Cold Start Issue--- '91 FJ80 (1 Viewer)

[Jonbdawg]

I recently purchased a '91 FJ80 but no stranger to Cruisers. I've owned two 100s and have a '70 FJ40 that is slowly being restored. I purchased the fj80 as a new toy/project for myself.

So we have new plugs and wires, all fluids and replaced the cold start injector. After it warms up it runs and cranks great. The cold start is still an issue and need some advice of where to look next. It takes several minutes to crank. It will crank and stall out about twice before finally catching. I'm sure there is a thread out there and if so please direct me to it. Appreciate all the help.

 

[BILT4ME]

@jonheld
@LS1FJ40

As usual.......

 

[mct75]

Off the top of my head, cold start injector (which you replaced), CSI timer switch (this was my issue, see avatar), and fuel pressure regulator / damper / VSV are all suspects. I'm not the expert though.

 

[rmblaire]

My 91 cranks for a bit as well. My fuel system is all new from the pump forward. Also, I have to open the throttle while it is cranking (which I believe allows more air past the "flapper" in the intake). If I don't open the throttle, it will crank indefinitely with no fire. Throttle open = 5 sec of cranking and VROOM.

 

[Jonbdawg]

Off the top of my head, cold start injector (which you replaced), CSI timer switch (this was my issue, see avatar), and fuel pressure regulator / damper / VSV are all suspects. I'm not the expert though.

The cold start injector was recently replaced. It did seem to help but still not exactly where it should be.

 

[LS1FJ40]

My 92 is cranking a little sluggish. I am replacing the battery as PM as it's a 5 year old Optima.

I think the Cold Start Injector is part of my problem but wondering about fuel pump as well as I have the same "give it gas and it fires right up" symptom.

 

[Jonbdawg]

Strange on the give it gas thing. I didn't think an efi system would respond to that? I'm obviously no mechanic though.

 

[mct75]

This sounds like the exact scenario the fuel pressure VSV is supposed to prevent. It maxes out the fuel pressure while cranking and for a few seconds afterward to prevent hard starts. As the engine cranks, manifold pressure drops which causes fuel pressure (and thus flow) to drop as well. The mixture needs to be richer during starting as the gasoline can't atomize as well in a cold engine.

 

[mct75]

FWIW, the FSM states that if it will start with the gas depressed, it could also be the ISC valve. When you shut the engine off, can you hear some rapid ticking/clicking from the intake manifold area? When you cut the AC on, does the engine speed increase? Those are the easy tests for the ISC.

 

[Jonbdawg]

FWIW, the FSM states that if it will start with the gas depressed, it could also be the ISC valve. When you shut the engine off, can you hear some rapid ticking/clicking from the intake manifold area? When you cut the AC on, does the engine speed increase? Those are the easy tests for the ISC.

I'll check this afternoon and follow up. Thanks!!

 

[Jonbdawg]

FWIW, the FSM states that if it will start with the gas depressed, it could also be the ISC valve. When you shut the engine off, can you hear some rapid ticking/clicking from the intake manifold area? When you cut the AC on, does the engine speed increase? Those are the easy tests for the ISC.

Cranks with pedal depressed. The only clicking is 3-4 clicks when engine is cut off. (Tried several times and heard the same noise each time) No engine change with the AC.

 

[Jonbdawg]

@jonheld
@LS1FJ40

As usual.......[/QUOTE

Any other thoughts of it being the fuel pressure vsv? Seems to make sense

Thanks Jb

 

[mct75]

Remove the vacuum line from the fuel pressure regulator. If it fixes it, the VSV is the issue.

Note that you should not drive it this way.

 

[ward93]

What does the vsv do? I'm having similar issues

 

[ward93]

And what's the part number for the VSV