68 small block fuel pump
Thread Starter
Drifting
Joined: Nov 2016
Posts: 1,956
Likes: 575
From: Pittsburgh PA
68 small block fuel pump
I'm looking for a good stock replacement fuel pump for my L79.
I'm having the hard cold start issues, still troubleshooting, but am starting to suspect my pump is allowing everything to drain.
pump is not original, its an aftermarket pump- carter I believe.
question- Do ALL fuel pumps have a check valve in them? I found someone on ebay selling Ac delco fuel pumps, but when i inquired about a check valve they said no the pump did not have one.
I'm having the hard cold start issues, still troubleshooting, but am starting to suspect my pump is allowing everything to drain.
pump is not original, its an aftermarket pump- carter I believe.
question- Do ALL fuel pumps have a check valve in them? I found someone on ebay selling Ac delco fuel pumps, but when i inquired about a check valve they said no the pump did not have one.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,444
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
You need to look elsewhere for the problem. Your carb fuel bowls hold more than enough fuel to cause the squirters to squirt when you pump the throttle. The motor rotating from the starter pumps more fuel
Bad pumps symptoms are fuel starvation going down the road
I would look at all ignition parts first and timing. Plugs wires cap rotor coil condenser, and points if you have them.
Bad pumps symptoms are fuel starvation going down the road
I would look at all ignition parts first and timing. Plugs wires cap rotor coil condenser, and points if you have them.
Thread Starter
Drifting
Joined: Nov 2016
Posts: 1,956
Likes: 575
From: Pittsburgh PA
well following Lars paper, it says a qjet will drain if the fuel pump check valve is no good
car runs good and restarts good other than cold restart. would think timing or another component would show itself all the time, not just on cold starts
car runs good and restarts good other than cold restart. would think timing or another component would show itself all the time, not just on cold starts
Burning Brakes
Joined: Oct 2001
Posts: 916
Likes: 196
From: TX
Hey TigerJoe
I had cold start problem and it is cured.
Three things I would suggest looking at that I did. They all helped.
1. Napa Gold 3051 filter on the carb has a check valve.
2. Replaced fuel pump cause it was leaking. Dont know if this helped with cold start.
3. Bumped initial timing from factory 4 degrees to 12 degrees! I think this was the biggest help!!
VS
Forgot to mention I also switched from ported to manifold vacuum. I think this is a big deal, too!!
When i bought the vette about 5 years ago it would take forever to start after sitting up for a few days. Did all the above after about 6 months of living with the poor starting characteristics and have not had any trouble since.
I had cold start problem and it is cured.
Three things I would suggest looking at that I did. They all helped.
1. Napa Gold 3051 filter on the carb has a check valve.
2. Replaced fuel pump cause it was leaking. Dont know if this helped with cold start.
3. Bumped initial timing from factory 4 degrees to 12 degrees! I think this was the biggest help!!
VS
Forgot to mention I also switched from ported to manifold vacuum. I think this is a big deal, too!!
When i bought the vette about 5 years ago it would take forever to start after sitting up for a few days. Did all the above after about 6 months of living with the poor starting characteristics and have not had any trouble since.
Last edited by VERYSOON; May 8, 2021 at 11:23 AM. Reason: remembered something important
Tech Contributor
Joined: Aug 1999
Posts: 14,356
Likes: 6,332
From: At my Bar drinking and wrenching in Lafayette Colorado
You're thinking he has a Holley. The '68 L79 used the Q-Jet, and it will drain back through the needle/seat and fuel pump to make the bowl fuel level low enough that the accel pump well won't re-fill after 1 stroke if the fuel pump checkvale is leaking.
Lars
Last edited by lars; May 8, 2021 at 12:24 PM.
Tech Contributor
Joined: Aug 1999
Posts: 14,356
Likes: 6,332
From: At my Bar drinking and wrenching in Lafayette Colorado
Yes, it had a return, which will release fuel pressure on the line. But it won't siphon the fuel out of the carb like a drain-back problem does with a leaking pump checkvalve.
Lars
Lars
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,444
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
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Burning Brakes
Joined: Oct 2001
Posts: 916
Likes: 196
From: TX
Sorry about that. I bought one from Napa for my 1969 350. It says "Made in S. Korea with Carter engineering" on the label. I was told it has a checkvalve. I have used it for four years now without issue. The fuel outlet faces the wrong way but I used the correct S shaped hose from Zip and did not have a problem with connecting.
VS
Cruising
Joined: Feb 2014
Posts: 12
Likes: 0
initial timing 8 to 12
Hey TigerJoe
I had cold start problem and it is cured.
Three things I would suggest looking at that I did. They all helped.
1. Napa Gold 3051 filter on the carb has a check valve.
2. Replaced fuel pump cause it was leaking. Dont know if this helped with cold start.
3. Bumped initial timing from factory 4 degrees to 12 degrees! I think this was the biggest help!!
VS
Forgot to mention I also switched from ported to manifold vacuum. I think this is a big deal, too!!
When i bought the vette about 5 years ago it would take forever to start after sitting up for a few days. Did all the above after about 6 months of living with the poor starting characteristics and have not had any trouble since.
I had cold start problem and it is cured.
Three things I would suggest looking at that I did. They all helped.
1. Napa Gold 3051 filter on the carb has a check valve.
2. Replaced fuel pump cause it was leaking. Dont know if this helped with cold start.
3. Bumped initial timing from factory 4 degrees to 12 degrees! I think this was the biggest help!!
VS
Forgot to mention I also switched from ported to manifold vacuum. I think this is a big deal, too!!
When i bought the vette about 5 years ago it would take forever to start after sitting up for a few days. Did all the above after about 6 months of living with the poor starting characteristics and have not had any trouble since.