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Topic: is it my fuel pump??

in Forum: C3 Fuel, Emission Control, and Exhaust Systems

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is it my fuel pump?? (1/6)
5/2/10 11:04am

engineguy63
Former Member
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Easthampton, MA - USA

Vette(s):
1970 corvette conv, 350 auto.

Joined: 5/27/2007
Posts: 114

Hi Guys just posted an insurance question and decided to go for a drive ......while awaiting some answers/opinions. Whent out to the garage and the 1970 roadster would not start .....just drove it an hour earlier.. I pulled the air cleaner off and blipped the throttle a few times and did not see any stream of gas beeing squirtted, so I pulled the rubber line and filter off feeding the carb....( rubber line beacuse i added an inline fuel filter last year ) and after cranking it 10-15 seconds no fuel coming out of the fuel line. I am suspect of fuel pump, seams to make sense.......... anything else I am not conscidering. And how big of a project is changing out fuel pump. Thanks Eric M.

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is it my fuel pump?? (2/6)
5/2/10 11:35am

Redwingvette

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Waterford, MI - USA

Vette(s):
1973 Red coupe

Joined: 9/13/2002
Posts: 1735

Sounds like the fuel pump to me. It is not a real bad job to change but!!!!.

The best way to do it is to put some small clamps on the rubber hoses so it does not drain the tank when you disconnect them from the pump. I place a jack stand on the passenger side just behind the front tire and remove the tire. This will give you some room to work. Next you can use a long extension on your ratchet to take the bolts out. There is plenty of room if you look between the inner fender and the frame rail if you use enough extensions and work from inside the wheel well.

The biggest porblem when reinstalling the new pump is keeping the push rod up as you push the pump in place. I have used some thick grease and pushed it up onto the rod. This will usually work to hold it up long enough to get the pump in place. The other medthod you can use is to remove the bolt on the front of the motor where the rod channel is. Then you replace it with a longer bolt and finger tighten it against the rod. That can be a bit tricky if you have alot of stuff in the way on the front of the motor.

Now would be agood time to replace the rubber hoses. Make sure you buy the correct S-shaped hoses. If you try to just use a straight hose it will pinch off and stop the flow of fuel. Yopu will get some gas spilled on you. I would also change the hoses at the tank at the same time.

Redwingvette2010-05-02 08:40:05

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73 coupe L48, Flat-top pistons, Performer RPM Heads, Crane Cam and roller rockers, Holley 650 vac sec. Performer intake,
3.55 gear BTO 200-4R trans,
Leather seats, Seatbelt Plus 3point seatbelts, Pioneer CD player
Magnaflow Exhuast System

Dewitt radiator and dual electric fans

Borgeson Steering box

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is it my fuel pump?? (3/6)
5/2/10 9:58pm

ossw1
Former Member
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Rocklin, CA - USA

Vette(s):
1970 T-Top350/350hp numbers matching 4 speed. It's a mess and 1970 Convertible 4 speed.

Joined: 4/2/2005
Posts: 484

Hey to make sure its the fuel pump run a hose form a gas can that runs to the fuel pump to rule out your fuel sender? I had the same problem thought it was my fuel pump change the pump to fine out it was my fuel sender.

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is it my fuel pump?? (4/6)
5/4/10 7:23pm

engineguy63
Former Member
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Easthampton, MA - USA

Vette(s):
1970 corvette conv, 350 auto.

Joined: 5/27/2007
Posts: 114

Hey guys

Thanks for the help............I would like to rule out any other causes before I start doing a fuel pump. My thought is that If I clamp off the rubber hose that feeds the pump and maybe use a piece of copper line stuck in the end to divert the fuel to a can...then release the clamp I should see a nice smooth fuel flow from the tank by gravity. If fuel flow is non existint or intermitent then maybe something in the tank or line. (correct?) I am betting on the pump , but, sounds like close to $100 when you get the pump, and s shaped hoses, and gasket sealer , etc etc etc, so I wanna know as sure as I can be. The other thought on replacing the pump (there is not a lot of room) is if the rod comes out do you have to fit it in a certain way......as a pushrod fits (into) a lifter or does the hole just set it where it needs to go ( sorry I never looked a one before and I am NOT a mechanic) Thanks for the help Eric M

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is it my fuel pump?? (5/6)
5/4/10 10:47pm

cthulhu

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Hot Springs, AR - USA

Vette(s):
69 Conv #'s match 427, TKO-600/.64, 3.36HD-Posi, HT, T/T, PS, PB, PW, SP, Leather, Comp XE264HR & Roller Rockers & Lifters, Air-Gap RPM intake, Holley St Av 770 VS, MSD 6AL+Dist+Blaster SS, K&N, Jet-Hot Hooker Side-Pipes, Steeroids, Al Rad, Spal Fans

Joined: 4/24/2004
Posts: 3231

make sure you take the hose off the input side of the pump and see if fuel is coming out. it could be a collapsed hose at the tank or clogged line. if fuel comes out of the input side and nothing from the output then you have narrowed it down. It can be a little more complex debugging a fuel problem that only occurs at higher speeds... but if you get no gas in the driveway it is pretty easy.

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is it my fuel pump?? (6/6)
5/4/10 11:28pm

Redwingvette

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Waterford, MI - USA

Vette(s):
1973 Red coupe

Joined: 9/13/2002
Posts: 1735

Sounds like you are doing things right. As far as the push rod goes, it can not come all the way out unless you remove the plate behind the pump. It just falls down far enough so you can not put the pump back in place.

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Dewitt radiator and dual electric fans

Borgeson Steering box

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