Heat soak/misfire

[xj94]

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Just started having the dreaded heat soak issue. I've heat shield the fuel rail, injectors and fuel line running to rail. Also shimmed the hood, still no help.In stop and go traffic with A/C off or on it misfires and shuts off, cold water on the rail gets it going again. I thought heat soak/ no starts occurs after its been sitting briefly after running. Here's some things that's wrong, maybe you guys can help get this thing running right.

1. changed fuel pump, still have to prime line on every start
2. new temp sending switch, gauge only reads 110 reads around 210 with thermo scan.

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[4.3LXJ]

Heat soak is usually on 96 and up, most noticeable on the 99 and up. That being said, the check valve i the regulator sounds like it is leaking back. You can replace that or you can run the key twice before starting. You might want to take a look at your idle air controller and see if it is dirty. A miss shouldn't kill it

[sbspence]

Yeah. The heat soak issue that the TSB refers to is one that affects the #3 injector on the '99 and up. Mine shows up when the temp humidity is high and I'm running tfe AC. When I shut it off and then restart within a few minutes it slobbers at idle and lasts only until you clear it's throat with a liberal throttle stab. It almost acts like its loading up but apparently the 3rd injector's fuel vaporizes due to underhood temps and the venting of the manifold. V annoying. Mine appears to have had the insulator installed big still acts up. It's just low on the list of things to fix.
Let us know what you find!


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[Mudderoy]

Have hood vents solved this problem for anyone?

[4.3LXJ]

The only one I know that solved the problem is Muddeprived on this forum. He is an inactive member here now, but is still active on CherokeeTalk. I helped him with some wiring on a fan timer that uses the efan for a few minutes after shut down. He says it worked. It blows air on the manifold area and apparently cools it down enough

[rv-errr]

Early model FORD vans had a blower that ran after shut down for several minuets to cure that problem. CURT

[sbspence]

Exactly this was common practice in the 80s ...not suuure why we went away from that? :bang: I'll have to check into that timer idea, or see i I can adapt Ford's old tech... hmmmm . I've wondered about the vents too. I'm sure they would help but might be a little too passive as the heat spikes very quickly when the fan shuts off.

[Mudderoy]

If it's cooling the fuel rail, I'm surprised no one has attached a good old fashioned heat sink!

[4.3LXJ]

If it's cooling the fuel rail, I'm surprised no one has attached a good old fashioned heat sink!

I think if you did that in high temps, it would act in reverse and absorb heat and make it worse

[sbspence]

From what I've gathered it's actually just the #3 injector and the TSB part just covers from the injector to the intake so not sure a rail fix would help. Now a fan timer and hood vents might just help. I tested it a few times by simply opening the hood when shutting off when hot and restarting and the problem is not there. The build up of underhood heat on shut down seems to be the issue. I would rather remove the heat issue than bandage the #3 injector up like the TSB says. Shrug.


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[Cheromaniac]

Here's another alternative that'll definitely alleviate the heat soak issue:

http://www.angelfire.com/my/fan/manifold.html

[sbspence]

That is a great idea thanks for sharing!! :bacondance: