Hot restart issue (1 Viewer)

[MattMud]

1997 1FZFE with Wits End turbo
New OEM short block
Rebuilt head
New OEM starter
New OEM fuel pump (sock and surroundings were super clean)
New fuel pressure regulator
Rebuilt injectors
Temps range from 185 to 192.
Volts charging at 14.2.
Both ends of coil wire are clean and brand new OEM and so too are plugs and wires

Symptoms: runs great and starts up cold as it should. About 50% of the time if I turn off and run inside for an errand, come back 5-10 mins later and restart, it will always start but not go past 800 rpms and die. Hit key again and it will crank for 4-5 seconds and then start as it should (predictably - never requires a third try).

I have swapped out the MAF, fuel pump relay, and the coil from another good running 80 without these symptoms.

Any ideas of what is causing this hot start and immediately die issue?

Thanks in advance!

 

[-Spike-]

Stab in the dark- sounds fuel related, like the pump isn't running on the first hot start attempt, then has to run a bit on the second try before it fires up. There's a logic circuit in there somewhere, but I don't remember how it works.

 

[Shipwreck]

Since your symptoms seem to be idle speed related, I would follow the fsm to double check overall vacuum as well as the TPS sensor, IAC valve or throttle cable. With all of the recent engine work, it may possible that that one or more of the valves got messed up during disassembly / reassembly.

 

[doc_random]

I had similar (but not identical) symptoms and it was fixed by replacing the fusible links . I'm in AZ and the under hood temps climb for short errands. Are you in the southern US?
Mine was no crank after 2-4 errands if they were in close together. Called AAA one time after I popped the hood and it started up before they arrived. My two cents.

 

[Malleus]

 

[MattMud]

Thanks for the input. I'm going to swap the IAC and maybe TPS? from a donor vehicle to see if anything changes. I took the IAC valve off of mine just now and cleaned it. It was sticky as though it had syrup or honey on it. Is that right? I've got to work on getting the lower screw out of the donor so that's got me stalled right now.

 

[Malleus]

That's carbon and oil from the PCV valve leaking into the intake. I'd concentrate on validating the old IAC, before I just swapped parts. If it passes the tests, it's good. IME, the throttle body must be removed to get at the lower screw. Especially if it's been there since the factory. I buy two new to install when I pull one off.

 

[doc_random]

80 hard starting when hot - turns over but have to pump the gas

This is a relatively new situation that has just started in the past year to year and a half. I have no issues starting the 80 when it's cold or been sitting. Generally I have no issues starting the 80. However, the last few times I've been on the beach, driving, when I get to an area where...

forum.ih8mud.com

@concretejungle Did you resolve your issue from last year?

 

[concretejungle]

Not exactly, no. It still happens occasionally when I've run the rig pretty hard and it's really hot.

One thing I try to do, and I am assuming it helps, is when I'm planning on shutting the truck off I'll let it idle for a minute or so before turning it off. I think I'm letting the coolant flow and heat dissipate just a little, at least that's what I think.

But the really weird thing is that if I either, walk away and come back after it's cooled it starts fine, OR, if I start to pump the gas just a little it will stumble to a start. Kind of weird considering it's a fuel injected motor.

 

[doc_random]

 

[-Spike-]

Not exactly, no. It still happens occasionally when I've run the rig pretty hard and it's really hot.

One thing I try to do, and I am assuming it helps, is when I'm planning on shutting the truck off I'll let it idle for a minute or so before turning it off. I think I'm letting the coolant flow and heat dissipate just a little, at least that's what I think.

But the really weird thing is that if I either, walk away and come back after it's cooled it starts fine, OR, if I start to pump the gas just a little it will stumble to a start. Kind of weird considering it's a fuel injected motor.

You may have a leaking injector or 6, causing a rich condition on start-up in some situations. Opening the throttle allows more air to mix with the fuel that's already in there, so it can start.

 

[concretejungle]

Interesting take on the leaking injector. I will say that when I did my motor rebuild I had the injectors sent off, cleaned and returned. I reinstalled with new 0-rings. I do not visually see any leaking or smell gas.

 

[Michael Hanson]

Hi, How old is the fuel pump?

 

[MattMud]

Well, I started another thread yesterday because everything went crazy when I got water intrusion somewhere in my wire harness. See that thread if helpful. Short story is that I swapped the harness today and it solved the issue. We’ll see if it solves this hot start and die issue.

 

[concretejungle]

Hi, How old is the fuel pump?

New fuel pump when I did the motor rebuild. So the same age as the injectors and everything else..... maybe 5 years old.

 

[Karl Andersson]

New starter just clicks too!

On Friday I thought I smoked my starter trying to loosen the crank pulley bolt so I got a new one. The new starter just clicks too! The battery is good and the connections good WTF! Can anyone suggest something here? Is there a fuse or relay that I can check? Thanks

forum.ih8mud.com

Check post #6 and #18.
I am having a similar issue and I believe this might be the answer. I have not had a chance to check the voltage at my starter yet when hot.

If you get a chance to check this out before I do, please let us know what you see.


I am going to give this kit a try to simplify things: Painless Wiring - https://www.painlessperformance.com/wc/30202

 

[MattMud]

Thanks Karl. Are you chasing a hot start and then die issue or a starter failing to engage reliably?

 

[Karl Andersson]

Thanks Karl. Are you chasing a hot start and then die issue or a starter failing to engage reliably?

Now that I have gone back and read your original post more carefully, our issue is pretty different.

I have an Intermittent starting issue that mostly occurs when motor is hot. Once started, it stays running and does not die. My issue occurs if I stop somewhere and turn off the motor, the starter just clicks once and will not start when i try to start it. If i wait like 15 minutes, it will start.

I ordered the Hot Shot kit linked above and will try to get it installed soon. I believe this will fix my issue - your results may vary. I will read original posts more carefully before responding but this jumped out at me as I was on here researching my own starting issues. GOOD LUCK!

 

[MattMud]

No issues at all. I learn a LOT from reading threads of problems I'm not facing so I appreciate the community.

 

[concretejungle]

Now that I have gone back and read your original post more carefully, our issue is pretty different.

I have an Intermittent starting issue that mostly occurs when motor is hot. Once started, it stays running and does not die. My issue occurs if I stop somewhere and turn off the motor, the starter just clicks once and will not start when i try to start it. If i wait like 15 minutes, it will start.

I ordered the Hot Shot kit linked above and will try to get it installed soon. I believe this will fix my issue - your results may vary. I will read original posts more carefully before responding but this jumped out at me as I was on here researching my own starting issues. GOOD LUCK!

I have had this issue in the past. I've replaced everything wire and the starter. I very rarely get it, but it does still occasionally happen. The only thing I have not replaced is the ignition.

at one point I had a loose wire from my starter up to the battery box. If I had the hot start issue I would just tap the wire on the positive and the truck would start. I removed it last time I replaced the starter and have almost had zero starting issues; but have had it happen twice this summer.