5 replies to this topic

[Gunpilot]

So I just installed a newly rebuild 1.8 in my 1996 Miata. I set all cams and crank timing marks prior to install. Car fired right up and runs great. Now to verify timing.

My question is.. Do I reference timing before I jump the TEN and GND pin, or after? I have asked this before, but did not get a clear answer (or did not seem clear to me)

Before jumping, the car idles at 1000 RPM and indicates 0 and 10 degrees (2 marks on my crank pully)

After jumping, idle increases a bit and timing indicates 14 degrees and the other mark is off the indicator.

So is this good, or do I advance timing after jumping so it is 14 when I remove jumper?

[Mike Collins]

Set timing WITH the jumper wire.

[Keith Novak]

What does the jumper actually do anyway? I notice that when I plug in the jumper, the idle changes. I set the idle to about 750 with the jumper in and then the timing and finally when I pull the jumper back out, the idle doesn’t change back.

[dstevens]

The jumper puts the ECU in a setup/diagnostic mode. It tells the computer that you are working to set the timing and not driving the car so it will respond accordingly when you are setting the timing vs driving.

[Keith Novak]

The jumper puts the ECU in a setup/diagnostic mode. It tells the computer that you are working to set the timing and not driving the car so it will respond accordingly when you are setting the timing vs driving.

Ahhh...so basically it puts the ECU in manual mode so that you can create a baseline setup that it will use for adjustments while driving?

[davecarama]

The jumper puts the ECU in a setup/diagnostic mode. It tells the computer that you are working to set the timing and not driving the car so it will respond accordingly when you are setting the timing vs driving.

It turns everything else off. The fans won't run, etc, so there is no extra electrical draw on the motor. That is why it seems to spin a little quicker.

DC