- Thread starter
- #41
Your welcome. I know if my rig was road worthy my results may be of more use to others but I thought I’d just post up what I’ve done anyway as it may be of some help to someone.
Holley Sniper Install. 74 F.5
- Thread starter Steamer
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
Your welcome. I know if my rig was road worthy my results may be of more use to others but I thought I’d just post up what I’ve done anyway as it may be of some help to someone.
Cool rig and great write up.
So ya know the TPS in these things is not very water resistant. Killed a couple of them hosing off the motor. Last one I used a bunch of dielectric grease on the connector and its held up better. And yea, a thicker gasket or spacer should clear up that whistle.
- Thread starter
- #43
Thanks for the tip on the tps Brian. I'm still chasing the whiney noise. I'm missing the rubber bumper/plug that's in the regulator cover that pushes in on the regulator. It was never in there so I didn't miss it and still don't know if it's still supposed to be in there. On the Holley forums I see where they were replacing bad regulators with a new regulator and cover to go with it. That's where I learned about the rubber thing. I just put a post up asking if the rubber thingy's are still used and if I should have one. I'm suspecting my regulator is not being held tight in place and vibration may be causing the whining sound. No instructions came with the replacement regulator and no cover or rubber thingy came with it either. I see you're active on that forum also.
Hi Steamer. That rubber plug is a spacer to keep the regulator seated against the fuel pressure. I can't imagine they no longer install that part. It's also part of what damages the regulator. The regulator with o-ring is a tight fit into the throttle-body, and if you use the cover, or you finger to press the FPR in the center it will deform and damage it. You need to carefully press the FPR from the edges as much as possible, then install the cover with rubber spacer to hold it in place. I shaved down the spacer on mine a little, as extra insurance I wasn't squishing the FPR from the center.
Long story short: Pretty sure you need that rubber plug/spacer.
B.
edit: re the noise. My experience is with the 4bbl version so I'm not sure if the gasket trick will correct that extra noise thing thats happening with yours.
Long story short: Pretty sure you need that rubber plug/spacer.
B.
edit: re the noise. My experience is with the 4bbl version so I'm not sure if the gasket trick will correct that extra noise thing thats happening with yours.
- Thread starter
- #46
Thanks Brian. I just got off the phone with Holley tech and they also told me that the rubber thingy is suppose to be in there and they are going to send me one.
New from Holley, my regulator was put in crooked so it couldn't seat all the way in. Then, without the rubber thing in there the cover was forced on and the metal thing on the cover that holds the rubber, was smashed into the FPR.
When the rubber gets here I'll check the pressure it puts on the FPR and shave if necessary as you suggested.
I'm believing the whistle noise I have at a particular rpm is the gasket/reed effect and will try out thicker gaskets. Or double gaskets if I can't find thicker. As for the separate other whiney, mosquito sort of noise that seems to be coming from the regulator area, I'm hoping it will be resolved with the proper FPR install. We'll find out when ever my rubber thing arrives.
New from Holley, my regulator was put in crooked so it couldn't seat all the way in. Then, without the rubber thing in there the cover was forced on and the metal thing on the cover that holds the rubber, was smashed into the FPR.
When the rubber gets here I'll check the pressure it puts on the FPR and shave if necessary as you suggested.
I'm believing the whistle noise I have at a particular rpm is the gasket/reed effect and will try out thicker gaskets. Or double gaskets if I can't find thicker. As for the separate other whiney, mosquito sort of noise that seems to be coming from the regulator area, I'm hoping it will be resolved with the proper FPR install. We'll find out when ever my rubber thing arrives.
Glad I might have helped a little.
If you have any more questions feel free to hit me up. I've had mine for a couple years now so have learned a thing or two about them.
Also, if you need any more parts or info I highly recommend efisystempro.com . The owner is very helpful and knowledgeable with fair prices. That's my go-to if I need anything.
If you have any more questions feel free to hit me up. I've had mine for a couple years now so have learned a thing or two about them.
Also, if you need any more parts or info I highly recommend efisystempro.com . The owner is very helpful and knowledgeable with fair prices. That's my go-to if I need anything.
- Thread starter
- #49
Well my rubber thingy came in last week. They also sent a new FPR and cover gasket/o-ring. The missing rubber thingy looks like a sliced off piece of thick walled silicone fuel hose. When installing it, I noticed that it put just a little pressure on the FPR. I've been running it (in the yard) every day and no trace of the whining noise. So I guess & hope that problem is resolved. I'll get a trail test in soon.
I'm trying to learn the software that comes with the Sniper. I doubt I can learn it all as it gets complicated but if I can just nail down the basics, I'll be doing good. I find it amazing how much control you have over it although with just one adjustment to my fuel prime before start, I'm running great as is. Well I think so anyway. If a pro were to analyze my data logs, I might find out it can be tuned better. Pretty cool that I can post or email a data log for someone to read.
For anyone not familiar with this, here's a pic of one of my data logs. I started the logging just before a cold start, idled about two minutes, a little throttle change and then ended it in about 3 minutes. Readings I selected to show on the graph are from top to bottom......
1. Air fuel ratio (pink)
2. Cooling temp sensor (red line, hard to see)
3. Manifold absolute pressure (blue
4. Injector pulse wave (green)
5. RPM (red)
6. Fuel Flow ( dark red) near bottom
I'm trying to learn the software that comes with the Sniper. I doubt I can learn it all as it gets complicated but if I can just nail down the basics, I'll be doing good. I find it amazing how much control you have over it although with just one adjustment to my fuel prime before start, I'm running great as is. Well I think so anyway. If a pro were to analyze my data logs, I might find out it can be tuned better. Pretty cool that I can post or email a data log for someone to read.
For anyone not familiar with this, here's a pic of one of my data logs. I started the logging just before a cold start, idled about two minutes, a little throttle change and then ended it in about 3 minutes. Readings I selected to show on the graph are from top to bottom......
1. Air fuel ratio (pink)
2. Cooling temp sensor (red line, hard to see)
3. Manifold absolute pressure (blue
4. Injector pulse wave (green)
5. RPM (red)
6. Fuel Flow ( dark red) near bottom
Last edited:
RE: the whiny sound....
My AFI TBI had a whiny vibration sound along the firewall (very annoying) and essentially, I had snugged my homemade steel fuel line too tightly to nearby metal objects. I loosened the clamps and let the steel line 'float' and the noise was gone. I could have inserted a rubber segment between the pump and steel line, but I was trying to keep the high pressure fuel system 'all steel' all the way to the TBI unit for fire safety and reliability.
The hard steel line was taking the fuel pump vibrations and transferring them to larger surfaces that would radiate the sound. Give any steel lines some 'room to move'
Steve
My AFI TBI had a whiny vibration sound along the firewall (very annoying) and essentially, I had snugged my homemade steel fuel line too tightly to nearby metal objects. I loosened the clamps and let the steel line 'float' and the noise was gone. I could have inserted a rubber segment between the pump and steel line, but I was trying to keep the high pressure fuel system 'all steel' all the way to the TBI unit for fire safety and reliability.
The hard steel line was taking the fuel pump vibrations and transferring them to larger surfaces that would radiate the sound. Give any steel lines some 'room to move'
Steve
- Thread starter
- #52
Keep in mind all my body work forward of the firewall is gone and replaced with homemade sheet metal.
So., I thought I would post up my latest Sniper developments. I have not been on the trails for a few months because of a mild overheating issue which led to building a custom radiator frame & shroud for the 4-row Champion, switching to an 8-blade fan blade and doing some major flushing. But that’s another story. I also replaced my vehicle trailer so setting that up has taken a lot of my time.
Anyway, on the last two trips out in the swamp, after about an hour or two of running, the Walbro GSL 394 pump started to whine quite noticeably. I mostly crawl in the swamp but when conditions let me and I got up to 6-9 mph for about 15 minutes, the engine temp dropped some, and the whine would stop. When trail conditions forced me back to 2-4 mph, the temp would rise, and the whine would return.
I know my pump should not be in the engine bay but that’s where my rather large Racor filter/separator is mounted which I’m now using as a pre-filter so that’s where the pump is. My two-part solution for this whining problem was #1, get the F.5 to run cooler like it used to. And #2, isolate the pump from engine bay heat. Dropping the engine heat turned into a few months’ work like mentioned above but for the pump isolation and after several designs, I came up with a slick and simple idea. Without relocating the pump or changing hoses, I simply encased the pump into a 2” PVC tee with two plugs. The pump is suspended in the tee with an air space all around it. The bull of the tee exits the fender well where outside air gets to it. I used Sil-Glyde instead of glue, so the plugs go in and out by hand for and easy pump change.
So., I thought I would post up my latest Sniper developments. I have not been on the trails for a few months because of a mild overheating issue which led to building a custom radiator frame & shroud for the 4-row Champion, switching to an 8-blade fan blade and doing some major flushing. But that’s another story. I also replaced my vehicle trailer so setting that up has taken a lot of my time.
Anyway, on the last two trips out in the swamp, after about an hour or two of running, the Walbro GSL 394 pump started to whine quite noticeably. I mostly crawl in the swamp but when conditions let me and I got up to 6-9 mph for about 15 minutes, the engine temp dropped some, and the whine would stop. When trail conditions forced me back to 2-4 mph, the temp would rise, and the whine would return.
I know my pump should not be in the engine bay but that’s where my rather large Racor filter/separator is mounted which I’m now using as a pre-filter so that’s where the pump is. My two-part solution for this whining problem was #1, get the F.5 to run cooler like it used to. And #2, isolate the pump from engine bay heat. Dropping the engine heat turned into a few months’ work like mentioned above but for the pump isolation and after several designs, I came up with a slick and simple idea. Without relocating the pump or changing hoses, I simply encased the pump into a 2” PVC tee with two plugs. The pump is suspended in the tee with an air space all around it. The bull of the tee exits the fender well where outside air gets to it. I used Sil-Glyde instead of glue, so the plugs go in and out by hand for and easy pump change.
- Thread starter
- #53
Figuring that the whine was from the pump overheating, I thought I had the problem solved. But, while sitting still and doing a four-hour flush with Thermocure and varying the idle speed with the hand throttle now and then, at 3-1/2 hours the engine started to stumble. The fuel pressure was bouncing back and forth from 60psi to 20 psi. So, I shut it down. I felt the PVC tee enclosure and it was warm but not hot. I reached into the tee from the outside to feel the pump and burnt the hell out of my finger.
Sooo, the pump is generating its own heat and not getting it from the engine bay. But why? I then took a temp reading on my fuel tank and it was 130 deg F. Ah, Got it! These Walbro pumps pump way more volume than we need so more fuel gets returned than is used by the Sniper. It’s like a heating system. Fuel keeps circulating to the hot engine bay and close to the exhaust manifold then back to the tank so the tank and fuel will keep getting hotter and hotter. And finally, the pump starts cavatating and doesn’t get the cooling from the fuel, so it starts overheating.
My problem is probably amplified since I’m only ever traveling at a few MPH in the trails so I have less air movement about the engine bay and also around my tank. My tank is homemade aluminum and only 14 gal.
So, since the pump is the lowest GPM I can find that’ll do 60 PSI, I decided to try out an idea I found discussed on a Corvette forum where guys were trying to reduce excessive return flow. The solution was to wire a resistor in series with the pump to reduce voltage and consequently reduce flow along with reduced pump amperage. So, I got some resistors of various sizes and tried a 0.5 ohm first. I turned the key on for pre-start and I thought the pump wasn’t running right because it was much quieter than usual but the gauge popped right up to 60 PSI. So I started it and it fired right up as it usually does. Ran it for an hour in the yard and all seems good. The resistor was just dangling hooked up temporary and when I went to disconnect it I got more burnt fingers. (dummy). Then I read where it needs to be mounted to a metal base to carry off the heat. Since the 0.5 ohm seems to work fine, it’s now mounted to the fender well with some heat sink compound and a little make shift cooling fin on the opposite side. It doesn’t get so hot now.
I’m real pleased with this set up and can’t wait to get it back on the trail.
Sooo, the pump is generating its own heat and not getting it from the engine bay. But why? I then took a temp reading on my fuel tank and it was 130 deg F. Ah, Got it! These Walbro pumps pump way more volume than we need so more fuel gets returned than is used by the Sniper. It’s like a heating system. Fuel keeps circulating to the hot engine bay and close to the exhaust manifold then back to the tank so the tank and fuel will keep getting hotter and hotter. And finally, the pump starts cavatating and doesn’t get the cooling from the fuel, so it starts overheating.
My problem is probably amplified since I’m only ever traveling at a few MPH in the trails so I have less air movement about the engine bay and also around my tank. My tank is homemade aluminum and only 14 gal.
So, since the pump is the lowest GPM I can find that’ll do 60 PSI, I decided to try out an idea I found discussed on a Corvette forum where guys were trying to reduce excessive return flow. The solution was to wire a resistor in series with the pump to reduce voltage and consequently reduce flow along with reduced pump amperage. So, I got some resistors of various sizes and tried a 0.5 ohm first. I turned the key on for pre-start and I thought the pump wasn’t running right because it was much quieter than usual but the gauge popped right up to 60 PSI. So I started it and it fired right up as it usually does. Ran it for an hour in the yard and all seems good. The resistor was just dangling hooked up temporary and when I went to disconnect it I got more burnt fingers. (dummy). Then I read where it needs to be mounted to a metal base to carry off the heat. Since the 0.5 ohm seems to work fine, it’s now mounted to the fender well with some heat sink compound and a little make shift cooling fin on the opposite side. It doesn’t get so hot now.
I’m real pleased with this set up and can’t wait to get it back on the trail.
- Thread starter
- #54
Also, to further reduce heated fuel returning to the tank, I’m gonna try a re-plumb and eliminate the return line over the manifold by using a remote regulator/filter. I know GA Architect had issues doing this but I’m gonna give this one from Holley a try. The filter element is changeable and the regulator is the same one that's in the Sniper. There's two versions of this cast aluminum or billet. This if the billet.
- Thread starter
- #55
Well the Holley filter/regulator is mounted and plumbed in. For trial purposes I just moved the hose from the pump discharge to the filt/reg outlet. This leaves two post filters in play for now but this is temporary. The return is disconnected from the Sniper and the return outlet is capped off. The internal regulator is still inside. The return line is now permanently plumbed from the filt/reg to the tank. It took a few pre-starts to fill the drained supply line, but it finally started and runs well and maintains 62 psi.
I took some voltage readings to see just what that 0.5-ohm resistor was doing.
Engine off and pump running. Battery 12.6 V. Voltage to pump 8.9 V.
Engine and pump running. Battery 14.2 V. Voltage to pump 9.9 V.
Cranking with pump running. Battery 10.87 V. Voltage to pump 6.1
I just need to make better electrical connections then I’m ready for a trail test.
I’ll leave the supply line and two filters as is for now but after a trail test, I’ll remove the extra filter and re-route the supply strait over the valve cover to reduce its length and exposure to heat. I’ll remove the internal regulator from the Sniper as well. I also think I’ll reduce the supply line to 5/16. That’s a 30 percent reduction from 3/8 which will increase velocity and reduce the time fuel is getting heated. And, I found some cool high temp silicone covered fuel line insulation on Amazon. “FIRE SLEEVE”
I took some voltage readings to see just what that 0.5-ohm resistor was doing.
Engine off and pump running. Battery 12.6 V. Voltage to pump 8.9 V.
Engine and pump running. Battery 14.2 V. Voltage to pump 9.9 V.
Cranking with pump running. Battery 10.87 V. Voltage to pump 6.1
I just need to make better electrical connections then I’m ready for a trail test.
I’ll leave the supply line and two filters as is for now but after a trail test, I’ll remove the extra filter and re-route the supply strait over the valve cover to reduce its length and exposure to heat. I’ll remove the internal regulator from the Sniper as well. I also think I’ll reduce the supply line to 5/16. That’s a 30 percent reduction from 3/8 which will increase velocity and reduce the time fuel is getting heated. And, I found some cool high temp silicone covered fuel line insulation on Amazon. “FIRE SLEEVE”
