Fuel trim/cells questions
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Fuel trim/cells questions
Car has -15% LTrims at idle even on both sides. idles in FTC 16 mostly sometimes 18. Stumbles on snap throttle (when it goes to FTC 18) and pulsewidth goes from 2.1 or so ms to almost 9 ms, even though its only at 2500 rpm. if you gradually increase it only gets to 4-5 ms. So BLMs in FTC 18 must be stuck adding a bunch of fuel im guesing, idles at 60 kpa so its sees high load and adds bit of fuel. All things add up and you can kill the car if you blip throttle a couple times makes hard start.
Like i said idle ltrims even, but steady throtle in nuetral and drivers side goes +25 and pass -15%
Im leaning towards saying the car car is actually rich as a whole (ltrims agree at idle and part throttle) but drivers side has vacuum leak - that we havent been able to find. leak shows leaner than actual so overfuel, ndead injector would show leaner cylinder so run richer, seems to point to problem on drivers side.
This FTC 18, supposed to be related to the Charcoal Canister Purge. How so?
Like i said idle ltrims even, but steady throtle in nuetral and drivers side goes +25 and pass -15%
Im leaning towards saying the car car is actually rich as a whole (ltrims agree at idle and part throttle) but drivers side has vacuum leak - that we havent been able to find. leak shows leaner than actual so overfuel, ndead injector would show leaner cylinder so run richer, seems to point to problem on drivers side.
This FTC 18, supposed to be related to the Charcoal Canister Purge. How so?
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From: Hell was full so they sent me to NJ
Re: Fuel trim/cells questions
Originally posted by LTOne4Fun
[B]Car has -15% LTrims at idle even on both sides. idles in FTC 16 mostly sometimes 18. Stumbles on snap throttle (when it goes to FTC 18) and pulsewidth goes from 2.1 or so ms to almost 9 ms, even though its only at 2500 rpm. if you gradually increase it only gets to 4-5 ms. So BLMs in FTC 18 must be stuck adding a bunch of fuel im guesing, idles at 60 kpa so its sees high load and adds bit of fuel. All things add up and you can kill the car if you blip throttle a couple times makes hard start.
[B]Car has -15% LTrims at idle even on both sides. idles in FTC 16 mostly sometimes 18. Stumbles on snap throttle (when it goes to FTC 18) and pulsewidth goes from 2.1 or so ms to almost 9 ms, even though its only at 2500 rpm. if you gradually increase it only gets to 4-5 ms. So BLMs in FTC 18 must be stuck adding a bunch of fuel im guesing, idles at 60 kpa so its sees high load and adds bit of fuel. All things add up and you can kill the car if you blip throttle a couple times makes hard start.
Also, when you move the throttle rapidly open, you will get longer pulse widths, than when you move the throttle slowly. The PCM is acting just like the "accelerator pump" on a carb'd setup, and adding an extra shot of fuel. I don't thing your analysis is correct.
Why does it idle at 60kPa? Cam? Excessively high idle? Throttle blades to far open? What is the TPS at idle? What are the IAC counts?
Like i said idle ltrims even, but steady throtle in nuetral and drivers side goes +25 and pass -15%
This FTC 18, supposed to be related to the Charcoal Canister Purge. How so?
DTC 18 = injector circuit problems. EEC purge solenoid is DTC 26.
And...... finally.... this belongs in "LT1 Tech" or the "Computer......" forum, not here on Advanced Tech. Where would you like me to move it?
Last edited by Injuneer; Feb 18, 2004 at 11:34 PM.
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