2.3L ('83-'97) Hard restart issue with distinctive pattern

[turner]

This one has me puzzled. 1987 2.3L. The pattern is perfectly consistent, I took video that starts with the truck running (from cold), and goes through the symtoms below.

https://youtube.com/shorts/2mB6WbhteIA?feature=share

Symptoms:

• Runs perfectly from cold, drives for any length of time or distance, no issues.
• (After parking and turning off) Trying to restart-- will fire right away, surge to 2000 rpm, then shut itself off immediately
• After that single surge, it won't fire at all for some period of time (5min, 30min, 6 hours)
• This week while driving, it also shut off while on throttle moving down the road. No sputtering or coughing, just immediately stopped firing like flipping a switch.

I have the factory manual + emissions/diagnostic manual, so I've gone through their troubleshooting procedures. Here's what I've tried:

1. Replaced (original) fuel pump relay because the contacts looked a little melty.
2. Back-probed TFI connector to make sure it gets 12V on the right wires at the right times, using this site's guide. Checked out good
3. Replaced TFI module
4. Coil measured good, spark is good, plugs are good (new), wires are good (6 mo old), battery is good
5. Bypassed cutout switches for good measure (inertia + clutch switches)
6. Ignition switch is 6mo old
7. Pulled distributor, replaced pickup coil + drive gear. Cap + rotor are 6mo old.
8. No obvious loom issues/grounds
9. Only code is TPS voltage out of range, which is always the case (unless I've recently adjusted it)
10. After the symptoms have started (won't restart), there is no spark at the coil wire while cranking (haven't rechecked this since overhauling dizzy)

Because of the way the engine shut off while driving, I figured it HAD to be spark. But the way the engine surges then dies after sitting, made me think maybe the fuel pump isn't working when hot, and the engine is using it's last gulp. The consistency is what's puzzling me. If the electrics aren't sending a spark on restart, how does that surge happen? And so consistently? Always the exact same amount of time from start to surge to shutoff.

To do:

• Test for spark while symptoms are active (again, since I've rebuilt dizzy/TFI)
• Check fuel pressure while symptoms are active

Does this ring any bells for the experts here?

 

[Terrys87]

One of the toughest issues I ever had was getting spark and not firing. It wound up be the coil. I just thought if there was spark it would ignite fuel. I see you have checked your coil. There are two measurements you can do on a coil. Have you done both checks?

I wonder if fuel pump could be getting hot? Try cleaning all of your grounds? There are several grounds on a truck.

 

[turner]

I did measure both primary & secondary resistance. Maybe I should repeat that test while the symptom is present... get the truck to where it won't start then test it.

Might as well find the grounds and clean them.

If the fuel pump cut out with this EFI system, would the truck shut off abruptly like a switch? I've run out of fuel (too many times) with carb'd vehicles and it didn't feel like that.

 

[Terrys87]

I only run an efi out of fuel one time, seemed like it did buck and sputter for a moment and then completely died.

Here is some of the grounds. Don't miss the one on the frame of the main battery cable.

https://www.therangerstation.com/forums/proxy.php?image=https%3A%2F%2Fcimg2.ibsrv.net%2Fgimg%2Fwww.ranger-forums.com-vbulletin%2F2000x1504%2Fimg_1914_32c988bfe7af1276c9f68a15a3225c228802162a.jpeg&hash=f76e201a5fb4d0065f21c527c41575da Starting at post 39

 

[SenorNoob]

Maybe I should repeat that test while the symptom is present...

Absolutely a good idea.

 

[turner]

Starting at post 39

That link goes straight to an image, is there a thread laying them all out?

 

[Terrys87]

@turner https://www.therangerstation.com/fo...nd-add-information-as-i-find-it.204634/page-3

Start at post 39. I tried it again. I am not the best at this computer thing. On the main graound wire, there is a center that is attached to the frame. I thought I posted it but it is tucked behind the inner fender.

 

[ShhhhhDougsHere]

I did 20 years in prison I've been out 11 months.
When I first went to prison coil packs and individual coils for each spark plug we're just really taking hold. As far as I knew or know of.

I had a friend that had a vehicle that had the same exact symptoms that you're having exactly.

At that time the coil pack could be taken apart into two pieces.
It was one of them two pieces of the coil pack that was the problem.
I can't remember what they were called or which one was bad.

You need to do the test when you're having the problem like you've already stated yourself you need to do.
But you put it as a question not a statement. Only you used a period instead of question mark.

I don't know if you live in the city or in the country or whatever but drive your truck around the block or whatever and get it to shut off again and then test your coils or coil pack whatever it is.

Now truly I'm a novice to this new technology and vehicles as I already stated I did 20 years in prison.
With that said I'm confident you need a new coil.

If I'm wrong please feel fully free to make sure everyone knows I was wrong .
Please make sure that I know I was wrong.
And feel free to rub it in as much as you would like.

And once again I write a book.

 

[ShhhhhDougsHere]

P.s. to my latest book.

The problem is caused when the coil gets hot and something inside of it shorts out.

I could have edited my last post and put that in there but I felt it'd be better to just post again in case someone's already reading my post and I know it's a big book in comparison to most posts.

 

[Uncle Gump]

You really need one of these...

And one of these...

 

[ShhhhhDougsHere]

@Uncle Gump I'll gladly give you my address if you give me 2 of each those for free.
In person So I can give a big hug as payment.

And then while you're at my house, I'll pick your brain about a bunch of other stuff.
I know you got a bunch of knowledge in there.

 

[RobbieD]

You really need one of these...

Now, THAT is a real man's roach clip!

 

[Uncle Gump]

@Uncle Gump I'll gladly give you my address if you give me 2 of each those for free.
In person So I can give a big hug as payment.

And then while you're at my house, I'll pick your brain about a bunch of other stuff.
I know you got a bunch of knowledge in there.

I might have a spare spark tester... I'll poje around in my ignition drawer next time out in the garage.

 

[ShhhhhDougsHere]

@Uncle Gump I bet you do.
Remember I live in Dayton Ohio.
And I'm on parole so I can't leave Ohio.
You'll have to bring it to me so you can get that hug.

 

[turner]

Thanks guys. I've got a spark tester, that's how I determined that it has good spark normally, and no spark from coil when the symptoms are present. I've been putting off buying a fuel pressure gauge, because I mainly work on carb'd cars and already own one for that pressure range. This is the only vehicle with higher EFI pressures I'll probably ever own.

I went ahead and bought a coil, figure it's worth having a spare even if this one is ok. Of course today I couldn't get the symptoms to show up, the truck is waiting for me to have an appointment I can miss! It idled and idled and restarted on command, even after getting the engine nice and hot over the course of an hour.

I really can't do test drives, I live at the top of a hill so anywhere I go, I'd need a tow back.