Ok guys I'm at my wits end here. I have a 1990 fj62 fi 3fe engine. it randomly started burning too much fuel. a lot too much, and raw black fuel is coming out the tail pipe. so its constantly flooding. it will not give a read out on anyones diagnostic machines either. my mechanic is lost. on a side note it started running a little hot while at stop lights at first and now it will over heat in less then 10 min from starting now. i don't think i could even take it to the shop without a wrecker. Help!!! is this a head gasket issue and what do i do?
FJ 62 Fuel issues
- Thread starter ward93
- Start date
-
- Tags
- fuel injection
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
My 2 cents...
For the fuel issue I'd look at the cold start injector first. It may be causing the overheat as well... Next the fuel pressure regulator.
For the fuel issue I'd look at the cold start injector first. It may be causing the overheat as well... Next the fuel pressure regulator.
does the CEL ever come on? there's alot that can go on with these engines and ECUs. as stated, the cold start injector could be dumping too much due to either a bad injector, a bad cold start timer, or a bad temp sensor, or bad wiring to any of the above...find the FSM for a heck of a deal thread in the calssified section and download the manuals relating to 3FE and get cozy and start reading. make sure to Thank Marshall for his contributions of those FSMs.
Yeah cold start injector would be a good start. Mine was totally caked in soot.
After that I'm wondering if a regular injector could be stuck open? Not sure what could cause the dumping of fuel other than an injector or maybe the ECU is bad?
Some of the other sensors could be causing the ecu to release too much fuel.
Maybe the throttle position sensor is off?
You might want to use the manual to test the various sensors.
After that I'm wondering if a regular injector could be stuck open? Not sure what could cause the dumping of fuel other than an injector or maybe the ECU is bad?
Some of the other sensors could be causing the ecu to release too much fuel.
Maybe the throttle position sensor is off?
You might want to use the manual to test the various sensors.
- Thread starter
- #6
you guys are awesome ill keep y'all posted with pictures soon as well. i think one issue is my FPR through further research. but i need a FSM first so thanks for the thread. let y'all know whats up.
- Thread starter
- #7
and CEL and ECU?
This is by far one of the most helpful forums that I have used for my various hobbies. Any question I have has already been answered here or can be answered by a bunch of the members. Very impressive.
A sign of a bad forum is if I know more than most of the members.
A sign of a bad forum is if I know more than most of the members.
CEL = check engine light
ECU = engine control unit
tps MUST be adjusted and verified with ohm meter...
ECU = engine control unit
tps MUST be adjusted and verified with ohm meter...
- Thread starter
- #11
those downloadable pdfs are amazing thanks so much i can now test all the electrical junk. are there any coolant system plans.?
- Thread starter
- #12
ok guys
I put in a used fpr and it solved the fuel issue for two days then it started back. the ove heating is a combination of the fuel and me being an idiot. i was checking the coolent at the radiator cap and it looked full. it was two gal low and i didn't realize this till i opened the thermostat housing to replace the stat and leaking gasket ( where all the coolent went) eg im dumb. anyone noticed that u can't ad fluid unless u disconnect the top hose? any way i also realized that my cold start timer is broken clean off. could this be part of the fuel issue? anyway im ordering one of those the next paycheck
I put in a used fpr and it solved the fuel issue for two days then it started back. the ove heating is a combination of the fuel and me being an idiot. i was checking the coolent at the radiator cap and it looked full. it was two gal low and i didn't realize this till i opened the thermostat housing to replace the stat and leaking gasket ( where all the coolent went) eg im dumb. anyone noticed that u can't ad fluid unless u disconnect the top hose? any way i also realized that my cold start timer is broken clean off. could this be part of the fuel issue? anyway im ordering one of those the next paycheck
You're making progress!
It sounds like you need to carefully go through the entire cooling system with the FSM and be sure that all the gaskets and o-rings are in place. Replace your t-stat, and test the new one in a pot of water beforehand (even if dealer-new) to be sure it works. Check all the hoses for bulging and leaks and replace as needed.
It sounds like you need to carefully go through the entire cooling system with the FSM and be sure that all the gaskets and o-rings are in place. Replace your t-stat, and test the new one in a pot of water beforehand (even if dealer-new) to be sure it works. Check all the hoses for bulging and leaks and replace as needed.
- Thread starter
- #14
I am and it feels great. Yeah I'm in the process of checking for leaks I need to pressure test the system. Also what does the cold start timer switch do exactly? Now that I replaced the tstat the over heating issue stopped. But I think my broken timer switch is messing things up
timer controls the cold start injector. a broken one could allow the csi to keep dumping even after warm...
- Thread starter
- #16
Well that explained my issue exactly my fuel is way too rich and I only have trouble starting when
- Thread starter
- #17
And it's in and off only does it sometimes
dirty injectors could also allow too much fuel to dump and not be all that consistent. not hard to RnR, just need some gaskets and go over the steps in your head a few times. Injector RX or Witch Hunter do injector service for decent rates. Find a spare set of OEM to send in for service if your truck must run daily...
- Thread starter
- #19
ok so took a better look to day and my cold start timber switch is in perfect condition, but the weird hole nut slot thing where it is supposed to screw in looks like the threads are broken off. any ideas where u get a new one of these slots or can i hold in the timer switch with a moldable putty
- Thread starter
- #20
Ok so fixed over heating by rebuilt the thermostat housing and replace the stat. Overheating fixed. My cold start timer is broken off how ever so I'm addressing that at the moment. But issue still exists even after a new Fpr. Idk what to do next but Desmond which I was planning on already but further down the road, to rule erg issues, and fix cold start timer. If that's not it I'm stumped. I really don't want to spend an arm and a led replacing everything mechanical either but the engine it's self. Any new ideas?