Need to replace fuel pump and assembly
#1
Need to replace fuel pump and assembly
Here's what I got going on in my car right now. 85 z28 started out at 305 TPI switched to carbed 305 bored out with cams, headers. But this fuel pump crap looks like it was an easy fix but it slowly leaks fuel out of this micro electric oump. All I want to do is get this back to stock and put a cover over it because I don't want fuel inside my car. I could use any and all help. I'm not sure how to rewire everything and what to do about buying a new fuel pump as I know some brands are bad quality. Any suggestions would be great
#2
Senior Member
iTrader: (2)
Join Date: May 2003
Location: Huntsville, AL
Posts: 539
Likes: 0
Received 2 Likes
on
2 Posts
Car: 87 GTA, 88 GTA, 92 TA, 72 RS SS
Engine: 350, 350, 305, 396
Transmission: T56, 700r4, 700r4, T56
Axle/Gears: 3.42, 3.23, 3.23, 3.73
Re: Need to replace fuel pump and assembly
Man that's a horrible hack job.. If you go back stock you will have a high pressure pump feeding the carburetor which won't work without a return style regulator to get the pressure down.
You could change the in tank pump to a lower pressure TBI unit, you would still need a regulator but it would not bypass as much fuel back to the tank..
You could change the in tank pump to a lower pressure TBI unit, you would still need a regulator but it would not bypass as much fuel back to the tank..
#3
Re: Need to replace fuel pump and assembly
Man that's a horrible hack job.. If you go back stock you will have a high pressure pump feeding the carburetor which won't work without a return style regulator to get the pressure down.
You could change the in tank pump to a lower pressure TBI unit, you would still need a regulator but it would not bypass as much fuel back to the tank..
You could change the in tank pump to a lower pressure TBI unit, you would still need a regulator but it would not bypass as much fuel back to the tank..
#5
Re: Need to replace fuel pump and assembly
Trending Topics
#8
Senior Member
iTrader: (1)
Join Date: Dec 2012
Location: Western NY
Posts: 629
Likes: 0
Received 2 Likes
on
2 Posts
Car: 88 convertible
Engine: 5.7L
Transmission: 4+3 maual
Axle/Gears: 3.07
Re: Need to replace fuel pump and assembly
battman has the right idea. Replace the in-tank pump with a lower pressure TBI pump and use the stock fuel lines (feed and return) as intended. You will need to plumb in a fuel pressure regulator that is suitable for a carb but that is fairly simple. Don't know if your engine has a mechanical fuel pump provision or even if the cam has a fuel pump lobe so some type of electric pump is the easiest way to go. Stock is usually the most cost effective and easiest system to duplicate so following that design is probably the best route. GL!
#10
Re: Need to replace fuel pump and assembly
would this cause issues as my engine started out as TPI? I'm really clueless at all this stuff
#11
Re: Need to replace fuel pump and assembly
battman has the right idea. Replace the in-tank pump with a lower pressure TBI pump and use the stock fuel lines (feed and return) as intended. You will need to plumb in a fuel pressure regulator that is suitable for a carb but that is fairly simple. Don't know if your engine has a mechanical fuel pump provision or even if the cam has a fuel pump lobe so some type of electric pump is the easiest way to go. Stock is usually the most cost effective and easiest system to duplicate so following that design is probably the best route. GL!
#12
Re: Need to replace fuel pump and assembly
I forgot to add it has an edelbrock 650 thunder series 4 bbl carb
#13
Member
Re: Need to replace fuel pump and assembly
If you're handy with a soldering iron you can join them together and use heat-shrink tubing. Otherwise you would have to replace the entire line(s) from the tank to the connector towards the front. I would at the least solder them to ensure a permanent intermittent free operation.
#14
Senior Member
Join Date: Jan 2008
Location: Massachusetts
Posts: 631
Likes: 0
Received 7 Likes
on
6 Posts
Car: 86' IROC
Engine: Supercharged 350
Transmission: T56
Axle/Gears: 3.45
Re: Need to replace fuel pump and assembly
If it were me, Id be checking to make sure the cam has a fuel pump lobe, and there is a good hole in the block for the fuel pump pushrod where you can slap a mechanical pump on there. Solder up the wires, Use shrink wrap, Then wrap them up in loom and then tape up the loom nice and tight. Take out the electric intank pump, Bypass it with hose, Double clamp each end, and verify the system works before you weld and seam seal up that hole. Might have to pour some gas in the carb to get it going. No regulators to fail and spray fuel everywhere, No dropping the tank again, And no figuring out where to mount that cheapo Mr Gasket electric pump thats in there at the moment thats probably gonna leave you stranded somewhere
#15
Senior Member
Join Date: Jan 2008
Location: Massachusetts
Posts: 631
Likes: 0
Received 7 Likes
on
6 Posts
Car: 86' IROC
Engine: Supercharged 350
Transmission: T56
Axle/Gears: 3.45
Re: Need to replace fuel pump and assembly
Not to mention thats probably the worst spot in the entire car for a inline pump to be in.
#16
Re: Need to replace fuel pump and assembly
If you're handy with a soldering iron you can join them together and use heat-shrink tubing. Otherwise you would have to replace the entire line(s) from the tank to the connector towards the front. I would at the least solder them to ensure a permanent intermittent free operation.
#17
Re: Need to replace fuel pump and assembly
If you're handy with a soldering iron you can join them together and use heat-shrink tubing. Otherwise you would have to replace the entire line(s) from the tank to the connector towards the front. I would at the least solder them to ensure a permanent intermittent free operation.
If it were me, Id be checking to make sure the cam has a fuel pump lobe, and there is a good hole in the block for the fuel pump pushrod where you can slap a mechanical pump on there. Solder up the wires, Use shrink wrap, Then wrap them up in loom and then tape up the loom nice and tight. Take out the electric intank pump, Bypass it with hose, Double clamp each end, and verify the system works before you weld and seam seal up that hole. Might have to pour some gas in the carb to get it going. No regulators to fail and spray fuel everywhere, No dropping the tank again, And no figuring out where to mount that cheapo Mr Gasket electric pump thats in there at the moment thats probably gonna leave you stranded somewhere
#18
Re: Need to replace fuel pump and assembly
If you're handy with a soldering iron you can join them together and use heat-shrink tubing. Otherwise you would have to replace the entire line(s) from the tank to the connector towards the front. I would at the least solder them to ensure a permanent intermittent free operation.
If it were me, Id be checking to make sure the cam has a fuel pump lobe, and there is a good hole in the block for the fuel pump pushrod where you can slap a mechanical pump on there. Solder up the wires, Use shrink wrap, Then wrap them up in loom and then tape up the loom nice and tight. Take out the electric intank pump, Bypass it with hose, Double clamp each end, and verify the system works before you weld and seam seal up that hole. Might have to pour some gas in the carb to get it going. No regulators to fail and spray fuel everywhere, No dropping the tank again, And no figuring out where to mount that cheapo Mr Gasket electric pump thats in there at the moment thats probably gonna leave you stranded somewhere
#19
Senior Member
Join Date: Jan 2008
Location: Massachusetts
Posts: 631
Likes: 0
Received 7 Likes
on
6 Posts
Car: 86' IROC
Engine: Supercharged 350
Transmission: T56
Axle/Gears: 3.45
Re: Need to replace fuel pump and assembly
Correct, no regulator needed. I would verify you can run the mechanical before you buy anything. Some engines the block was never machined for the pushrod. I might have a fairly new mechanical pump and pushrod kicking around too if you need it. I went efi/electric pump last year.
#20
Member
Re: Need to replace fuel pump and assembly
is going to the fuel pump relay ( or was) at one point.
#21
Supreme Member
iTrader: (15)
Re: Need to replace fuel pump and assembly
If the car originally had an intank pump then the wires should be purple for the sender, black for common ground and Grey for the Fuel Pump. The interior cabin side female three prong connector looks like it was cut off or removed? You can buy a new sending unit which consists of the entire intank unit minus the fuel pump, the hard lines that connect to the soft lines inboard of the driver's rear wheel and the three pronged connector.
#22
Re: Need to replace fuel pump and assembly
If the car originally had an intank pump then the wires should be purple for the sender, black for common ground and Grey for the Fuel Pump. The interior cabin side female three prong connector looks like it was cut off or removed? You can buy a new sending unit which consists of the entire intank unit minus the fuel pump, the hard lines that connect to the soft lines inboard of the driver's rear wheel and the three pronged connector.
This is what is going on as per the wiring
#23
Member
Re: Need to replace fuel pump and assembly
Hard to make out the colors but there are 3 wires coming from the fuel assmbly - blk(gnd),
tan(?) 12v operation - that leaves the orange(?) which is connected and is used for the fuel gauge on the dash. That is all!
tan(?) 12v operation - that leaves the orange(?) which is connected and is used for the fuel gauge on the dash. That is all!
#24
Supreme Member
iTrader: (15)
Re: Need to replace fuel pump and assembly
Source:
http://austinthirdgen.org/mkportal/m...ine_wiring.gif
http://www.austinthirdgen.org/mkport...uges_part1.gif
#25
Supreme Member
iTrader: (15)
Re: Need to replace fuel pump and assembly
Nothing should need rewired, just reconnect the body wiring to the sending unit wiring. Then just reconnect the hoses/lines. You should probably go ahead and replace the fuel pump while it is easy to do with your trap door open. For a fuel pump go with the AC Delco fuel pump EP381 it was used in the Typoons and Grand Nationals. The Holley Fuel pump didn't last very long in my car and was noisey, the EP381 is a little quieter and so far so good on the life span.
#26
Member
Re: Need to replace fuel pump and assembly
That Austin site has some great docs/diagrams. The one GM factory Service Manual for the 3rd gen that I have refers to another manual for electrical connection, which I don't have. Great source.
#27
Re: Need to replace fuel pump and assembly
Nothing should need rewired, just reconnect the body wiring to the sending unit wiring. Then just reconnect the hoses/lines. You should probably go ahead and replace the fuel pump while it is easy to do with your trap door open. For a fuel pump go with the AC Delco fuel pump EP381 it was used in the Typoons and Grand Nationals. The Holley Fuel pump didn't last very long in my car and was noisey, the EP381 is a little quieter and so far so good on the life span.
#28
Supreme Member
iTrader: (15)
Re: Need to replace fuel pump and assembly
1. Use a TBI stock fuel pump in the tank and good name brand fuel regulator. If you are using a TBI pump you will need to use fuel hose that is rated for the higher pressures of Fuel injection.
2. The fuel pump is actually connected to the sending unit with a short length of tube. I would just remove the pump and use a short length of hard line in place of the intank pump. Then install your pre-existing little electric fuel pump under the hood with a regulator. You won't have to use EFI hose for this.
#29
Re: Need to replace fuel pump and assembly
I misread your initial post, I thought you were going back to EFI. If you are staying carb you have 2 options:
1. Use a TBI stock fuel pump in the tank and good name brand fuel regulator. If you are using a TBI pump you will need to use fuel hose that is rated for the higher pressures of Fuel injection.
2. The fuel pump is actually connected to the sending unit with a short length of tube. I would just remove the pump and use a short length of hard line in place of the intank pump. Then install your pre-existing little electric fuel pump under the hood with a regulator. You won't have to use EFI hose for this.
1. Use a TBI stock fuel pump in the tank and good name brand fuel regulator. If you are using a TBI pump you will need to use fuel hose that is rated for the higher pressures of Fuel injection.
2. The fuel pump is actually connected to the sending unit with a short length of tube. I would just remove the pump and use a short length of hard line in place of the intank pump. Then install your pre-existing little electric fuel pump under the hood with a regulator. You won't have to use EFI hose for this.
Thread
Thread Starter
Forum
Replies
Last Post
ChrisMPG
Tech / General Engine
4
08-21-2016 10:44 AM
Mike.Johnson
Electronics
0
08-10-2016 08:43 PM