ka24e Advance Timing Problem

[timelapseracing]

I've hit an interesting (read PIA) problem - I'm not getting any timing advance off idle from the ecu. I've swapped out computers, swapped wiring harnesses - no help... I can set idle advance at 15-17 degrees - the motor starts and runs fine, but no advance timing even after it warms up. I've recallibrated the throttle position sensor, and checked for voltage off the leads to the crank angle sensor. The only think I haven't been able to do yet is to check running voltage out of the distributor to the ecu.

Any other ideas for reasons why no timing advance.

Thanks,Jason.

[180fan]

huh? you've got a KA24E right? I don't believe there's a CAS, but just a run of the mill distributor. You adjust your timing through the distributor. You'll see two bolts that hold the distributor to the block. It'll be on your exhaust manifold side (driver side). You'll then see a bundle of 5 wires, 4 which run to the spark plugs. Now at the base, you'll see those two 12mm bolts and you loosen them, not remove, but loosen them. With your timing light on the crank markers, rotate your distributor to advance your timing. The markers run from -5, 0, 5, 10, 15, 20.

The only way your KA24E will differ from that setup is if you're not using a standard KA24E found in 89-90 240's.

[Larry Pengilly]

If you are watching the timing on a scan tool or nissan consult you should be able to watch the timing jump around while idling and when you crack the throttle.

We used to turn on the AC the timing should change.

if you have your BASE (at the distributer) timing set at 15 deg. and it still has no timing control you might want to switch to a different distributer and see what is going on.

what year is this car??

most of the nissan distributers used a Optical pickup system in the distributer, take cap off, remove rotor and then remove that protective cover carefully, you should see a little silver wheel with lots of hols in it around the edge, and a black module thing. that is the optical pick up. If it is dirty, bent, or just not plain working you might want to test that.

Hope that helps.

later

Larry PengillyNissan North America Technical Center

[timelapseracing]

Actually - the ecu controls the advance, and if you take a look at the size of the rotor head where it contacts the posts in the distributor cap it is quite large, actually covering many degrees of possible ignition, the computer can fire the cyl. at any point on that sweep. The optical disc in this case looks fine. I haven't been able to check the sensor which reads it (this is the crank angle sensor). At 5-6000 rpm you probably are pushing 30-35 degrees of total advance, up from the 15 you set it at when you loosen the two bolts and adjust it at idle.

I'm hoping I'm right and there are no other sensors that feed the ecu information that controls advance. I'm not sure about the idle air controller on the back of the intake manifold, it might also be involved. My next step is to get another distributor and swap that to see if it fixes it.

I'm just watching timing on the crank pully with a timing light and the retard dial. I also marked off additional increments of timing on the crank pully. Reving it while shooting the timing light. The car is a 1989, air cond was removed most of the interior is removed, the car is for SCCA road racing in ITA. Basically stock motor, intake, but with an open exhaust - should be no effect on advance timing unless the absence of the AC and controls could be related, but I doubt that.

Thanks for the feedback,Jason.