Riddle me this... hot start 'N dies, miss / cut out only in summer

[Ron88]

coil secondary voltage may be too low when hot

 

[pieceofchevy]

pickup coil in the dist?

 

[SAATR]

You must be registered for see images attach

 

[Dariusz Salomon]

Durangos and jeeps had the problem with ECM units overheating(especially when it was hot) and would stall. So I agree with one of the guys who suggested to try to warm the ecm with hairdrier.
Mine has similar problem-I start it-it idles for a while and will stall(usually within first minute or 2-3-always on or when revs get close to idle-i.e.when approaching junction-yes it can be dangerous). It doesn't always happen but once it wouldn't start at all-I had to call assistance. But I believe my problem is either pump or pump harness(I read all about it just not addressed the issue yet) since it doesn't stall on lpg( propane converted). Then again I never start it on propane.
I changed the fuel filter and it helped a little but didn't eliminate the problem. Changed the plugs wires and distributor and it didn't help at all.
I also tested the relay and the relay socket in the fuse box-everything seem to be in order. Thise are the steps you can take too. There's also pressure test for the pump but I got no pressure gauge so it will have to wait.

 

[PlayingWithTBI]

So I agree with one of the guys who suggested to try to warm the ecm with hairdrier.

@SAATR was talking about the ICM (Ignition Control Module) not the ECM (Engine Control Module)

 

[Pinger]

Durangos and jeeps had the problem with ECM units overheating(especially when it was hot) and would stall. So I agree with one of the guys who suggested to try to warm the ecm with hairdrier.
Mine has similar problem-I start it-it idles for a while and will stall(usually within first minute or 2-3-always on or when revs get close to idle-i.e.when approaching junction-yes it can be dangerous). It doesn't always happen but once it wouldn't start at all-I had to call assistance. But I believe my problem is either pump or pump harness(I read all about it just not addressed the issue yet) since it doesn't stall on lpg( propane converted). Then again I never start it on propane.
I changed the fuel filter and it helped a little but didn't eliminate the problem. Changed the plugs wires and distributor and it didn't help at all.
I also tested the relay and the relay socket in the fuse box-everything seem to be in order. Thise are the steps you can take too. There's also pressure test for the pump but I got no pressure gauge so it will have to wait.

We have a few things in common.
We are in the UK, running with LPG and have a petrol related problem. Mine is an occasional refusal to start on petrol (sometimes runs for a second then dies, sometimes refuses to fire at all). Mine is probably PassLock related.
I can however, 'force' mine to start on LPG (and it's as well done that way as LPG doesn't need enrichment from cold). If you don't know how to do the forced start I can explain how to (assuming our systems are similar - AEB 175 mixer set-up) but better done on another (new) thread I think. Start one if you want to talk LPG.....

 

[Steven Lindahl]

ICM, no doubt. Also check pickup coil. A ***** to replace (distributor disassembly) but prone to burnout with age.

 

[Mike Duckworth]

That pickup coil is critical for solid ignition. If it is the original one.

 

[mtl111]

I remember issues we had with my Dad's 88' GMC 1/2 ton 2wd, would start and run great, no issues, then it would die with no warning. No missing or stumbling at all. Pull to the side of the road, sometimes it would start up with a few tries, other times you might be there 30 min. We tried everything and it turned out to be the pickup coil in the distributor. It had around 180k miles on it at the time. As others have said, it's a pain to replace because of having to pull the distributor.

The OP's truck is a 97', Vortec engines don't have a pickup coil in the distributor like the older TBI engines

Sent from my SAMSUNG-SM-G930A using Tapatalk
The OP's truck is a 97', Vortec engines don't have a pickup coil in the distributor like the older TBI engines.

 

[Busted Knuckle]

Starts right up when cold and runs excellent all winter long and short trips around town. smooth and powerful from idle to redline.

The problem is during summer after a 60+ mile highway drive, It will run great the initial drive until shutoff. When trying to restart it cranks a bit longer, fires, revs up (as usual) then dies. Have to crank awhile and manually give it throttle so it stays running. Will run slightly rough from idle to redline, cuts out if you mash the gas or even smooth gentle throttle inputs. Definitely a miss like electrical or no fuel? Once you let it cool down for at least an hour, it fires up, revs, idles fine.

This was a once a year random problem only with the hard starts when warm. This year is the first time it has missed or cut out throughout the RPM range after a heat soaked hot start

NO Service Engine Soon light.

What do you think the problem is?

Anyone experience something similar?

97 K1500 Vortec 5.7 Black Bear Tune. 210k miles
original poppet spider fuel injection
Fuel pump (2nd time) replaced 30k miles ago with Delphi pump along with new fuel filter
New plugs, cap, rotor, wires 20k miles ago
New Bosh O2 sensors (all 4) 20k miles ago
New high flow catalytic converters 20k miles ago
Engine grounds are clean

Possibly the ignition module. At that mileage you need to change the entire distributor. I suggest something like this: UNITED MOTOR PRODUCTS 9362
With any of them, remove the ignition module, clean off the compound, and replace it with PC heatsink compound such as the Noctua NT-H1. I'd also use a Delphi or ACDelco rotor in place of what they send. Ref: https://www.amazon.com/Noctua-NT-H1...arctic+ceramic+compound&qid=1593459643&sr=8-8

https://www.rockauto.com/en/moreinfo.php?pk=1130207&cc=1303063&jsn=460