PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

Car stuck in open loop when idling

Old Mar 13, 2007 | 06:08 AM
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Default Car stuck in open loop when idling

Setup is 232/236 cam, heads.

It keeps goping back into open loop when I stop and idle for a minute. When I start driving for a minute again it goes back to closed loop but then will revert to open loop again when idling. My O2's are around 500-600 all the time and i am pretty sure that my flange gaskets that connect my headers to the x-pipe are leaking right now since I forgot to buy new ones when I put the exhaust back on after installing the engine. It seems to run Ok but i just want it to stay in closed loop. Any suggestions?

Also it seems to run a decent AFR while touching the gas but seems to richen up a lot when I get off the gas, either in gear or not in gear.

Last edited by brad8266; Mar 13, 2007 at 06:39 AM.
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Old Mar 13, 2007 | 09:31 AM
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Originally Posted by brad8266
Setup is 232/236 cam, heads.

It keeps goping back into open loop when I stop and idle for a minute. When I start driving for a minute again it goes back to closed loop but then will revert to open loop again when idling. My O2's are around 500-600 all the time and i am pretty sure that my flange gaskets that connect my headers to the x-pipe are leaking right now since I forgot to buy new ones when I put the exhaust back on after installing the engine. It seems to run Ok but i just want it to stay in closed loop. Any suggestions?

Also it seems to run a decent AFR while touching the gas but seems to richen up a lot when I get off the gas, either in gear or not in gear.
Someone else tune it? They may have set it up to idle in open loop. Common practice for a cammed car. Not sure on the richening on decel. Could be a number of things.
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Old Mar 13, 2007 | 09:33 AM
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Originally Posted by edcmat-l1
Someone else tune it? They may have set it up to idle in open loop. Common practice for a cammed car. Not sure on the richening on decel. Could be a number of things.
No i do all my own tuning. i wont mind it idling in open loop as long as I can control it. Right now it just does it on its own.
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Old Mar 13, 2007 | 11:30 AM
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Originally Posted by brad8266
No i do all my own tuning. i wont mind it idling in open loop as long as I can control it. Right now it just does it on its own.
Sounds like you've done some stuff thats making it do that. Did you set your PE to zero below 1200 RPM? Theres some other stuff that will make it do that too. If you want to PM me we can talk about it.
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Old Mar 13, 2007 | 11:32 AM
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Originally Posted by edcmat-l1
Sounds like you've done some stuff thats making it do that. Did you set your PE to zero below 1200 RPM? Theres some other stuff that will make it do that too. If you want to PM me we can talk about it.
My tune is just about the same as it was before i did the engine swap, the only changes I made so far with the cam is I changed the idle settings and changes the idle area timing and fueling. I havent touched the PE or anything else for that matter. My MAF is unplugged too if that makes any difference.
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Old Mar 13, 2007 | 11:42 AM
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Originally Posted by brad8266
My tune is just about the same as it was before i did the engine swap, the only changes I made so far with the cam is I changed the idle settings and changes the idle area timing and fueling. I havent touched the PE or anything else for that matter. My MAF is unplugged too if that makes any difference.
Ok, if you havent done anything to make it idle in OL, then take a look at your FTs both long and short. If they're too far off, when it gets to a certain correction point, the computer says, 'hey, I'm having to overcompensate and I dont think I should be', and then bink!, it goes into OL.
The MAF being unplugged should have no effect. You can run OL/CL with or without MAF. Doesnt matter.
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Old Mar 13, 2007 | 12:02 PM
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Originally Posted by edcmat-l1
Ok, if you havent done anything to make it idle in OL, then take a look at your FTs both long and short. If they're too far off, when it gets to a certain correction point, the computer says, 'hey, I'm having to overcompensate and I dont think I should be', and then bink!, it goes into OL.
The MAF being unplugged should have no effect. You can run OL/CL with or without MAF. Doesnt matter.
Ok, the fuel trims must be very far off then because the trims stop working. I havent really tweaked the whole fuel tables yet so that could be the cause. I need to get this thing on a loading dyno and get some readings.
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Old Mar 13, 2007 | 12:13 PM
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Originally Posted by brad8266
Ok, the fuel trims must be very far off then because the trims stop working. I havent really tweaked the whole fuel tables yet so that could be the cause. I need to get this thing on a loading dyno and get some readings.
You can sort out the idle area of the fuel map without a dyno. But when you get it close, it will actually run worse. Then you have to do some stuff intentionally to make it idle in open loop. If the trims stopped working thats a good sign they're way out of whack.
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Old Mar 13, 2007 | 12:15 PM
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Originally Posted by edcmat-l1
You can sort out the idle area of the fuel map without a dyno. But when you get it close, it will actually run worse. Then you have to do some stuff intentionally to make it idle in open loop. If the trims stopped working thats a good sign they're way out of whack.
Well all i did was take fuel out, maybe Ill try adding it back. I really dont feel like messing with it though until next week when i get my HP tuners. LS1 edit is starting to get on my nerves, it was easy with a stock motor but is a lot harder to use to tune with a cam.
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Old Mar 13, 2007 | 12:35 PM
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Originally Posted by brad8266
Well all i did was take fuel out, maybe Ill try adding it back. I really dont feel like messing with it though until next week when i get my HP tuners. LS1 edit is starting to get on my nerves, it was easy with a stock motor but is a lot harder to use to tune with a cam.
Yeah, hptuners or the other one. Dont want to start hptuners/efi live debate.
Need any help let me know.
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Old Mar 13, 2007 | 12:38 PM
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Originally Posted by edcmat-l1
Yeah, hptuners or the other one. Dont want to start hptuners/efi live debate.
Need any help let me know.
Thanks man. yeah im not going to start a debate here, I am buying HPT with a 1 bar enchancement, the decision has been made already.
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