets try and correct that now:
1) sensor below #6 & #8 plugs IS the one that drives the gauges only; If it's reading LO verify that the plug is connected to the sensor
2) sensor in the base below the TB goes to the ECM ONLY; only the ECM controls the main fan behind the radiator
3) sensor below #1 & #3 plugs is the aux fan switch and ONLY controls the booster fan in front of the radiator.

The oil temp will typically read around or 10deg above coolant temp.

How do you know the car overheats if you can't read coolant temp, have you ever seen it happen??

To test operation of the main fan open the connector in the A/C pressure line; the ECM should bring on the fan soon as you start the engine.

Since you found debris in the booster fan housing, remove the radiator shroud, main fan shroud & the main fan and clean the debris from between the radiator and the A/C condensor. Also blow air and/or water from rear to front through the radiotor fins to blow out any debris that may be clogging the radiator fins.

 

everything he said is right. the only other thing I would do is verify the moron that owned your car before you didn't take out the thermostat.
If the car has the aluminum heads, and it has over heated, check the parting line under the exhaust manifolds where the head meets the block near the motor mounts. If there's any scale, or evidence of water leakage in the past, I would be very cautious this summer and expect the head gasket to leak, seep, allow water in the oil, or vice versa. The 113 heads don't have a lot of meat, and will not live with temperature abuse very well.
If you live where there's always leaves from trees in the fall, Mid America has a grid to keep debris out. The debris seems to fall way when the car is shut off, and the airflow stops.

 

Thermostat was there, I replaced it when I had things apart and I used my shop vac and got most of the junk from between the fans.

My large fan kicks on any time I start the car, even when its cold. The green/white wire on the drivers side has been cut and looks to be grounded, but the list above shows the fan being controlled by the unit under the T/B.

I do not know if over heats for sure, thats the secondary reason for needing to get this gauge working so I can tell, LOL. If it doesn't that will sure help.

I think it may have a bad head gasket or head, not positive yet but it might.

 

You did post the year. I read right over it. I apologize. Everything I said applies, but you can ignore the '84 and '85 stuff. 65Z01 pretty much repeated what I posted.

It would be great if you can locate the other end of that green/white and splice it back together. The main fan is not controlled by the ECT sensor directly. It is controlled by the ECM and the prom programming. The ECM uses the engine temp info for may things including cold idle speed, fuel mixture, especially when the engine is cold, etc. The ECT sensor only lets the ECM know the engine temp. It is the prom programming that determines when the fan should be switched on or off.

Since the wiring is known to be butchered for the main fan, it would pay to be sure that you really have the gauge sending unit in your right side head. As a test of the gauge and wiring, the gauge should read "Low" with the wire disconnected, and full scale (290°?) with the wire grounded.

RACE ON!!!

 

On the driver side of the motor? Do you have picture of the wire by chance? I took one out of there and put in a new one, it had the green/white wire going to it. The one I just put in looks like the one on the passenger side head near the oil dipstick tube. A spade connector is used to stick the wire onto both of them now.

 

The driver's side is the LEFT side. On the left (driver's) side of the engine between the number 1 and 3 spark plugs, should be the auxiliary fan switch. It connects to a green/white wire. If you ground that wire with the ignition "On" the auxiliary fan should run.

On the right (passenger) side of the engine between the number 6 and 8 spark plugs, should be the IP gauge sending unit. My '84 uses a blue wire to connect to that sender. I suspect your '89 does also. That is the wire to can disconnect and ground to check the gauge and wiring.

Did you possibly install a gauge sending unit where the aux fan switch goes? The wires should have different connectors.

RACE ON!!!

 

One thing I'm wondering is if you didn't put the wrong switch in the drivers head...my 87 doesn't have a spade conncetion on the aux. fan, but it is a green/white wire. That switch from the factory let the aux. fan come on around 228 degrees...you can purchase different temp range switches for that...so I'm curious where did you buy that switch at? And did you tell them it was for the aux. fan? Looks like CFI beat me to it.

 

Rick - Good to see you back! When you get a chance, empty your In Box.

 

Ok here are some photos:

This is the unit I replaced because the wire was just hangning there. It is on the driver side. This is the wire that is grounded, or appears to be at seen in the next photo. This is why I thought the big/main fan was always running.

http://www.nloc.net/photopost/data/2...m/DSC01268.JPG

This is the yellow wire that runs up to a screw which grounds a green/white wire that appears to have been originally connected to the above item.

http://www.nloc.net/photopost/data/2...m/DSC01269.JPG



Passenger side unit:

http://www.nloc.net/photopost/data/2...m/DSC01271.JPG

Again:

http://www.nloc.net/photopost/data/2...m/DSC01270.JPG

The two units appear to be the same in physical description now, prior the one on the drivers side had a different end to it for the wire, but the wire was not connected it was just stuck inside to appear to be connected.

 

ok, if the main fan comes on all the time....you need to verify.
1. turn on the air. does it stay on. turn it off ....does it stay on?
2. a dk grn/white wire is a control wire for the fan relay, and it is the ecm internal ground wire.
3. if you do have a grn/white wire at the temp switch, it probably is a wire that the previous owner found that was probably long enough to work.
4. the fan comes on also when you turn on the air, and the A/C pressure switch sends a signal to the ecm that the pressure in the line has risen to the point that the ecm knows that the air is on, and a fan is needed.
5. find the fan relay, it should be on the fenderwell under the master cylinder, and towards the engine a little bit.
The fan relay should have:
A. an ignition switched brn wire
B. a battery powered orange wire
C. a dk grn/white wire to the ecm for relay coil ground
D. a blk/pnk wire that goes to the fan motor
The other avenue the fan will run is:
1. air on,
A. There is a dark blue wire on the A/C pressure switch on the r/h side of the car that makes the ground for the ECM.this turns on the gnd thru the ecm to gnd the fan relay coil. the fan relay has power already (thru the brn wire) then gets the ground (thru grn/wht wire) to activate the fan motor thru the relay power contacts (orange wire). Then the orange wire turns into the pink/blk wire on the other side of the relay and goes to the fan positive.
If I could make it more difficult, I would have.

 

I removed the wire that I felt was grounding the wire, and the fan does not just come on anymore.

The green/white wire goes into that group of wires you mentioned near the master, its cut in half and one end goes to a grounding point.

The color wires are a tad different but that may just be perception too.

 

Go back to post #14. Perform the tests I suggested there. With ignition "On", check the gauge reading with the wire to the right side sensor disconnected, and then again with that wire grounded. Once you have those results, again, with the ignition "On", remove the wire from the device in the left head and ground it. Does that cause the auxiliary fan to run? If it doesn't, trace that wire from the left side device. It should connect to terminal "B" of the auxiliary fan relay.

RACE ON!!!