Faults codes: 100, 110, 300,1346, 1351 - vvti '98 LS400

[LS400GUY]

Here's my problem guys: I've just changed the tb, cranked it up and it ran nicely at the startup rpms, once it warmed up the idle became irratic - fluctuating and almost dying out.

I pulled fault codes: 100 (MAF), 110 (IAT SENSOR), and "pending" codes 300 (random multiple cyl misfire) code: 1346 (vvti sensor circuit - bank 1, and 1351 (vvti sensor cir. bank 2).
Any ideas what went wrong - it ran just fine before I changed the TB. I did disasemble the right cam, but put everything back the way it was.
Would the timing be off, because I thought the vvti adjusted the timing automatically, or hopefully maybe I didn't plug an electrical or vacuum hose, any help from the resident 1uz vvti experts would be very much appreciated. Thanks much.

Cheers,

LS400GUY

 

[LS400GUY]

Here's my problem guys: I've just changed the tb, cranked it up and it ran nicely at the startup rpms, once it warmed up the idle became irratic - fluctuating and almost dying out.

I pulled fault codes: 100 (MAF), 110 (IAT SENSOR), and "pending" codes 300 (random multiple cyl misfire) code: 1346 (vvti sensor circuit - bank 1, and 1351 (vvti sensor cir. bank 2).
Any ideas what went wrong - it ran just fine before I changed the TB. I did disasemble the right cam, but put everything back the way it was.
Would the timing be off, because I thought the vvti adjusted the timing automatically, or hopefully maybe I didn't plug an electrical or vacuum hose, any help from the resident 1uz vvti experts would be very much appreciated. Thanks much.

Cheers,

LS400GUY

By the way, the engine runs very smoothly for the 1st 10 minutes, the erratic idling starts when the engine warms up. Any idea why this happens? Thanks.

 

[hiluxfan]

Doesnt matter if its VVTI, you still have to assemble it with the correct cam timing.

 

[gloverman]

I would check the cam timing along with the breather hose to the RH cam cover. The VVti motors I have worked on haven't run with the AFM unpluged. I would also check the APS and TPS are set perfectly. This is very important on VVti motors. Did you pull the VVti unit apart by any chance? When was the last oil change? Cheers

 

[LS400GUY]

Doesnt matter if its VVTI, you still have to assemble it with the correct cam timing.

Thanks hiluxfan, I'm sure I had everything set on the tdc timing marks, otherwise the eng would not start and run so smoothly while cold, the problem occurs after eng warm up, I've just started a thread about the TPS being out of adjustment - especially if it activates after eng warmup. I'm convinced that whatever it is, it has to activate after eng warm up. By pushing the throttle valve open by hand to clean the bore may have thrown the TPS out of adj. - what's your take on this possibility? Thanks again my friend.

Cheers.

LS400GUY

 

[LS400GUY]

I would check the cam timing along with the breather hose to the RH cam cover. The VVti motors I have worked on haven't run with the AFM unpluged. I would also check the APS and TPS are set perfectly. This is very important on VVti motors. Did you pull the VVti unit apart by any chance? When was the last oil change? Cheers

Hi Glove:

Thanks for responding. What is the AFM & APS? Would the cam timing be a problem if the eng starts quickly and runs very smoothly and quietly during the 1st 10 mins. of eng warmup? My thinking is it would be erratic whether the eng is cold or hot if the timing is off, does that make sense.
Thanks again.

LS400GUY

 

[LS400GUY]

I would check the cam timing along with the breather hose to the RH cam cover. The VVti motors I have worked on haven't run with the AFM unpluged. I would also check the APS and TPS are set perfectly. This is very important on VVti motors. Did you pull the VVti unit apart by any chance? When was the last oil change? Cheers

BTW, I did pull the front part of rh cam vvti, I didn't touch the seal or the gearing under the cam cover. There was a little oil coming out when I removed the center bolt. I did change the oil right after changing the timing belt. Like I said, it starts and runs beautifully during the 1st 8 - 10 minutes, once the eng warms up, then I can hear a clicking sound and it goes into the erratic idle. Thanks again.

 

[gloverman]

AFM is Air flow meter
APS is acceleration position sensor - its the one on the RH side of the throttle body.

Does the throttoe work correctly once it has started running different?
Where does the clicking come from. Also try unpluging the VVti solenoids and see if it makes a difference.

Pushing the throttle plate open should not throw the TPS out of adjustment. I do it all the time.

The two most likely areas are the TB and the RH cam so recheck everything in those areas. Why did you change the TB?

Cheers

 

[LS400GUY]

AFM is Air flow meter
APS is acceleration position sensor - its the one on the RH side of the throttle body.

Does the throttoe work correctly once it has started running different?
Where does the clicking come from. Also try unpluging the VVti solenoids and see if it makes a difference.

Pushing the throttle plate open should not throw the TPS out of adjustment. I do it all the time.

The two most likely areas are the TB and the RH cam so recheck everything in those areas. Why did you change the TB?

Cheers

Thanks for the advice Glove, I didn't change the TB (throttle body), the TB I changed was the (Timing Belt.

So far both cam pulleys line up at TDC with the crank, I will pull the RH cam cover and check the vvti timing mark since I did interfere with it originally. Would I be able to locate the timing mark on the RH cam once I remove the cover? Thanks again for the advice.

LS400GUY