A/T Oil Temp Light

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wncwheeler

wncwheeler

Joined
Oct 1, 2007
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9
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34
I got the radiator on my truck straightened out and flushed everything out. However if the engine is cold it will start right up fine and run great no lights on the dash or anything, however if I turn it off an turn it back on while the engine is warm the A/T Oil Temp light comes on and it wont start, it sounds like it is starved for gas. Any ideas what this could be? Does this light/sensor have a switch that will cause the truck to not start? would there be a chance that is going bad?

Thanks for all the help in advance!!

Ben
 
ah sorry

its a 91, it has maybe 180k on it. That may be true, this is my first one so Im not sure! that could mean I have bigger problems, anyone else know if these lights come on anytime the key is in the ignition?

Im thinking if this is true maybe it has vapor lock, could this be true?

Thanks so much
Ben
 
Its hard to diagnose your problem from just the symptoms you have stated. I've had a car that wouldn't restart when warm because of a bad fuel pump, so that's where I would start.
 
Yes, the lights I mentioned do in fact come on with the key in the ON position with the motor not running. I just verified this.
I wouldn't be concerned with the AT Temp light as that doesn't come on when the motor is running which would indicate a severe temp issue with the AT.
I would be focused on the CE light. Does the CE light come on when you turn the key to the ON position when the truck is in a no-start condition?
Very hard to vapor lock a pressurized fuel rail. Most likely EFI circuit related or possible fuel pressure regulator failure.
 
Great thanks, no check engine light, Im going to pull a fuel line as soon as the rain clears and see if its getting gas. In my 77 40 Ive had trouble with vapor lock could this be a possibility? I guess now that the lights not causing the problem Im going to start trouble shooting for any other reasons I can think of.

Once again thanks so much for the help
Ben
 
Usually don't have vapor lock on an EFI truck, but stranger things have happened. Does it have a fan on the driver side near the firewall? Some of the 62's with 3FE's had those, didn't know if the 80's of that era had them too. They were designed to prevent vapor lock on carbureted trucks, but I don't know if it is something that is functional on the 3FE. Fuel pump would be what i'd check first. The dash light is probably nothing to do with the issue.
 
EFI

Thanks, wouldnt the EFI being dead prevent it to start all together? right now it just wont start when the engine is warm. Im reading over it now thanks for the link!

And thanks 99UZJay, It does have the fan however I havent heard it come on or working yet. I guess I will keep plugging away at it and see if I can figure anything else that could cause the problem, Also this is Ben, Dannys son from CS.

Thanks for all the help!

Ben
 
99UZJay said:
The engine starts though (from what I have been told) and won't start if warm, doesn't sound like an EFI problem if it cold starts, but not warm...
Click to expand...

If the CE light isn't coming on the truck will not start as there is no spark or power to the fuel pump or any engine sensor. In this case the only thing working are the fuel injectors. The fuel rail is pressurized from the starter circuit, but there is no spark. This is most likely related to the EFI circutry. The CE light is a tally from the ECU basically showing that the circuit is energized when the motor is not running.
 
Alrighty thanks,

Is there any link to the engine being warm and the EFI system, I cant wrap my mind around how the EFI is only working when its cold and at what point in the system there is something shutting it off after I turn off the motor and not letting it back on until the engine is cooled. I think it could have something to do with the ignition or fuel at start up, the reason I think this is because if it were happening during regular use it would cut off while driving and it isnt, or hasn't yet!

Thanks

Ben
 
Man I won't lie, I am not as well versed with the FJ80 as I am the FZJ80, I have never owned one with a 3FE, but have had several with 2F's and 1FZ-FE but i'd check that EFI fuse and make sure, cause apparently if the CE light does not come on with the turn of the key it is either 1. the bulb has burnt out, or 2. that EFI fuse. All of mine have been OBD II or too old to be OBD anything. But if it starts when it is cold that doesn't make any good sense. Your dad spoke with me tonight to see if I could help diagnose this problem... But as I said, i'm not too sure with 3FE trucks...
 
Fuses

Checked the fuse's and there all good execpt the one that says something about "fan" is missing, I assume this is the electric fan behind the grill. Im planning on getting a new fuses in there tomorrow but Im not thinking that is whats causing the problem so I am going to keep moving through the checklist. I did a dash light check I found in the owners manuel and the check engine light is working so Ive determined its not the bulb.

Thanks
Ben
 
If the EFI fuse was blown then the truck would never run. No start when hot is very typical of faulty EFI related wiring/contacts. The fact that the CE light isn't coming on is telling me either the EFI relay is faulty or the logic from the ECU that's firing the relay coil is faulty. This is typically related to old and crusty contacts in the fusebox for the EFI relay itself and/or the EFI fuse and/or connector EB1 in the engine bay. While there are a few other causes for the CE light not to illuminate, they are typically not related to temperature.
The common cause for this is the EFI relay becomes very hot from the combination of poor contacts and the heat from the manifold and goes intermittant. Without proper troubleshooting it's hard to pinpoint, but I would start there.
There are literally 100s of threads on this subject with regards to a 3FE motor.
 
Thanks

Jon thanks so much for the help, Im going to try and go through it tomorrow and replace the relay. I will begin to read through the old posts as well, initally when I thought it was trans related I couldnt find much on the topic but now that I have ruled that out Im sure there will be previous related threads I can read.

Thanks again,
Ben
 
jonheld said:
If the EFI fuse was blown then the truck would never run. No start when hot is very typical of faulty EFI related wiring/contacts. The fact that the CE light isn't coming on is telling me either the EFI relay is faulty or the logic from the ECU that's firing the relay coil is faulty. This is typically related to old and crusty contacts in the fusebox for the EFI relay itself and/or the EFI fuse and/or connector EB1 in the engine bay. While there are a few other causes for the CE light not to illuminate, they are typically not related to temperature.
The common cause for this is the EFI relay becomes very hot from the combination of poor contacts and the heat from the manifold and goes intermittant. Without proper troubleshooting it's hard to pinpoint, but I would start there.
There are literally 100s of threads on this subject with regards to a 3FE motor.
Click to expand...

so what you're saying is that there is no way the ce light could burn out
 
Just read over some bad relay threads and I think thats my problem, everyone seems to have similar symptoms and it seems to be somewhat common, going tomorrow to get a new one and will report back.

Thanks
Ben
 
I'd get some electrical contact cleaner and a tooth brush and clean them contacts as well, also slather some dielectric grease on the new pins of that fuse to keep the corrosion at bay...
 
Ben- sounds like the efi relay- good luck with it. Jay and Jon thanks for the help, Get a Hyanes Manual too

Danny
 
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