PCM Automatic Reset on Refueling?
Thread Starter
Drifting
Joined: Jul 2000
Posts: 1,289
Likes: 0
From: Newport Beach, CA, USA
PCM Automatic Reset on Refueling?
When our cars are driven normally around town and in traffic, the "temporary" PCM maps will often take the power down a notch. In everyday driving this is often a reality as it is just not possible to do much WOT.
When we go to a DE event, etc. and want full performance, we can do the PCM relearn procedure by removing a fuse and replacing it so the PCM returns to the "hard" or permanent PCM program.
Does our car's PCM "automatically" reset each time we go below a 1/4 tank or so of fuel and then refuel? If true, this would be great since we could just refuel before a DE event and then step on it and not have to mess with fuses.
Any good answers out there?
When we go to a DE event, etc. and want full performance, we can do the PCM relearn procedure by removing a fuse and replacing it so the PCM returns to the "hard" or permanent PCM program.
Does our car's PCM "automatically" reset each time we go below a 1/4 tank or so of fuel and then refuel? If true, this would be great since we could just refuel before a DE event and then step on it and not have to mess with fuses.
Any good answers out there?
Supporting Vendor
Joined: Feb 2000
Posts: 7,302
Likes: 1
From: Los Angeles, CA
St. Jude Donor '03-'04-'05-'06
Re: PCM Automatic Reset on Refueling? (Mako)
Mako,
According to Steve Cole at TTS, the PCM resets everytime you refuel 5 or more gallons. The PCM is reset for higher octane fuel, but when it senses the 91 octane we have available here in CA, the PCM causes the vehicle to run accordingly.
You will lose some power because of the 91 octane unless you are running some good race fuel like MMT (Turbo 108.) It doesn't matter if the car is heavily modded or stock. The car will adjust to the 91 octane by pulling a bit of timing out of the car to prevent detonation.
Shawn
According to Steve Cole at TTS, the PCM resets everytime you refuel 5 or more gallons. The PCM is reset for higher octane fuel, but when it senses the 91 octane we have available here in CA, the PCM causes the vehicle to run accordingly.
You will lose some power because of the 91 octane unless you are running some good race fuel like MMT (Turbo 108.) It doesn't matter if the car is heavily modded or stock. The car will adjust to the 91 octane by pulling a bit of timing out of the car to prevent detonation.
Shawn
Thread Starter
Drifting
Joined: Jul 2000
Posts: 1,289
Likes: 0
From: Newport Beach, CA, USA
Re: PCM Automatic Reset on Refueling? (L.A.P.D.)
Shawn:
Thanks for the response, but I am not sure that is exactly what I meant.
My car is custom tuned for our terrible CA 91 octane. The car is so fast and loud on WOT that it is not really possible to drive aggressively daily and stay out of jail. The PCM then relearns "softer" temporary programing to go with the sane day-to-day driving.
When I go to a DE event and want all the power I can get from my permanent custom programming, I just want to know if I can simply refuel and get on it, or if I need to pull fuse #23, etc. and do a PCM relearn to recapture my permanent programing.
Thanks for your thoughts!
Thanks for the response, but I am not sure that is exactly what I meant.
My car is custom tuned for our terrible CA 91 octane. The car is so fast and loud on WOT that it is not really possible to drive aggressively daily and stay out of jail. The PCM then relearns "softer" temporary programing to go with the sane day-to-day driving.
When I go to a DE event and want all the power I can get from my permanent custom programming, I just want to know if I can simply refuel and get on it, or if I need to pull fuse #23, etc. and do a PCM relearn to recapture my permanent programing.
Thanks for your thoughts!
Burning Brakes
Joined: Oct 2001
Posts: 1,146
Likes: 0
From: The Internet
Re: PCM Automatic Reset on Refueling? (L.A.P.D.)
Is that fact or supposition, Shawn? As, IMHO, that sounds a rather arbitrary and complicated way of doing things. I can't work out why a continuous or short-term weighted average wouldn't produce similar or better results and be easier on the firmware. Not picking a fight with you but it sounds like the kind of stuff urban legends spring from.
Safety Car
Joined: Sep 2001
Posts: 4,411
Likes: 1
From: Wilmington NC
Re: PCM Automatic Reset on Refueling? (chocoholic)
Is that fact or supposition, Shawn? As, IMHO, that sounds a rather arbitrary and complicated way of doing things. I can't work out why a continuous or short-term weighted average wouldn't produce similar or better results and be easier on the firmware. Not picking a fight with you but it sounds like the kind of stuff urban legends spring from.
Safety Car
Joined: Sep 2001
Posts: 4,411
Likes: 1
From: Wilmington NC
Re: PCM Automatic Reset on Refueling? (L.A.P.D.)
Mako,
You will lose some power because of the 91 octane unless you are running some good race fuel like MMT (Turbo 108.) It doesn't matter if the car is heavily modded or stock. The car will adjust to the 91 octane by pulling a bit of timing out of the car to prevent detonation.
Shawn
You will lose some power because of the 91 octane unless you are running some good race fuel like MMT (Turbo 108.) It doesn't matter if the car is heavily modded or stock. The car will adjust to the 91 octane by pulling a bit of timing out of the car to prevent detonation.
Shawn
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Burning Brakes
Joined: Oct 2001
Posts: 1,146
Likes: 0
From: The Internet
Re: PCM Automatic Reset on Refueling? (Richin Chicago)
Good point, yes, that would be the knock sensors and that I totally agree with. Oh yes, I like the allusion to the 900 octane :)
[Modified by chocoholic, 11:45 PM 7/30/2002]
[Modified by chocoholic, 11:45 PM 7/30/2002]
