1987 F250 4x4 Build Thread
#31
04-29-2015, 11:35 AM
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With a new fuel regulator, I'm still not able to get above 4 psi. I am going to check pressure at the pump tonight and see if that's all I'm getting. Can anybody tell me what the pressure should be? The truck was originally EFI, so I would think it would be a lot higher, but I have no idea if the pump was swapped out when the engine was. If a low pressure pump was put in, what pressure do those typically put out? I am thinking about just going aftermarket/universal and putting a single pump & regulator on the frame. What would I need to do to the in-tank pump to allow gas to flow freely through it, assuming I disconnect the wiring. I really just want to use it as a fuel pick-up.
Keep in mind that all the fuel pressure needs to do with a carb is get the float bowl full. As long as there's enough pressure to lift the fuel to the carb you've got enough pressure.
I suppose where you have the fuel pressure sensor would make a difference. 2 psi at the frame rail would be less pressure than 2 psi at the carb. My pressure sensor is at the carb.
But I can't see your 4 psi being a problem.
#32
04-29-2015, 12:02 PM
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I have a cheap electric fuel pressure gage on my Bronco (can't swear to its accuracy) and I get 2 psi with no problems.
Keep in mind that all the fuel pressure needs to do with a carb is get the float bowl full. As long as there's enough pressure to lift the fuel to the carb you've got enough pressure.
I suppose where you have the fuel pressure sensor would make a difference. 2 psi at the frame rail would be less pressure than 2 psi at the carb. My pressure sensor is at the carb.
But I can't see your 4 psi being a problem.
Keep in mind that all the fuel pressure needs to do with a carb is get the float bowl full. As long as there's enough pressure to lift the fuel to the carb you've got enough pressure.
I suppose where you have the fuel pressure sensor would make a difference. 2 psi at the frame rail would be less pressure than 2 psi at the carb. My pressure sensor is at the carb.
But I can't see your 4 psi being a problem.
#33
04-29-2015, 12:48 PM
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#34
04-29-2015, 01:15 PM
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Have you checked fuel volume. that's a big must with most any carburetor including yours because theirs plenty of combinations to play with to get psi even just taking a reading but volume will be cut and dry either its good or its bad. how did you set and adjust your timing?
As far as timing goes, I used a timing light and set it to 10* advanced.
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04-29-2015, 01:37 PM
#37
04-29-2015, 03:11 PM
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Measuring fuel flow in to a bucket would be your best choice that's what id do and what a lot of people do. If the truck is popping or pining that sounds like a timing issue especially if it happened as soon as you replaced the distributor. How does it run if you disconnect the advance on it. The guys truck in the video sounds like he got the cam that had flames on the box.
#38
04-29-2015, 03:28 PM
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Measuring fuel flow in to a bucket would be your best choice that's what id do and what a lot of people do. If the truck is popping or pining that sounds like a timing issue especially if it happened as soon as you replaced the distributor. How does it run if you disconnect the advance on it. The guys truck in the video sounds like he got the cam that had flames on the box.
#39
04-29-2015, 03:40 PM
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#40
04-29-2015, 03:50 PM
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When I got the truck, the SPOUT was hooked up to manifold vacuum. It ran fine, but the timing at idle was way more advanced than when unhooked. With the current new distributor and vacuum hooked up to the right spot, there is no difference between unhooked/hooked up SPOUT. I may try hooking it back up to manifold vacuum and see if that changes anything. Is there any way to check vacuum advance under load without making my wife ride under the hood with a timing light?
#41
04-29-2015, 03:52 PM
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#43
04-29-2015, 04:13 PM
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Did you drive the truck with it un hooked or just at an idle. All you want your vacuum advance to do is keep the engine happy when you put your foot down on the throttle or under load at moderate rpm. if it runs fine unhooked then you can save your wife an adventure 
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something like that sounds possible you could verify by comparing the crank pulley to piston position . sorry for the double post i tried to add to it and i hit post instead of edit.
.something like that sounds possible you could verify by comparing the crank pulley to piston position . sorry for the double post i tried to add to it and i hit post instead of edit.
#45
04-29-2015, 04:47 PM
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1977 F-150 4x4 Burnout - YouTube
I hope that my truck will be doing this soon. Right now though, I'd be happy with a smooth acceleration. A man can dream, right?
I hope that my truck will be doing this soon. Right now though, I'd be happy with a smooth acceleration. A man can dream, right?
I am going to sit back and see where your problem leads as I don't know carbs that well but I am hoping our next brick will be a 87 F250 4x4 ZF5 460 super cab that I am looking at (last year of the brick I need to complete my collection).
Trav