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Car acting odd after disconnecting battery...

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Old Jan 22, 2008, 06:31 PM
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Car acting odd after disconnecting battery (idle issues)...

To make a long story short, I disconnected my battery terminal while changing my plugs yesterday.. time got away from me and I didn't get around to changing the plugs so I just reconnected the plug wires and battery and started it up to make sure everything was good. This morning I started the car up and it idled fine and warmed up. The problem came when I actually got to drive the car. I made it to about the end of my apartment complex and hit the clutch and the RPM's dropped down below the 1000 it's set at and the car died out. I started it back up, let it idle a little, revved it a little, and it was ok, but when I drove it back down to my garage it had the same issue of the RPM's dropping down to low when I hit the clutch. It would either try to die out or actually die out so I had to feather the gas to keep it alive.

I've never had ANY issues with this car at all so I'm a little stumped... The car has the following mods:

Helix 02 housing
10.5 Hotside
Helix 3" dp
Perrin test pipe w/02 sim
HKS Carbon-Ti catback
HKS 272 cams
HKS racing suction intake
Exedy twin disk clutch
HKS EVC-V ebc

The car has been road tuned for the mods except the 272's and the 10.5 hotside. It did, however, have 264's in the car in the tune. I'm thinking since the ecu was reset that I probably just need to go out and drive it and let the ecu relearn the cams a little (btw, the car is going to get dyno tuned in about 2 weeks after I get my intercooler setup in and on). Does this diagnosis sound right to you guys? Any advice would be appreciated. Thanks!
Old Jan 22, 2008, 06:34 PM
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you reset your fuel trims when you disconnected the battery. So if the fuel trims compensated for the cams before at idle, then now they aren't until it adjusts itself again.
Old Jan 22, 2008, 06:38 PM
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That's what I was thinking... any chance it would relearn by idling/free revs as opposed to taking it out and driving it and risking it dying out on me?
Old Jan 22, 2008, 06:44 PM
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Originally Posted by razorlab
you reset your fuel trims when you disconnected the battery. So if the fuel trims compensated for the cams before at idle, then now they aren't until it adjusts itself again.
Exactly
Old Jan 22, 2008, 06:54 PM
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Thanks guys! Can I get the ecu to relearn to compensate by letting it sit and idle/idle rev or am I going to have to drive it and put some load on it?
Old Jan 22, 2008, 07:00 PM
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Originally Posted by dbotkin5
Thanks guys! Can I get the ecu to relearn to compensate by letting it sit and idle/idle rev or am I going to have to drive it and put some load on it?
all of the above.
Old Jan 22, 2008, 07:08 PM
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ok, I'll let it idle and go through some rpm ranges for a while before taking it out again. Thanks for the quick responses!!
Old Jan 22, 2008, 07:12 PM
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i hope it works out for you
Old Jan 22, 2008, 08:02 PM
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why not get your injectors setup properly?
Old Jan 22, 2008, 09:25 PM
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i would have though it was the spark plugs, beucase that's the only thing he changed.


So, by disconnecting the battery, your fuel trims reset them selves?
Old Jan 23, 2008, 03:34 AM
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If it is the case of the fuel trims, doesn't this also possibly mean his fuel trims are way off? If resetting the battery/ecu causes the car to run like this, I would suspect his fuel trims are off in left field, or maybe I am...
Old Jan 23, 2008, 07:10 AM
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It's in the shop manual after disconnecting the battery the car has to idle after it's warmed up for 10 minutes to learn to idle again.
Old Jan 23, 2008, 07:48 AM
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You can reset the ECU with the fuse in the engine compartment and not lose your clock or radio settings. It's the 20amp fuse closest to the front of the car (4th slot back).
Old Jan 23, 2008, 09:10 AM
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I wasn't TRYING to reset the ecu lol but that's good to know. I'm gonna let it sit and idle for a while tonight and then take it out (when there's no traffic) and drive it for a while. Thanks for the input though guys.

As for the injectors, I don't think I need to upgrade my injectors yet on stock turbo will I? The car is going to get tuned in about 2 weeks but I'm holding off until my front mount kit comes in from ETS

Last edited by dbotkin5; Jan 23, 2008 at 09:22 AM.
Old Jan 27, 2008, 04:34 PM
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Your fine as stated the car needs to relearn. Mine usually takes a couple of drive cycles


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