'92 FJ80 power loss?

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gnarlytoes

gnarlytoes

10 Year 15 Year
Joined
Nov 11, 2010
Threads
47
Messages
383
Location
Beech Bluff, Tennessee
The other day on my way home from work my '92 with 3FE suddenly lost power. Engine still running, just would not accelerate. Like it was either starving for fuel or timing retarded. At same time, transmission kept going back and forth from 2nd to 3rd. I pulled over and it idled high. Pressing the accelerator it stumbled and built rpm slowly even in neutral. No CEL. Suddenly the idle returned to normal and I drove it the rest of the way home with no problem.

I thought maybe fuel filter. I replaced the fuel filter and everything seemed fine for a few days. Then it did it again. Once again high idle, no power or acceleration, no CEL.

Any ideas what to check next?
 
Sounds like a normal 3fe, step on gas and nothing really happens.:flipoff2:

Sorry, couldn't help it...:hillbilly:
 
The transmission knows nothing about the engine except the speed and throttle position.

The 1FZ guys normally blame stumbling issues on the TPS. Not sure if 3FE has the same symptoms.
 
Fuel pump sock/filter (in tank) needs to be replaced if you haven't done so. 30 minutes MOL to remove second row seats pull back carpet and remove the fuel pump via access hole.
 
gnarlytoes said:
Not saying that could not be the culprit, but I replaced the fuel pump and pre-filter this past spring.
Click to expand...
How was the tank? Clean and no rust? If not clean you might change the sock again and check the fuel pump baffle supply tube with a wire to make sure it isn't clogged.
 
SUMMIT CRUISERS said:
How was the tank? Clean and no rust? If not clean you might change the sock again and check the fuel pump baffle supply tube with a wire to make sure it isn't clogged.
Click to expand...
It was pretty clean. A little very fine rust from where it sat a few years ago. Just enough to tint the fuel. I drained and flushed it then.

I will order another pre-filter and change it and check the supply tube.
 
I have been having similar issues to you since a head gasket and top end rebuild last year. One thing I might read into is the Rodney's Party Trick. Last summer my truck would bog down and lose all power. It ended up being the trans valve body. I did the party trick a couple times and it made a big difference. Still happens on occasion, stopping and letting the truck idle for a bit, then it comes back to life as if nothing happened. I also did the fuel sock with no change.
 
Update:

Symptoms still occasionally occurring after replacing fuel pre-filter and checking fuel pump. Yesterday afternoon it did it again on the way home from my dad's and did not get better. I limped it the last couple of miles home with almost no power or acceleration and still no CEL. Yes the CEL comes on with switch and goes off after it cranks. I then started reading everything I could find about the symptoms.

This morning I cranked it and same thing. Stumbled and not wanting to accelerate even in neutral. So I went and got some MAF cleaner and throttle body cleaner. Removed both and cleaned thoroughly. I even removed the TPS, after putting four witness marks so I could get it back exactly where it was, and cleaned it.

The difference when I started it was night and day. Runs smooth and accelerates like it should. The only problem was idle was about 1100 rpm after engine got to operating temperature. I had made sure to set the idle adjustment screw back exactly it was also, but apparently it had not been anywhere near where it should be. I wound up turning it in over a complete turn to get the idle speed back to around 650 rpm. Once I got the idle set, I ran it in completely and back and it was just about 1/2 turn.

So hopefully I've got it fixed. I guess I will have to wait and see if it does it again.
 
My FJ80 is doing the same thing, was thinking bad gas or fuel filter. I'm doing the filter today, guess I need to clean MAF and TPS today also.
 
Throttle Position Sensor.
 
FYI, the 3FE doesn't have an "idle adjustment screw". If you are referring to the forward facing screw on the top of the intake next to the ISC valve, that sets the idle air intake. While it will have a temporary effect on idle speed, the idle speed is set by the ECU and the ECU will continue to bump the ISC valve to properly set the idle. This is why it is important to set the ISC valve according to the FSM. The ECU is not very smart (1986 technology) and needs to make certain assumptions in order to keep things within the operational window.

The idle air intake screw should be 1/4 to 1/2 turn out from fully seated. and NOT idle speed should be 650.
 
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