Engine cuts out/sputters under electrical load

[MarkusMcBride]

Hi again, I'm back a year and a half after rebuild motor and tranny (rebuild February 2020) in my 87 2.9L 4x4 ranger.

This truck is my daily and it will be moving me and all my worldly possessions across 800km of mountain ranges and rolling plains in 2 weeks time. I will start a new job then and won't have as much time to work on it. I need to solve this damn issue NOW.

I fixed an issue I'd been having last night more on that below. There is still one bug that has been haunting me for about 1.5 years now. It got really bad before the rebuild, and afterwards it was better but never gone. What happens is the motor will cut out completely for a split second under load and does it more often when there is a voltage demand. It's worse at night when I have the headlights on.
Example: I'll be going up a hill at night, highbeams on, and then honk the horn and it really starts doing it. The engine is sputtering and bucking like the coil is sending intermittent power. I did this to test my theory that its worse when there is a greater voltage demand. When it cuts out it is a sharp cut out, not a hesitation.
It is not restricted to the horn. Or even to the headlights. Could be day time and it could happen under load just going up a hill though it is more likely to occur with heavier voltage demands.
I am going to try swapping out the battery today to see if theres any improvement there.

The issue existed before and after these improvements:

• Alternator is new
• This started around the same tie my gas gauge quit working, not sure if they're related but:
• new HP fuel pump, new sending unit, gas gauge still does not work
• New TPS and harness
• New coil, plugs, wires
• New dizzy with Elec ignition module mounted to it
• New ECU computer for an 88
• Deleted the EGR
• I've been over the grounds and I've installed extra grounds as well but who knows
• New IAC valve
• New MAP

Yesterday I fixed a problem that was becoming a major pita. I'll start by saying that this issue began about 6 months ago after I ran out of gas several times (gas gauge does not work). So, under load going up hill or just hauling ass the truck would lose power/hesitate around 3500+ rpm. It wasnt consistent, sometimes it would take me up just over 4000rpm before the power loss. It felt like a fuel issue and I got to the bottom of it first crack:

The black "single function fuel reservoir" on the frame. Now I tore through this forum and others to educate myself as much as I could before tackling it and some people say there was a filter in the reservoir in 87's and some say no filter. There is an inline filter already after the HP pump on the frame which I changed. Well, there is also a cartridge filter in the reservoir and it was dirty as hell. Changed it out, reinstalled the reservoir and she'll sing up to 5000rpm now. Not that I take it there too often but when I'm pulling a trailer with 2 motorcycles in it through mountain passes up here in British Columbia, I do need to be able to hit 4k and then some from time to time. (I need to move across the province in 2 weeks). So, for anyone who is experiencing what appears to be a fuel shortage under load, make sure you check that reservoir for a second filter. If the engine had light loading for a bit, the LP pump in the tank would have a chance to pressurize enough fuel passed the filter so that I could hammer down temporarily but not for long before it was struggling to keep up.

One problem down, one to go. Any thoughts, feedback, troubleshooting tips are welcome. @PetroleumJunkie412 you still on here? I was skimming through our last correspondence and next thing I knew I was scanning ebay for a cosworth 2.9. Maybe one day. I do think if I get to the bottom of the above issue I'll at least order some pacesetter headers and pull them awful manifolds off.
Here she is:

 

[MarkusMcBride]

Also should add: I read the codes off it many times before, though nothing made sense. I can't remember what those codes were anymore now and so I will try and pull the codes again here soon and post. I tend to think it might just be more confusing than anything however. Those early EFI computers were primitive and vague as hell.

 

[Paulos]

There are a number of things that can cause similar symptoms. You might try checking out the links on this google search.

ford ranger 2.9 cutting out - Google Search

The things that personally come to mind are the ignition module and/or ignition module connector (cheap quality ignition module that came with the distributor), ECM (new does not necessarily mean good), TPS, coil and/or connector, alternator.
I'd try to get the alternator tested under a load.
A quality ignition module is a must, and the 34 year old connector is suspect from my personal experience. While the truck is idling, wiggle the connector (especially in and out) to see if it affects the engine.

 

[MarkusMcBride]

Right now I'm looking into the ignition switch - I'll have one today to swap out and see. The gas gauge, the TFI ignition module, alternator, they are all tied into the ignition switch.
Stay tuned

I've already shaken/pulled on every plug, wire, harness I can find on the truck while its running including the TFI module connector and gotten no results. ECM is brand new and made no difference when I swapped the original one out for it. I'd have a hard time believing both the original and the brand new ECM's were both faulty in the same way.

Bad connector somewhere was my first thoughts. I've had issues with them in the past.

I've searched well over a dozen links regarding rangers cutting out and frustratingly, most of them are dead end posts with no conclusion as to what worked/didnt work. I have to get some results here so I'm going to keep trying stuff.

 

[MarkusMcBride]

Update: tried new ignition swich. No buenos. Problem persists. I'm going to go back to the coil. Triple check the connector and the main wire to distributor.

 

[PetroleumJunkie412]

Hi again, I'm back a year and a half after rebuild motor and tranny (rebuild February 2020) in my 87 2.9L 4x4 ranger.

This truck is my daily and it will be moving me and all my worldly possessions across 800km of mountain ranges and rolling plains in 2 weeks time. I will start a new job then and won't have as much time to work on it. I need to solve this damn issue NOW.

I fixed an issue I'd been having last night more on that below. There is still one bug that has been haunting me for about 1.5 years now. It got really bad before the rebuild, and afterwards it was better but never gone. What happens is the motor will cut out completely for a split second under load and does it more often when there is a voltage demand. It's worse at night when I have the headlights on.
Example: I'll be going up a hill at night, highbeams on, and then honk the horn and it really starts doing it. The engine is sputtering and bucking like the coil is sending intermittent power. I did this to test my theory that its worse when there is a greater voltage demand. When it cuts out it is a sharp cut out, not a hesitation.
It is not restricted to the horn. Or even to the headlights. Could be day time and it could happen under load just going up a hill though it is more likely to occur with heavier voltage demands.
I am going to try swapping out the battery today to see if theres any improvement there.

The issue existed before and after these improvements:

• Alternator is new
• This started around the same tie my gas gauge quit working, not sure if they're related but:
• new HP fuel pump, new sending unit, gas gauge still does not work
• New TPS and harness
• New coil, plugs, wires
• New dizzy with Elec ignition module mounted to it
• New ECU computer for an 88
• Deleted the EGR
• I've been over the grounds and I've installed extra grounds as well but who knows
• New IAC valve
• New MAP

Yesterday I fixed a problem that was becoming a major pita. I'll start by saying that this issue began about 6 months ago after I ran out of gas several times (gas gauge does not work). So, under load going up hill or just hauling ass the truck would lose power/hesitate around 3500+ rpm. It wasnt consistent, sometimes it would take me up just over 4000rpm before the power loss. It felt like a fuel issue and I got to the bottom of it first crack:

The black "single function fuel reservoir" on the frame. Now I tore through this forum and others to educate myself as much as I could before tackling it and some people say there was a filter in the reservoir in 87's and some say no filter. There is an inline filter already after the HP pump on the frame which I changed. Well, there is also a cartridge filter in the reservoir and it was dirty as hell. Changed it out, reinstalled the reservoir and she'll sing up to 5000rpm now. Not that I take it there too often but when I'm pulling a trailer with 2 motorcycles in it through mountain passes up here in British Columbia, I do need to be able to hit 4k and then some from time to time. (I need to move across the province in 2 weeks). So, for anyone who is experiencing what appears to be a fuel shortage under load, make sure you check that reservoir for a second filter. If the engine had light loading for a bit, the LP pump in the tank would have a chance to pressurize enough fuel passed the filter so that I could hammer down temporarily but not for long before it was struggling to keep up.

One problem down, one to go. Any thoughts, feedback, troubleshooting tips are welcome. @PetroleumJunkie412 you still on here? I was skimming through our last correspondence and next thing I knew I was scanning ebay for a cosworth 2.9. Maybe one day. I do think if I get to the bottom of the above issue I'll at least order some pacesetter headers and pull them awful manifolds off.
Here she is:
View attachment 65497

Not dead yet, though a few have tried!

 

[JerrySab]

Ok this is going to be super annoying, because it's such low hanging fruit.

I had a similar issue with my '88, after I replaced injectors. This truck sat listless in pretty high heat for awhile, which caused much of the wiring insulation to become brittle and crack. I got a little too hamfisted with the wiring bundle trying to get the old ass injector clips off, and managed to expose portions of both positive and ground wiring that would then short out IAC, random injectors, air charge sensor was in there too I think. It was a party. I wanted to share, also because the ground for the in-tank fuel pump goes a pretty long distance and has ample opportunity to crap out, much like the other wiring did. Which may be the reason for dead gas gauge. Good luck man, your truck looks fantastic.

 

[MarkusMcBride]

Couldnt find any cracked wires. Mine all seem to be in decent shape as far as cracking goes.

We pulled terminal off battery to see how truck would run off alternator alone and she was all over the place, 10v to 15.5v, ran rough as hell. Is that normal? I thought they would run not terrible off just the alternator. Anyways, we tested the voltage with alt charging and it came in at 14.5v, so a little high. Next up we disconnected the alternator to run solely off the battery and the truck DOES NOT CUT OUT under voltage demand and loading the motor. So we might be onto something. Going to order a voltage reg off rockauto because Lordco wants $100 for one. I'll get back on it when I get the part and replace. I am hoping this could be it. I dont know why a brand new alternator would be wonky like that but if it solves it I wont ask questions. Stay tuned.

 

[JerrySab]

Fingers crossed, hope this solves it!

 

[Jazzer]

Bad diode in the alternator throwing some AC into the mix?

-Jazzer