91 Fj80 Won't Start When HOT HELP!!!

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Jul 25, 2009
El Paso
Hey guys, here for your help again.

Here is my situation, I had my 91 as a daily driver and everything was going just great. She sat for a few months, she would start but run and idle very roughly, I got that fixed. It was a vacuum leak via the injectors. Took all that apart and replaced the seals on the injectors and cleaned them too, replaced the FPR & FPD, she is now running like a champ, no more stutter or backfire.

I took the time and replaced all the injectors connectors because they were very brittle.

NOTE: The no start when hot was still present before I did the injector job.

The problem I am having now is that it will not start no matter how long it cranks for if the motor is hot, I did use some fuel starting fluid and it will start right up even when hot and stay running no matter what but if I dare shut it off and try again it will not fire up unless I use the starter fluid again.

Oh I forgot to mention I did replace my fuel pump as it was part of the other issues along with the fuel filter.

My guess is that somehow the injectors aren't opening when the starter kicks in, I jumped the connectors to the fuel pump and tried starting and no go.

The relay does get very hot after running a while but even if I replace it with a fresh one it will not start, I will end up getting the relay relocated so I don´t get all the heat from the manifold.

I am kind of stuck here, I've gone through some of the posts here but nothing has yielded anything up to now, I appreciate all the help I can get.

Last edited:
Look up the troubleshooting list for the 3FE created/posted by @jonheld.
Thanks for the info, I will check my afm. It might not be sending a signal to the COR, I do get the charge, at temp and check engine lights when the switch is on.

Thanks again.
Thanks for the info, I will check my afm. It might not be sending a signal to the COR, I do get the charge, at temp and check engine lights when the switch is on.

Thanks again.
If you jumped B+ to FP on the diagnostic connector then you bypassed all the fuel pump logic. THe COR is not in play once you jump the pins.
You mentioned that you replaced the fuel pump, fuel pressure regulator, and fuel damper. Was the no start when hot present before all these replacements?
Yup, it wouldn't start when it was warm before I even replaced this. I replaced them because it hesitated and I ended up checking the fuel pressure and it was quite low. Once I replaced those components it runs quite well but it just will not start once it warms up.

Yeah I did bypass the fuel pump, I hear it run but it just doesn't start unless some other fuel is introduced (injectors not feeding the engine).
The CEL does light up, tried the EFI fuse with two different fuses when it gets hot and it will not start up.
I would install a fuel pressure gauge where the cold start fuel line comes from. A fuel pressure kit is available at Autozone on their free rental program. Had a similar issue years back on my son's 92. Turns out the Fuel Damper went bad was bypassing the fuel back to the tank causing occasional no start issues and when tested had no fuel pressure.
Here's the thread: Intermittent Starting Problem Solved
I just read you replaced the FPR and FPD. Hows the screw on the FPD? Screwed in all the way? I still think I would check fuel pressure with a tester to verify what's going on.
Last edited:
I didn't really move the screw when I installed the new FPD, I tested the pressure before replacing, should the screw be all the way in?

I bypassed the fuel pump and it will not start even then, I did read your post that is one of the reasons I changed it but no go, I am thinking is something is telling the injectors not to open up.
Thanks for your help, gone through that one too.

Mine doesn't die after she starts, she runs quite good. It did run really bad and would die before changing the FPD and FPD.
What is very odd to me is that if a foreign fuel source is introduced it will start no matter if the engine is warm and it will run just fine but if I shut it down it will not start again unless I use the starter fluid again. I keep trying, it is no longer my daily driver but I want to put it back in action at least 3 days a week.
Last edited:
Efi relay... been here. I get a couple napa ones and keep spares....
EFI relay. Switch to the Camry relay a la @jonheld. You can get one for $3 at every junkyard in the world. Grab a couple for fun.

Or be cheap and relocate it inside.

The exhaust manifold spits hot fire at the EFI Relay in He black fuse box under the hood. Probably causing the metal to expand and not allow the relay to close (or is it open?) The Camry Relay is plastic.
I do have some spare EFI Relays and when I switch it for a cool one it will not start anyway. I'll look into the Camry relay, thanks.
I'm not real familiar with the 3fe but it does use a cold start injector. I use to have an 87 celica and I had a hot start problem, and I figured out if I floored the accelerator when trying to start it it would start every time. Later on I figured out that the problem was that the cold start injector time switch was rotting away from corrosion, and the ecu thought the engine was cold all the time. This caused the injector to flood the engine when it was hot and opening the throttle when I started it allowed extra air in so it wouldn't flood. Just a thought
I sure will give that a try, I tested the sensor and it tested ok but I'll double check it to make sure, thanks for your input. I will update you on this tomorrow, thanks again.
Let us know how that goes ^

Also- I just solved my hot start issue a few weeks ago on my 3FE with the Ford relay. I think my wiring to the starter solenoid has just enough corrosion on it for enough of an amp drop to not engage the starter solenoid when hot. Been cranking like a champ for a few weeks straight now. Hot, cold, warm- doesn't matter.

I got the info from a thread from @SUMMIT CRUISERS when he helped me out with my hot start problems, but I'll find my thread and link it here too if you'd like.

The starter fluid is strange though.

Users who are viewing this thread

Top Bottom