Engine dies randomly - starts back up fine (1 Viewer)

[Box Rocket]

Been searching the past few days without a lot of luck but looking for suggestions on where to start with this and what to check.

Context....
1995 1FZ with 242K miles. HG replaced. No engine mods. New group31 Battery. Engine temps have been slightly warmer for the past 2 weeks (normally 190*-194*, recently will occasionally rise to ~205*-210* could just be summer temps)

I have an intermittent P0301 (bad O2 sensor) code that I haven't fixed yet.

Truck is running fine, not stumbling, no rough/low idle. No issues on the highway, but a few times in city driving as I slow to a stop the engine will shut off. No CEL. Starts right back up and seems to run fine. Engine temps don't seem to be a factor as it has happened at lower "normal" temps.

Haven't been able to repeat it with any consistency to pinpoint any specifics that might cause it. Seems totally random.

Suggestions?

 

[sirzepp]

Hey Adam...how's it goin'? I randomly saw your post on the sidebar and thought I'd check in.

I have no idea what is going on with your truck...but I'm wondering if it has an aftermarket alarm installed. If so...is it possible that is somehow the culprit (ignition cut-off related). OR...do these trucks have transponder keys? (I don't think so...I have one and you'd think I would know that)...if so...is it possible there's something going on there?

 

[Box Rocket]

Hey Adam...how's it goin'? I randomly saw your post on the sidebar and thought I'd check in.

I have no idea what is going on with your truck...but I'm wondering if it has an aftermarket alarm installed. If so...is it possible that is somehow the culprit (ignition cut-off related). OR...do these trucks have transponder keys? (I don't think so...I have one and you'd think I would know that)...if so...is it possible there's something going on there?

Thanks Jeff. As some point the truck had an aftermarket alarm. I had all of it removed soon after buying the truck.

 

[BILT4ME]

Fusible links?

Harness behind the EGR drooping due to heat and shorting?

Vacuum leak?

 

[Box Rocket]

Fusible links?

Harness behind the EGR drooping due to heat and shorting?

Vacuum leak?

Are there any common vacuum leak culprits?

It's possible that the harness could the issue. I was getting a short in the harness during Cruise Moab, but repaired the wires that looked to be shorting and recovered the harness with some heat resistant covering. When this was happening at Cruise Moab the truck would stumble and have a rough idle for a few moments before stopping. It also threw an engine code, which I'm not getting this time.

I've considered the fusible link as well, but was not sure if they can have an intermittent issue like this? I have always thought they were an item that when it had a problem it just stopped. Am I wrong? I have a new fusible link in my parts stash but would like to confirm it's the issue before replacing if possible.

Thanks for the suggestions!

 

[Box Rocket]

Can a cracked intake tube cause this? Just thought of this and it's something I hadn't checked yet.

 

[AcuWiz]

I had almost the same issue and then a bit later got a code for the really common emissions (P04010 or something close) replaced the little filter and has not done it since, 3 plus years now.

 

[Box Rocket]

I had almost the same issue and then a bit later got a code for the really common emissions (P04010 or something close) replaced the little filter and has not done it since, 3 plus years now.

Which filter are you referring to?

 

[NLXTACY]

Can a cracked intake tube cause this? Just thought of this and it's something I hadn't checked yet.

Naw, it throws a CEL and makes the truck drive like crap but I've never heard of it stalling.

 

[NLXTACY]

A bad fusible link can be intermittent for sure. Worth checking.

Does the truck just shut off or does it buck
a little first?

 

[Box Rocket]

A bad fusible link can be intermittent for sure. Worth checking.

Does the truck just shut off or does it buck
a little first?

just shuts off. no bucking. First couple times I didn't even realize it had shut off.

 

[NLXTACY]

No Christmas tree on the dash?

 

[Box Rocket]

No Christmas tree on the dash?

once it shuts off, the typical CEL and battery lights come on like when the motor is in the ON postion but not started.

 

[NLXTACY]

Then I'm going to say it's electrical and not a fuel delivery issue. Fusible is a culprit as is the harness.

 

[Box Rocket]

I agree. definitely seems to be electrical to me. I'll probably change the fusible link and see what happens, then start chasing the harness, which I'm not looking forward to. Any other parts of the harness besides behind the EGR that are common areas of trouble?

 

[NLXTACY]

I agree. definitely seems to be electrical to me. I'll probably change the fusible link and see what happens, then start chasing the harness, which I'm not looking forward to. Any other parts of the harness besides behind the EGR that are common areas of trouble?

Yes, right behind the glovebox. There is a section that tends to get pinched. There is a thread here about it.

 

[AcuWiz]

Which filter are you referring to?

It is on the back of the motor I wanna say it had a blue sticker, about the same size as a can of Skoal...I did not drive it today or I would go snap a pic for you. I'll try to do that tomorrow when I am home.

 

[NLXTACY]

It is on the back of the motor I wanna say it had a blue sticker, about the same size as a can of Skoal...I did not drive it today or I would go snap a pic for you. I'll try to do that tomorrow when I am home.

Modulator. It's part of the EGR system.

 

[retrofive]

I agree. definitely seems to be electrical to me. I'll probably change the fusible link and see what happens, then start chasing the harness, which I'm not looking forward to. Any other parts of the harness besides behind the EGR that are common areas of trouble?

Yes, right behind the glovebox. There is a section that tends to get pinched. There is a thread here about it.

Those are my thoughts to start tracking. Links are cheap and easy, so hopefully the cure, the rest of the harness.... ya I hate electrical.

 

[NMC_EXP]

Don't know if it is relevant to your fuel injected vehicle ......

My '79 FJ40 had a random die without a whimper when I would close the throttle and downshift to make a turn. It would start right back up.

Turned out to be the idle control solenoid. This was years ago, think I have the component terminology correct.