I've got a strange problem. My 87 4Runner's 22RE stutters when I turn the headlights on nearly every time. For just a second it seems to miss a spark or two. It's a brief but pretty severe drop off, enough to see the RPMs drop by a couple of hundred on the tach. I just sort of shrugged it off until it nearly killed it entering the interstate a few days ago. The battery is only a week old, and it did this with the old one, so I can eliminate that.

Has anyone experienced this? Any of you Yota guru's have a clue what could cause this?

 

Check the power wire from the positive battery terminal to the fuse box next to the battery, its common for that wire to go bad and cause the kind of problems your having. If the wire is bad replace it. I upgraded this wire on my 86 4Runner with a piece of 4 gauge wire because that one little wire is what`s completeing the charging circuit, and in my opinion the stock wire it to small.

 

I checked that wire and the previous owner had replaced it with two pieces of thin wire that were only loosely attached to the fuse box connection point. I replaced them with a piece of 8 gauge battery cable that I securely connected to the fuse box. Unfortunately the problem is the same as it ever was. Although I'm glad to have that hatched job they did fixed.

Any other ideas as to what it could be?

 

I would check all of the grounds, and maybe add a few more. Toyota did a poor job when it comes the grounds, not enough and to small.

 

check the headlight connector plugs for corrosion. Corrosion can also cause dim lights

 

I had this same problem and it was a weak battery-to-chassis ground

 

Mine did this, and i fixed it the other day never had another problem with it.

There is a ground wire that runs from your negative battery terminal to the body of the truck somewhere.
That wire is either loose or disconnected.
Check it out and let us know what you find.

 

Since the battery was recently replaced, double check the battery clamps and ground cable

Mine did the exact same thing 2 years ago coming back from Yosemite. Every time I touched anything that pulled a bit of power the engine felt like it shut off for a second. When I finally pulled into the next parts store to check on it, the truck wouldn't restart. No juice, no power, nada, zip . . . the battery clamp had somehow jumped off the post and the truck was running purely on the alternator, which is fine until you increase electrical load and the system voltage drops for a second

 

i agree with the inadequate ground theory. I just replaced the rear wiring harness on my 86 4x4 turbo. bad ground has caused the fuel pump to have less psi. Which ,in turn , causes the engine to run lean/hotter.I was also losing tail lamps, due to corroded wires/grounding points.If grounds are comprimised, The + wires work hotter than usual..kev

 

mine did the same...but on a worse level. would even get over 25mph with the headlights or any other electrcal device on...turned out to be the alternator.

but yes, check all wires for lose or corroded connections, or shorts or anything. best of luck to you man

 

Sooooooo did you check the ground?

 

Thanks for all your suggestions. So far I've checked the engine compartment grounds in this guide:

https://www.yotatech.com/forums/f116...-guide-194413/

1 and 4 were bolt-roundingly secure. 3 was oily so I cleaned everything up with a steel brush. I haven't been able to get to 2 yet. Battery clamps and ground cable are as solid as they can be. The under hood fuse block wiring looks good and the idle is right on. So far the problem is unchanged.

Tomorrow I'll pull and check the connections to the alternator. I'll also check the headlight connections for corrosion.

 

Sounds like progress.

See, my battery has a wire running from the Negetive terminal to the body of the truck, And when that wire had come lose this was the problem i was experiencing.

So if there is not a wire there, you may possibly need to put one in because it fixed my deal.

 

So your negative terminal is connected to the body and to the engine block, or just to the body? If it's supposed to be connected to both, that could be the problem.

Come to think of it, there was a small piece of maybe 12 gauge wire dangling free from the negative terminal, unconnected to anything, when I got this rig a few weeks ago. I'll bet that's it.

This engine was swapped in by the previous owners years ago. Little by little I'm figuring out that they didn't put much energy into getting the wiring right. The connection from the positive terminal to the fuse box wasn't even secured; it was just bouncing around freely barely making contact with the terminal on the fuse box.

 

Problem solved. There should be a second ground from the negative battery terminal to the body. I just connected a piece of 8 gauge battery cable to a bolt near the battery inside the engine compartment and, bam, problem solved.

Well, problem solved eventually. At first I connected the negative terminal to the bolt that the fuse box was grounded to. For some reason my radio kept shutting off. I moved the new cable to its own ground point and I've had no problems since.

Thanks again for the help.

 

I had the same problem, looked @ everything. Turns out all I had to do was adjust the VALVES!

 

What? How is the engine stuttering when the headlights are turned on related to the valves being out of adjustment?