1jz first start attempt

[mk3chip]

This is my first megasquirt project, and my first attempt to post log files and composite loggs, so bear with me.

MS3 Ms3x
Tunerstudio v2.6.04
1jzgte supra engine
12 tooth crank wheel
single tooth on cam (rear cam sensor)
Both VR sensors set to rising edge.

During cranking, I get full sync, with no indication of sync loss (shown in logger during cranking). when cranking and starting the car there is what seems to be a missfire and it wont stay running. I noticed the sync light on the dash would flash between full and half sync. On the composite logger i can see there are several sync losses indicated. What confuses me is there always seems to be 24 crank events for every cam event. Where is the sync loss? What am i missing?

I have not touched the adjustment pots since they were set for VR sensors, while assembling the board.

Any help is appreciated, thanks in advance.

Dustin

[radial]

Crank takes 2 revolutions pr cam revolution in a 4-stroke engine. So you counting 24 crank pulses pr cam is a normal behavior.

But something is wrong with your Tooth 1 angle.

- The rear cam sensor = about 10 degrees Tooth 1 angle. yours are around 60.
- The front cam sensor = about 360 degrees Tooth 1 angle.

I'd recommend to figure out why your tooth 1 angle is outside spec.
Prime suspects are incorrect polarity on the sensors, or incorrect wiring of coils.


You should also mention what coils you are running, and what sort of igniter you are using.

[mk3chip]

radial thanks for the reply, you were exactly correct! The cam sensor was wired backwards! After switching the pins at the sensor and setting tooth 1 angle to 10, timing was very close, tooth logger showed no sync loss while cranking, and it fired right up. After adding some fuel and closing the idle valve a bit, it idles perfectly with no sync loss since switching the wires.

I was wrong in my previous post, there was not always 24 crank teeth for every cam tooth. Sometimes there was 23, 24, or 25 teeth logged. (I figured out how to zoom in the tooth logger and that there is more than fits on the screen for each page) Anyways this is sort of a moot point, i just wanted to point out that there was justification for the logged sync loss, I just wasn't looking close enough.

Did I mention it runs?? I am so excited. I have been working on his project for 2 years, and its finally coming together.

Thanks again radial, your advice was spot on.

P.S., I am running coils from a toyota 1zz, with internal ignitors.

[mk3chip]

At high rpm my cam sensor seems to be losing signal. It happens between 6k and 7k. Trying to rev to 8k for now.

The sensor and all the wiring are new. Should i try adjusting the trim pots? I thought I would ask before going that direction.

Thanks.

[Suprazz]

yes adjust the pot and it should help. Start with the CAM pot adjustement.

[mk3chip]

Sorry for the late reply.

After reading all the information I could find, I adjusted R11, 2 turns clockwise, and it worked!

An extra 1500 rpm, on the top end of this setup, is working very well for me. Thanks!!!!!