1991 fj80 will start but dies.

[crzrcrzy]

Heya, I just recently got my 91 fj80 back on the road. It was running alright. Idled fine in park but would drop idle to 450-500 rpms when put in gear. Recently will start but not Stay running unless I'm on the throttle. I can hold it at idle but as soon as I let off the throttle she dies. I've cleaned and inspected the ISC. All seems fine there. I haven't found any vacuum leaks. It happened quite suddenly while driving.

 

[ppc]

@crz2crz
Have you checked the underside of the intake tube for cracks which would allow unmetered air into the engine.
Have you been messing with connector on the AFM?

 

[crzrcrzy]

The intake tube was cracked in several places. I patched it up and wrapped the out of it with electrical tape. Haven't messed with the afm.

 

[jonheld]

You still have an air leak. The top end of the motor wants to be air tight.

 

[crzrcrzy]

You still have an air leak. The top end of the motor wants to be air tight.

Thanks for all the info. I had time this weekend to dig back into this. I've replaced the intake tubes with hps silicone tubes. Checked the maf, all good. Checked the tps, all good Checked the isc, all good. No vacuum leaks that I can find. It is desmogged. Will start right up but not idle. Any other suggestions?

 

[efjayatee]

Idle control valve?

 

[crzrcrzy]

Checked. Seems to be within spec.

 

[crzrcrzy]

I do have a consistent miss at all ranges of rpm. Could this point to something?

 

[crzrcrzy]

I feel like it's something stupid simple. I just can't find it.

 

[Dexter]

I feel like it's something stupid simple. I just can't find it.

Were you able to diagnose this issue? I have ran through the checklist and am awaiting a Circuit Opening Relay to arrive in hopes it is my solution.