If a hard shift is not a current issue, you can install a relay to work off the neutral safety switch and wire an input into the IAC kickdown (typically used by the AC compressor) to raise the idle during a shift to help reduce a stall.
What boat is it in? I have a similar pair of 5.7's and plan on converting them this winter. I thought the sniper was self tuning? Have you come across anyone else who has converted their twin sbc's ? Im interested if there was any fuel mileage increase?
@@stevenehrke2730 it’s a 33 foot Searay Sundancer I got in rough condition. I’m learning that I will need an ECU for both engines. I have two GMC trucks with bad transmissions at my car lot I’ve been considering pulling the engines out and doing a 6.0 LS Swap that would bolt right in considering the 5.7 is nothing more than a small block Chevrolet. Meaning I would get more HP less fuel consumption, and less parts to buy because the engine is already fuel injected. That means I could theoretically add stock supercharger’s from a Cadillac, Corvette, or Camaro, and would only have buy the ECU’s.
@@thomasstrickland0 for it an i/o boat or a true inboard? If inboard you need to see if you currently have a counter rotating engine or if the trans can do it for you. Something like a zf. I looked into the ls swap myself. But switching transmissions wasn’t in the cards. Using a stock 411 ecm could work, but the tuning credits needed alone will be $650 for the software to do both. It can be done, but ls you’ll need the manifolds, risers, marine alt and starters, and manual truck flywheels. Adapt the raw water pumps as well.
@@fordtechchris it’s a nice boat. Since the last time I have pulled the engines in the trucks. I installed a new transmission on the right side of the boat, so the prop would spin correctly. The engines are installed. I was waiting to get all of this done because I had to replace the transom. That was hell. I think it’s built better than factory now. The hard parts are done anyway. I went with the Holley Dominator because I’m running two engines, and I can control more using 1 interface and two GM factory ECM’s, and I’ve decided to go with closed loop cooling instead of fresh water.
I would like to applaud your ingenuity and determination! I too am in the process of doing an efi conversion on a merc 3.0 and have been studying the software manual. I was wondering if your sniper is controlling the fuel pump? When you turn the key the pump should come on for a few seconds for the priming shot then shut off until the motor is actually at the run rpm. This could impact your erratic idle. Anyways, nice job!
As far as I can tell, yes it does turn it on for a few seconds, then runs the pump continuously. Good point though, I should verify fuel pressure when the trouble is happening, thank you!
If you are still having problems at the boat ramp with the motor dying going into gear you may want to look to see if there is a ignition cut on your linkages on the motor. I don’t know what brand motor you have but I have worked on a lot of MerCruiser engines that have it. It’s purpose is to make the shift from neutral into forward or reverse smoother by cutting the timing for a split second. I’ve seen a handful get out of adjustment to where they generally die in reverse. Hard to explain in UA-cam comment but hopefully that helps!
Great job on the install I've thought about doing this myself but from a few videos I've watched it seems like people are having alot of issues with it with that being said in all honesty with all the time and money you have invested I can't believe you seem to still have a good attitude about the system lol if it were me I'd be totally upset with it I mean a properly tuned carburetor would probably be less trouble for you at this point and have the boat running great
Yes it would! I need to do another update, but it turned out there was an ignition interrupter that was causing all kinds of trouble with the system losing the RPM signal. It's running so much better now, also I think there is something in the fuel tank causing an issue with my pickup, so I'm working that bug out
Love seeing that State of Jefferson sign behind you.
Yeah, I used to be a resident, but left for Idaho.
I left for Texas. Idaho was one of our considerations as well.@@fordtechchris
Great update.
If a hard shift is not a current issue, you can install a relay to work off the neutral safety switch and wire an input into the IAC kickdown (typically used by the AC compressor) to raise the idle during a shift to help reduce a stall.
I was thinking of a similar thing. I ended up disabling the ignition kill switch that engages when shifting and now it's not dying going in to gear
che differenza di potenza e velocità da carburarote a holley sniper efi
Thanks man. I know I’m late to the show. I’m getting ready to do this to my twin 5.7’s. Would be nice if I could use one ECU for both engines.
What boat is it in? I have a similar pair of 5.7's and plan on converting them this winter. I thought the sniper was self tuning? Have you come across anyone else who has converted their twin sbc's ? Im interested if there was any fuel mileage increase?
@@stevenehrke2730 it’s a 33 foot Searay Sundancer I got in rough condition. I’m learning that I will need an ECU for both engines. I have two GMC trucks with bad transmissions at my car lot I’ve been considering pulling the engines out and doing a 6.0 LS Swap that would bolt right in considering the 5.7 is nothing more than a small block Chevrolet. Meaning I would get more HP less fuel consumption, and less parts to buy because the engine is already fuel injected. That means I could theoretically add stock supercharger’s from a Cadillac, Corvette, or Camaro, and would only have buy the ECU’s.
@@thomasstrickland0 for it an i/o boat or a true inboard? If inboard you need to see if you currently have a counter rotating engine or if the trans can do it for you. Something like a zf. I looked into the ls swap myself. But switching transmissions wasn’t in the cards. Using a stock 411 ecm could work, but the tuning credits needed alone will be $650 for the software to do both. It can be done, but ls you’ll need the manifolds, risers, marine alt and starters, and manual truck flywheels. Adapt the raw water pumps as well.
That will be a fun project! Sea Rays are nice boats
@@fordtechchris it’s a nice boat. Since the last time I have pulled the engines in the trucks. I installed a new transmission on the right side of the boat, so the prop would spin correctly. The engines are installed. I was waiting to get all of this done because I had to replace the transom. That was hell. I think it’s built better than factory now. The hard parts are done anyway. I went with the Holley Dominator because I’m running two engines, and I can control more using 1 interface and two GM factory ECM’s, and I’ve decided to go with closed loop cooling instead of fresh water.
I would like to applaud your ingenuity and determination! I too am in the process of doing an efi conversion on a merc 3.0 and have been studying the software manual. I was wondering if your sniper is controlling the fuel pump? When you turn the key the pump should come on for a few seconds for the priming shot then shut off until the motor is actually at the run rpm. This could impact your erratic idle. Anyways, nice job!
As far as I can tell, yes it does turn it on for a few seconds, then runs the pump continuously. Good point though, I should verify fuel pressure when the trouble is happening, thank you!
If you are still having problems at the boat ramp with the motor dying going into gear you may want to look to see if there is a ignition cut on your linkages on the motor.
I don’t know what brand motor you have but I have worked on a lot of MerCruiser engines that have it. It’s purpose is to make the shift from neutral into forward or reverse smoother by cutting the timing for a split second. I’ve seen a handful get out of adjustment to where they generally die in reverse.
Hard to explain in UA-cam comment but hopefully that helps!
It's an OMC, but that makes sense, I'll check it this spring before taking it out!
Great job on the install I've thought about doing this myself but from a few videos I've watched it seems like people are having alot of issues with it with that being said in all honesty with all the time and money you have invested I can't believe you seem to still have a good attitude about the system lol if it were me I'd be totally upset with it I mean a properly tuned carburetor would probably be less trouble for you at this point and have the boat running great
Yes it would! I need to do another update, but it turned out there was an ignition interrupter that was causing all kinds of trouble with the system losing the RPM signal. It's running so much better now, also I think there is something in the fuel tank causing an issue with my pickup, so I'm working that bug out
Did you install the o2 sensor? great video thanks
Yes, I was able to screw it in to a dry pocket in the backside of the manifold. If you find my first video, I show how it was done.
Your stalling because it cuts off cylinders while switching gears and messing with the computer
Is that in the distributor?
@@fordtechchris there is a switch at the shifting rod that grounds out some cylinders to make the motor rpm drop so it goes into gear easier
@@markburke5410 I will investigate this and see if I can come up with a work around... Thank you!
@@fordtechchris should be located near the linkage for the forward and reverse , mine also has a reset switch ( breaker type )