Low boost

Hydro-idi · Feb 17, 2018

Not sure why your still confused on this. Many members including myself have mentioned that your engine needs more fuel if you want more turbo psi. Reread entire thread. Everything you have mentioned points me to say the ip isn’t putting out enough juice.
A 3 inch dp will really help with lag & egts, but won’t change the fact that your engine can use more fuel.

pelky350 · Feb 17, 2018

My injection pump is like 10xxx miles on it it shouldn't already be defueling? Or could that be happening? It's a 90cc from r and d I couldn't imagine it already be dying??

pelky350 · Feb 17, 2018

It could almost make sense though it's not really pulling hard in the higher rpms, 2500+ In 4th gear it's slowly climbs beyond that with no smoke. The 90cc isn't supposed to "defuel" till like 3500 I belive

pelky350 · Feb 17, 2018

What if I'm having a problem with air intrusion somewhere like tank selector valve? Or my rear tank being completely dry and unused and use my front tank? Or the rubber line before the lift pump? Or somewhere?

no mufflers · Feb 17, 2018

Do you have a working pyro? If you have it floored and only getting 800* then it needs more fuel.

I have a 90cc pump also and I can get 17 lbs with little smoke but only a max of 900*. I know it can take more fuel.

I know we have different turbos.

Thewespaul · Feb 17, 2018

You would have hard starting or have it bucking while driving.

When you modify a pump for higher output, there’s two ways to achieve that. First you can mechanically change how much the fuel by porting etc. second you can adjust the fuel output by putting more tension on the “leaf spring” this either works on the test stand or it breaks and the pump seizes.

On a worn pump tightening the leaf spring can make it perform to spec, but it’s on a short fuse and doesn’t last long at that spec without some real mechanical changes. Anything more than 80cc that I build gets more than a leaf spring adjustment. And for the price Justin sells those lower output pumps at I guarantee it’s nothing more than a leaf spring adjustment, otherwise he’s doing charity work and not making any money.

pelky350 · Feb 17, 2018

I just noticed my truck idling weird actin funny like it's starving for fuel or about to die, looked under hood at fuel pressure guage and t bouncing between 2psi and 7 psi all over the place basically now, failing lift pump cause this maybe? It's only like a year old now. Fuel filter just changed

IDIBRONCO · Feb 17, 2018

If you're sure that your fuel pressure gauge is accurate, then the lift pump's probably a good place to look. It may be bad right out of the box, so, yes, it could be failing at only a year old. Either that, or check for air intrusion before the lift pump. If, by some chance, there is air intrusion, then that's probably what's defueling your injector pump and causing your low boost/power issue. If it's starting to idle funny, maybe it's getting worse.

pelky350 · Feb 17, 2018

I'm thinking air intrusion pre lift pump, the harder it sucks The more air maybe? Causing a lack of fuel the higher the rpms? And the bouncing needle, it's a brand new guage installed 2 days ago

Thewespaul · Feb 17, 2018

Lower fuel pressure will retard your timing at higher rpms as well

pelky350 · Feb 17, 2018

Yeah something is defiantly going on it's idling weird, you can heard it almost loping at idle now and it's getting really quiet. Like it's running out of fuel sorta almost misfiring

IDIBRONCO · Feb 17, 2018

Thewespaul said:
Lower fuel pressure will retard your timing at higher rpms as well

Also resulting in less power.

Macrobb · Feb 17, 2018

A.K.A. you aren't getting the fuel to the pump. This is why measuring the pressure /under load/ matters - if you have a restriction, the lift pump may be able to put out enough pressure, but once your IP starts asking for more flow... then you have issues.

Macrobb · Feb 17, 2018

Thewespaul said:
When you modify a pump for higher output, there’s two ways to achieve that. First you can mechanically change how much the fuel by porting etc. second you can adjust the fuel output by putting more tension on the “leaf spring” this either works on the test stand or it breaks and the pump seizes.

On a worn pump tightening the leaf spring can make it perform to spec, but it’s on a short fuse and doesn’t last long at that spec without some real mechanical changes. Anything more than 80cc that I build gets more than a leaf spring adjustment. And for the price Justin sells those lower output pumps at I guarantee it’s nothing more than a leaf spring adjustment, otherwise he’s doing charity work and not making any money.

I call BS on some of this. The leaf spring is simply there to keep the plungers from filling further than they are 'limited' to. The leaf spring won't break from being 'maxed out', it's just pushed against the (çurved) rotor below it. If the spring was removed completely, I'd bet the pump would still work(I'll have to try this), because it would be limited by the cam ring instead - like a DB4 rotor(I think).
On a worn pump, well, you are dealing with leakage due to the wear... but I see no reason why it would "fail sooner" or have the output drop depending on the leaf spring position. What usually happens is either the advance piston wearing out(unrelated to fuel flow), or hot starting issues due to head/rotor clearance(again, not something that the plungers would really affect).
I'Ve maxed out several pumps, and I have had no issues doing it.

pelky350 · Feb 18, 2018

I'll throw in a lift pump in the morning doesn't take more than like an hour to do so why not? I can probably warrantee this one and they won't ask me questions anyway lol

Low boost

Hydro-idi

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pelky350

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pelky350

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pelky350

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no mufflers

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Thewespaul

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pelky350

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IDIBRONCO

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pelky350

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Thewespaul

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pelky350

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IDIBRONCO

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Macrobb

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pelky350

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