Lift pump pressure questions
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Lift pump pressure questions
So I got a 06 5.9 with one of those Fass 100 Titanium series pumps and it's not old at all but I've noticed that when the key is in the on position, (not cranking), sometimes my gauge shows its got pressure ( usually when it's cold outside) and sometimes it shows 0 ( usually when it's warm), so I guess my question is is that typical behavior for lift pump pressure? Any thoughts would be appreciated.
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From: Whitehorse, cultural hub of the universe..
Since you have a gauge, bump the starter,
without starting the engine, and see if the lift pump runs. It should spool up for 20-30 seconds then shut off. If it’s working, you’ll get a pressure reading.
without starting the engine, and see if the lift pump runs. It should spool up for 20-30 seconds then shut off. If it’s working, you’ll get a pressure reading.
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Okay tried it and everything works accordingly. Still wonder if you're supposed to have pressure at the injection pump before you crank everything time or if it matters as long as it's pumping fuel while cranking and running.
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From: Whitehorse, cultural hub of the universe..
As long as it has pressure while cranking and running, you should be good.
some residual pressure is held in the system while shut off. So the pressure rise is almost instant
some residual pressure is held in the system while shut off. So the pressure rise is almost instant
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I suppose. I've had this starting problem with it for some time and I've figured that maybe it has something to do with the fuel delivery to the engine. Usually happens after its sat long enough. It'll act like it's getting ready to fire and then it's like it loses something and misfires. But once the pump is actually running longer than a few seconds it fires off pretty well. I kinda wonder if it's possible to have a leak on the suction straw on the sending unit. I did the thing where you modify the factory one instead of getting an aftermarket one.
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It’s not normal for the lift pump pressure to vary like that. The pressure should be steady when the key is on, even when it's not cranking. The issue could be with the pump, the gauge, or connections. It’s a good idea to have the pump and gauge checked to find out what might be causing the problem
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LomaBrekke, SarahChavez and RanniWins, I challenge all of you to completely fill in your profile. Tell us what trucks you are driving, where you live etc. Personally I do not believe that you are human. Anybody else suspect the same thing? What is the point of questions such as "Any update" or "All good now"?
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LomaBrekke, SarahChavez and RanniWins, I challenge all of you to completely fill in your profile. Tell us what trucks you are driving, where you live etc. Personally I do not believe that you are human. Anybody else suspect the same thing? What is the point of questions such as "Any update" or "All good now"?
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So I've tried a few things since I last posted. Switching the tube's didn't do anything BTW but I put a new banjo bolt check valve and banjo washers on the back of the head thinking I may be losing vacuum and that didn't work. And I thought maybe there's something wrong with my tuner so I turned it back to stock to see if that would work and still kept happening. So I was wondering if it's possible if there's something wrong with the APP sensor. Would that cause it to misfire or stumble on startup every once in a while?
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