Lt1 swapped lt4 hpfp issue

s3rics213 · 03-28-2020, 04:43 PM

Update: Harness 12689504 will be a direct swap for harnesses for anyone with a 2019 trying to upgrade the hpfp to the lt4 pump.
Original:
Everyone that’s done the lt4 hpfp upgrade where the connectors the same. My connectors don’t match up. Lt4 pump 12694529 and my old pumps numbers 12697967. First pics new pump second is old.

Anyone have any idea thought these are plug and play.

2019 camaro ss
Injectors already swapped and d1x with 10 psi

TJay74 · 03-30-2020, 10:47 AM

My guess is that new "LT4 / HPFP" is the wrong pump. Have you cross checked the part # on it?

s3rics213 · 03-30-2020, 11:48 AM

Quote:

Originally Posted by TJay74

My guess is that new "LT4 / HPFP" is the wrong pump. Have you cross checked the part # on it?

Yes the lt4 pump number hasn’t changed from 18 to 19-20 zl1. It’s the lt1 on the 19 that changed from the electrical. Even the dealership shows that the pumps completely changed on the lt1 and the lt4 stayed the same.

New_image · 03-31-2020, 09:27 PM

I would like to hear more on this. My pump and injectors are on the shelf. Waiting on my supercharger to show up before I start the install.

s3rics213 · 04-01-2020, 12:20 AM

Quote:

Originally Posted by New_image

I would like to hear more on this. My pump and injectors are on the shelf. Waiting on my supercharger to show up before I start the install.

I ordered a new harness and I can supply pn later just won’t have access to the shop and car till Friday to see if it works.

Update:
Looks like harness 12689504 will be a direct swap for harnesses for anyone with a 2019 trying to upgrade the hpfp to the lt4 pump. Will be swapping on Friday to verify.

New_image · 04-01-2020, 03:38 PM

Quote:

Originally Posted by s3rics213

I ordered a new harness and I can supply pn later just won’t have access to the shop and car till Friday to see if it works.

Update:
Looks like harness 12689504 will be a direct swap for harnesses for anyone with a 2019 trying to upgrade the hpfp to the lt4 pump. Will be swapping on Friday to verify.

👍

ADM PERFORMANCE · 04-02-2020, 12:18 PM

We use the lt4 harness all the time from the camaro zl1 and corvette.

s3rics213 · 04-02-2020, 08:54 PM

Quote:

Originally Posted by ADM PERFORMANCE

We use the lt4 harness all the time from the camaro zl1 and corvette.

Airstang93 · 04-26-2021, 03:20 AM

Quote:

Originally Posted by s3rics213

I ordered a new harness and I can supply pn later just won’t have access to the shop and car till Friday to see if it works.

Update:
Looks like harness 12689504 will be a direct swap for harnesses for anyone with a 2019 trying to upgrade the hpfp to the lt4 pump. Will be swapping on Friday to verify.

Did you order direct from GM?

MrRuss · 04-26-2021, 12:52 PM

I am also upgrading to LT4 fueling on my 2016 SS in preparation for an LT4 SC install. As far as I know I will need injectors, both fuel pumps and a voltage booster but having trouble finding the exact part numbers. Rock auto has half a dozen injectors for a 2017 ZL1 and I'm not sure which one is correct. Any help would be much appreciated. I also know I need to change my flex fuel to ZL1.

Also any other parts needed? How about a good install write up?

Puddin · 04-26-2021, 02:01 PM

Quote:

Originally Posted by MrRuss

I am also upgrading to LT4 fueling on my 2016 SS in preparation for an LT4 SC install. As far as I know I will need injectors, both fuel pumps and a voltage booster but having trouble finding the exact part numbers. Rock auto has half a dozen injectors for a 2017 ZL1 and I'm not sure which one is correct. Any help would be much appreciated. I also know I need to change my flex fuel to ZL1.

Also any other parts needed? How about a good install write up?

Why would you need to change your flex fuel sensor?

MrRuss · 04-26-2021, 02:36 PM

Quote:

Originally Posted by Puddin

Why would you need to change your flex fuel sensor?

It's my understanding that the flex fuel kit is different for the LT4 vs. LT1

EDFHOBBIES · 04-26-2021, 02:38 PM

The top pic is exactly what came off my 2016 SS.. It was a direct swap for my LT4 pump off my 17 ZL1... I gave my wife's SS my LT4 pump and injectors I took the SS pump and injectors for my zl1. about 4 mos. ago one of my SS injectors off her car died so I just put all new Lt4 injectors and lt4 pump back.

LT4 pump I used
GM 12688607
AC/Delco HPM1036

EDFHOBBIES · 04-26-2021, 02:40 PM

Quote:

Originally Posted by MrRuss

It's my understanding that the flex fuel kit is different for the LT4 vs. LT1

Not sure about flex fuel kit but definitely the AUX pump kit on a ss and zl1 are different most likely from the map sensor.

03-28-2020, 04:43 PM	#1
s3rics213 Drives: 2019 1LE/ss 2014 ss/rs summit white Join Date: May 2016 Location: Charlotte Posts: 131 View My Garage	Lt1 swapped lt4 hpfp issue Update: Harness 12689504 will be a direct swap for harnesses for anyone with a 2019 trying to upgrade the hpfp to the lt4 pump. Original: Everyone that’s done the lt4 hpfp upgrade where the connectors the same. My connectors don’t match up. Lt4 pump 12694529 and my old pumps numbers 12697967. First pics new pump second is old. Anyone have any idea thought these are plug and play. 2019 camaro ss Injectors already swapped and d1x with 10 psi Attached Images __________________ 2019 ss/1LE d1x, LT4 fuel System, Triple meth nozzle, ported BTR, 2” Texas speed headers, Built 377 SPDC motor, CTporting heads, TooHighPsi port system, SMG aux. 1014/800 on E55/meth 890/750 on 93/meth Working on tuning the port system for full e. With questions just message me here for a faster response. https://www.facebook.com/eric.willia...ibextid=LQQJ4d Last edited by s3rics213; 04-03-2020 at 05:20 PM. Reason: Solved

03-30-2020, 10:47 AM	#2
TJay74 Drives: 17 Camaro SS 1LE & 16 Sierra AT CC Join Date: Nov 2016 Location: Norman, OK Posts: 2,424	My guess is that new "LT4 / HPFP" is the wrong pump. Have you cross checked the part # on it? __________________ 2019 Corvette Z06 2LZ A8 - Halltech CAI, AWE non-catted X-pipe, Mamo V2 ported TB 592rwhp, bone stock 566rwhp 2017 Camaro SS 1LE - Procharger D1SC w/ Tial 2" BOV & Race intercooler / ARH full length catless headers / Alky meth injection system - 650rwhp on conservative tune SOLD

04-02-2020, 12:18 PM	#7
ADM PERFORMANCE Drives: Anything I want Join Date: Oct 2008 Location: DfW - Texas Posts: 5,405	Swapping harness is the correct way to do this We use the lt4 harness all the time from the camaro zl1 and corvette.

04-26-2021, 12:52 PM	#10
MrRuss Drives: 2016 Camaro 2SS Join Date: Mar 2018 Location: Chandler, AZ Posts: 207	I am also upgrading to LT4 fueling on my 2016 SS in preparation for an LT4 SC install. As far as I know I will need injectors, both fuel pumps and a voltage booster but having trouble finding the exact part numbers. Rock auto has half a dozen injectors for a 2017 ZL1 and I'm not sure which one is correct. Any help would be much appreciated. I also know I need to change my flex fuel to ZL1. Also any other parts needed? How about a good install write up? __________________ Mr Russ Tim "the tool man" Taylor is my hero My Garage: '16 Chevrolet Camaro 2SS, Summit White, Adrenaline Red -- Rotofab CAI, Soler TB, 1 7/8 coated LT's, Full 3" mids, 3" Stainless Works NPP mufflers, Flex Fuel, E85/91 tuned '20 Honda Oddysey Elite 25th Anniversary Edition --wifes car, she said "No more SUV's" after the 2 CX-9's totaled

04-26-2021, 02:38 PM	#13
EDFHOBBIES Dyno Show Queen LOL Drives: 16 SS & 17 ZL1 Both Yellow Join Date: Jan 2014 Location: Houston Posts: 4,345 View My Garage	The top pic is exactly what came off my 2016 SS.. It was a direct swap for my LT4 pump off my 17 ZL1... I gave my wife's SS my LT4 pump and injectors I took the SS pump and injectors for my zl1. about 4 mos. ago one of my SS injectors off her car died so I just put all new Lt4 injectors and lt4 pump back. LT4 pump I used GM 12688607 AC/Delco HPM1036 __________________ Kong Ported 2650, Crawford Racing Port Injection, Weapon X 112mm Adapter, NW112mm TB, Livernois Ported LT4 Heads, Lingenfelter GT32 stealth cam, Haltech Elite, and Carbon by Trufiber

03-31-2020, 09:27 PM	#4
New_image Drives: 2019 Camaro 1LE Join Date: Dec 2019 Location: Washington Posts: 35	I would like to hear more on this. My pump and injectors are on the shelf. Waiting on my supercharger to show up before I start the install.

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