LS400 high speed missfire since cambelt job

[gmacrae]

Howzit guys... just thought I'd drop in here to see if anyone could give me any idea whats going on with my LS400 (UCF20).

I replaced the cambelt, waterpump, idler, tensioner, front main seal, and since then the car has this weird missfire between 5000 and 5500 revs. Its very similar to a rev limit. If i floor it, it does this miss/pop/fart for about 2 seconds before it changes gear. No error codes coming up.

Anyone got any idea what might be goin on here?

Cheers

Gene

 

[gloverman]

Hello

Have your rechecked the cam timong? I would also connect a scanner and check the live data carefully and check to see if there is a clean cam and crank signal. Maybe scope these too. Check all the connections are good and that all the plug leads are attached properly.

 

[spf_lexus]

How old are the ignition components? Did these symptoms occur before the timing belt job?

 

[gmacrae]

Car was running mint before the cambelt job...

I re-checked cam timing after installing the tensioner a couple of times, but not since it's been running... will do that.

The rotors/caps/leads are a few years old at least, i've never done them. Plugs are fairly new, platinum. Wondering if one of the old leads didn't like all the movement maybe?

 

[gmacrae]

Also... when i fired it up the first time, the LH coil was unplugged. It ran arcing this coil to the nearest ground for about 10 seconds (impressive arc btw! prob more than an inch). This can damage coils correct?

 

[gmacrae]

cam timing is fine, reset ecu again and checked all connections, still doing it

 

[gmacrae]

OK, while driving around the cel light came up and TRC-OFF started flashing for about 30 seconds... i just checked codes and got 13 - no2 cam sensor.

I've read that this usually means the timing is out... but its not. Timing is exactly as it was before the job was done. I'm wondering if one of the sensors are not bolted back in properly or something.

 

[spf_lexus]

I think i know whats up. Take your cam covers off and check the cam sensor wires that are routed between the timing belt. If the sensor wire isnt routed EXACTLY as it was before it was removed, the timing belt will saw through the wires or cause them wires to short out. This happened to me the 1st time I did a timing belt job.

Cam sensors rarely fail but due to its close proximity to the timing belt I would give it a check.

 

[gmacrae]

I think i know whats up. Take your cam covers off and check the cam sensor wires that are routed between the timing belt. If the sensor wire isnt routed EXACTLY as it was before it was removed, the timing belt will saw through the wires or cause them wires to short out. This happened to me the 1st time I did a timing belt job.

Cam sensors rarely fail but due to its close proximity to the timing belt I would give it a check.

thats kinda what im thinking, thanks man, will do

 

[Peewee]

On my car it was the accessories belt that cut into the cam sensor wiring.
Pull the inlet piping over the radiator off and have a good look at it.

Its supposed to be clipped under the top coil, but it comes loose pretty easy.