no idle and a big stumble, sometimes

[ripple]

I have two fj60 2F problems, possibly related, both are intermitten and seem to occur when engine is warmed up.

ONE: Stalls upon decellaration. If I restart with full choke and gradually release the choke I get my idle again.

TWO: Loss of power, stumble, hesitation at higher rpms ~2000+

Fuel filter ok, Fuel pump ok, float level correct, new accelerator pump, EGR bypassed/plugged, air filter ok

I am searching for a vacuum leak........

If she would only just quit completely, I'm dyyyyyyin....

 

[FJ40Jim]

Both symptoms sound like possible decel fuel cut problems.

One could be decel fuel cut turning off idle fuel, but then not seeing signal to turn fuel back on.
Two could be fuel cut turning off idle fuel above the 1800RPM cutoff point.

I would try hardwiring ground side of idle cut solenoid, see if symptom goes away.

 

[ripple]

Hardwired ground seems to be helping but I am not sure.

I hard wired, the truck died every time after starting, giving gas.
I hooked up the plug to the solenoid, same thing.
I pulled the solenoid and it tested good, it may have been stuck.
I hard wired ground and the truck started up and would keep running with a little choke.
I hooked up the plug to the solenoid with the same result.

With maximum idle adjustment I still need a little choke to keep an idle.

The truck doesn't die on decel and I can't reproduce the stumble on accel when the truck is warmed up. Landcruiser's usually aren't this wierd, it might be me.

 

[ripple]

thanks jimmyc.
it is the signal to the fuel decel solenoid
I have now hotwired the fuel decel to stay on constantly.
I'm on the road but now I need to know where the signal
should be coming from.

thanks again, i avoided a long road of carb rebuild, fuel pump, vac line hell, I hope I can repay the forum with good advice in the future

 

[FJ40Jim]

Ripple,
The ICS gets +12V when the key is on.
It gets ground through the emission computer, based on inputs from speed, tach and MAP sensors.

The most common failure is bad sensor input causing confusion in the computer.

The second most common failure is the computer itself.

 

[ripple]

thanks, and now my next questions

What literature do i need to start testing these electrical components?

If my egr is disabled, then haven't I confused the computer?

Is there any harm aside from poor gas mileage that hotwiring and direct ground to the decel solenoid would cause till I fix it right?

thank again

 

[FJ40Jim]

What literature do i need to start testing these electrical components?

The emissions FSM and a wiring diagram.

If my egr is disabled, then haven't I confused the computer?

No, it is not smart enough to see that it's EGR signal is doing nothing.

Is there any harm aside from poor gas mileage that hotwiring and direct ground to the decel solenoid would cause till I fix it right?

The exhaust is stinky in the decel phase, which makes the cat work harder.

FWIW, the '78-earlier trucks just have the ICS powered by ignition switch, no decel system. Seems to work OK on those non-catalyst vehicles.

 

[ripple]

Thanks again,
It feels so good to be on the road again.