O2 Cutting Out - FP and Temp
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From: Near the Arctic Circle
Engine: 350 TBI
O2 Cutting Out - FP and Temp
I have four questions:
1) I installed a heated O2 sensor (AFS-74) in a test pipe where the cat was because the unheated O2 in the exhaust manifold was not staying in CL at idle and because I wanted to read both cylinder banks. It now stays in CL at idle, but it drops out of closed loop in during decelleration. Is there a setting that is causing this?
2) I bumped up my fuel pressure because my DC was hitting the mid-90s. The temperatures have been in the 90s and I still have high DCs. My fuel pressure gauge read closer to 14 when I got back from a logging run. I know gauges are affected by temperatures but does anyone know by how much.
3) I can only purchase E10 in the great nanny state where I live. My thought was to address this after tuning to 14.7. Is it correct to assume that I should make a correction to acount for this before I begin tuning (based on the early thread)? I have read all the information and want to make sure I do this correctly. I seem to recall a thread on how to do this in the EBL, but I cannot find this.
4) I am pushing out 73# from my injectors. Does it make sense that my slightly modified LO5 could require this much fuel? I have stock ported heads, open element intake, 2" TBI, and EBL. (I did put in larger injectors and it was a disaster. I found out, as you already know, that you cannot rely on the injector number. I have three sets - 55#, 61# and 65#. I had them cleaned and flowed and the results at 12 PSI were 63.8#, 67.2#, and 72.5#). I installed a ZT-2 yesterday and thought I would verify the AFR before I go down this path again. I hope to test it today.
My thanks to Rbob, Ronny, Dimented, and those I cannot remember for great posts. I am fairly new to tuning and am taking it slow. I sincerely appreciate all your contributions.
1) I installed a heated O2 sensor (AFS-74) in a test pipe where the cat was because the unheated O2 in the exhaust manifold was not staying in CL at idle and because I wanted to read both cylinder banks. It now stays in CL at idle, but it drops out of closed loop in during decelleration. Is there a setting that is causing this?
2) I bumped up my fuel pressure because my DC was hitting the mid-90s. The temperatures have been in the 90s and I still have high DCs. My fuel pressure gauge read closer to 14 when I got back from a logging run. I know gauges are affected by temperatures but does anyone know by how much.
3) I can only purchase E10 in the great nanny state where I live. My thought was to address this after tuning to 14.7. Is it correct to assume that I should make a correction to acount for this before I begin tuning (based on the early thread)? I have read all the information and want to make sure I do this correctly. I seem to recall a thread on how to do this in the EBL, but I cannot find this.
4) I am pushing out 73# from my injectors. Does it make sense that my slightly modified LO5 could require this much fuel? I have stock ported heads, open element intake, 2" TBI, and EBL. (I did put in larger injectors and it was a disaster. I found out, as you already know, that you cannot rely on the injector number. I have three sets - 55#, 61# and 65#. I had them cleaned and flowed and the results at 12 PSI were 63.8#, 67.2#, and 72.5#). I installed a ZT-2 yesterday and thought I would verify the AFR before I go down this path again. I hope to test it today.
My thanks to Rbob, Ronny, Dimented, and those I cannot remember for great posts. I am fairly new to tuning and am taking it slow. I sincerely appreciate all your contributions.
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From: Chasing Electrons
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Re: O2 Cutting Out - FP and Temp
For 1, yes, stock cal has open loop decel set. Prevents surging when using large injectors: Option Word 3 - Bit 5 - OpDcl
2, if using a liquid filled gage they only report the proper psi at 72 F (hopefully). I've never seen any spec on the temperature when calibrated. However, they drop like a rock as the temperature increases. You can test this by hot-wiring the FP on (usually there is a test lead), and warming the gage with a hair dryer.
3, if running E10 best to set the stoich constant to 14.2. Then change the open loop AFR table by the percent of 14.2 divided by 14.7. Easy to do in TP. Highlight table and using the toolbox multiply by 0.965, then do the same with the WOT AFR table.
4, 73#/hr isn't all that far off with a decent running 350. As GM spec'd the injectors they typically went static at low RPM. Just ease into and crowd the RPM and load upward. Check as you go for AFR. Then give the engine what it wants.
RBob.
2, if using a liquid filled gage they only report the proper psi at 72 F (hopefully). I've never seen any spec on the temperature when calibrated. However, they drop like a rock as the temperature increases. You can test this by hot-wiring the FP on (usually there is a test lead), and warming the gage with a hair dryer.
3, if running E10 best to set the stoich constant to 14.2. Then change the open loop AFR table by the percent of 14.2 divided by 14.7. Easy to do in TP. Highlight table and using the toolbox multiply by 0.965, then do the same with the WOT AFR table.
4, 73#/hr isn't all that far off with a decent running 350. As GM spec'd the injectors they typically went static at low RPM. Just ease into and crowd the RPM and load upward. Check as you go for AFR. Then give the engine what it wants.
RBob.
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