1jzvvti sync loss at Low Rpm

[koa31]

Hey
I'm using a 1jz vvti from a jzs171 toyota crown. Very similar to the 2jzvvti with 36-2 and 3 toothed cam. I was able to get the vehicle to idle smoothly with no break ups. Upon revving the engine, it loses sync at about 1800 rpm. I have been researching throughout the forum for about a couple weeks now and have come to a rock solid deadend now. I have tried changing cam input capture( it ran worst at idle and still couldn't get past that 1800rpm limit due to sync loss) and adding a 10k resistor between the sensor and the MS. Adding the 10k resistor also made it worse. I have asked on other threads about this issue but no response. Is this a noise issue?

Is there any other things I can attempt to hopefully make the motor rev?

I am attaching logs from before adding the resistor and after as well as a msq

Thanks,
Kadeem

[nathaninwa]

I'm running MS3Pro on a non vvti 2j. Since there are no pots on the inside to adjust I had to all mine externally. I have a 10k in series with the vr+, a 1k shunted (soldered across) thevr+/- and I have vr- parreleled grounded to sensor ground.

I get minor timing percent errors while cranking and an occasional plus/minus 1* while running (but had read this is phantom) with zero sync errors.

I was getting 11 and 17 during cranking before the gauntlet of resistors and spiking timing.

[koa31]

I'm running MS3Pro on a non vvti 2j. Since there are no pots on the inside to adjust I had to all mine externally. I have a 10k in series with the vr+, a 1k shunted (soldered across) thevr+/- and I have vr- parreleled grounded to sensor ground.

I get minor timing percent errors while cranking and an occasional plus/minus 1* while running (but had read this is phantom) with zero sync errors.

I was getting 11 and 17 during cranking before the gauntlet of resistors and spiking timing.

Im using ms3x v3.57 are you doing this with both the cam and crank?

[nathaninwa]

Yes, both lines are buffered. Now, I helped with a 1j non vvti install and itwon't run with the vr- connected to sensor ground, so just the series 10k and the shunted 1k for him.

[koa31]

Yes, both lines are buffered. Now, I helped with a 1j non vvti install and itwon't run with the vr- connected to sensor ground, so just the series 10k and the shunted 1k for him.

Ok cool! Thanks! I'll give that a try.

Is there any other option that i could possibly try? Any input will help.

[radial]

All VR pots are maximum counter-clockwise, right?
It sounds like you might have a too weak signal, and adding resistors wont help.

My 1j non vvti has all pots to max counterclockwise. no syncloss what so ever.
I use falling edge on cam trigger.

[quark2501]

Hi

To make my 1jz run without breakups. I had to change the polarity on one of the sensors (swap the 2 wires around) and the change the capture edge. This Worked 100%

[koa31]

All VR pots are maximum counter-clockwise, right?
It sounds like you might have a too weak signal, and adding resistors wont help.

My 1j non vvti has all pots to max counterclockwise. no syncloss what so ever.
I use falling edge on cam trigger.

Yea all pots are fully counter clockwise.
By cam trigger do you mean the ignition capture input? Im using the Spark Mode 2jz vvti. Can I have a copy of your msq?

Thanks Radial, you have been very helpful.

Hi

To make my 1jz run without breakups. I had to change the polarity on one of the sensors (swap the 2 wires around) and the change the capture edge. This Worked 100%

I tried changing the capture edge, got worse but i will try switching the wires around on the crank and/or the cam. Thanks Quark!

[quark2501]

It only Works in combination. Changing one thing only will make it worse.

[koa31]

After the polarity and the capture edge to falling, I got the motor to rev tp 2800rpm before it loses sync. I tried adding a resistor between the cam signal and the MS just to see if there would be a difference, but only got worse.

Is there any thing else I could try? I am thinking to shave 2 teeth off the camshaft, I feel like that may be the problem here.

[nathaninwa]

With the engine running have you verified timing? I see the firmware has a vvti mode so not much to change. I do notice your dwell time is low. I think the stock igniter limits dwell to like 2.7ms, so get this up to about 2.5 and see what happens.

In a regular datalog, what are the sync errors?

[quark2501]

You only did it to the cam sensor right?

[koa31]

With the engine running have you verified timing? I see the firmware has a vvti mode so not much to change. I do notice your dwell time is low. I think the stock igniter limits dwell to like 2.7ms, so get this up to about 2.5 and see what happens.

In a regular datalog, what are the sync errors?

I have not verified timing the the falling edge capture. Ok I will change the dwell time and see if any changes occur. I have gotten sync errors. and just realized I did not save it.... Iwill get one next time I can and post it.

You only did it to the cam sensor right?

Yes switched the cam and the crank. After switching to falling edge, the tooth logger showed 2 high lines which indicated wrong polarity. That got an extra 1000 rpm, which I am very grateful for.

[quark2501]

Only the cam. Change the crank back to oem

[quark2501]

Did you get it running?

[koa31]

Sorry for the late reply fellas. Had a couple exams this week.

Only the cam. Change the crank back to oem

I did and it wouldn't say on for 2 seconds... I must have had it incorrect from the beginning...

Did you get it running?

It is acting as it did before, losing sync at that 2600-2800 rpm range. Rised the dwell, still no difference in the losing sync range.

I did however get a couple data logs and view them via Megalogviewer. I am receiving a loss sync reason 84? Reason 84 does not exist on the msextra loss sync remedies... I even got a reason 85 when I swapped the wires around. Soo yea lol Joone posted about this sometime ago and haven't reply to the person attempting to help him

I am posting a couple data logs of the different trials here

[koa31]

Anyone? Can anyone explain this loss sync reason 84? Any solutions? Ignition capture is on falling edge. I switched the Polarities around on the cam and crank wires. Didnt yield better results, barely idle...

Thanks

[joooeone]

after switching to falling edge the car was running better and could rev it up to 4500 5000 rpm can rev it up more because i dont have it tune

[koa31]

after switching to falling edge the car was running better and could rev it up to 4500 5000 rpm can rev it up more because I dont have it tune

Ive read a couple of your threads, and have been trying to model all you have done. I appreciate the help. Are you still experiencing a sync lost reason 84? I just don't have any way of figuring out what that means. I can get mine to about 2700 rpm and then it experiences a loss of sync.

[ELFS-MS]

For high speed placement of two zener diodes can solve the problem looks the attached schematic (MS3 V3 board).
It can be mounted outside the box for testing or in place of the jump VRIN.

Board V3.57-changed.pdf