The Ford Barn

Admiral · 09-27-2014, 03:13 PM

Guys,

Slowly but surely I'm working the bugs out of my "new" 1936 sedan. At long last the brakes are adjusted reasonably well, the points are set properly and it got a brand-new cap and rotor. She seems to run really well but now I've got a new intermittent problem and I think it's fuel starvation but I want some Ford Barn Experts® to chime in (that's YOU

).

The issue seems to happen when I'm driving in high gear at, let's say, 30 miles an hour. If I roll on the accelerator to wide-open throttle in order to get moving the car will pull just fine. But once I get around 45 or 50 MPH it stops accelerating and falls totally flat. In fact this afternoon it outright quit on me and I had to coast into a subdivision to stop.

Now in situations like this, which have happened a few times so far since I've been shaking the car down, if I hit the momentary switch for the inline electric fuel pump the engine seems to stop stumbling altogether and continue accelerating. Also, I've checked the inline fuel filter and it's clean as a whistle (very easy to blow through). Is something wrong with my mechanical fuel pump? Does the pushrod need to be made longer or is there some sort of other adjustment? It was professionally rebuild by the guy that did the engine.

Thanks!

- Craig

Admiral · 09-27-2014, 03:31 PM

Oh, and three other points I forgot to mention in my previous post.

1) I'm running a later-style (not sure which year) mechanical pump with a glass sediment bowl.

2) I installed the inline electric pump ONLY for priming and to help with vapor lock. I want the car to run exclusively on the mechanical pump.

3) Speaking of vapor lock, I DO NOT think this is the problem. The weather's only in the 70s and when I touch the mechanical pump after the stumbling problem happens it's barely warm to the touch.

Thanks!

Ken/Alabama · 09-27-2014, 03:46 PM

The electric pump could be causing the mechanical pump to starve. Some electric pumps will cause a restriction on the suction side of the mechanical pump. If that's not the problem it's gonna be the mechanical pump itself.

ford38v8 · 09-27-2014, 04:01 PM

Craig, I've had exactly the same thing happen to me. Fixed it at the side of the road by crawling under and tightening the hose clamps on the filter/fuel pump. It's as simple as that, there is a small air leak at a connection, which will not leak gas but will suck in enough air to make the mechanical pump work overtime to barely keep the engine running until it requires more fuel than the pump is able pull along with the air leak.

Look there, and also look at the flex line on the firewall, and look at the cork gasket on the glass bowl, as well as the cork gasket on the fuel pump, and the fiber gsasket at the top of the fuel pump. These are all the locations that will suck air, and likely the last one you monkeyed with is the culprit.

WestCoast · 09-27-2014, 05:05 PM

well you have a fuel problem, because the engines runs better when the electric pump is on, first plug the fuel at the carb, turn on electric pump and check the fuel line from the tank to the carb, any leaks will show up as dripping fuel or a wet spot on the fuel line, check fuel pressure at carb, it should be around 2 to 2 1/2#, if not take a good look at the mechanical pump, it probably defective, and check float level in carb, if its to low there wont be enough fuel in carb to keep engine running at high speed or on hard pulls

George/Maine · 09-27-2014, 05:20 PM

Sponsored Links (Register now to hide all advertisements)

Blow the line back to tank and remove electric pump ,one or the other not both.

ford38v8 · 09-27-2014, 05:57 PM

Hey guys, have you ever heard of the KISS method? I'll stick to my original diagnosis.

George/Maine · 09-27-2014, 06:34 PM

I just had a problem like that.
I removed the top of carb and removed all the dirt in bowl.
Blow it out and is running good now.

Bruce Compton, Canada · 09-27-2014, 08:54 PM

You mentioned that you are using a fuel pump with the glass bowl, so check the mating surface where the glass bowl meets the fuel pump. Overtightening the clamp often pulls down two sides of the top enough that the gasket can't make a 360 degree seal and the pump will suck air although the minor fuel leak evaporates before you can trace it. Remove the gasket and see if the glass bowl rocks back and forth on the bare metal surface. I've straightened lots of them out very carefully with a small press. Good luck : Bruce

4dFord/SC · 09-27-2014, 10:15 PM

The electric pump should have a fuel filter; check to see that it is not clogged with debris from the tank.

supereal · 09-28-2014, 01:28 PM

I had the same problem. It got so bad that the inline electric pump didn't help. It turned out to be a partially clogged fuel line between the tank and the firewall. My best guess is that the alcohol in today's gas found holes in the copper coating, causing rust to build up.' as I run a big inline filter near the tank to catch crud from there. I would have saved lots of time and money by spending $20 on a new line.

09-27-2014, 03:13 PM	#1
Admiral Senior Member Join Date: Jul 2011 Location: Oakland County, Michigan Posts: 562	Fuel starvation or something else? Guys, Slowly but surely I'm working the bugs out of my "new" 1936 sedan. At long last the brakes are adjusted reasonably well, the points are set properly and it got a brand-new cap and rotor. She seems to run really well but now I've got a new intermittent problem and I think it's fuel starvation but I want some Ford Barn Experts® to chime in (that's YOU ). The issue seems to happen when I'm driving in high gear at, let's say, 30 miles an hour. If I roll on the accelerator to wide-open throttle in order to get moving the car will pull just fine. But once I get around 45 or 50 MPH it stops accelerating and falls totally flat. In fact this afternoon it outright quit on me and I had to coast into a subdivision to stop. Now in situations like this, which have happened a few times so far since I've been shaking the car down, if I hit the momentary switch for the inline electric fuel pump the engine seems to stop stumbling altogether and continue accelerating. Also, I've checked the inline fuel filter and it's clean as a whistle (very easy to blow through). Is something wrong with my mechanical fuel pump? Does the pushrod need to be made longer or is there some sort of other adjustment? It was professionally rebuild by the guy that did the engine. Thanks! - Craig

09-27-2014, 03:31 PM	#2
Admiral Senior Member Join Date: Jul 2011 Location: Oakland County, Michigan Posts: 562	Re: Fuel starvation or something else? Oh, and three other points I forgot to mention in my previous post. 1) I'm running a later-style (not sure which year) mechanical pump with a glass sediment bowl. 2) I installed the inline electric pump ONLY for priming and to help with vapor lock. I want the car to run exclusively on the mechanical pump. 3) Speaking of vapor lock, I DO NOT think this is the problem. The weather's only in the 70s and when I touch the mechanical pump after the stumbling problem happens it's barely warm to the touch. Thanks!

09-27-2014, 03:46 PM	#3
Ken/Alabama Senior Member Join Date: May 2010 Location: Alabama Posts: 3,395	Re: Fuel starvation or something else? The electric pump could be causing the mechanical pump to starve. Some electric pumps will cause a restriction on the suction side of the mechanical pump. If that's not the problem it's gonna be the mechanical pump itself.

09-27-2014, 04:01 PM	#4
ford38v8 Senior Member Join Date: Jul 2011 Location: SF Bay Area Posts: 7,285	Re: Fuel starvation or something else? Craig, I've had exactly the same thing happen to me. Fixed it at the side of the road by crawling under and tightening the hose clamps on the filter/fuel pump. It's as simple as that, there is a small air leak at a connection, which will not leak gas but will suck in enough air to make the mechanical pump work overtime to barely keep the engine running until it requires more fuel than the pump is able pull along with the air leak. Look there, and also look at the flex line on the firewall, and look at the cork gasket on the glass bowl, as well as the cork gasket on the fuel pump, and the fiber gsasket at the top of the fuel pump. These are all the locations that will suck air, and likely the last one you monkeyed with is the culprit. __________________ Alan

09-27-2014, 05:05 PM	#5
WestCoast Senior Member Join Date: Sep 2014 Location: oroville calif Posts: 892	Re: Fuel starvation or something else? well you have a fuel problem, because the engines runs better when the electric pump is on, first plug the fuel at the carb, turn on electric pump and check the fuel line from the tank to the carb, any leaks will show up as dripping fuel or a wet spot on the fuel line, check fuel pressure at carb, it should be around 2 to 2 1/2#, if not take a good look at the mechanical pump, it probably defective, and check float level in carb, if its to low there wont be enough fuel in carb to keep engine running at high speed or on hard pulls

09-27-2014, 05:20 PM	#6
George/Maine Senior Member Join Date: May 2010 Location: Mid coast Maine Posts: 1,878	Re: Fuel starvation or something else? Sponsored Links (Register now to hide all advertisements) Blow the line back to tank and remove electric pump ,one or the other not both.

09-27-2014, 05:57 PM	#7
ford38v8 Senior Member Join Date: Jul 2011 Location: SF Bay Area Posts: 7,285	Re: Fuel starvation or something else? Hey guys, have you ever heard of the KISS method? I'll stick to my original diagnosis. __________________ Alan

09-27-2014, 06:34 PM	#8
George/Maine Senior Member Join Date: May 2010 Location: Mid coast Maine Posts: 1,878	Re: Fuel starvation or something else? I just had a problem like that. I removed the top of carb and removed all the dirt in bowl. Blow it out and is running good now.

09-27-2014, 08:54 PM	#9
Bruce Compton, Canada Senior Member Join Date: May 2010 Posts: 426	Re: Fuel starvation or something else? You mentioned that you are using a fuel pump with the glass bowl, so check the mating surface where the glass bowl meets the fuel pump. Overtightening the clamp often pulls down two sides of the top enough that the gasket can't make a 360 degree seal and the pump will suck air although the minor fuel leak evaporates before you can trace it. Remove the gasket and see if the glass bowl rocks back and forth on the bare metal surface. I've straightened lots of them out very carefully with a small press. Good luck : Bruce

09-27-2014, 10:15 PM	#10
4dFord/SC Senior Member Join Date: May 2010 Location: Columbia, SC Posts: 1,579	Re: Fuel starvation or something else? The electric pump should have a fuel filter; check to see that it is not clogged with debris from the tank.

09-28-2014, 01:28 PM	#11
supereal Senior Member Join Date: Jul 2014 Location: Iowa Posts: 1,634	Re: Fuel starvation or something else? I had the same problem. It got so bad that the inline electric pump didn't help. It turned out to be a partially clogged fuel line between the tank and the firewall. My best guess is that the alcohol in today's gas found holes in the copper coating, causing rust to build up.' as I run a big inline filter near the tank to catch crud from there. I would have saved lots of time and money by spending $20 on a new line.