Computer Diagnostics and Tuning Technical discussion on diagnostics and programming of the F-body computers

PE idle....

Old Jul 7, 2005 | 12:29 PM
  #1  
xxsaint69x's Avatar
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From: Peachtree City, GA
PE idle....

So i finally got it to work..how much should i lean it out in the 400-1200 range?

Right now i have -8 in there. Seems to run rich stil...What values do you guys use?
Thanks
Marcin
Old Jul 7, 2005 | 02:13 PM
  #2  
redcamaroz28's Avatar
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From: UCF
Re: PE idle....

I was going to attempt this later on today. I am going to set my PE value 0 so that it is not adding or subtracting fuel from the fuel tables while in PE mode. (Correct me if I'm wrong in my thinking here) Then I will adjust fueling with the Maf tables.
I'll post up later with my results. I also do not have a WB O2 so I will be aiming for 800-900mv from the stock O2 readings.

Ryan
Old Jul 16, 2005 | 05:32 AM
  #3  
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Re: PE idle....

I would start to lean out about 5 % and check results then do another 5% and so on. When you start to detect a lean surge at idle you know you've gone too far and can richen it up a tad. This will not necessarily clean up all of the gas smell if you have a large cam in there, but it can make it a bit better.

BTW, My car idled decent with an 18:1 AFR reading on the wideband. Started to lean surge any leaner than that.

Steve
Old Jul 17, 2005 | 05:30 PM
  #4  
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Re: PE idle....

My PE values are around -20% and my O2s hang between .08-.150 mV.
Old Jul 17, 2005 | 09:29 PM
  #5  
Ricardo's Avatar
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Re: PE idle....

Are you doing this with LT1 edit?
I zeroed the PE/Temp table and had -25% on the PE/RPM table from 400 t0 1200 RPM. It was still running rich at idle. My injector pulses were close to 4 ms at an idle speed of 950 RPM. I was also getting quite some cam surge up to 2000 RPM.
Then I decided to go open loop and things changed dramatically. I have absolutely no cam surge and my A/F ratio is 14.5 up to 3600 RPM and 13.2 up to 6500 RPM.
I have now 3ms injector pulse duration at idle and my AF meter reads 17:1 ratio.
Im running the GMPP 847 cam.
Old Jul 20, 2005 | 08:31 AM
  #6  
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Re: PE idle....

The O2's are going to read low with heavy idle overlap. That's normal. Don't try to add fuel to get them to read 900mV, that would be WAAAAY too much. You're probably in the ballpark if the O2 isn't switching, and just reads lean all the time. Like someone else said, their WB was reading like 17:1 for a decent idle. The actual combustion AFR is, of course, richer than this, but you can't detect that from the exhaust since some unburned mixture (which has oxygen content) is making it there, making any exhaust oxygen sensor think the mixture is lean, when it really isn't.
Old Dec 14, 2005 | 06:16 PM
  #7  
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Re: PE idle....

Please Help guys, im going through this as well. The PE vs Temp table was left stock, and have -14.8 in the 800 and 1200 values in the PE vs RPM table. I also have the blm locker on, and my LTerms are staying at 128, but my STerms are going up to about 140-142 (Thanks to turboz for limiting my STerms in Tunercat), but yet the car is still ideling really rich. 12.8-13.0 What is going on? It seems that no matter how much fuel I pull from the PE vs RPM table, the car still runs rich because the STerms I guess are compensating?
Old Jul 16, 2009 | 07:20 PM
  #8  
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From: Ann Arbor, MI
I'm going to bring this thread back from the dead to pose the same question as the previous post. I'm having the same issue. I have PE idle enabled in the same way the the previous poster does. I don't have the BLMs locked though. At idle, the LTMs stay at 128 but the STI walks up to 150. When I reset the long terms, the engine idles quite well in open loop. However, when it enters closed loop, the integrator starts moving upward and I get rich smoke out the tailpipe along with that lovely, eye burning stench. Has there been any development on this issue in the last 4 years?
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