So the 3.4 in my 89 4Runner is having major issues with the ignition timing. The motor, ECM, wiring, everything, is from a 96 3.4 manual trans 4Runner. It starts up and runs well at idle with no CEL, but timing shows 2-3 BTDC, when it should be 18-21 BTDC. The engine doesn't want to rev and starts cutting out around 3.5K. You can go drive the truck around, but it has no power above 1.5K or so. After its warmed up, timing retards further to 5-6 ATDC. When I pull the cam sensor plug, the CEL comes on, but timing does not change (5-6 ATDC). When I remove the crank sensor plug, the engine won't start.

So far I've replaced the cam sensor, crank sensor, ECM, ignitor, spark plugs and done diagnostic checks on the TPS, MAF, Coils, Plug wires and verified the ECM is getting signal from all of those sensors. I read up on the way the 5VZE determines timing and the ECM just takes input from the crank and cam sensors, then sends the timing signal to the ignitor. If knock is detected, timing gets retarded.

I replaced the timing belt (didn't remove the cams) as well, but double checked everything is aligned properly per the FSM.

I'm down to two possible things: 1. Something mechanical is messed up- Crank pulley tooth bent / broken causing the crank sensor to send a bad signal to the ECM. 2. Knock sensors - but I doubt it.

I'm hoping that somebody has experienced this problem before. I've got lots of suggestions on the FB 3.4 swap forum, but unfortunately nothing has worked yet. TIA.

 

I inspected the crank gear with a bore scope by removing my crankshaft sensor. All teeth are intact, so that's not the problem.

 

For anyone that has this problem in the future...it ended up being plug E9 pin 11. I was sending 12v constant voltage to the ECM when it should have been 6v only during cranking, causing the ECM to think the engine was trying to start all the time. As a result it pulled timing and richened the mixture. Once I removed pin 11 and replaced it with the signal from the Starter trigger, it fired up and ran perfect. This also fixed my OBD2 connection problem, as the ECM will not accept an OBD2 connection if the ECM thinks the engine is trying to start.