Mike Frye

John, I looked it up and I keep getting stuck on the same thing. I don't have the ability to do a true CO test. The test ports are not even connected anymore, but are plugged. The only way I can test CO is using Ken's Blink'r and that seemed good according to his instructions (it blinked ).

So I guess without a CO tester and oscilloscope I can't technically complete the test procedures.

Thanks,

I think you're right, the one I have on the bench and the ones that Adam had just seem to sit there until you energize them one way or another. No power=no movement.

Do you still have the same thing going on where you put the jumper across B&C and it idles up higher?

Cosmo Kramer

Last time I checked yes. I did it twice to make sure I went from 1050 rpm on the tach to about 1200, not a big difference but it was a bit more. Unlike your car, my idle doesn't really fluctuate and it runs fairly smooth. Right now I am doing a couple other projects on the car to get it on the road so I can drive it and get some miles on it and diagnose it further. The only other symptom I have is at light throttle in neutral it doesn't seem to run clean (slight shudder) until about 2000 rpm then it smooths out. This isn't noticeable while driving though. I am starting to wonder if the TPS has the timing advanced 10 deg at idle like Porken said on my thread.

Mike Frye

Gotcha. Yeah, mine seems to be doing OK timing wise according to the WSM (about 10deg at idle, 20+ off idle, then 40+ at WOT, IIRC) which means the TPS inputs are getting back to the LH and EZ OK. Easy enough to check with a timing gun. You might also try getting hold of one of Porken's 32V'r tools to verify cam timing. I just used one this weekend to fix my timing which was way off and the low RPM accelleration is noticeably smoother.

I'm surprised that Wally said the car should idle down instead of up when you jump it and both of our cars are doing the opposite, but no one on here seems to know what could cause that.

John Speake

Hi Mike,
I guess Porken's gadet is probably good to get you near enough, basically you are adjusting idle CO to get the O2 loop centered within its operating range.

I had forgotten you were using his gadget.

FYI if you disconnect the O2 sensor, the O2 circuits in the LH revert to the mid range setting of the loop. So you could disconenct the sensor, and adjust the idle mixture pot to see if that changes the surging idle issue. Count the number of turns you make clockwise) richer) or anticlockwise (weaker) so you can revert easilly back where you started.

John


[QUOTE=Mike Frye;6393124]John, I looked it up and I keep getting stuck on the same thing. I don't have the ability to do a true CO test. The test ports are not even connected anymore, but are plugged. The only way I can test CO is using Ken's Blink'r and that seemed good according to his instructions (it blinked ).

So I guess without a CO tester and oscilloscope I can't technically complete the test procedures.

QUOTE]

Cosmo Kramer

Definately on my "to do" list!!

I am starting to wonder if B & C just disable the ISV ie. remove power from it completely? If that is the case, the valve just would be floating and could open and close with engine vacuum, where as the 87+ it would close via the spring pressure and drop the idle. This may be the same on the 86.5, not sure. On our cars, B & C would have to ground the terminal that closes the ISV.

Mike Frye

Good point. I have to dig in there this weekend and possibly swap out the ISV to verify that that's not the problem. While I'm in there I can meter the plug and see what happens when B&C are jumpered.

Tom924S

AFAIK, jumpering B-C sets the valve 50% open. So if it's closed before (hot engine), jumpering will allow more metered air in which will increase the RPM just as if you opened the throttle. Jumpering when the engine is cold (valve is 100% open) should result in RPM drop since it's closing half-way not letting enough air in when it's needed to maintain proper idle.

"Properly adjusted, there should be no difference in idle speed with the jumper or without. Remove jumper when finished." - https://www.911chips.com/dmeconvr.htm