1991 fj80 crank but no start.. Will start the next morning ...?!?!??!??

[Markoloma]

My Dad always said you need 1/2" of spark.

My experiance is a 1/4 is usually fine. But if all you can get is a little piddling 1/8.....then you have other problems.

My downfall was I would always just pull the coil wire. Easy. That didn't test the cap and rotor which can be the path of least resistance as Jonheld pointed out.

Interesting.. So if that's the case. Why would it RANDOMLY stop working.. And then the next morning always fire right up?

My distributor IS missing one or the little screws on the side.. Not sore if that's going to be an issue. I'll have to check once I pick it up. It's stranded in a parking lot right now.

 

[fonman]

I just wanted to be sure that you really do have good spark. That when you test the spark you can draw a nice strong zap... more than just across a plug in open air.



UOTE="Markoloma, post: 9399952, member: 102255"]Interesting.. So if that's the case. Why would it RANDOMLY stop working.. And then the next morning always fire right up?

My distributor IS missing one or the little screws on the side.. Not sore if that's going to be an issue. I'll have to check once I pick it up. It's stranded in a parking lot right now.[/QUOTE]

 

[jonheld]

Interesting.. So if that's the case. Why would it RANDOMLY stop working.. And then the next morning always fire right up?

Because the fuel rail is over pressurized. Letting it sit for a time allows it to depressurize. Just a theory I have
Check the condition of the cap/rotor anyway because it is prudent to do so.

 

[thex1231]

I've had my 91 with the same problem for a while and I've thrown parts at it but no go.

It will only start with starter fluid and will remain on and running fine until I shut it off and try to restart.

It is basically the same case you had.


I've changed the pump, fpr, wiring to efi relay among many other things.

Pressure is stable at 40 psi.


Let me know if you ever got this solved.

Thanks

 

[jonheld]

I've had my 91 with the same problem for a while and I've thrown parts at it but no go.

It will only start with starter fluid and will remain on and running fine until I shut it off and try to restart.

It is basically the same case you had.


I've changed the pump, fpr, wiring to efi relay among many other things.

Pressure is stable at 40 psi.


Let me know if you ever got this solved.

Thanks

If the engine runs well after starting then the EFI circuit can't be the issue. Move away from that.
You need to check fuel pressure during startup. The fuel pump is fired by the starter circuit during cranking and the flap in the AFM after it starts sucking air.

 

[thex1231]

Fuel pressure is at a steady 40 psi when cranking and pressure is maintained.

It will only start with starter fluid, it runs fine once it starts and will stay running fine.

I changed the coolant sensor and connector yesterday since it threw code 22 and it started stumbling a couple days ago.

I just can't figure out why it won't start on its own.

 

[jonheld]

Fuel pressure is at a steady 40 psi when cranking and pressure is maintained.

It will only start with starter fluid, it runs fine once it starts and will stay running fine.

I changed the coolant sensor and connector yesterday since it threw code 22 and it started stumbling a couple days ago.

I just can't figure out why it won't start on its own.

Have you checked the basics like cap/rotor condition?

 

[thex1231]

I've replaced them recently, the fail to start was there before and after the replacement.

Plugs and wires have also been replaced.

It has spark when it cranks.

 

[jonheld]

Is it only from a cold start or will it fail to start after running for a while?

 

[thex1231]

It used to be only when warm or hot. Now it is cold or hot.

If I try to star it right after shut down it will start but if I leave it for a minute or two it won't.

The fuel pressure remains at 40 for a good 20 minutes and then it starts draining but comes right up as soon as I hit the starter.

The cold start injector was working but I need to check it again.

 

[jonheld]

Have you tried starting it while stepping on the accelerator pedal?

 

[thex1231]

No, I will do that a little later and report back.

Thanks for the help, this has me really frustrated.

 

[thex1231]

I'll try to post a video tomorrow.

 

[thex1231]

Have you tried starting it while stepping on the accelerator pedal?

So I held the accelerator down while cranking (cold) and it started, it stumbled a bit then it stabilized.

When it's cold and I press hard on the accelerator it will stumble and smells rich.

Once warm the hesitation goes away.

Tried starting it again after 5 minutes running with the pedal down and it will not start.

 

[jonheld]

So I held the accelerator down while cranking (cold) and it started, it stumbled a bit then it stabilized.

When it's cold and I press hard on the accelerator it will stumble and smells rich.

Once warm the hesitation goes away.

Tried starting it again after 5 minutes running with the pedal down and it will not start.

Do you have the FSM?
There is a section on troubleshooting. In your case it points to the ISC valve and there is a section on diagnostic tests.

 

[thex1231]

Do you have the FSM?
There is a section on troubleshooting. In your case it points to the ISC valve and there is a section on diagnostic tests.

I do have it, I will diagnose it today and report the back the results.

One thing I did was remove the coolant lines that go to the isc and intake manifold but it already had that no start problem.

Do those affect it in any way?

 

[thex1231]

No go partner, the isc is working to specs, it closes and opens as it should.

 

[thex1231]

Do you have the FSM?
There is a section on troubleshooting. In your case it points to the ISC valve and there is a section on diagnostic tests.

Here are a few videos of the symptoms.


This will show the hesitation when accelerating (COLD).






This one will show the no start.

 

[thex1231]

Do you have the FSM?
There is a section on troubleshooting. In your case it points to the ISC valve and there is a section on diagnostic tests.

The engine will no longer hesitate once it starts warming up.

 

[jonheld]

When did this issue start?
Was it good one day and bad the next?
Does the cold start injector and the cold start injector time switch work?