There is a thermisor mounted on the manifold. Lots of time these get disconnected. In your FSM there should be a picture. If you search here you'll find one I'm sure.
Truck won't REstart.
- Thread starter SoCalJohn
- Start date
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I am not sure from the posts if you got your problem fixed SoCalJohn.
However, I just wanted to take the time to thank everyone here for saving me a trip to a mechanic that probably wouldn't be able to fix my wife's 91, with out replacing everything remotely related to the problem. (unless he reads mud too!!)
No CEL = No Start = Bad EFI Relay (in my case anyway).
Dead lc last night + read mud today = lc fixed!
Good luck SoCalJohn, I am certain that the folks here can help.
However, I just wanted to take the time to thank everyone here for saving me a trip to a mechanic that probably wouldn't be able to fix my wife's 91, with out replacing everything remotely related to the problem. (unless he reads mud too!!)
No CEL = No Start = Bad EFI Relay (in my case anyway).
Dead lc last night + read mud today = lc fixed!
Good luck SoCalJohn, I am certain that the folks here can help.
I'd give ya a "Woohoo!" like I did for SoCalJohn back in post #8, except it'd probably jinx you too.
Cheers,
Curtis
- Thread starter
- #44
Thanks lc_nut Well, back from my trip , with OUT my LANDCRUISER. Had to leave it at home, and take the "minivan". At least I got about 25mph and could pass cars uphill. Many back roads I had to pass by........
Zion, was great!
The day before i left, took the truck in to TOYOTA of Orange, on a saturday, and they "identified" that my wiring harness is causing my issues. It least the inspection was free. The service guy took three days to find the old part #. I plan to order this from CDan, I sure I will save some significant bucks. They claim my fan is operatable, but just never comes on in the 91, unless you are in the desert full time or pulling heavy loads up hills. Does this sound right? At least the mechanic was old as dirt and "used" to work on this issues years ago, before they upgranded to another wiring harness.
I believe this harnness runs around the front of and above the radiator. Is this a do it yourself job?? I don't mind unbolting things. Or is a repair with a qualified wiring expert more in line. Unfourtunately they would not pinpint where the wire was bad.
Zion, was great!The day before i left, took the truck in to TOYOTA of Orange, on a saturday, and they "identified" that my wiring harness is causing my issues. It least the inspection was free. The service guy took three days to find the old part #. I plan to order this from CDan, I sure I will save some significant bucks. They claim my fan is operatable, but just never comes on in the 91, unless you are in the desert full time or pulling heavy loads up hills. Does this sound right? At least the mechanic was old as dirt and "used" to work on this issues years ago, before they upgranded to another wiring harness.
I believe this harnness runs around the front of and above the radiator. Is this a do it yourself job?? I don't mind unbolting things. Or is a repair with a qualified wiring expert more in line. Unfourtunately they would not pinpint where the wire was bad.
Bull****.
I don't know the exact parameters, but it should come on virtually every time you shut off the engine in warm weather. In addition, I'm not sure it's ever meant to come on while the rig is running.
I F*CKING H8T THIEVING MECHANICS!!
Oh, and the wiring that needs to be addressed (in addition to getting the fan operational) is almost guaranteed to be what's addressed in Jon Held's write up.
Curtis
You made Curtis swear!!
You know, I don't think I have ever heard the fan come on in the 91. The fan always seems to come on in the 60's and and the 55 with the 2F transplant (complete with fan).
Another interesting item was that I pulled three relays out of EFI Minitruck harnesses in my garage (Yea Toyota! same part number) and none of them had the signs of overheating that the dead one from the 91 had (discolored copper power terminals).
I think I'll look at that fan circuit.
Another interesting item was that I pulled three relays out of EFI Minitruck harnesses in my garage (Yea Toyota! same part number) and none of them had the signs of overheating that the dead one from the 91 had (discolored copper power terminals).
I think I'll look at that fan circuit.
Couple of things here.
#1. The engine cooling fan works off of manifold temp. Mine comes on in the winter as well. Old guy wrong about this.
#2. The harness that runs inside the radiator support is headlights, EFI and alternator IIRC. However, If there is +12 in the fusebox as shown in some of my preious posts, then there is +12 in the fusebox. A new harness will not give you more +12.
Did you replace the fusible links off the positive battery terminal?
Have you followed my flowchart?
Have you inspected the fusebox wiring?
Have you tried making a jumper and jumping out the EFI relay?
Thermo-switch for the fan might be dead.
I do not know the specs on the switch, so I do not know for certain. (No FSM either!)
In any case I jumped the sw to ground and the fan came on. I have a dead 60, so... I may try swapping them unless some knows what temp it should switch at.
Does yours act this way SoCalJohn?
I do not know the specs on the switch, so I do not know for certain. (No FSM either!)
In any case I jumped the sw to ground and the fan came on. I have a dead 60, so... I may try swapping them unless some knows what temp it should switch at.
Does yours act this way SoCalJohn?
I couldn't find anything about it in my FSM.
Now I'm getting paranoid as well: Seems I used to *always* hear the fan when shutting down the rig; now I can't really recall having heard it for a while...
Mr. Held, ya got anything on this for us?
Curtis
I've been sick...
I really need to download the FSM, or just buy one from Mr. Held. (I had one once, but why I don't have it now is like a bad, bad country song...)
The switch is not a switch. It is a thermistor. I steamed it, and it was not warm enough to change. So, I heated it up with the stove, and it started to respond. I let it get to about 10K before, I decided I had abused it enough.
It looks like the circuit uses the thermistor to control a sensitive relay that controls a power relay for the fan.
I have used this forum for years, and almost never posted anything. (Usually someone else has had the same issues). I think I need to search and see if someone else has had this problem before.
I found a thread for the 60 series. I believe they are the same on the 91. Can anyone verify that the circuits are similar?
https://forum.ih8mud.com/60-series-wagons/180691-carb-cooling-fan-info.html
I really need to download the FSM, or just buy one from Mr. Held. (I had one once, but why I don't have it now is like a bad, bad country song...)
The switch is not a switch. It is a thermistor. I steamed it, and it was not warm enough to change. So, I heated it up with the stove, and it started to respond. I let it get to about 10K before, I decided I had abused it enough.
It looks like the circuit uses the thermistor to control a sensitive relay that controls a power relay for the fan.
I have used this forum for years, and almost never posted anything. (Usually someone else has had the same issues). I think I need to search and see if someone else has had this problem before.
I found a thread for the 60 series. I believe they are the same on the 91. Can anyone verify that the circuits are similar?
https://forum.ih8mud.com/60-series-wagons/180691-carb-cooling-fan-info.html
Last edited:
- Thread starter
- #53
(The switch is not a switch. It is a thermistor. I steamed it, and it was not warm enough to change. So, I heated it up with the stove, and it started to respond. I let it get to about 10K before, I decided I had abused it enough.)
I plan on working on this issue again this sunday, testing the fan. I will have a buddy much more skilled in electronics by my side to much more accurately inspect the wire harness and plug to see if he can do what JonHeld did.
Funny thing, its cooled down a little, here, and have not had any no start issues for a week. But at least I have a shiney new fuel regulator, new fusible link and a new positive battery clamp.
I plan on working on this issue again this sunday, testing the fan. I will have a buddy much more skilled in electronics by my side to much more accurately inspect the wire harness and plug to see if he can do what JonHeld did.
Funny thing, its cooled down a little, here, and have not had any no start issues for a week. But at least I have a shiney new fuel regulator, new fusible link and a new positive battery clamp.
- Thread starter
- #54
Smalll update and questions. Have time again to work on this.
Plan to upgrade the plug to the EFI Relay as JonHeld describes from 12 gauge to 10 gauge wire and bypass the wiring harnness. But also am testing my manifold fan heat thermisol... Does any one know the operating resistance range for this sensor to turn on the fan? What should the ohms read when testing it cold. I know my fan works, just need to figure out why it is not getting the signal to turn on.
I may have two issues to deal with.I also need to look at the connectivity from the thermisol to the timer(?) that kicks on and turns off the fan. From other posts, this seems to be located in my kick panels under the front foot wells.
Thanks all.
Plan to upgrade the plug to the EFI Relay as JonHeld describes from 12 gauge to 10 gauge wire and bypass the wiring harnness. But also am testing my manifold fan heat thermisol... Does any one know the operating resistance range for this sensor to turn on the fan? What should the ohms read when testing it cold. I know my fan works, just need to figure out why it is not getting the signal to turn on.
I may have two issues to deal with.I also need to look at the connectivity from the thermisol to the timer(?) that kicks on and turns off the fan. From other posts, this seems to be located in my kick panels under the front foot wells.
Thanks all.
- Thread starter
- #56
It is on a small bracket mounted on the left side of the engine with one bolt, about 12 inches below the EFI unit. A single wire comes down to it out of another wireharness. If you are looking at the driver side of the block look just past the Brake Master Cylinder and down a little.
Manifold temp sensor:
90C/194F approx 4K ohms
110C/230F approx 2K ohms
From the FSM.
The fan motor relay is in the drivers kick, the fan control ecu is in the passenger kick.
90C/194F approx 4K ohms
110C/230F approx 2K ohms
From the FSM.
The fan motor relay is in the drivers kick, the fan control ecu is in the passenger kick.
- Thread starter
- #59
Thank you JonHeld .
What chapter, Jon?
