Sniper system fuel pressure issue

[RattyBarracuda]

Your bleeding down issue. Some in tank pumps have a valve that keeps the system at a pressure for extend "off" periods.
Ive seen it on OE multiport systems frequently. A bad check valve in the in tank pump causing a rapid leak down if pressure with power off.

 

[matthon]

It runs for about 10-20 seconds and quits. Then coughs and spits.

Mine did this when my O2 sensor went bad.
When replaced, it took a drive around the block to figure itself out.

Does the Sniper have an error code section on the controller?

 

[plymouth4onthefloor]

check out that:
https://forums.holley.com/forum/holley-efi/sniper-efi/378158-fuel-pressure-seems-high-erratic

Be a member in the Holley forum, very helpfull

 

[MV8]

Just a thought ....

Shouldn't the pump run continuously? Maybe a power issue with the pump.

Or does the pump have an internal pressure switch so it cycles depending on pressure

IMHO, any oem efi, key in RUN, pump runs for a second or two then off until the engine is turning over. What makes it turn back on can be oil pressure builds over 5psi or so, a vane airflow meter switch, or the ecu based on input from the motor like a crank trigger. This primes the system but the injectors do not open to wet the intake. I don't know how long the sniper keeps the pump on.

On the Sniper, the fuel "prime" setting must be enabled and the amount is adjustable. Key in RUN, after 2.5 seconds, the injectors will wet the intake. I expect the pump is still running at that point in time. It will also adjust the amount based on the coolant temp. Leaving the key on too long without cranking will reprime each time. When the screen has loaded, the pump and injectors are priming.

Some systems also have an inertia switch that the pump control wiring is run through. It is a cup with two contacts in the bowl, a metal ball, and a magnet. A good hit and the ball comes out of the bowl, breaking the connection and shutting off the pump. There is a reset button to put the ball back in the bowl. Most fords have this switch.


I said 58.5 psi before but holley references 58.5 for the regulator, then 60 psi, but say to check that it is between 55 and 60 psi so not critical on this.

 

[MV8]

Bricud, in other words, if the "prime" function is enabled on a Sniper, the fuel pressure will quickly drop to zero (because the injectors open). Easy to switch it off and retest.

 

[bricud]

Thanks for all your input. The most recent info is that I replaced the regulator with a tanks Inc Regulator ($98) hoping for a better quality one that doesn't bleed down. I find that it holds pressure better after the prime and I was able to set it at 59 psi. Engine starts consistently but seems to run lean. (afr) around 17 at fast idle (1300 rpm). Before I address the Sniper tuning issues, I need to address an issue with leaking orb (O ring boss) fittings. I have taken the fittings apart and replaced the o rings with after market ones but have the same issue of leaking fuel. I am wondering if this and the first regulator are just cheaply made with poor quality components. Both were made in China. Anyway, are the more expensive ones like the aeromotive A1000 Gen II EFI Fuel Pressure Regulator going to fix my issues? I am concerned about the orb (o ring boss) fittings. They seem to be really loose and I know the O ring makes the seal but I can't get past wondering why the threads seem so loosly fitting? Seems kind of dangerous to wonder if the loose threaded fittings are going to pop loose at some point and spray gas on the engine... I read some reviews on the tanks Inc one I have and others have had the same issue with leaks. I also noticed that almost all of the fuel regulators have the orb connections. Any experience of recommendations? Thanks.

 

[MV8]

Why is the hot idle set to 1300? This set with the wizard where you set the efi to the basic specs for your engine. It sounds like it came off a smaller engine and you didn't make the changes in wizard. There is a lot more to it than that. You'd need to share a sharp pic or file of the data logging table and/or other settings. You can transfer with a special cable or memory stick to your PC and use their software to work on it with that and send data back and forth on the web.

Orings should be lubricated before installation; especially when one side/seat is rotating to clamp it. I don't know about your thread fit but the threads don't seal anything and the fitting does not need to be very tight to seal a new oring that is the correct size and thickness.

Black orings are made out of several different materials and tend to swell with ethanol exposure (brown are better for that). I suggest you get replacements from holley. Swollen orings don't fit properly and get pinched and ruined. They can be left out to dry and shrink back and the swelling can help sealing but make it difficult to impossible to put back in if swollen. Pics would be nice.

 

[bricud]

The engine speed was right after startup. I haven’t been able to run it long enough to fully heat up due to fuel leaks. I did go through the wizard and set it up for a 408 with a street/strip cam. Target idle is 700. I bought the system used from someone else that had it on a larger engine. I’ll go through the wizard again and double check settings. One thing that crossed my mind is if it should be set up for a racing cam. I’m using a Comp Cam with 286/294 duration and .544/.541 lift and 1.6:1 rockers. Perhaps this could contribute to my slightly lean cold engine?? Anyway still looking for comments on the fuel regulator. Thanks.

 

[MadScientistMat]

The reason for ORBs is quick trackside repairs - you don't have to deal with pipe thread sealant. They're sealed as soon as you torque them down with no worries about pipe dope or have Teflon tape get loose. If they're finger tight something is wrong, but they aren't torqued down as tight as a similar size bolt either.

 

[MV8]

The engine speed was right after startup. I haven’t been able to run it long enough to fully heat up due to fuel leaks. I did go through the wizard and set it up for a 408 with a street/strip cam. Target idle is 700. I bought the system used from someone else that had it on a larger engine. I’ll go through the wizard again and double check settings. One thing that crossed my mind is if it should be set up for a racing cam. I’m using a Comp Cam with 286/294 duration and .544/.541 lift and 1.6:1 rockers. Perhaps this could contribute to my slightly lean cold engine?? Anyway still looking for comments on the fuel regulator. Thanks.

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You can switch back and forth between mild and street strip setting. How much vac did you normally have at idle with a carb?

Key on, engine off, home screen, select monitors then engine startup. What does the MAP,CTS,TPS,IAC, and battery volts show? Tach should show "stall".

Is the fuel only setup using your existing spark system? EDIT: looks like you are using the original distributor. What does the ignition setup say? Is your distributor locked so there is no mechanical advance?

 

[MV8]

It doesn't look like this system supports a crank trigger. You can use the unaltered original ignition to trigger off the coil primary wire or lock it out to let the sniper handle timing.

 

[MV8]

Some of the sniper systems over the years support a crank trigger while others do not. What model do you have?

 

[kaharshs]

One of my sniper 1 kits works great with the stock internal fuel regulator. Another sniper I had never reduced the pressure correctly. Holley sent me 2 new internal regulators and I tried 3 different fuel pumps. I finally had to remove the stock fuel pressure regulator and install an adjustable regulator on the return line. Fixed my fuel pressure issue. Glad a regulator solved your. I have had good luck with evil energy brand off Amazon for all my AN stuff and regulators. You may need to reset your throttle blade opening so the IAC is working correctly. The previous owner may have adjusted them. Also you may need to adjust your coolant temperature enrichment.