Howardkats

Looking for help from more experienced minds. Backstory: I purchased a '95 4Runner with a 3VZE 5spd last spring for $400 to be a father and son project, it had a blown motor. The young man I bought it from tore the top end of the motor apart to find a head gasket failure at 138K miles, he threw all the parts in the back of the truck + extra parts from various GM vehicles. Waded up the wire harness to the side. We pulled the short block out and had the machine work done. The driver side head was cracked and we had to get another core. We rebuilt it by hand, bought quality parts, all new tune up parts, fuel injectors, OE knock sensor, and Denso O2 sensor. We did do a cross over delete using Yotatech's exhaust bypass delete. We fired it up and it did start, we got it timed, ran it for the break in period. When we went to drive it was super doggy, no power, rough idle. Messed with it some more checking for vac leaks, made sure all the connectors were hooked up. We went through many of the diagnostic materials from the manual. We found we didn't have some vacuum lines connected incorrectly, messing up the EGR valve. Went through all the EGR components and found the EGR valve was really gummed up, the action was notchy and the EGR Vac Solenoid was crusty. We replaced the EGR Valve and the vac solenoid. We checked the EGR solenoid as well and it operated correctly. Also check the fuel pressure, we have 38 lbs at the fuel rail so I don't believe we have a fuel pump problem. We diagnosed the Air meter as out of spec using an ohm meter. We sent it in to A1 Cardone and they rebuilt it and sent it back. That resulted in no change. Still had a truck that was hard to start, with an erratic idle, doggy on power and after driving for 5 mins could barely get back on it's own power acting like it's choking out. The common denominator left with all the symptoms we had was a bad PCM. We sent that in to G7 and they diagnosed a hardware failure. They repaired and sent it back stating this issue is usually caused by a short. Went through all the wiring again, all the grounds were good. Aside from taking apart the harness loom and ohm checking every wire between the PCM and each sensor or electrical component I couldn't find any issue. We plugged the PCM in, crossed our fingers and started it up. It started right up had a smooth idle, was feeling victorious until we pulled it out of the garage and it was acting doggy again. Acting like I needed to give it too much gas to get to move, it stalled pulling out of the driveway and wouldn't start again. I pushed it back in, got it started again with some extra gas pedal action. It would idle but a couple observations while idling and playing with the throttle. It would run smooth, I would hear a click of sorts (almost the sound of arcing) and the truck would stammer and sound choked and then it would return to normal function. Kind of good running for 10 sec, terrible for another 10 sec and back and forth while revving it from 1200 - 2000 rpm. When I was leaning over the fender looking for arcing I almost felt a shock on my arm - maybe it was my imagination. I shut everything down, disconnected the battery and called it a night. Sorry for the long dissertation . . .

Any one else have a similar experience and or find a diagnosis - any idea on which avenue to pursue? We haven't checked the distributor, or the ignitor but I wouldn't think those components are causing this issue. Maybe I blew the PCM again with a short? Thanks in advance!

87-4runner

Sounds easy... but the first thing is try to solve is.
is it a fuel or fire problem?
From there you can start diagnosing or eliminating by testing or some trial and error.
It's just twice as hard till you cut the dynamics in half.
easy stuff first
Plugs, plug wires, dizzy cap...
Check timing
TPS

SideSwipe

Yeah easy stuff first, Fuel filter and ignition components would be my first go to. then the hard stuff if that doesnt help. cant count how many times the easy stuff was the answer to a headache inducing situation

Howardkats

Easy stuff is ruled out, changed out stuff like the fuel filter before we ever first fired it up. Will dig into it tomorrow and start from ground zero - hate buying other peoples messes, you never know what was lurking before they tore it apart.

87-4runner

I'm not familiar with the 3vze
the 22re you can unplug the TPS and if it will Rev normally but won't with it plugged in... your TPS is bad.

swampedout

Which fender were you leaning on?
my buddy has an ignition coil with worn insulation that will zap you. Sounds like you do have an arc somewhere. Watch all the wires on your ignitipn circuit, maybe put a strong light to help. Look for that blue light. Oftentimes you will hear it too.

Dan135

My son and I re-built a 94 Pickup with a 3vze and we had plenty of mysterious electrical issues. Are you getting any engine codes? Are any fuses blowing - especially the 15 Amp EFI fuse? Have you looked for arcing in the engine bay with the lights out (mainly around the plug wires)?