RPM's hanging with S. Wong chip and rough idle - again

[redcoupe86]

Had to post this again - my post timed out the first time -

I have an 86 that as a SW chip - great chip! The orginial ower had the chip installed and was on older programed chip that basically as I understand it didn't recognize the O2 sensor. I sent the chip back and had SW update the programe so that it recognizes the O2 sensor and he added some program that holds the rpms from dropping to quickly, mainly for lightened flywheels but he said it would also be good for older cars that have a lag time between the ICV timing and engine RPM.

I had the car tuned for idle mix for the original SW chip that didn't recognize the O2 and since installig the remapped chip my idle is now rougher - almost like its seeking, but at a lower RPM. I read the instructions and it seems on some later cars there might be a problem with idle speed. I've messed around with that to no avail. I just end up raising the idle to around 950 +/- rpm to mask some of the affects.

Also the RPM's seem to hand around 2k (then drop like a second after letting the thottle go) when the throttle is blipped. I did mess with my linkage to make sure the throttle was openning all the way and Im not sure if its a sticky linkage or the chip making the rpm's hang?

Any thoughts?

[BeauBlues]

I'd suggest you check the linkage first. My car does the same thing when I drive it for long periods of time. I havent gotten around to it yet, but I need to replace the engine bell crank bushings and grease everything up. Just play around with the pedal and the throttle at the engine and feel for any sticking or sluggishness.

[jbrinkley]

I did mess with my linkage

your off idle switch still making contact?

(redflex is the company for the camera vans)
damn aussies

[redcoupe86]

ahhhhhhh, I didn't think to check that!

Thanks Jerry. Also need to check for stick linkage. Maybe you can come over sat. and help me with that.

[jbrinkley]

i could i think

as long as nobody spends the night

[redcoupe86]

ok. did a quick check. I soon as i press the throttle back the micro switch makes a "click". I can also press on the pedal and I soon as I do that I can hear the "click" as well. No matter how fast or how much a press the pedal back and forth the "click" happens just as quickly.

I would think that if the linkage was sticky I could release the pedal and there wouldn't be a "click" of the micro switch closing, but mine does.

[scottb]

Have you had the mixture checked on a gas analyzer since putting in the remapped chip? If not, that's where I'd start.

[redcoupe86]

No I haven't and I thats my next step. I just didn't know if anybody else had the hanging RPM thing or not. I pretty sure a analyzer will fix the idle issue, but I not sure about the hangging rpm.

Originally Posted by scottb

Have you had the mixture checked on a gas analyzer since putting in the remapped chip? If not, that's where I'd start.

[AvonGil]

Same thing happened to my car. It was the cruise control cable. The plastic part that anchors to the throttle was cracked and did not allow it to close quickly enough. I deemed it dangerous, so off it came. Never a problem after that.

[redcoupe86]

I have already deleted the cruise, is there anything that could still hang it up - I cant remember . . .

Originally Posted by AvonGil

Same thing happened to my car. It was the cruise control cable. The plastic part that anchors to the throttle was cracked and did not allow it to close quickly enough. I deemed it dangerous, so off it came. Never a problem after that.

[Lorenfb]

"Any thoughts?"

Maybe do the most logical; i.e. put the stock chip back in and THEN troubleshoot!

[theclaw]

Have you asked Steve?

[redcoupe86]

I did put the stock chip back in before I sent the SW chip back in to get reprogrammed - the car ran like crap. It kept almost dieing and I couldn't really drive it. And I can't put the orginal SW chip in becase it's been reprogrammed. So I can't get back to a base line unfortunately.

Originally Posted by Lorenfb

"Any thoughts?"

Maybe do the most logical; i.e. put the stock chip back in and THEN troubleshoot!

[Lorenfb]

"I did put the stock chip back in before I sent the SW chip back in to get reprogrammed - the car ran like crap."

Then fix the problem FIRST before complicating things with UNKNOWN chips!!!!!!!!!!!!!!!!!!

[livi]

Good to see you keep up the high spirit, loren!

[UK Carrera]

Yes, but he has a point.

I have an SW chip in my car and I am very pleased but I'm confused by this thread - why is the car running so poorly with the stock chip? This does suggest other issues.

[Duckworth]

Have you slowly examined for vaccuum leaks ?


...How much work involved to re-program -back again to factory settings ?




________________

'82 Targa - sold

[Steve W]

Most likely your problem is a result of two causes. The idle microswitch is not activating consistently, leaving the rpm high and hanging until you blip the pedal. To take out throttle slack, you want to do it under the car at the bell crank, shortening the rod going from the pedal assembly to the tranny bell crank. If you try shortening the rod next to the throttle body to achieve full throttle, you'll end up just shifting the throttle travel, so it doesn't return to idle properly. Make sure you have enough slack at rest to not cause any potential hangups.

Next, using a multimeter or test light, verify consistent activation of the idle microswitch. Just because you can hear a click, doesn't indicate if the switch is sticky, dirty, or faulty. Ideally you want to see near 0 ohms when activated.

With the above in check, a rough idle is usually indicative of a overlean idle mixture. Ideally, you want the idle mixture adjusted to between 0.6 and 0.8% measured before the cat (U.S. cars). Or you can use a digital multimeter, and adjust the idle mixture so the O2 sensor output signal (disconnected from the car) evenly fluctuates between 0.2 and 0.7 volts at idle at normal running temp. The mixture is adjusted under the air flow meter with a 3mm allen wrench in the location illustrated below:



As a quick adjustment, I'd richen the mixture by turning the screw inside by about 2-3 turns clockwise and see how it idles - it should be smoother and a bit higher.

As the final adjustment, fine tune the base idle speed to about 880 rpm with the idle speed adjustment screw, after jumpering the B-C test bridge:

[redcoupe86]

Hold on there cowboy! I didn't HAVE the problem before, it started once the chip was reprogrammed, before that everything was tip top. I just wanted to ECU to recognize and use the 02 sensor.

Originally Posted by Lorenfb

"I did put the stock chip back in before I sent the SW chip back in to get reprogrammed - the car ran like crap."

Then fix the problem FIRST before complicating things with UNKNOWN chips!!!!!!!!!!!!!!!!!!

[redcoupe86]

thanks for the info Steve. I ended up adjusting the throttle play at the pedal - by the tranny and at the throttle as well, so I might have screwed myself in that matter. I'm not sure what I should do first to adjust it correctly. What was happening originally was I would press the pedal and the throttle arm at the throttle had about 3/16 or so more tralve till it came in contact with the throttle body.

Understand that I also had about 1/2" of slack in the pedal, meaning that I could raise the pedal from its resting position up 1/2" due to the slack. So I figured if I could shorten the length of the over all throttle rod assembly I would essentially PULL the pedal height up. So I kept shortening the the distance through all 3 adjustment areas until I had raised the pedal up so that the extra 1/2" of travel would allow me to pull the thottle closed all the way.

After reading your description below I'm still not clear I understand the comment about "shifting the throttle travle". Why does this happen again? Also you mention "leaving the rpm high and hanging until you blip the pedal". Thats not exactly what happening. What happens is I blip the throttle once and the rpm hang and come down by themselves a second or so without touching the pedal again.

Also, before the reprogramming there were no issues with the microswitch. I have also tested the switch prior to the reprogramming and it measured ok. But I will test it again to be sure.

Originally Posted by Steve W

Most likely your problem is a result of two causes. The idle microswitch is not activating consistently, leaving the rpm high and hanging until you blip the pedal. To take out throttle slack, you want to do it under the car at the bell crank, shortening the rod going from the pedal assembly to the tranny bell crank. If you try shortening the rod next to the throttle body to achieve full throttle, you'll end up just shifting the throttle travel, so it doesn't return to idle properly. Make sure you have enough slack at rest to not cause any potential hangups.

Next, using a multimeter or test light, verify consistent activation of the idle microswitch. Just because you can hear a click, doesn't indicate if the switch is sticky, dirty, or faulty. Ideally you want to see near 0 ohms when activated.

With the above in check, a rough idle is usually indicative of a overlean idle mixture. Ideally, you want the idle mixture adjusted to between 0.6 and 0.8% measured before the cat (U.S. cars). Or you can use a digital multimeter, and adjust the idle mixture so the O2 sensor output signal (disconnected from the car) evenly fluctuates between 0.2 and 0.7 volts at idle at normal running temp. The mixture is adjusted under the air flow meter with a 3mm allen wrench in the location illustrated below:



As a quick adjustment, I'd richen the mixture by turning the screw inside by about 2-3 turns clockwise and see how it idles - it should be smoother and a bit higher.

As the final adjustment, fine tune the base idle speed to about 880 rpm with the idle speed adjustment screw, after jumpering the B-C test bridge: