Sanman

Hi everyone, I'm new on this list so please bear with me for a bit if I post my questions in the wrong section.

I have an '87 T2, and would like some input on some problems I have with it.

While trying to track down my high (1100 - 1500 RPM) idle problem, I found that the leading and trailing wires are both giving me the same timing readings. They are both way advanced, and exactly the same. When I retard the timing as much as the CAS will go, the idle drops a bit, but I still have no change between the leading and trailing timing. I've tried another ECU and have checked the CAS resistance (OK). I don't know what else to check. Could the CAS be mechanically stuck in an advanced position? or is it all electronic?

Any ideas?

Thanks, Sanman.

HAILERS

Frankly speaking, you CANNOT set the timing if the rpm is over approx 1000rpm. The ECU automatically advances the timing at that rpm approx.
You MUST get the idle down around 750 approx to set the timing. You seem to have a air leak, throttle cable toooooo tight, idle stop screw screwed in tooooo much, a thermowax/fast idle cam problem, throttle plate stuck open from gunk on the aft side of the throttle plate etc.

You might try to take the bac's plug off and see if that will help drop the idle. Not likely but could happen if the bac was stuck or the ECU's output is wrong/defective.

Silkworm

REALLY?? SUNOVA..

So that's why my timing never looked right..

Thanks Hailers, didn't know that.

PaulC

Sanman

I've gone through the factory manual for air leaks / high idle twice, and checked everything in the section. I've checked or replaced ALL sensors, and also swaped an ECU. I've changed all vac hoses, and replaced all the gaskets from the lower intake back to the AFM. I've even tried another TB. Basically, I've been through 'the usuals' and need some creative ideas. One strange thing to me is that I am getting the same timing readings on both the trailing and leading wires. Has anyone else ever encountered this?

Thanks.

HAILERS

Silkworm be a messin with me! Sanman,all I can say is pull the intercooler off and look at the throttle stop screw and make sure its not holding the throttle body open. Its the screw with a 8mm size jamnut on it.

Both trail and lead on the same mark? Make sure your inductive devive isn't crossing or touching one of the other wires. Or take your inductive device and clamp it directly after the coil where the wire is coming out of the coil. Make a difference??????

Silkworm

I'm not! Honest! I didn't know that.. I can't get my race car to idle at 750, so I just tried to set my timing at 1500RPM, but I could never get it to come down to anywhere near 5 BTDC..

PaulC

Sanman

I've been through all of that Hailers. I've had the intake off many times, I've replaced the TPS, and have been over the TB countless times. I've checked everything to do with the throttle including thermowax, cable, throttle stop...everything. I'm hooking up the timing light right at the coils, and I'm getting the same readings on L1 and T1. I think this is where the problem lies. I think my next step is to try another CAS, or a neutral / 5th switch. That's basically all there is left. I even tried another ECU.

HAILERS

Silkworm, I only know what I've seen with a timing light and reving the engine with the light on the marks. I THINK its around 1000/1100 that I see the timing start to advance. In that range for sure.

You must have one of those street ported or better engines. I understand they won't idle under a thousand. Only know that from what I've read on this site. Sooooo.....I wonder how they set the timing on their cars???????? Serious question. Just gotta be somewhere below 1000 and it could be set, it seems to me. Does not have to be 750, just below the trigger point where the ECU advances the timing.