The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 07-26-2017, 10:08 AM   #1
carnut$
Registered User
 
Join Date: Jul 2017
Location: Morgantown, IN
Posts: 3
Stock C10 tank w/ efi

I installed a '94 LT1 EFI 350 into my '71 shortbed. I'm using the stock behind the seat fuel tank w/eec. I'm running and external FI pump. I've plumbed the pressure side from the stock (single line) sending unit, and the low pressure return through the passenger side/top tank tube. I'm wondering if my vented gas cap is "breathing" enough. Sometimes the truck will rpm surge & sometimes even die, making me wonder if it's vapor locking.
carnut$ is offline   Reply With Quote
Old 07-26-2017, 10:34 AM   #2
ga-stepside
Senior Member
 
ga-stepside's Avatar
 
Join Date: Jan 2016
Location: Sugar Hill GA
Posts: 369
Re: Stock C10 tank w/ efi

I have a LT1 in my 280z. How much pressure are you getting at the engine? It should be 40-43 psi. Plus is the pump close to the tank. electric pumps don't pull well, they are designed to push. How big is your input line to the engine? It should be 3/8 with the return no smaller than 5/16.
__________________
1967 C10 Step side
1970 AMX 390
1977 Datsun 280Z highly modified with '95 LT1 power
ga-stepside is offline   Reply With Quote
Old 07-26-2017, 10:53 AM   #3
carnut$
Registered User
 
Join Date: Jul 2017
Location: Morgantown, IN
Posts: 3
Re: Stock C10 tank w/ efi

I mounted the pump down on the frame rail (under the dvrs door). Gauge at the fuel rail reads 42 lbs.
Pressure side into engine is 3/8" & fuel return is 5/16".
The surging is very sporadic, as well as the dying. Most of the time it runs perfect.
carnut$ is offline   Reply With Quote
Old 07-26-2017, 11:07 AM   #4
Andy4639
Old member
 
Andy4639's Avatar
 
Join Date: Jan 2002
Location: Liberty, & Garden City S.C. , U.S.
Posts: 19,945
Thumbs up Re: Stock C10 tank w/ efi

Quote:
Originally Posted by carnut$ View Post
I mounted the pump down on the frame rail (under the dvrs door). Gauge at the fuel rail reads 42 lbs.
Pressure side into engine is 3/8" & fuel return is 5/16".
The surging is very sporadic, as well as the dying. Most of the time it runs perfect.
At the time it does this is the tank near empty? Could be loosing fuel pressure from the tank side if in a curve are very low on gas.
__________________
1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver
Seeing the USA in a 71


Upstate SC GM Truck Club
2013,14 and 2016 Hot Rod Pour Tour


http://upstategmtrucks.com/



Get out and drive the truck this summer and have some fun!
It sucks not being able to hear!

LWB trucks rule, if you don't think so measure your SWB!
After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.
Andy4639 is offline   Reply With Quote
Old 07-26-2017, 11:24 AM   #5
Warrens69GMC
Registered User
 
Warrens69GMC's Avatar
 
Join Date: Jan 2003
Location: Safford,AZ
Posts: 3,612
Re: Stock C10 tank w/ efi

When it surges can you remove the gas cap while running and it "fixes" the problem?
Warrens69GMC is offline   Reply With Quote
Old 07-26-2017, 01:06 PM   #6
carnut$
Registered User
 
Join Date: Jul 2017
Location: Morgantown, IN
Posts: 3
Re: Stock C10 tank w/ efi

It does it so infrequently, it's hard to pin it down. Yesterday it did it parked/running perfectly still in the driveway. I wished I'd thought quick enough to remove the gas cap then to see if it recovers.
carnut$ is offline   Reply With Quote
Old 07-26-2017, 04:05 PM   #7
anew4961
Senior Member
 
Join Date: Jun 2017
Location: burlington north carolina
Posts: 1,030
Re: Stock C10 tank w/ efi

I went through all this on a rear mounted tank. the fuel pump needs to be as close to the tank as you can get it the tank does need to be vented outside of the cab and have a good return line. you can get sending units with two lines
anew4961 is offline   Reply With Quote
Reply

Bookmarks

Tags
efi, fuel, injection, tank, vented


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 02:19 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com