’99 Land Cruiser (333k miles) — No Start After Timing Belt Job

[dusty6467]

I recently developed a coolant leak on my ‘99 Land Cruiser (333k miles), so I figured it was a good time to tackle the timing belt, pulleys, water pump, and related maintenance while I was in there.

I installed the Aisin kit, added fresh coolant, changed the oil, charged the battery, and attempted to start it. The engine turns over just fine and occasionally sputters like it wants to start, but it won’t fire up completely. Before this, the truck had never had a starting issue—aside from a past EFI fuse box problem, which I already resolved.

I tore everything back down and hoped to find something obvious—like a pinched or frayed camshaft position sensor wire—but it looks fine. I re-verified the timing alignment, and both the crankshaft and cam pulleys are lined up perfectly (see attached photos).

I did discover I installed the belt alignment ring backwards, which frayed the edge of the new timing belt. I’m now thinking I should replace the belt again just to be safe.

I’m leaning toward a camshaft sensor issue at this point, so I’ve ordered a replacement. While checking the wiring harness at the camshaft position sensor with the ignition ON, I found no voltage. Is the cam sensor supposed to be powered? Or is it just a passive sensor that sends data to the ECU without needing 5V or 12V supply?

I’ve searched the forums but haven’t been able to confirm whether the sensor is powered. Any input would be appreciated—thanks in advance!

 

[excessive]

something must have been left unplugged, MAF, camshaft position, crank angle , etc

 

[dusty6467]

something must have been left unplugged, MAF, camshaft position, crank angle , etc

That’s what I’m thinking too—it seems like an electrical issue. All the sensors and harness clips I can find are plugged in, so I’m going to start checking voltage and resistance across everything.

Do you know if the camshaft sensor is passive or powered? If it’s supposed to receive power, that could be the issue—I’m not getting any voltage to it with the ignition on.

 

[excessive]

i do know there are tests in the FSM for every sensor

 

[dusty6467]

Ya, here are the pertinent pages from FSM. It doesn’t look like the camshaft wiring from ECM sends power to the sensor, so I’m gonna measure resistance between them to rule out wiring issue or faulty ECM. It appears the sensor is passive and only sends a magnetic signal back to the ECM.

 

[offoradjunkie]

Did you check the fuse or relay for the camshaft position sensor?

 

[dusty6467]

Did you check the fuse or relay for the camshaft position sensor?

I’ve checked all the fuses, and they’re all in good condition except for the heated mirror fuse, which I’ve already replaced. I haven’t tested the relays yet, but I plan to check their resistance next.

Another thought occurred to me—with the timing belt guide plate installed backward, with the teeth pinching the belt, it might have created enough friction to slow the crankshaft, potentially preventing the engine from achieving combustion?

 

[excessive]

post up when you find the fix , for all those curious

 

[dusty6467]

For sure, new crankshaft sensor came in today so gonna try to get everything back on over the weekend and see if she purrs

 

[dusty6467]

SOLVED - sort of…

I’m not exactly sure what the culprit was, but after reassembling everything, she fired right up and ran like a sewing machine. The only issue I noticed during disassembly was the timing belt guide being installed backwards — that could very well have been the root of the problem. I also replaced the crank sensor with a new one, but since the resistance readings were identical to the old sensor, I doubt the original was faulty.

In addition, I’ve got a makeshift EFI fuse-to-relay setup in place to work around a faulty fuse box until I can afford a proper replacement. I replaced the wires and cleaned up the connections in that area, so it’s possible the issue was there as well.

I wish I could say for certain what fixed it, but either way, she’s running great now!

 

[dusty6467]

pretty sure this was my culprit