injection pump timing quick question

renjaminfrankln

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Unfortunately I am still having a bit of an issue with it. The truck runs and drives great, it starts fine and everything else seems good. Good power, no smoke unless I stomp on the pedal. No water in oil and no oil in coolant. Pressure gauge indicates 4psi at idle at the filter head. I'm going to double check, but no visible leaks.

I am still having a problem with it not wanting to settle down to a nice idle. Its better than it was, when the truck is warm I can chop the throttle at 2000 RPM and it will almost, but not stall. Previously the truck would stall right out. It also had problems holding a constant RPM, however those problems are solved now with the new IP. (The RPM wandering in the video is just me)

When I got the truck it did not do this, you could chop the throttle and it would settle right down to 650-700 RPM. Here in the video you can see it drops well below 650, almost stalls, and then comes back up. The truck is warm in the video, I drove it around until it reached normal operating temp.

I did get the air box chopped and I was waiting on a new air filter before I could drive it.


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Thewespaul

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Can you operate the throttle under the hood and watch the fuel pressure as you change the throttle?
 

renjaminfrankln

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Can you operate the throttle under the hood and watch the fuel pressure as you change the throttle?

This is with the old injection pump. I haven't changed anything except the IP and the hard line from the IP to filter head (I replaced the one you see in the video with the clear hose with a brand new line from Ford). I can easily re-install the pressure gauge and repeat this test if you think it could be an issue.

You can see it holds around 4 PSI. IT is interesting to note a quick drop in pressure when the throttle is let off.

The lift pump and the fuel filter were replaced a few weeks before I started having this problem.

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icanfixall

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What type of injectors and where did you purchase them from if they too got replaced? Might be a fuel line restriction issues too.Sometimes the fuel tank suction heads break up. Then get sucked into the lines causing restrictions to flow and volume. Main place pieces get trapped in the fuel tank switching valve. Its a horrible messy job removing this valve and then you drill out the body rivets. To fit the rivets you just buy some self tapping screws. There is a tutorial on how to open these and clean out the trash if any is found. But dropping both tanks is the best idea for cleaning out the broken pieces. Dropping a full tank is impossible too so run the tanks down to 1/4 level. Even then its still hard as hell to drop. Fuel moves all over the tanks. The side tanks is simple to drop. The rear tank is horrible. You need to cut loose the fuel lines running across the frame rails so there is more room to work as the tanks drops.
 

Thewespaul

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What is it idling at? I can’t really see in the video from my phone screen. You may try turning the idle up to 750 or 800 and see if the droop goes away, it may need to be driven a bit to clear up any calibration fluid still in the pump. How old is the fuel in the tanks?
 

renjaminfrankln

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Gary, fuel supply lines are new from the FSV forward. I do not suspect a restriction as it pulls great through the gears. Injectors were recently pop tested and balanced.

It is idling around 700 - my tach matches what Gary's Tach-N-Time unit says.

Fuel can't be more than a month old. It looks clear and clean.

I have not driven it much. Just enough to get it fully warmed up. A couple miles around town. I will turn the idle up a bit and drive it more.
 

Thewespaul

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Keep us posted Ren, these types of issues are really hard to detect on a test stand where your rpms are static and you set up your fueling at each rpm level, but with how that thing specd out with the hot cranking I was concerned with the condition of the core they sent me, if it turns out this one isn’t useable I will build you another pump, as I said when we talked on the phone if this pump was set at the stock na calibration it wouldn’t have made hot cranking fuel spec and it wouldn’t have been a rebuildable core.
 

renjaminfrankln

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Keep us posted Ren, these types of issues are really hard to detect on a test stand where your rpms are static and you set up your fueling at each rpm level, but with how that thing specd out with the hot cranking I was concerned with the condition of the core they sent me, if it turns out this one isn’t useable I will build you another pump, as I said when we talked on the phone if this pump was set at the stock na calibration it wouldn’t have made hot cranking fuel spec and it wouldn’t have been a rebuildable core.

Thanks. As much as I don't want to pull the pump off again I am pretty damn quick at it now.

I'll drive it tonight and put the fuel pressure gauge back on it.
 

Thewespaul

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Hopefully we don’t have to pull it off, this is the first time I’ve had an issue with any of my pumps, and I’d like to keep that record!
 

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