87Slowrunner

I recently went with my heart and not my brain and bought a 1987 4Runner that was “someone else’s project”. I’ve been fighting lots of mismatched parts and hack job repairs ever since (but I guess I’m having fun)

It’s never run right since I day one and It’s had a bunch of “classic” 22re issues. Over time I’ve gone from an engine that would not start to one that’s “almost there”. Here’s what I’ve done and where I’m at and I need some help getting to run well.

What I’ve done:

· New spark plugs, cap, rotor, wires
· No known vacuum leaks
· Compression at 150psi on all 4 cylinders
· TPS failed. Replaced with new unit and I believe that it’s set correctly. Timing jumper still would not cause a drop in RPM.
· I verified and fixed the 4 engine grounds and the ignition/coil ground on the fender. Cleaning the ignition/coil ground made a big difference. Jumper now caused RPM to drop...timing set correctly (the timing is still an issue, read on).
· Air gap ok. Distributor pickup ok. Coil ok. Igniter ok.
· AFM tested and checked out ok
· Tested cold start stuff and it appears to be ok (not leaking, etc.)
· The distributor is not “off one tooth”
· The timing chain is not “off one tooth”….BUT it’s probably pretty tired and there is a broken guide which I found last night (after deciding to not light the truck on fire, i decided it would be better to fix this soon)
· Valves are all with in adjustment specs
· No trouble codes

So, here’s where I’m at after all that work:

The engine now starts great but rarely idles great…usually the “good” idle only last for a few seconds. Soon after, good idle becomes lopey and the exhaust becomes rich. It does this if the engine is cold or hot. It pretty clear to me that the ECU is “switching gears” to a new mode (open? closed?) and then it runs like garbage.

If I move the throttle when its idling poorly it stumbles badly and sometimes will backfire through the intake. It will run ok (but not great) at WOT. Also, after releasing the throttle and going back to idle, it will idle well for a few seconds and then go back to crap. This is with the timing set correctly. If I make the timing way, way advanced (like the distributor turned all the way) it will run better but still crappy.

I’ve “searched” the forum and I’ve found some posts with similar issues but none of them actually have a happy ending. So…the purpose of this post is two fold: to actually fix this issue and then document it for the next guy. So, with that said:

· Does anyone have any ideas on what to do next? I think this is an open vs. closed loop thing (which I don’t completely understand yet). At start up, is it in open or closed loop?

· So, there’s a bunch of ECM test procedures in the FSM (which I haven’t read yet). Anyone have any “if I only did it this way” thoughts for testing the ECM? Or “don’t bother testing the ECM since you probably need a new one”

· Are there any other important grounds or other things that I forgot to check?

· Could this be a fuel related thing? Fuel pressure or a bad injector?

Any help would be appreciated

Team420

150psi is well below spec... its good that they are all even, but 180 is spec.

Gotta be certain that your tps is set correctly... this will cause problems if not.

Might wanna test your ect(engine coolant temp) sensor.
also... no KNOWN vacuum leaks... But are you certain there isnt any?
How many miles on the o2 sensor? Might be time to swap it.

87Slowrunner

I don't believe that you're correct about the compression. Factory spec is 171 psi but 140 to 171 is acceptable. I don't know how many miles on the engine because I think it was swapped in by the previous owner. I'm pretty certain that the TPS is correctly set. I checked it with a ohms meter.

I'll check the ECT. Is that the same sensor that sends data the temp gauge on the dash? If so, its working. Would the 02 sensor trip the CEL?

Team420

I just checked the fsm... you are correct about the compression

The ect sensor is not the same as the one that sends data to the dash gauge.... I dont recall where it is on the 22re, but it should be on the same block that has the cold start injector time switch, or whatever its called.
A bad o2 sensor will only show a code when theres a short in the connection, or no connection at all.... but it may be very dirty and not sending accurate data to the ecu.

87Slowrunner

I'm going out to the garage to tinker with the ect and 02 sensor.....

87Slowrunner

After some delay I got to it. I replaced the o2 sensor with an arguably cleaner (and free) used one. More importantly I found that the plug to ECT was not pushed all the way in by the previous owner. After reinstalling the metal clip on the plug, adjusting the timing (again), and it runs much much better.

The idle is still a little rough, but I'm sure I'll figure it out later...or I'll accept that its a 27 year old truck and be happy with a "little rough"