Thread: yet ANOTHER idle/timing thread

So i have a b14 with a erratic idle/timing problem. Here is what it the car has.

-fresh sr20de. everything rebuilt. great compression across the board.

-stock maf right now, the 53j, it has been replaced a few months ago because i had a bad one. maf read 1.45V in timing mode

-brand new TPS set at .45 closed, 4.05 fully open.

-Brand new IACV thats opperating correctly, verfiied with ConZult software and my tester.

-No Vac leaks, smoke tested and visual inspected, and the vaccuum gauge reads a healthy -hg.

-96 manual G20 ECU.

-Good knock sensor, tested and verified.

So now with the above mentioned criteria, here is what happens. When the car is cold, starts right up, cold idle at about 1350 for as long as the AAC is on and then goes down to about 1100, and seems ok. Timing is fine, verfied with the Scanguage plugged into the OBD2 port.
Once the car has been idling for about a minute or so it dips down in the idle where it should sit at around 820-900 the motor seems to retard the timing to 3*, but what is throwing me off is the knock sensor is good and the MAF is good. Soon as i blip the throttle is gets out of it, levels out at 1,000 when coming down off the rev, but then it drops to where it should sit and it retards timing back to 3*.

When i have the car in timing idle/timing adjustment with the ConZult software, it holds steady at around 920 RPM and the timing reads 15* and the timing light verifies that the timing is 15*. AS SOON as i close out of the timing/idle adjustment screen on the ConZult, the car goes back to this retarted idle at 3* almost as if it has a huge Lopy cam and its fighting itself. Open the timing/idle adjustment back up and the car is perfect, the idle is where it should sit, timing at 15*, close out of it, and it goes back to the 3*

Now, the above mentioned symptoms always happen. What is rare, which is 1 out of 15 cold starts, the car will stall itself out and die, and right after it stalls and i go to turn the car over, it has no spark. If i wait about a minute, i crank it over, i have spark and the motor turns over and starts right up.

My question is, has anyone dealt with an erratic problem like this and culprit ended up being the distributor? I am leaning on the distributor because it came off an unknown condition sr20 and it looked like it was in rough shape when i got it.

Is there a way to test the distributor with my Fluke multimeter or visually inspect it?

No obvious solutions occurred to me as I was reading about your problem. But I want to make sure that you understand that the scan gauge tool doesn't really read your base physical timing -- it just assumes that you have it set properly at 15* and so it reads "15*" unless the ECU has altered the setting in response to inputs from the engine. In your post, you say that you have confirmed the physical timing is at 15* with the ECU in "Set Timing & Idle Mode," so you should be OK with respect to base timing. Further, it's absolutely normal for the timing reading on your scan tool to jump around at idle (when the ECU is NOT in "set Timing Mode") because this is one of the ways that the ECU steadies the idle and keeps it constant when things are working well.

Usually, when you switch into "Set Timing & Idle Mode," that's when you will get a lopey idle if the idle speed is set too low with the screw at the idle adjust valve. But you seem to have the opposite happening, which is the weird thing.

The only way that I know to test your distributor is to swap in another one and see what happens.

Good luck with your issue.

Well i wouldnt really be too concearned if the timing was jumping around a little bit, but on the conzult i see 3-15 in a very very erratic manner and the car just doesnt like it, the oil pressure drops a little like its struggling too. The scan tool doesnt even catch the bouncing, it only reports 3. but i can see the very very fast influx of 3-11-15-7-3-11-random-random number on the laptop, and i know i shouldnt be trusting it too much but the car is confirming with the way its running.

well im going to do the one thing i hate doing and thats replacing parts when i dont even know if the one im taking out it bad/good and the one im putting in it is also used because the last thing i want is a reman.

It sounds like your ECU is desperately adjusting your timing to maintain the best possible idle given the signals it is getting from your engine. The weird thing is that you say your idle is fine when you are in Set Timing Mode -- indicating that the physical condition and settings of the engine are OK.

When you are in Set Idle/Timing Mode, and you try to lower or raise the idle speed using the screw on the idle adjust valve, do you get the expected result?

I do, the motor responds instantly and accordingly to the turn of the screw, the timing sits solid at 15*, no problems.

I replaced the distributor with another unit, and the car seems to be a whole different car. I think the Cam Angle Sensor on the other one was bad maybe causing the distributor to tell the ECU that the car was not where it should be, and retarding the timing automatically. Does that sound plausible?

I'm not sure whether your explanation makes sense or not. But I'm glad that your problem seems to be resolved.

Enjoy the ride.

Bill