Jason's 70 Big Block SWB Project

[knomadd]

Ok, we'll you've eliminated what was offline when using the gas can... Meaning fuel tank and line up to the disconnect point. That's good. Check the temp of your fuel pump too. How old is the pump? Is it possible it's failing?

[jeh]

Originally Posted by knomadd

Ok, we'll you've eliminated what was offline when using the gas can... Meaning fuel tank and line up to the disconnect point. That's good. Check the temp of your fuel pump too. How old is the pump? Is it possible it's failing?

Pump is new

[Xeen]

This sounds like a job for a engine expert to me.
I wish I had the experience to help you out on this.
I sent a message to a friend of mine about this issue, maybe he will have an idea of whats going on with it.

[Vic1947]

Originally Posted by jeh

...We looked at the sight glass in the carb and there was no fuel. So for some reason after it runs a while I'm losing fuel, we took the filter off and it did have some aluminum shavings in it. I suppose that happened when I had the filler neck raised up on the Boyd's tank. I took the fuel pump off and took it apart and cleaned it up too. Right now I'm draining all the gas out of the tank and I'm going to put an extra filter I have back at the tank also. Any suggestions guys?????

Based on your observations, Jason, fuel delivery is the likely culprit. Vapor lock is very rare in modern fuel systems. Even non-return style fuel pumps have enough volume and pressure to keep fuel flowing in high heat environments. The symptoms you describe [cold start okay, engine dies soon after] are consistent with the clues [low fuel in the carb bowls, aluminum shavings in the filter].

As with Occam's razor, the simplest solution is probably the right one. If the tank was modified and shavings are present in the filter, you need to flush every component in the fuel system. Where possible, use a coffee strainer or paint filter to monitor for particles at each step.

1. Drain the tank.
2. Purge the line with compressed air [or better yet, flush the line with clean fuel from a can using an external electric fuel pump - observing good safety practices of course].
3. Cycle clean fuel thru the fuel pump into a catch can.
4. Are you running a return line? If so, make sure it's connected, working and the line to the tank is clear by purging it with compressed air.
5. Purge the line from the fuel pump to the filter ahead of the dual feed.
6. Remove and purge the dual feed.
7. Remove front and rear fuel bowls and clean out any sediment or filings.
8. If the carb is equipped with fail safe wire screen filters, remove and clean them.
9. Reassemble the fuel system with clean filters and test.

I know you've done some of the steps above, you just have to be sure the source of the contamination doesn't keep recreating the problem. Putting in a filter back at the tank is a good start. Using a methodical, thorough approach to the entire system is the only way to eliminate it as the source of the failure. If the problem persists after flushing the fuel system, it may come down to a faulty fuel pump. A fuel pressure gauge at the dual feed would give you an indication of the system health up to that point. Barry Grant used to offer a vibration dampening, fluid filled gauge but there may be others out there as well. Good luck and keep us posted.

[jeh]

Originally Posted by Vic1947

Based on your observations, Jason, fuel delivery is the likely culprit. Vapor lock is very rare in modern fuel systems. Even non-return style fuel pumps have enough volume and pressure to keep fuel flowing in high heat environments. The symptoms you describe [cold start okay, engine dies soon after] are consistent with the clues [low fuel in the carb bowls, aluminum shavings in the filter].

As with Occam's razor, the simplest solution is probably the right one. If the tank was modified and shavings are present in the filter, you need to flush every component in the fuel system. Where possible, use a coffee strainer or paint filter to monitor for particles at each step.

1. Drain the tank.
2. Purge the line with compressed air [or better yet, flush the line with clean fuel from a can using an external electric fuel pump - observing good safety practices of course].
3. Cycle clean fuel thru the fuel pump into a catch can.
4. Are you running a return line? If so, make sure it's connected, working and the line to the tank is clear by purging it with compressed air.
5. Purge the line from the fuel pump to the filter ahead of the dual feed.
6. Remove and purge the dual feed.
7. Remove front and rear fuel bowls and clean out any sediment or filings.
8. If the carb is equipped with fail safe wire screen filters, remove and clean them.
9. Reassemble the fuel system with clean filters and test.

I know you've done some of the steps above, you just have to be sure the source of the contamination doesn't keep recreating the problem. Putting in a filter back at the tank is a good start. Using a methodical, thorough approach to the entire system is the only way to eliminate it as the source of the failure. If the problem persists after flushing the fuel system, it may come down to a faulty fuel pump. A fuel pressure gauge at the dual feed would give you an indication of the system health up to that point. Barry Grant used to offer a vibration dampening, fluid filled gauge but there may be others out there as well. Good luck and keep us posted.

Thanks Vic, I was hoping to here your thoughts on this. I am defiantly going to clean and purge the system like you said above. In the meantime I thing I figured it out. Last night I pulled the pump back off and checked the rod to make sure it was ok and moved freely, everything was good. This morning I put the pump back on and ran the hose to a can of gas and started it up. It fired right up like it should, I held the throttle around 1000 to 2000 rpm's till it died around 10 minutes later. As soon as it died I unhooked the fuel hose at the carb and ran it to an empty bottle. I unhooked the hot wire to the dist. and had my son crank it over. Crank, crank, crank and no fuel came into the bottle. So that should narrow it down to the pump being junk. Would you agree? Maybe the shavings ate up the pump?

[Vic1947]

Originally Posted by jeh

Crank, crank, crank and no fuel came into the bottle. So that should narrow it down to the pump being junk. Would you agree? Maybe the shavings ate up the pump?

That would be my guess if I were in your shoes. The diaphragm could have been damaged. Or, it's also possible you could still have a blockage upstream. Before I popped for a new pump, I'd disconnect the inlet hose and setup a temporary fuel line out of a fuel jug and crank it over again to see if that makes a difference. If not, you've found the problem. I think you're on the right track.

[jeh]

Thanks again Vic, I already jumped the gun and ordered a new pump for Summit Racing today....

[Vic1947]

Originally Posted by jeh

Thanks again Vic, I already jumped the gun and ordered a new pump for Summit Racing today....

I'd be surprised if that's not it, given what you've found so far. Not to sound like a broken record ...or a corrupted music download , but to avoid a repeat performance, a thorough cleanup and a filter between tank and pump will help protect the new piece. Good luck, your truck is awesome!

[jeh]

Originally Posted by Vic1947

I'd be surprised if that's not it, given what you've found so far. Not to sound like a broken record ...or a corrupted music download , but to avoid a repeat performance, a thorough cleanup and a filter between tank and pump will help protect the new piece. Good luck, your truck is awesome!

Thanks again Vic, I've been watching your build also, I don't know anybody that wouldn't want to own a truck that you've built. Very, very clean and meticulous work going on there. This afternoon I flushed out the tank and all of the lines to get ready for the new pump and new filter I'm going to put right out of the tank. Thanks for the help

[Bennett68C10]

Hopefully the new pump solves your problem Jason so you can get out on the road and enjoy that beautiful truck.

[mcbassin]

Hope you get the fuel problem sorted out. I'm ready for your burnout video.....

[nlped]

Beautiful truck. Sub'd

[jeh]

Originally Posted by Bennett68C10

Hopefully the new pump solves your problem Jason so you can get out on the road and enjoy that beautiful truck.

I should find out tomorrow evening after work if this is the fix...

Originally Posted by mcbassin

Hope you get the fuel problem sorted out. I'm ready for your burnout video.....

I promise, when I get things sorted out I'll post a video.

Originally Posted by nlped

Beautiful truck. Sub'd

Thanks man

[jeh]

Put new pump on this evening and new filter between the tank and pump. Fired the ole girl up and still have the same problem I don't know what else to do. I felt the fuel lines around the front of the motor and the closest place at the exhaust and no where was even very warm so I don't know if it vapor lock or not. Confusion, confusion!!!!!

[sduckworth13]

Dang, sorry to hear that you can't get this sorted out. I wonder if the issue might be related to the alternator. I remember you had a issue with it awhile back. Is it charging ok? I wonder if it has anything to do with the your electrical system? I wish I could be more help.

[nlped]

^^^ I was thinking along the same lines, but the distributor. I had an hei that acted like this when it got hot, but when cooled off...no problems? But you say you loose fuel pressure with heat?, or am I dreaming?

[Vic1947]

So, when the problem reoccurred, did you unhook the fuel line at the dual feed inlet and crank the engine over like you did before? As I recall, you said no fuel was coming out of the original pump when the engine died and you spun it over with the starter. If that's still true, I wonder if there's something in the tank like a piece of paper sitting next to the fuel fitting. Gets sucked up against the fitting and restricts it while running but falls away and allows fuel to flow after it sits and equalizes. Grabbing at straws here.

If the new pump fails to put out fuel with the line disconnected and cranking the engine over, you might also remove the pump again and manually rotate the engine while holding pressure against the pump rod to verify the pump lobe on the cam is good.

Don't know. If you confirm the fuel pump is working and the fuel bowls in the carb are now full, it's gotta be something else.

[Xeen]

When you used the gas can to try to eliminate potential sources of the problem was there a fuel filter in between the gas can and the pump?
If so eliminate the fuel filter and try this again.
I have seen fuel filters do exactly what you are describing.
Have you tried eliminating the entire fuel supply line and put your gas can right next to the fuel pump at the front of the truck?
You need to get to the point where you have successfully eliminated the fuel supply system as a possible source of the problem.

[knomadd]

I agree with the statements above... Check to see if you can narrow it down to before or after the pump. Hopefully it's not both. If you disconnect the pump from the carb and still get no fuel when cranking, it's obviously before the pump. I'd suggest checking for debris again. Clogged filter, or fuel tank outlet, etc.

If your problem is happening between the tank and pump, then it's likely not vapor lock. Unless it's really close to your exhaust, but even then, probably a stretch.

If it looks like the problem is between the pump and carb, then (if the pump checks out as good) it could be a filter, clogged or dirty fuel line, possibly filter in carb (not familiar with QFT carbs, so there may or may not be a filter element in the fuel inlet), or possibly the intake is so hot the fuel bowls are boiling the fuel. I didn't see a carb spacer. If your problem seems to be near the carb, try adding a spacer between the carb and intake. This would only make a difference if you're seeing very hot engine temps, or high engine bay ambient temps.

Sorry I didn't read through everything (I'm at work) but I'm assuming you're using a mechanical pump. If it's electric, check to make sure your wires are good.

[mcbassin]

Sorry if I missed it, but did you replace the filter at the carb too? Can you add a pressure gage inline to see if you are getting a drop when symptom returns? I know you have a nice looking hard line, so that may be difficult.

[jeh]

Originally Posted by sduckworth13

Dang, sorry to hear that you can't get this sorted out. I wonder if the issue might be related to the alternator. I remember you had a issue with it awhile back. Is it charging ok? I wonder if it has anything to do with the your electrical system? I wish I could be more help.

It seems to charging OK

Originally Posted by nlped

^^^ I was thinking along the same lines, but the distributor. I had an hei that acted like this when it got hot, but when cooled off...no problems? But you say you loose fuel pressure with heat?, or am I dreaming?

With the old "new" pump, when it ran for a while and died I had no fuel going to the carb. I haven't looked into the new one that far.

Originally Posted by Vic1947

So, when the problem reoccurred, did you unhook the fuel line at the dual feed inlet and crank the engine over like you did before? As I recall, you said no fuel was coming out of the original pump when the engine died and you spun it over with the starter. If that's still true, I wonder if there's something in the tank like a piece of paper sitting next to the fuel fitting. Gets sucked up against the fitting and restricts it while running but falls away and allows fuel to flow after it sits and equalizes. Grabbing at straws here.

If the new pump fails to put out fuel with the line disconnected and cranking the engine over, you might also remove the pump again and manually rotate the engine while holding pressure against the pump rod to verify the pump lobe on the cam is good.

Don't know. If you confirm the fuel pump is working and the fuel bowls in the carb are now full, it's gotta be something else.

Vic, I was aggravated last night so I didn't check out anything.

Originally Posted by Xeen

When you used the gas can to try to eliminate potential sources of the problem was there a fuel filter in between the gas can and the pump?
If so eliminate the fuel filter and try this again.
I have seen fuel filters do exactly what you are describing.
Have you tried eliminating the entire fuel supply line and put your gas can right next to the fuel pump at the front of the truck?
You need to get to the point where you have successfully eliminated the fuel supply system as a possible source of the problem.

I tried that with the old"new" pump. I ran about a two foot hose from the pump to a can of gas and eliminated the filter between the pump and carb, that's when I was convicted the pump was bad.

Originally Posted by knomadd

I agree with the statements above... Check to see if you can narrow it down to before or after the pump. Hopefully it's not both. If you disconnect the pump from the carb and still get no fuel when cranking, it's obviously before the pump. I'd suggest checking for debris again. Clogged filter, or fuel tank outlet, etc.

If your problem is happening between the tank and pump, then it's likely not vapor lock. Unless it's really close to your exhaust, but even then, probably a stretch.

If it looks like the problem is between the pump and carb, then (if the pump checks out as good) it could be a filter, clogged or dirty fuel line, possibly filter in carb (not familiar with QFT carbs, so there may or may not be a filter element in the fuel inlet), or possibly the intake is so hot the fuel bowls are boiling the fuel. I didn't see a carb spacer. If your problem seems to be near the carb, try adding a spacer between the carb and intake. This would only make a difference if you're seeing very hot engine temps, or high engine bay ambient temps.

Sorry I didn't read through everything (I'm at work) but I'm assuming you're using a mechanical pump. If it's electric, check to make sure your wires are good.

I've cleaned and double cleaned the lines and filters and tank. I worked late this evening so I haven't messed with it anymore. It is a mechanical pump.

Originally Posted by mcbassin

Sorry if I missed it, but did you replace the filter at the carb too? Can you add a pressure gage inline to see if you are getting a drop when symptom returns? I know you have a nice looking hard line, so that may be difficult.

Mike, I do have a port at the "tee" where both lines go into the carb. I thought about a pressure gauge today also.

[Xeen]

Wow this is the craziest thing.
Vic and I were talking about it this morning and he mentioned possibly a flat lobe on the cam, but if this is a brand new cam I can't imagine that being the problem unless the cam was improperly cast but hey stranger things have happened.
I tell ya man I'm half tempted to recommend that you say to hell with it and get an electric fuel pump

[nlped]

Check the fuel pressure... If the pressure drops away, pull & check the fuel pump pushrod. Sounds dumb, but it may be worn and when the truck warms up and the demand increases a bit and the pump isn't being fully articulated.

Edit...another note...make SURE you have a big block fuel pump on there. If it actually has a small block pump, it isn't being actuated completely. I just went through that on my "new" camper, Chubby. Worth a look.

[Xeen]

Originally Posted by nlped

Check the fuel pressure... If the pressure drops away, pull & check the fuel pump pushrod. Sounds dumb, but it may be worn and when the truck warms up and the demand increases a bit and the pump isn't being fully articulated.

Edit...another note...make SURE you have a big block fuel pump on there. If it actually has a small block pump, it isn't being actuated completely. I just went through that on my "new" camper, Chubby. Worth a look.

^^^ This is good stuff!

[jeh]

Originally Posted by Xeen

Wow this is the craziest thing.
Vic and I were talking about it this morning and he mentioned possibly a flat lobe on the cam, but if this is a brand new cam I can't imagine that being the problem unless the cam was improperly cast but hey stranger things have happened.
I tell ya man I'm half tempted to recommend that you say to hell with it and get an electric fuel pump

Originally Posted by nlped

Check the fuel pressure... If the pressure drops away, pull & check the fuel pump pushrod. Sounds dumb, but it may be worn and when the truck warms up and the demand increases a bit and the pump isn't being fully articulated.

Edit...another note...make SURE you have a big block fuel pump on there. If it actually has a small block pump, it isn't being actuated completely. I just went through that on my "new" camper, Chubby. Worth a look.

Guys, I'm open for any suggestions at this point. Xeen, I do know that sometimes a person can get a bad part but this is some of what is pissing me off, I have a lot of money invested in this motor ( probably could have bought a crate motor cheaper) and every piece of it is brand new except the block and crank. We "broke it in" on the engine stand and everything was great, I've started it up and pulled in and out of the garage several times, no problems. Now that I'm ready for a drive nothing is working out nlped, the pump I bought from Summit Racing was listed for a big block, the push rod is a carbon fiber or something of that nature and Is supposed to be very cam friendly and almost indestructible, so the reviews say... I haven't checked the fuel pressure yet though. It's hard to make time for everything, we are working 7 days a week now and the parts stores around here don't have s**t. I almost have to order anything in the performance line from Summit or Jegs. A buddy of mine called me this evening and said he had a brand new carb I could throw on and try one evening. We'll see what happens. Thanks guys, I appreciate any suggestions.