66 C10 250 Fuel pump issue

[Sundy]

Hello all, I'm new, first post.

I either have a bad part out of the box or a real problem.

I bought a 66C10 with a 6 cylinder 250. When I got it it ran fine sitting still. When driving I get to 3rd gear it dies and takes a long time to restart, then it will run fine again.

The person I bought it from hand an electric fuel pump installed, which I didn't like the sound of anyway, so I installed a mechanical fuel pump. (Also replaced a nasty looking fuel sending unit) The new pump did nothing and it installed way too easily I think. I expected some resistance on the pump lever. After getting zero puming from this thing I took it off, cranked the engine until the cam offset was all the way facing the pump and put the pump back on. The lever doesn't even touch the cam as far as I can tell. There should be some resistance, right?

So, did I get the wrong fuel pump? It looks like the right thing but I didn't have one on there before so there's nothing to compare it to. Also, I can't move the lever by hand at all. Should it be all that stiff?

Or maybe this engine isn't what I was told and I've ordered the wrong fuel pump. But do they even vary from one to another on a chevy inline 6 cylinder?

Thanks in advance for any advice!
Sundy

[geezer#99]

Take a pic of your motor!

[RichardJ]

I'm waiting to see this picture also. I may be thinking the same thing.

[68gmsee]

Maybe the cam lobe is worn. Take a look at this thread and scroll down to compare the differences between 250 and 350 pumps in case you got the wrong one. http://67-72chevytrucks.com/vboard/s...d.php?t=395517

Worn cam lobe may be the reason it was converted to electric???

[Sundy]

Thanks for the replays and the link, this confirms I do have a pump for a 6 cylinder. Been running around doing Christmas stuff today, I can post some pictures of the motor tomorrow, probably.

Worn cam lobe....sounds like a deep thing to fix.
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[68gmsee]

Originally Posted by Sundy

Thanks for the replays and the link, this confirms I do have a pump for a 6 cylinder. Been running around doing Christmas stuff today, I can post some pictures of the motor tomorrow, probably.

Worn cam lobe....sounds like a deep thing to fix.
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Probably don't need a pic of the motor. 250 and 292 are the same pn just different location. If you suspect something not right with pump, just go to another parts store and ask to see the pump. You can compare it that way.

One other thing to check is the output of the pump at the carb inlet. Disonnect the coil to distributor so engine doesn't start and place the end in a plastic jug and have someone crank the engine. Should pump about 1 pint in less than 30 seconds.

Other possibilities are sediment in tank and/or restricted fuel line from tank to pump.

[ChrisDollins]

Are these engines like the sbc's and have the pushrod in there from the cam to the pump?

Chris
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[68gmsee]

Originally Posted by ChrisDollins

Are these engines like the sbc's and have the pushrod in there from the cam to the pump?

Chris
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No, they work off the cam lobe.

[68gmsee]

Originally Posted by Sundy

.......Worn cam lobe....sounds like a deep thing to fix.
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It can be but it may be a good way to learn about your engine. The way I told my nephew who wanted to buy my truck: if you want to own a vintage vehicle, you have to be able to learn how to work on it or have a large bank account.

Fortunately for us, these older trucks are simple to work on once you get a basic understanding of how they work. Lots of info on the net and on this site to help you through the toughest problems.
Check the cam lobe or have someone check out for you and go for it...

[Sundy]

Ok, I'm a dumbass but I have a good excuse. The guy who put the electric fuel pump on put the blank plate on upside down. It has the same shape as the fuel pump so when I installed the pump I simply lined it up with the shape of the gunk. Yes, upside down. I just looked at a bunch of pictures online and the fuel lines all come out of the top.

Is that right? That's as far as I've gotten today.

Thanks
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[RichardJ]

Yes! When I bought my truck, I found the same thing had been done with the pump, including the electric fuel pump.

[Sundy]

Awesome, thanks.

I just used the electric pump to pump a whole lot of nasty dark orange gas and into a jug. The filter, new, has dozens of rust flakes in it. And that's with a new fuel sending unit with a mesh sock on it. The gas coming out now looks clean so I guess I'll leave well enough alone. I'll connect the mechanical pump to the hoses later. The rest of the day is Christmas stuff.

Thanks for the help!
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[68gmsee]

Originally Posted by Sundy

Ok, I'm a dumbass but I have a good excuse. The guy who put the electric fuel pump on put the blank plate on upside down. It has the same shape as the fuel pump so when I installed the pump I simply lined it up with the shape of the gunk. Yes, upside down. I just looked at a bunch of pictures online and the fuel lines all come out of the top.

Is that right? That's as far as I've gotten today.

Thanks
Posted via Mobile Device

Wow! Never heard of this before. Great work in doing some research and fixing the problem. I guess in this case, a picture of the engine as Geezer and Richard mentioned above would have quickly found the reason it wasn't working.

[Sundy]

I found a few minutes to connect the fuel lines. At first it looked like nothing was going to happen so I sprayed some starter fluid in the carb to get it cranking faster and move the air out of the lines. I had drained the lines before swapping out the electric pump. The see thru filter filled in no time and the engine started. Fuel is flowing. I'll take a hose off and check the rate as suggested when I have someone here to turn the key for me.

Now to fix the timing. The front lifter cover leaked oil pretty bad so I had to remove the distributor to change the gasket. Whoever put the last one on just bent the thing around the distributor to get it on and mushed the gasket out of place. I'm sure I got the gasket and cover back on right. The distributor...not so much. Another day I guess. I need to go find the family now, I'm going to be in trouble for screwing with this truck all day.

Thanks
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[68gmsee]

Originally Posted by Sundy

...... I need to go find the family now, I'm going to be in trouble for screwing with this truck all day.

Thanks
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Yep. Happens to all of us. It's Christmas day so you need to be with them and have a Merry Christmas.

There are some that consider their trucks family, however, they (trucks) are very patient. They will wait for you.

[speedy_steve]

Well, to revive what appears to be an old thread, I stumbled onto something today and maybe someone can learn from my lesson as well as what appears others learned too. When I picked the truck up initially, it would run fine at idle and lower speeds. Once I accelerated, it immediately began chugging like it was starving for fuel. I ordered a new fuel pump and a number of other parts. Today they came in and I did a cursory search online and realized that the pump had been installed upside down by the PO. Installed it correctly, and the build continues. Mine looked identical to the hoot above. Now you know.

[Thebng]

Speedy Steve,
I had a similar experience to what you described only my pump was in the correct way. The problem I found out was that my pump was not pumping enough volume. Truck would start, idle fine and drive for about two minutes fine. Then it would start bucking and cutting out. Once I let my foot off the pedal, it would idle fine then another minute later would start cutting out. I always thought that fuel pump failure was an all or nothing thing so I suspected everything else first. I rebuilt the carb, blew out the lines, looked at the ignition and the advance as well as looking for vac leaks.... I tore my hair out for a month before finally replacing the fuel pump and problem solved. When I pulled my pump, I noticed the plastic plate riveted to the arm was missing and the rivet was sheared off which could reduce some movement of the pump arm. Can't be good the metal arm riding on the cam lobe and the plastic plate and rivet floating around in my oil pan. Just glad I caught it when I did. All fine now.