GM Eco Reflash Fuel Rail Question - Tuning Forum

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GM Eco Reflash Fuel Rail Question
Friday, June 29, 2012 5:18 AM
Long story short, I got a second PCM and the GM Eco Reflash to hold me off until I can get a custom tune.

The setup: I've got a stock GM Eco Supercharger Kit (Brand New) installed. I have an 02 Eco with an 02 rail with the the injectors that came with the kit installed in the 02 rail (yes everything fits just fine).

The problem: There seems to be a tender spot when cruising (not in boost) where I press the gas and it gets rich (11.X A/F) and I have to ease off a bit to bring it back to 14.8. If I set the cruise control you can watch it go to 11.x when I got up an incline and back to 14.8 when I'm driving level.

The question: I understand the GM reflash sucks, but is what I'm seeing normal? I'm thinking there is an issue with the fact that it is an 02 fuel rail which has a different FPR than the 03. IF this is not a normal occurrence with the flash, do any of you feel its worth while to swap to an 03 fuel rail set up?

Input is appreciated as always.

Thanks





Re: GM Eco Reflash Fuel Rail Question
Friday, June 29, 2012 7:05 AM
As long as the injectors fit in there it should be fine. Many 03+ swap to your fuel rail (02) to run the cobalt ss s/c injectors. I'd assume what your seeing is normal.
Re: GM Eco Reflash Fuel Rail Question
Friday, June 29, 2012 2:40 PM
seems to me like you might just be hitting PE mode...what are the RPMs when this happens? It is not uncommon at all for an engine to require more gas going up a hill then it will when at level driving or going down a hill. This all has to do with engine load and things that you cant see with gauges.

I am not saying that this if for sure the reason you are seeing the changes, but it makes sense to me.

I took a drive up to Payson (in the mountains) from Phoenix (in the valley) and was in 11 or 12s most of the time going up hill in 4th gear just cruising. The engines just requires more fuel to do the same amount of work when the load on it changes.



Re: GM Eco Reflash Fuel Rail Question
Saturday, June 30, 2012 11:39 AM
I just swapped to the 02 rail, fitment was better and also allowed for the use of a aeromotive fuel pressure reg off a LT1



1989 Turbo Trans Am #82, 2007 Cobalt SS G85





Re: GM Eco Reflash Fuel Rail Question
Saturday, June 30, 2012 12:47 PM
Yea, it sounds like you are just going into PE and that is normal.


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Re: GM Eco Reflash Fuel Rail Question
Monday, July 02, 2012 5:06 AM
Thanks for the input fellas. I feel more comfortable knowing its likely normal.




Re: GM Eco Reflash Fuel Rail Question
Monday, July 02, 2012 5:50 AM
EvoFire wrote:

seems to me like you might just be hitting PE mode...what are the RPMs when this happens? It is not uncommon at all for an engine to require more gas going up a hill then it will when at level driving or going down a hill. This all has to do with engine load and things that you cant see with gauges.

I am not saying that this if for sure the reason you are seeing the changes, but it makes sense to me.

I took a drive up to Payson (in the mountains) from Phoenix (in the valley) and was in 11 or 12s most of the time going up hill in 4th gear just cruising. The engines just requires more fuel to do the same amount of work when the load on it changes.


I agree, and lkely seeiing a couple pounds of boost as well.



FU Tuning



Re: GM Eco Reflash Fuel Rail Question
Monday, July 02, 2012 4:57 PM
Addicted to meth wrote:

EvoFire wrote:

seems to me like you might just be hitting PE mode...what are the RPMs when this happens? It is not uncommon at all for an engine to require more gas going up a hill then it will when at level driving or going down a hill. This all has to do with engine load and things that you cant see with gauges.

I am not saying that this if for sure the reason you are seeing the changes, but it makes sense to me.

I took a drive up to Payson (in the mountains) from Phoenix (in the valley) and was in 11 or 12s most of the time going up hill in 4th gear just cruising. The engines just requires more fuel to do the same amount of work when the load on it changes.


I agree, and lkely seeiing a couple pounds of boost as well.


this is true. i didnt mention the boost part becuase i didnt feel it was related to the OPs issue. but yes going up a hill at a normal speed foot not on the gas can result in low boost readings....i know (via data log) that the last time i went to Payson, i spent about 46 out of the 77 miles getting there in boost. Not because I was racing the car or whatever, just becuase of engine load and things of the sort.



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