Cylinders 2 & 4 Not Firing
 

So this has been haunting me for 2 weeks now. I restored the engine bay on my 1987 4Runner 22RE. Engine ran very good prior to restoration. I ended up replacing a lot of components (coil, cap, wires, plugs, injectors, hoses, starter, radiator, water pump, the list goes on and on).

Once I got everything back together, I fired it up and it runs very poorly. After a lot of testing, I eventually discovered that cylinders 2 and 4 weren't firing. I can pull the plug wires on 1 and 3 and the engine dies. There is no change in idle speed when I pull 2 and 4. However, I do get a good spark on all plugs. This led me to the fuel side.

I listened to each injector with a screwdriver and can hear 1 and 3 firing. However, I can't hear 2 and 4. This led me to check the injector wiring. I'm getting good voltage on all injector plugs (ranges from 10 to 13v for each pin). I even plugged the #4 harness into a spare injector and I didn't operate.

Does anyone have any ideas why this is happening? What am I missing. Ground wires are all good. What would cause this to happen?

There should be a resistor for the injectors, inside there's just 2 resistors. The blue wire feeds injectors 2&4, and the yellow wire goes to 1 and 3. check the resistor and blue wire . it could have been pinched or shorted during the rebuild.

I would suspect the crimp in the wire harness. It is a poor design. It can pass a resistance check and still fail or the crimp just broke loose. Here >>> https://www.yotatech.com/forums/f199...l#post51897320 is what all I went thru when mine wasnt firing. You can try the $3 noid light and see if it sending the signal from the computer. If you get some flashes, I would remove the crimp and solder the wires together. 2 and 4 share the same crimp.

lol, i like the comment that you don't know why they would do this....... you own a yota, you should expect poor electrical design in anything electrical. the whole thing should be electrically under-built and over-engineered.... but that somehow doesn't take away from it's legendary reliability and performance. if a yota was gm, it'd be a bulletproof 4wd toranado that lost weight.

Thanks for the feedback. I'm hoping that once I redo the wiring it will fix the problem. Started tearing into it last night. Once I got it open I noticed someone had already replaced these connections years ago... poorly I might add. The wires were also badly corroded. I've got the old splices cut out, wires cleaned, and new splices installed. Hope to get it back together tonight and test it out.

good luck. i can't tell you how many times poor repairs can be more troublesome than the original failure.

Replaced all four injector harnesses and wiring back to original splices. Started it up and she runs much better. No more shaking or sputtering. Only problem now is that my idle surges and drops. I had the idle set high and haven't adjusted the new TPS yet. I'm assuming once I make those adjustments it will idle fine. However, after the injector ordeal I probable shouldn't assume anything.

If you want to read thru the next two pages https://www.yotatech.com/forums/f199...l#post52146627 this will give you an idea of how your intake is dirty and the sensors need cleaning.

Another thing that I would do to help with the idle is to raise the front end as high as possible. I jack my truck up and I am 6 feet tall that the radiator is at my shoulders. Let the motor run and cycle the thermostat 3 or 4 times with the radiator cap off to get the air out of the system. You will see it called Burping the System on here.