Is this normal?!

[conlyn]

https://youtu.be/Ml8ai7-hnAo

Running in circles with this thing. Seriously about to set fire to it.
Thought this was abnormal prior to the racetronix pump harness and accufab regulator.

Seriously have no ideas at the point, only thing I can think of is possibly a bad injector?

 

[ItsMyTy]

Re: Is this normal?!

try a non-harbor freight gauge.

the injectors are batch fire, resulting in the large pressure drop you are seeing. a better gauge may have more dampening in the readout.

 

[Slyclone]

Re: Is this normal?!

Probably, a piece of shit fuel pump or one that's dieing?

I believe that's called hammering.

I was just digging through the bed of my syclone and found the gauge box ( hypertech fuel pressure gauge can be found through jegs, or amazon?). It describes a few conditions on the actual gauge box and hammering was actually one I remember. I high lighted it on the box. I saw the same thing before.

I replaced my pump a while back.. I did see this hammering as mentioned. Something to think about. The fuel gauge should be where you set it. None of that jumping around. Under load fuel pressure should rise. Its normal to see it go UP when driving.

I don't know if it helps but you can start there.

 

[conlyn]

Re: Is this normal?!

It has a band new racetronix pump as stated in the first post, and the gauge is good put it on my brothers new truck and it's smooth as butter

 

[Slyclone]

Re: Is this normal?!

Something is not right. Did you skip a step? How about the high pressure pulsation dampner??

I did not read the first post. Is it a pump? Or the little wire splice kit to run full power to your pump?

Just watched your video. Doesn't look good. Check your grounds

 

[conlyn]

Re: Is this normal?!

I did a pump and harness afrp , it was doing this prior to and didn't change anything

 

[conlyn]

Re: Is this normal?!

Would a bad pump cause this? Like I said in the first post it was doing the same prior to installing all new parts in the fuel system. The only thing left stock now are the lines and injectors, anyone have any idea of how I can trouble shoot this without throwing more parts into it

 

[ItsMyTy]

Re: Is this normal?!

It has a band new racetronix pump as stated in the first post, and the gauge is good put it on my brothers new truck and it's smooth as butter

Is your brother's new truck a syty with batch fire injectors?

 

[gringo76]

Re: Is this normal?!

mine done that once when I had a leak. could be any where, in the tank from pump to hat and all the way to the rails. mine ended up being a ripped o-ring at the hat to fuel line. fuel gauge did the same thing.

 

[conlyn]

Re: Is this normal?!

mine done that once when I had a leak. could be any where, in the tank from pump to hat and all the way to the rails. mine ended up being a ripped o-ring at the hat to fuel line. fuel gauge did the same thing.

Can you describe better where you're talking about? Already not stoked on dropping the tank again. Really hoping its something simple and not a faulty pump or anything.

Btw forgot to mention that fuel pressure bleeds off from 40lbs to around 30 shortly after killing the motor but takes a while to bleed down lower than that m m. Kinda why I was thinking it would be a injector leaking down

 

[gringo76]

Re: Is this normal?!

Can you describe better where you're talking about? Already not stoked on dropping the tank again. Really hoping its something simple and not a faulty pump or anything.

Btw forgot to mention that fuel pressure bleeds off from 40lbs to around 30 shortly after killing the motor but takes a while to bleed down lower than that m m. Kinda why I was thinking it would be a injector leaking down

my fuel pressure gauge did the exact same thing. bounced up and down and when key off fuel pressure would start to drop over a couple mins. mine had a ripped o-ring on the feed fuel line at the fuel hat. I replaced o-ring and fuel pressure is rock solid and when key off fuel pressure holds for 20 mins or so and slowly drops. cant say for sure yours is the same issue but sounds like you might have a leak some where, could be in the rubber hose in tank between pump and hat or even bad pump. I would check everything before dropping tank like fpr, all fitings. you could even with a little work pull upper intake off and pull fuel rail up leaving the injectors in fuel rail and key on to check them. I belive the injectors have retainers on them so they will not blow off with the fuel pressure but verify it first. if you just installed the racetronics pumps chances are its somewhere in the tank. I had those once. the y block for the dual pumps are a little weird as to having a positive position and if I remember there are two diff size O-rings in that y block. one for main line and smaller ones for pumps. make sure they are not backwards, that might cause a leak

 

[Static]

Re: Is this normal?!

Mine does this.

 

[Eric Sy GN]

Re: Is this normal?!

I'm not saying you don't have a problem, but like ItsMyTy said, its not uncommon with batch fire. Also, since we remove the pulsator in the tank with new fuel pumps, it can make it worse. I would use a liquid filled gauge to dampen it.
Eric

 

[SEL777]

Re: Is this normal?!

Did you check the filter yet like mentioned on the FB thread?

 

[gringo76]

Re: Is this normal?!

Only the fuel pressure regulator can cause that. Liquid doesn't compress. So when the injectors open, pressure falls. When they close, pressure rises. Only the pressure regulator can react to the pressure change and on most engines the pressure is pretty smooth, but on your engine it isn't. Only one component can influence pressure change and react to it. The fuel pressure regulator.

Way back, early EFI systems like Bosch had accumulators in them to keep system pressure steady, and hold a reserve of pressure to assist with hot restart. Modern systems rely on the limited volume within the pressure regulator to act as the accumulator. The diaphragm depresses the spring for a bit of volume before it opens at the relief pressure. That volume is the accumulator portion. That's why pressure holds after turning off the pump. Once the regulator spring has completely extended, there is no more pressure.

When evaluating pressure in liquids, it is important to keep in mind that liquids don't compress. So any residual pressure is being applied by another source. Like the spring in the pressure regulator. It's not like air in a tire. Air compresses.

Sounds logical but mine had a leaking o ring and did the same thing. True story , not saying it's his prob just a possibility.

 

[conlyn]

Re: Is this normal?!

So I should set fuel pressure with the motor not running and the fuel pump jumped?
Reason I'm asking is that I've replaced every hard part on the system and am still getting terrible motor response I barely wants to rev over 3 grand and yes I've also replaced the entire ignition and set the timing to 0 with the tan wire unhooked. I'm at a loss as to why it's being so temperamental and I was really trying to get this thing running stock before I added anymore parts to it, I do have a set of 60 pound injectors and a 3 bar I was going to add to it when I had everything running right but I'm thinking that maybe getting a TT chip to run them and see if it is indeed an injector issue good idea or bad?

 

[conlyn]

Re: Is this normal?!

And it was doing the same with the stock fpr before I added the accufab unit so I don't think it's that?

 

[gringo76]

Re: Is this normal?!

So I should set fuel pressure with the motor not running and the fuel pump jumped?
Reason I'm asking is that I've replaced every hard part on the system and am still getting terrible motor response I barely wants to rev over 3 grand and yes I've also replaced the entire ignition and set the timing to 0 with the tan wire unhooked. I'm at a loss as to why it's being so temperamental and I was really trying to get this thing running stock before I added anymore parts to it, I do have a set of 60 pound injectors and a 3 bar I was going to add to it when I had everything running right but I'm thinking that maybe getting a TT chip to run them and see if it is indeed an injector issue good idea or bad?

I always set fp with motor running at idle and pull off vaccum line on fpr. might try to jump fp with engine off just to see if pressure holds steady without the injectors running.

 

[conlyn]

Re: Is this normal?!

Well it's going to be impossible to see what the actual pressure is with the motor idling that's why I was asking

 

[Troyphoon]

Re: Is this normal?!

Did you ever figure out what the problem was? My truck just started doing this. I'm going to be replacing the pump tomorrow actually installing dual pumps.