90' 4runner, 22re...

My best guess is electrical but still unsure at this point . I was on a moderate trail off hwy. 4 in CA (by myself) , and motor quit on me, just died under moderate throttle. It would crank and crank but not turnover. Luckily I had left a flight plan with my buddy who was camped near by , he came looking for me on the trail after a few lonely hours .

Long story short , we 'fiddled' with all electrical connections , fuses, grounds, plug and wires, checked fuel pressure , and eventually it started back up after sitting on the trail for about 4 hours .

I'm baffled , the truck will start , idle , and run , right now , I literally drove it 200 miles back home, but I have no confidence taking it off road anywhere.

-No CEL
-I have good volts from battery, and with truck running.
-I've checked all fuses , and grounds
-I have fuel pressure at the banjo bolt

My best guess is something to do with a rough trail is jiggling/shaking some wire or connection somewhere causing it to cut out . Any help is appreciated ...









shortly before we died

 

Oh boy.

It could be anything, but like you, I would guess electrical. And since it's running now, I have no idea WHAT electrical problem you have.

I sometimes recommend spraying water in the engine compartment, looking for a short, but it doesn't look like you were in much water. (California? Well, I've read books that talked about water in California, long time ago.)

Next is shaking, but 200 miles of driving pretty much accomplished that.

So I would toss a multimeter in the back seat; if this happens to you again you can be systematic in your search. (and I would START by checking for spark, even if you have to use the hold-a-plug-wire-close-to-the-block method.)

 

Just a theory at this point , but i'm suspecting a bad ignition coil or ignition box . I run an MSD ignition coil, ignition box , dist. cap , and wires . When the truck was broke on the trail , I tried to arc a spark plug, and I didn't get a spark . Not even sure if I arced it correctly though , the plug boots were kind of in the way ...

Maybe all the welding I've been doing on the frame somehow fried the ignition coil or box ...

 

I would bet something came loose.

When you were checking things you must have fixed it.

If the coil is going bad it gets hot then quits cools down and works for awhile.

Tell me you were not welding without disconnecting the negative battery terminal??

Since I weld on so many customers vehicles and equipment disconnecting the battery is a habit.

Computers on Heavy Equipment are not cheap.

 

I think your suspicions of the ignition system have merit. It's possible a circuit in the igniter or coil (probably coil) is opening up when it gets hot. Traveling slowly on a trail can lead to higher underhood temps than blasting down the highway at 75mph heading home, due to less air flow.

You might try cooking those ignition components with a hair dryer while the truck is idling to see if you can stimulate the failure. Just don't melt the outside plastic, but otherwise don't be afraid to get things really hot. It'll take 5-10 minutes to heat things up enough.

 

It could be anything, so go ahead check out what people have been suggesting, BUT best to systematically troubleshoot like scope103 says above, the next time it happens.

It would also be a good idea to download a schematic (PDF) into our smartphones so we'll have it handy out there. Whole FSM filesize is 85 MB, Schematic ONLY is 900KB.

CHEERS!

 

Scope , wyoming , RJR, and RAD , those are all excellent suggestions ! Thanks .... yes I did and always do disconnect the batt. when welding ... heading out to the truck with the heat gun .

 

Scope is on target.


Some of the MSD products, like many things these days aren't what they once were. MSD coils are one of those things, especially the Blaster II. I'm not saying to replace it but definitely be suspicious of it.

 

Odin , agreed , a quick internet search shows many people with many different vehicles talking about MSD coil issues . The frustrating thing is that I can't seem to reproduce the motor stall here in the driveway , which makes diagnosis even more tricky...

 

I wonder if you shorted a wire and then while checking it unshorted it. In a dark place such as a shop, dark street, try checking under the hood with the truck running and look for blue archs.

 

Quick check... make sure EFI relay in kick panel driver side is securely seated.

 

My '90 had/has this same issue. A couple times it just flat out died and nothing worked. One of those times was the first day I bought it with the wife watching, ha. Mine was caused by a break in one of the battery terminal wires, WITHIN the sheathing. I cut the outer sheathing back, and saw when the wires were split.

How I figured it out was I turned it to 'start' position, then jiggled the battery terminal wires and things went on and off

I still need to fix it, but that is coming up as soon as I get a new windshield in there.














http://lamleydlm.blogspot.com/2015/0...h-of-2016.html

 

I'm aiming towards the MSD stuff as well.
A long time ago, I had an MSD 6AL box and blaster II coil laying around from an old project and I decided to put it in my truck. I made my own harness and made it so it was easily reversible back to the stock ignition.
It worked flawless for about a month and then one day, it stalled out of nowhere but it fired back up about a minute later. I was in a hurry so I figured if it did it again, I knew there was a problem I needed to find. About a week later it stalled on my way to jury duty but fired back up the same way as before. When I went to leave the court house for lunch, it would not start. I cranked and cranked but it just wouldn't fire. I knew the last thing I had messed with was the MSD stuff so I popped the hood and reverted back to the stock setup and it fired on the first try.
When I got home, I ripped that MSD crap out and it went right into the trash can. My truck has never stalled or failed to start again since.

 

I experienced something similar this week, turned out to be a short in the wiring harness where it was getting too hot, melted the insulation. In my case, it blew a fuse - replacing the fuse and jiggling the wiring harness at the troubled spot would kill the engine. I fixed the wiring and moved it further away with more protection.

 

Even though no CEL was present with my issue , I was able to pull codes 12,13,14 stored in the ECU , they were all ignition related . I got another igniter and ignition coil , pulled out the MSD ignition coil , and voila the truck is running great . It is not throwing any codes either . Still can't understand why it was so intermittent , and only would happen when I was off-roading, oh well . So hopefully that concludes this issue ...