starts but dies immediately - The 1947 - Present Chevrolet & GMC Truck Message Board Network

HTX86chevy · 05-20-2019, 02:14 PM

5.3 DBW and 4l60e into 72 c10 with Factory tank.

This is my 1st time doing an LS swap.
reworked harness myself using guide from (Brenden/Lt1swap.com)
had PCM done by Brenden also.

walbro 255 inline fuel pump

I have added grounds like crazy including 1 to PCM case

I have swapped fuel regulator 3 times and seem to be getting only 52psi on gauge

when I engage the key, I can hear the fuel pump run and stop after a few seconds. I turn the key to on and the engine cranks, starts and dies after 2-3 seconds. no sputtering or anything, just cuts off.

I don't have the OBD port wired up yet.

Any Ideas? what should be my next step?

**mongocanfly** · 05-20-2019, 03:05 PM

Is the maf hooked up?

HTX86chevy · 05-20-2019, 03:37 PM

Maf is NOT hooked up. Does it need that to run? I don't have a MAF sensor to hook up to. do I need to go get an air box and MAF sensor and hook that up?

Update: Ran out and Pulled MAF from my sons truck. hooked it up and she fired right up and ran perfectly.
I owe you a beer, sir. Thank you so much for taking the time to reply!

lutronjim · 05-20-2019, 09:10 PM

On my 'connect and cruise' the MAF had to mounted in the middle of at least a 12" straight tube. If I remember it wanted 4" diameter.

I initially bought a pretty chrome pipe from ebay - about 3" diameter. It ran but had a weird throttle response and continually set codes.

Might want to check when you mount yours.

**mongocanfly** · 05-20-2019, 09:32 PM

Haha...I might take you up on a rootbeer!..

JJ1972 · 05-21-2019, 11:02 AM

Check to see if you have oil pressure sending unit wired to PCM. It will start and then die. I know from experience.

bigdaddy4x4 · 05-21-2019, 04:19 PM

Quote:

Originally Posted by HTX86chevy

5.3 DBW and 4l60e into 72 c10 with Factory tank.

This is my 1st time doing an LS swap.
reworked harness myself using guide from (Brenden/Lt1swap.com)
had PCM done by Brenden also.

walbro 255 inline fuel pump

I have added grounds like crazy including 1 to PCM case

I have swapped fuel regulator 3 times and seem to be getting only 52psi on gauge

when I engage the key, I can hear the fuel pump run and stop after a few seconds. I turn the key to on and the engine cranks, starts and dies after 2-3 seconds. no sputtering or anything, just cuts off.

I don't have the OBD port wired up yet.

Any Ideas? what should be my next step?

was the vats removed ? and check the grounds again

05-20-2019, 02:14 PM	#1
HTX86chevy Registered User Join Date: Feb 2010 Location: Houston, Tx Posts: 349	starts but dies immediately 5.3 DBW and 4l60e into 72 c10 with Factory tank. This is my 1st time doing an LS swap. reworked harness myself using guide from (Brenden/Lt1swap.com) had PCM done by Brenden also. walbro 255 inline fuel pump I have added grounds like crazy including 1 to PCM case I have swapped fuel regulator 3 times and seem to be getting only 52psi on gauge when I engage the key, I can hear the fuel pump run and stop after a few seconds. I turn the key to on and the engine cranks, starts and dies after 2-3 seconds. no sputtering or anything, just cuts off. I don't have the OBD port wired up yet. Any Ideas? what should be my next step? __________________

05-20-2019, 03:05 PM	#2
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,671	Re: starts but dies immediately Is the maf hooked up? __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

05-20-2019, 03:37 PM	#3
HTX86chevy Registered User Join Date: Feb 2010 Location: Houston, Tx Posts: 349	Re: starts but dies immediately Maf is NOT hooked up. Does it need that to run? I don't have a MAF sensor to hook up to. do I need to go get an air box and MAF sensor and hook that up? Update: Ran out and Pulled MAF from my sons truck. hooked it up and she fired right up and ran perfectly. I owe you a beer, sir. Thank you so much for taking the time to reply! __________________ Last edited by HTX86chevy; 05-20-2019 at 03:45 PM.

05-20-2019, 09:10 PM	#4
lutronjim Registered User Join Date: Dec 2013 Location: Dunwoody,Ga Posts: 443	Re: starts but dies immediately On my 'connect and cruise' the MAF had to mounted in the middle of at least a 12" straight tube. If I remember it wanted 4" diameter. I initially bought a pretty chrome pipe from ebay - about 3" diameter. It ran but had a weird throttle response and continually set codes. Might want to check when you mount yours.

05-20-2019, 09:32 PM	#5
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,671	Re: starts but dies immediately Haha...I might take you up on a rootbeer!.. __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

05-21-2019, 11:02 AM	#6
JJ1972 Registered User Join Date: Jan 2009 Location: placerville, ca. Posts: 1	Re: starts but dies immediately Check to see if you have oil pressure sending unit wired to PCM. It will start and then die. I know from experience.



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