C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

91 vette

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Old Sep 1, 2003 | 12:40 PM
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Default 91 vette

is it normal when the car is in open loop to run rich?????when it goes into closed loop it goes from rich to lean i was told thats normal?? i installed 24# injectors and the blms is going 108 in closed loop it's at 128 in open loop is it true if i drive the car the ecm has to relearn and the blms will correct itself??
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Old Sep 1, 2003 | 12:48 PM
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Default Re: 91 vette (6spd)

is it normal when the car is in open loop to run rich?????when it goes into closed loop it goes from rich to lean i was told thats normal?? i installed 24# injectors and the blms is going 108 in closed loop it's at 128 in open loop is it true if i drive the car the ecm has to relearn and the blms will correct itself??
When the car is in open loop there is a standard set of variables the ECM runs with.. one being locked on a BLM of 128. When in closed loop you said it runs 108 which means it is very rich and is pulling fuel out. In essence running at BLM 108 the ECM is correcting itself, but is will not relearn it and apply it to open loop.
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Old Sep 1, 2003 | 12:53 PM
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:iagree:

Open loop is hard coded in the ECM and not modifiable by the ECM itself. But yes driving down the road its not uncommon to see your scanner going rich/lean/rich/lean.
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Old Sep 1, 2003 | 12:54 PM
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Default Re: 91 vette (-=Jeff=-)

so what do you think is my problem?????
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Old Sep 1, 2003 | 12:55 PM
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Default Re: 91 vette (6spd)

Well you installed injectors larger than what the car came with so the ECM has no choice but to try pulling some fuel out hence the 108 BLMs. What manufactuer are the injectors? If they're Ford SVOs then they are more like what a GM 26# injector would be like.
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Old Sep 1, 2003 | 12:58 PM
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Default Re: 91 vette (scorp508)

they are the ford light blue injector do you think i should put the stock 22#s back in or try a custom chip again??
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Old Sep 1, 2003 | 01:02 PM
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Default Re: 91 vette (6spd)

The larger injectors are honestly overkill unless you've heavily modified the car for way more horsepower. You could install a new chip with the injector contant modified to let it know what size injectors installed or install an adustable fuel pressure regulator (AFPR) to pull some fuel out across the entire band.
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Old Sep 1, 2003 | 01:06 PM
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Default Re: 91 vette (scorp508)

i did adjust my fuel regulator it's still saying 108 i droped it down to 36 with the line off are 22# injectors the size a 91 came with if so do you or know of anyone selling them????
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Old Sep 2, 2003 | 04:43 PM
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Default Re: 91 vette (6spd)

Your 91 came with 22 lb. injectors.
I installed a set of the light blue 24 lb. SVO injectors about a month ago.
Mine ran a little rich before reprogramming the EPROM.
BLMS were around 110..... it ran great.
With reprogramming they are around 126 to 130
Can't tell it runs any better.....

I bought the Ford injectors because I wasn't interested in the (sex) involved with GM or Accel injectors.
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