ACDelco E38 calibration value

American Delco GM ECUs and PCMs, ALDL, OBD 1.5.
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ACDelco E38 calibration value

Post by brcisna »

Hello All,

new to ECUing

Can anyone explain on an ACDelco E38 ECU,, what the value of KefPMC_b_VariableSpeedPump,,,would be enabled or disabled.,,,what would be the purpose of changing this.
Recently purchased an 2010 Chevrolet Suburban 5.3L that had an AFM delete done to it. It has a rough idle,I bought it 'as is'
The previous owner got an DiabloSport Predator2 to do the AFM delete in the ECU,,in the cam kit bundle he bought. which he did go through this to delete the AFM/DOD,in ECU

After reading the ECU with PowerPCM_Flasher,then loading this bin into Universal Patcher, I think this particular value is at a 'non default' vale as it has the little black check mark above the entry in the left pane. It is set to a value of 0. The DodSwitch value also has the little black check mark,,which I only assume is a non-default value. It is set to value of 1.

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Re: ACDelco E38 calibration value

Post by antus »

I dont know a lot about the e38 platform so take this with a grain of salt, but variable speed pump would be telling the pcm if the vehicle has a variable speed pump fitted and wired. dod is if deplacement on demand is fitted or enabled. I dont think universal patcher knows what default setting is, so I dont think the mark means its non-default. Someone else might have more information about that.

Do you know if the car ran poorly when the diablo AFM delete changed or has it degraded over time? If it was fine then its more likely a hardware problem thats starting to present itself.
Have you read the FAQ? For lots of information and links to significant threads see here:
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Re: ACDelco E38 calibration value

Post by brcisna »


Thanks for the feedback.
I am wondering if the Diablosport didnt really write back the tune correctly,After much digging have read were others with the E38 ECU's have had quirks using the Predator2. Never knew a thing about the Predator setups,,,but this generation is pretty old technology maybe 12 years old. I got the Predator2 with the truck.
Am leaning on buying another ECU,,have it GM / SPS reprogrammed.
The gentleman i bought it from seemed straight up,,and said,,it never run right after he done the AFM delete,,with the Predator2. He wasnt sure if that was actually it,,or something mechanical started to fall down. He got tired of chasing it,and got his wife another vehicle,as she is a traveling nurse,. Previous owner said the ruck run prefect before he done the AFM delete.

Compression, igntion, fuel injectors all seem as they should be. It actually sounds smooth at cold start,,once it comes off of fast idle,it starts degrading quickly ,,,and rpms flucuates,,,,then evens out,. Dont have a high end OBDII scanner to narrow things down. The motor runs very quiet,,unlike many of the LS motors,,have the lifter ticks,,even after replacing cam/lifters. The plugs are all black,,which makes me wonder about the VariblePumpSpeed setting in the calibration?
BTW. Universal Patcher does have a built in E38 checksum XDF that handles E38 ACDelco.Just noticed this by accident messing with this ECU.
What is your take on an ECU hardware flaking out? It is 13 years old,,,so who knows,

Thank again
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Re: ACDelco E38 calibration value

Post by kur4o »

I think you should start with a fresh stock bin and work from there.

Can you post your current bin, we can check if it is stock or not, or get an idea of what have been changed. Disabling DOD is a simple switch, so shouldn`t give any problems.

On hardware side injector drivers fails on these pcms fairly often.
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