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Still trying to figure out what's wrong with my truck, which suddenly started running really poorly. (Here's link to initial problem thread: https://www.yotatech.com/forums/f116...8-22re-319879/ ) Took a lot of stuff apart, checked wiring & sensors, fuel flow, &c. Got it all back together, and it still runs the same way :-( This morning I pulled the plugs, and #2 & #4 are wet, like the cylinders aren't firing. They all looked good right after it happened, but it hadn't been run much. Good spark to all plugs, compression is the same on all cylinders, valves don't seem to be stuck - I pulled the valve cover and checked all clearances. Any idea what could be causing this?
Here's a picture of the plugs, #1 on the left.
PS: And it runs exactly the same when I pull off the #2 and #4 plug wires :-(
try swappng the injector plugs, #1 with #2, and #3 with #4. if the problem migrates, the problem is in the wiring/injector connector. if the problem stays at #2 and #4, the injector is the problem. usually, there is just enough slack in the harness to allow the swap, but if the wiring is really stiff/brittle, you might not be able to do it.
alternatively, try a long screwdriver as a stethoscope to listen to the injectors fire (do it on all four, startimg with the two that work - so that you'll know what the injector is supposed to sound like). i've used this a few times to isolate an injector not firing.
My '89 pickup 22RE started running on three cylinders. I didn't know what it was, so I took it in and lo and behold; one injector had failed. I asked about the options. He said new or rebuilt. I asked about their experience with rebuilt and he said they work fine. That was 20,000 miles plus ago, and it still runs like a top at 204,000 miles...
try swappng the injector plugs, #1 with #2, and #3 with #4. if the problem migrates, the problem is in the wiring/injector connector. if the problem stays at #2 and #4, the injector is the problem. usually, there is just enough slack in the harness to allow the swap, but if the wiring is really stiff/brittle, you might not be able to do it.
Would it even run if I did that? Wouldn't it mess up the injection timing, like swapping plug wires around?
Was planning to see if I could get oscilloscope probes on the injector wires to check that. Though I don't see how/why two would fail at the same time...
Would it even run if I did that? Wouldn't it mess up the injection timing, like swapping plug wires around?
Was planning to see if I could get oscilloscope probes on the injector wires to check that. Though I don't see how/why two would fail at the same time...
22RE engines batch fire.
That is, all injectors open at the same time.
Doesn't matter which is wired to what plug.
Would it even run if I did that? Wouldn't it mess up the injection timing, like swapping plug wires around?
it will run just fine doing that. i've put thousands of miles on them with the injector connectors attached to the "wrong" injectors (literally over 20,000 miles). the 22re batch-fires (as noted above by millball). i have changed the physical injector connectors from the junk factory ones (which are damn near impossible to disconnect from the injector with the upper plenum still mounted) to some aftermarket connectors that have a much better release mechansim that can be unlocked with the intake components fully intact/assembled. takes a bit of time/patience, but i can swap the connectors to a different injector if i suspect an injector/fuel delivery problem.
from the date-stamp on the photo, i changed the conectors back in 2016 on '87 4runner #1. i just did the same swap a month ago on '87 4runner #2.
it will run just fine doing that. i've put thousands of miles on them with the injector connectors attached to the "wrong" injectors (literally over 20,000 miles). the 22re batch-fires (as noted above by millball). i have changed the physical injector connectors from the junk factory ones (which are damn near impossible to disconnect from the injector with the upper plenum still mounted) to some aftermarket connectors that have a much better release mechansim that can be unlocked with the intake components fully intact/assembled.
Interesting... Would you have a source for those connectors? Because I can't even get a probe on the wires to see if they're firing. I can really only see the #4, and I sure can't get my hands down there. Maybe I should just pull the plenum and stuff off, and re-route the wires? Because it looks like I'd have to pull the stuff off just to check wire continuity :-(
22RE engines batch fire.
That is, all injectors open at the same time.
This gave me an idea. Looking at the shop manual, I see that the ECU has two terminals, labeled No.10 and No.20, that go to injectors. Would one of them control the injectors for #1 and #3 cylinders, and the other for #2 and #4? If so, a broken wire on one of them could explain why it's only running on two cylinders. Anyone know if this is the case?
If I check continuity between No.10 and E01, or No.20 and E02, I should see a few ohms resistance if the wires are good, right? (That's with the connector unplugged.
PS: Looks like it does work that way. Sort of, anyway. Found a link to an old thread with a good diagram: https://www.yotatech.com/forums/f115...e-help-178975/ So #2 and #4 injectors run off the same power, and must have a common path back to the ECU that's somehow faulty. Now just have to figure out how to get to the wires.
That was it! Found a broken wire just where the injector wires from the resistor (the thing with fins on the passenger side fender) go into the harness. Connected it back up, and now it runs fine.
Don't know why I didn't spot this the first time around. I swear I looked at the wiring harness, and didn't spot anything. Though it was well hidden, under the harness bundle. I could see it was friction between the bundle and fender that eventually wore through it. The other wire had all the insulation rubbed off, too, and only about half the individual wire strands were still making contact. So might be something to check next time you look at things...
Oct 6, 2025 | 12:19 PM
