The Stovebolt Site Forums The Shop Area Engine Shop 235 Fuel Pump Question

I just replaced the fuel pump on my 54 4400. The engine is a '56 235. Now, this should be about the easiest job there is. However, I cannot get it to pump fuel now.

Q1: is there a push rod that I missed somehow that runs the fuel pump from the cam?

Q2: is there a priming sequence or something else I'm missing here?

When I put the new pump on, I could feel the plunger pushing against the cam, so I'm fairly convinced that it's in contact. I suppose it could be a bad pump.

The old pump did pump some fuel, but not enough to keep the engine running. Also, there was a strong odor of gasoline in the oil. These two things convinced me I had a fuel pump problem.

Thanks!

some say you should pump it a few times before you install it, I installed one on my 235 awhile back,, no problem, dont recall if I primed/pumped it first all not... not likely you got a bad pump that would do nothing,,and if it bolted on ok, you should have the plunger in but,,,,,,,,,,,,,,,maybe someone else will chime in.........

Well, that was what I was thinking. It didn't seem to be possible to install it incorrectly. I could feel the pressure of the plunger against the cam when I installed it.

I've cranked it for quite a bit and still haven't had any fuel pass through it yet.

Thanks for the reply!

Bolter Rush,

I think you need to verify that the suction side of the pump is clear...crapola in the tank?

You should do the same to the pressure, or discharge side if you have any reservations that it isn't pumping.

Inserting the pump lever over the lobe of the cam is sometimes tough. It sounds like you are pretty sure you have it right. If so, it should pump.

Check the "in" and the "out"...this will prove the pump.

Keep in mind that the carburetor might have received adequate fuel from the pump, but could have delivery problems itself. The carb is where the business takes place!

Any filter between pump and carburetor must be clean to pass fuel.

This will sound silly, but make real sure you have fuel in the tank!!


Stuart

Q1 no. Q2 no. It may sound silly but they can be put on upside down. Check your cam could be wore down. Clamp the pump in a vise & press the lever it should have suction on the inlet & pressure on the outlet. Check the fuel line from the tank. It could be plugged up or have a leak & sucking air. You may have a bad pump or wrong pump. These things set on shelves for a long time sometimes.

I'll check these things. I suppose it could be junk, but it's strange that the old one was pumping fuel, albeit weakly, but the new one won't. Same lines, same tank, etc. But, I'm intrigued by your statement that "Inserting the pump lever ove the loabe of the cam is sometimes tough." Could you elaborate a bit? Perhaps I've done something there that was not right? Is it possible to not get it positioned correctly? How can I tell if it is positioned correctly?

I've checked the fuel filter and the carborator. Both are fine. The truck will run if I pour fuel down the throat of the carb so I know I have spark.

Thanks for the tips!

Thanks Wrenchbender. I feel better knowing that at least there is no pushrod! lol! I suppose I could have bought a defective pump. I'll pull it off and see if I can feel the lobe with my finger for any groves or excessive wear. I guess it is a good idea to go ahead and check to see if I have the proper flow too...pressure and suction on the correct sides of the pump. And the lines.

I appreciate all the help! Plenty to look into now.

Have you pulled the line from the carb & turned the engine over to verify it's not pumping? If you don't get gas at that point pull the line from the outlet side of the pump & do it again. If you're getting gas there, the line between the pump & carb is plugged. If still no gas leaving the pump pull the feed line from the tank to the pump & verify you are getting gas to the pump. If are getting gas to the pump put your finger over the inlet hole & turn the engine over to see if you have suction. If so then put your finger over the outlet to see if you have air pushing your finger away. You have two small valves in the pump. One lets fuel in and the other lets it out. Both or either could be bad. Good luck.

Tiny, I have not done all that yet. Good suggestions. I have check the line at the carburetor and getting no fuel there. But, have not yet checked at the pump itself.

I got this pump from LMC Truck on the internet. Do you know if these are rebuilds or are they new?

Thanks!

Bolter Rush,

The difficulty of actually bolting the pump to the block would be determined by the lobe position on the camshaft. I think it would be accurate to say that even with the cam at the "heel", it takes some mashing and pushing to get the pump shoved up against the block to insert the bolts.

There is no priming procedure. This is a straightforward R&R. You sound quite knowledgeable so I am sure you will triumph soon.


Stuart

lol! Thanks atomarc. I agree it SEEMED pretty straight forward. I most likely have either a plugged line or a bad pump. I'm confident it's bolted up correctly. I didn't think there was a pushrod but I just wanted to be sure. Without the pushrod being an issue I believe the installation is correct.

Well, looks like I've got my Saturday booked up already. I've popped a beer and I'm loosing steam on troubleshooting at this time.

now if you were installing that booger on a chevy v-8 you might have a concern..........was the truck running good before with the old one?

Joker, the truck was running, but not well, before I changed out the pump. It was starving for fuel and there was a strong odor of fuel in the oil.

thanks, well at least if it runs with gas in the carb that is a good sign........you know the problem is down from there,,, make sure you check your fuel filter also and good luck with it... let us know what you find out,, I would head over and give you a hand but you will have it fixed before I get there

Hehe! It's the thought that counts, Joker.

I tried to help an aquaintence get his '50 running after he had replaced the fuel pump. He had installed it upside down and had it bolted on and the lines hooked up. They do go in just the opposite of a small block V8. The actuator arm should be pointing up when you insert it through the opening in the block. For what it's worth.

I have had rubber fuel lines thicken up internally and choke off flow without any evidence on the exterior. You might want to replace any rubber hoses, and check to make sure fuel dribbles out of the line if you unhook it from the suction side- these pumps need some gravity feed to work right.

Also check the flow at the outlet of the fuel tank, it should gush out when you remove the line.

Arpee...sorry I took a bit to get back. Yes, I can see that happening. However, I am sure this is bolted in correctly. Arm was pointing up, intake to the rear, outflow to the front.

Thanks!

Now, 4ontheFloor...you are on to something here. I removed the line from the pump...no gas. I removed the metal line from the short rubber line at the exit of the tank under the truck...no gas! I blew some air back into the tank at that point...heard it bubble in the tank...no gas. Did it again with a bit more force and, Eureka! Gas is flowing. Nasty, stinky dirty looking gas, but gas nontheless.

Therefore, I have found the problem (with many thanks to the help from here!). Now, I'm guessing I need to remove the tank and clean it. I notice a bolt which appears to go through the bottom fo the tank located above a hole in the floorboard just next to the fuel line. Would this be the drain? If I drain it from here and actually rinse it out with clean gas and drain again, would I be alright? Or do I need to remove and 'do it right'?

Second question: My fuel gauge is not working. I'm guessing it's the sending unit in the tank. Are the repairable? Or must I replace it?

Thanks!

Does it read full all of the time?

No, it reads Empty all the time. Hmmm...I'm about to learn something here I feel. What does that mean?

The default position with no connection (broken wire, etc.) is full and that's by far the most common. If yours is showing empty either the gauge is stuck (not likely but possible) or the sending unit float is frozen in the empty position. If you are going to pull the tank anyway this is the ideal time to check the sending unit.

Thanks, Tiny. That is very helpful. And hopeful. I was dreading having to find a new one. Perhaps (other than pulling the tank) it will be an easy fix.

If you do need a new sending unit holler. I have one I used on my 38 for a while that I'll let you have for a LOT less than you'll pay new. Hopefully you'll be able to save the original.

Thanks Tiny, that is very much appreciated. I'll check it out and let you know. How often is it that that gauge itself has gone bad?

I've never had one go bad & it's rare to see somebody complaining in here about it. I can't give you a specific though. With your reference to bad smelling & looking gas I'd be willing to bet it's the sending unit. Another thought is you shouldn't run the engine if you have old, bad gas in the tank. It can stick intake valves shut & bend pushrods. I discovered that the hard way.

Thanks for the tip. I'm going to remove and clean the tank before going any further with it. I'll check out the sending unit at that time. I'm hoping that I can unstick it. But, I may be asking for a price on yours after inspection.

my experience with gas gauges is if they read full=bad ground wire, if they read empty=bad hot wire

On the fuel pump,,short hose and small can of gas hooked to tank side of pump line removed from carb turn over if pump working you will have fuel at carb if not pump or cam bad,,if fuel at carb from can then...blow into tank with shop air use rag to seal opening around blower fuel should run at pump end of line if not tank empty or line plugged..on gauge ,,tank wire grounded read the not grounded and read if gauge travel full sweep tank unit bad if not dash unit or wiring..doc

Thanks guys for the tips. I'll keep you posted. I have to do the work as I can. That usually means weekends.

I am eager to see if I can get the gauge working. Have had some good info on that in these posts...sure thank you all for that!

I am having similar problems ,rebuilt carb because truck runs great 20 minutes later it dies. Pulled fuel line no fuel going to carb going to try and rebuild glass fuel pump because it sounds like a nightmare to put a different on in. Where can I get a rebuild kit?