PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

o2 delete cause idle issues?

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Old Aug 25, 2015 | 12:34 PM
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Default o2 delete cause idle issues?

Trying to find out if deleting the o2's and tuning it in closed loop (i think that's what it's called) will cause the engine idle inconsistent.

I had my o2's removed due to my exhaust is just headers w/ bullet mufflers. My computer was tuned and returned to me but now on start up in park and neutral rpms go up and down. I haven't ran the car enough to see if it gets any better after warmed up.
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Old Aug 25, 2015 | 12:41 PM
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It's called open loop actually, and with the proper tune there's no reason why it can't idle smoothly. Sounds like the tune needs more work. Do you know if your tuner did cold starts or just warm starts?

The ones that rush (and I'm not saying that's what your tuner did) just tune the car warm and send it off with everyone thinking that it runs fine. But then you let it sit overnight and start it up cold and it doesn't idle. A true tuner will make sure that it idles fine during all aspects.

I would go back to him first. Obviously you paid money for this tune so you should expect a smoothly running car if not he needs to fix it.
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Old Aug 25, 2015 | 02:21 PM
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Originally Posted by redtan
It's called open loop actually, and with the proper tune there's no reason why it can't idle smoothly. Sounds like the tune needs more work. Do you know if your tuner did cold starts or just warm starts?

The ones that rush (and I'm not saying that's what your tuner did) just tune the car warm and send it off with everyone thinking that it runs fine. But then you let it sit overnight and start it up cold and it doesn't idle. A true tuner will make sure that it idles fine during all aspects.

I would go back to him first. Obviously you paid money for this tune so you should expect a smoothly running car if not he needs to fix it.
Thanks for the response!

So this is a friend of friend who owns his own dyno/tuning shop. He's out of state and had me mail him the pcm. I've contacted him 3 times for other issues so didn't want to contact him again till I found out it's a tuning issue.

So far as cold start ups no it was never tuned on the car, just the computer was sent to him via mail.
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Old Aug 25, 2015 | 02:32 PM
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So this is a friend of friend who owns his own dyno/tuning shop. He's out of state and had me mail him the pcm. I've contacted him 3 times for other issues so didn't want to contact him again till I found out it's a tuning issue.

So far as cold start ups no it was never tuned on the car, just the computer was sent to him via mail.
That's a tricky situation, but in the end I would expect a properly running car. So even if it's mail order, you need to send him logs of the car running and he should be sending you back updates to fix whatever he sees. If you send him a log of the car struggling to idle after a cold start and he determines nothing's wrong with those then I would look into something mechanical. But if the idle gets better after warming up then I would think it's tune related.
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Old Aug 25, 2015 | 03:49 PM
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Originally Posted by redtan
That's a tricky situation, but in the end I would expect a properly running car. So even if it's mail order, you need to send him logs of the car running and he should be sending you back updates to fix whatever he sees. If you send him a log of the car struggling to idle after a cold start and he determines nothing's wrong with those then I would look into something mechanical. But if the idle gets better after warming up then I would think it's tune related.
Okay great, that helps alot! Thank you!
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