FJ62/3FE Starts then Dies

[Lead Head]

Hi All,

Slowly working through my complete frame-off rebuild/restoration of my '89 FJ62, and we got to the point today where it was time to fire the engine off. Well, with a bit of starting fluid, it came to life and idled okay for a little while. But after a couple of minutes it started breaking up and running really rough. Eventually it died. I could get it to restart and run for a bit - then it'd die. Each time it'd run for less and less time before it died. Eventually it got to the point where when you turned the key to start, it'd run for about half a second and die.

I'll give a break down of things I tried/observed:
- There was no check engine light while it was running
- Unplugging the engine coolant temp sensor or TPS made no difference in the dying behavior
- Shooting a bunch of carb cleaner down the intake would make it start and run longer - so it's not a spark issue (at least it seems like it's not)
- Brand new fuel pump
- Brand new fuel lines
- Brand new fuel filter
- I unplugged the cold start injector, and the start-die behavior did not change. So it's not like it's just running off the cold-start shot.
- When it was running, it didn't really respond to throttle. It'd just sort of hesitate and cut out.

Before we took everything to pieces last year, we did very the engine did start and ran. Everything has been sitting since. When we took it apart, we did not disconnect any wires off the engine - we just unplugged the harness from the PCM and draped it over the engine.

Any ideas or trouble shooting tips?

 

[too tall]

Try removing the intake tube and push the flap open on the AFM with the key on and see if the fuel pump runs. The circuit open relay will run the pump for a few seconds on initial startup then the AFM takes over. Sounds like the fuel pump is priming but not continuing to run off of the AFM.

 

[Seth S]

Sounds like a fueling issue if you can get it to run on starting fluid. Clogged fuel filter or the fuel pump shutting off. I’d jump the fuel pump relay and see if it stays running. Easy to do and rule out the pump

 

[Lead Head]

Pushed the flap and the fuel pump turns on.

I don't think it's a clogged fuel filter, since it's brand new, all the lines are new, the pump is new, and the tank was cleaned out. But I will do a fuel-flow check tomorrow I suppose.

 

[Seth S]

You can install a fuel pressure gage on the cold start injector with an adapter banjo. Easy way to watch your pressure during this problem

could be an fpr issue

 

[Lead Head]

Took the fuel return line off and jumped the pump - no fuel coming out of the rail.
Took the hose off the fuel filter going to the rail - no fuel going into the rail
Put more gas in the tank (I had only put ~2 gallons in it). Still no gas.

Took supply hose off the fuel filter - tons of grass spraying everywhere. Huh. Looked a little closer at the fuel filter and saw this:

Turns out a critter had made a nest inside my new fuel lines in the time between me making them, and me getting it all hooked up. When I turned the pump on for the first time, it just fired all that garbage right up the line and into the banjo fitting. None of seemed to have actually made it into the filter. Got that fitting cleaned out, and the thing fired right up and settled into a smooth idle.

Definitely a first for me.

 

[TexFJ]

Try removing the intake tube and push the flap open on the AFM with the key on and see if the fuel pump runs. The circuit open relay will run the pump for a few seconds on initial startup then the AFM takes over. Sounds like the fuel pump is priming but not continuing to run off of the AFM.

such a simple way of testing the FP and relay, and a quick way of turning on the FP if you lost your little jumper wire