[lamans71]

I am in the middle of this very change over myself, currently in the process of replacing the tank with a new Tanks Inc. EFI tank and their fuel pump. Been doing a lot of reading and learning about the different ways that others have done the fuel lines. I'm thinking about using the Sniper 4150 kit and using hard lines for both the supply and return lines with flex lines between the tank, EFI unit and hard lines.

The one reservation I have on the Sniper is that I have read and heard that its susceptible to noise issues as the ecu is attached to the EFI unit.

[Formulajones]

This may sound harsh but I'm not trying to come off that way.

On the RFI and EMI stuff I've read so much about, I can't help but wonder what kind of issues those cars had to start with before the EFI swap.
Not knocking other cars, but I've seen some pretty crappy cars I think I could find 10 other things to spend $1500 on before I worried about EFI.

I think it's a conglomerate of things. Some of it self inflicted, some of it could be the units fault, some of it the installation, the list goes on. Most of the time diagnostic issues end up coming down to the car itself having underlying problems that are simply magnified when EFI is installed.

I installed 2 Sniper Stealths on our cars and have experienced no RFI issues. Both of them are GM products that have rear engine distributors, with coils mounted back there as well, and the Sniper Stealth wiring comes right out of the back of the unit, right into the path of the distributor and coil on both cars. I still have no issues, and my plug wires on the Chevelle are at least 20 years old.

I think if you run good quality plugs wires, a good quality distributor cap, with resistor plugs, a good quality coil, and have everything properly grounded, that's probably half the battle right there.

Wiring it directly to the battery is also a big deal.

Having a really good fuel supply system is another big one that many people get stuck on trying to diagnose (not RFI related though).

The engine also has to be pretty sound with no internal mechanical issues, no exhaust leaks, no vacuum leaks etc.... If you have any of these problems the EFI will magnify that problem.

The other big complaint with these units I read all the time are the temp sensors. They tend to read a bit too high, and that skews the fuel table graphs making it very hard to tune, especially the cold start parameters and up throughout the fuel curve as the engine is warming up.

It's a simple fix, new sensors from the local parts store fixed both of mine, as they both had this issue. Other than that, they both have performed flawlessly.

It all sounds more scary than it is, but they are things that can drive people nuts. If you have a solid car that runs good for you now, the EFI swap will probably go smooth.

[Formulajones]

Something else they seem to make a big deal out of on the Holley forum are alternators. They always recommend a bigger newer style wiz bang alternator that is internally regulated that puts out some juice, as well as contains EMI better than older units.


However on both of our cars I've installed the Sniper on, they are running old style alternators with external regulators and I've seen no issues.

In fact at night with lights and accessories on, my chevelle with it's stock 37 amp alternator only showed about 12.7-12.8 volts idling at stop lights but immediately jumps to 13.7+ when I touch the gas. Which is pretty normal to see on these old cars. It has had no ill effects on the Sniper at all.

I later installed all LED lights inside and outside the car. Same driving at night my voltage is now 13.1 idling at stop lights, so just the bulbs alone was quite an improvement.

Never something I was worried about with this car for 35 years because factory mechanical gauges never showed it to the tenth degree. Now with the Sniper that monitors voltage on a digital scale, you notice these little things.
I had a spare 55 amp alternator on the shelf that I tossed on the car, and switched to an electronic style external voltage regulator instead of the original points triggered unit to see how things might change. It's still the same.

So my thought process on this is that you don't necessarily need the newest bestest alternator upgrades they promote on the forum unless you really want it.

[lamans71]

Formulajones, how did you route the fuel lines? As I plan on using the 4150 (not the stealth) it comes with an internal fuel pressure regulator and I'll need to plumb both a supply and return line to and from the EFI unit. Did you run the fuel lines up the back of the motor trans (thru the trans tunnel?) I'm worried about getting too close to the headers and 3in exhaust that I have on this car. I am thinking of running the lines around the EFI unit down the front of the motor like it would be stock to the supply and (new) return lines down by the frame rail.

[Formulajones]

Originally Posted by lamans71

Formulajones, how did you route the fuel lines? As I plan on using the 4150 (not the stealth) it comes with an internal fuel pressure regulator and I'll need to plumb both a supply and return line to and from the EFI unit. Did you run the fuel lines up the back of the motor trans (thru the trans tunnel?) I'm worried about getting too close to the headers and 3in exhaust that I have on this car. I am thinking of running the lines around the EFI unit down the front of the motor like it would be stock to the supply and (new) return lines down by the frame rail.

If you aren't worried about hiding things, and for ease of installation, running them down the front of the engine similar to the stock routing would be the way I'd do it. That's generally what I do on a typical install when I don't care about hiding things and have more freedom. On dad's I did his that way, since the regulator on his is mounted in the stock fuel pump location, I just ran his feed line down by the water pump like the factory had it.

On mine, I hid the regulator down low on the frame, return goes back along the frame from there, and hid the feed line under the heater box, behind the cylinder head coming into the back of the unit. I used the black braided -8 so it blends right in to the factory wire harness that runs right through there, making it hardly noticeable.

All that stuff you see in that picture in the front of the unit is soldered closed at the brass junction and closed off so no fuel is being pumped down to the mechanical fuel pump, which is also inop (push rod removed).
If I weren't trying to hide things on this car, I would have just removed the stock fuel pump, mounted the regulator there, and ran my feed line up the front of the engine.

[ZeGermanHam]

Originally Posted by Formulajones

On the RFI and EMI stuff I've read so much about, I can't help but wonder what kind of issues those cars had to start with before the EFI swap.

Absolutely agree with all of the points you laid out. These cars are super old now, have typically been owned by numerous people and seen countless repairs by all kinds of people. EFI won't work well if other areas of the car need attention.

[lamans71]

Originally Posted by Formulajones

If you aren't worried about hiding things, and for ease of installation, running them down the front of the engine similar to the stock routing would be the way I'd do it. That's generally what I do on a typical install when I don't care about hiding things and have more freedom. On dad's I did his that way, since the regulator on his is mounted in the stock fuel pump location, I just ran his feed line down by the water pump like the factory had it.

On mine, I hid the regulator down low on the frame, return goes back along the frame from there, and hid the feed line under the heater box, behind the cylinder head coming into the back of the unit. I used the black braided -8 so it blends right in to the factory wire harness that runs right through there, making it hardly noticeable.

All that stuff you see in that picture in the front of the unit is soldered closed at the brass junction and closed off so no fuel is being pumped down to the mechanical fuel pump, which is also inop (push rod removed).
If I weren't trying to hide things on this car, I would have just removed the stock fuel pump, mounted the regulator there, and ran my feed line up the front of the engine.

Thanks for that extra info on how you routed your fuel lines. Did you ever consider placing the regulator back by the tank, say up around the stand pipe area? That would really cut down on the return line length but I was not sure if a return line that short would be an issue. Just to be clear I'm not saying that the RFI and EMI noise issues are an extreme issue, only that if they are a problem it can be quite a nightmare to track down and solve sometimes. I stopped in to a local performance shop in Gilbert that is listed on the Holly site and chatted with them about the Sniper. They confirmed that 95% of the time it works fine but that 5% is a major hassle. For that reason they recommend the Terminator X over the Sniper as the ECU is remote located on the Terminator system. While that would be nice at over $2K for the Terminator it is outside my budget, plus its for a much higher performance level than I'm at.

[Formulajones]

Couple reasons I do it this way, I prefer a return the full length of the car. I actually prefer it as close to the carb, or EFI as I can get it. I like to keep the fuel circulating to keep the fuel cooler rather than sitting stagnant in the fuel line and collecting heat. Just one of the things I like to do here in AZ to battle any possible fuel heat soak issues.

I didn't go with the terminator X simply because of the remote mount ECU. I really didn't want even more wires to route, try to hide, find a place to hide the ECU etc.... I'd have to put that up inside a fender well somewhere because I'm not too hip on drilling big holes in the firewall to run large diameter harnesses through. The Sniper Stealth attracted me for lots of reasons, and one was the completely self contained computer with minimal wires coming out of the unit. Plus it looks just like a Holley carb, and everything I already had on the car bolted right up, throttle linkage, air cleaner, vacuum lines, etc....

I would have liked the terminator X to run the 4L80E though. But the other issues kept me from doing it.

[HWYSTR455]

True about the ALTs, but most do not cause issues. At one point, early in the EFI game, many recommended CS130 type ALTs to combat the potential EMI issues.

Most that I hear complain about EMI on the Sniper setups are Ford & Mopar installs, because the dizzy is right there. That's straight up spark scatter for those folks.

If you want ideas to run lines, look at the thread I put together for fuel line install, or either of the 2 build threads I have. All 3 give ideas of line routing.

Here's the one thread, other 2 are in my sig:

https://forums.maxperformanceinc.com...2+line+install


.

[Formulajones]

Another thing about running lines, even though Holley doesn't promote it, in fact there are way too many kits on the market that don't promote it, is that you should really have the regulator as close to the unit as possible.

They talk a lot about this on the Holley forum. Having the regulators as close to the unit as possible for the most accurate fuel pressure readings "AT THE UNIT" really helps the EFI run like it should, especially the self tuning aspect of these things because that entire fuel table and it's calculations are based off fuel pressure.

All these kits that regulate fuel way back at the tank are just kits to try to get more people on board with EFI using a lower price point by eliminating extra lines, fittings etc...and making it look simple. While it works, it's not optimum. But they don't want to tell you that.

[HWYSTR455]

Exactly.

[ID67goat]

Originally Posted by lamans71

Just to be clear I'm not saying that the RFI and EMI noise issues are an extreme issue, only that if they are a problem it can be quite a nightmare to track down and solve sometimes. I stopped in to a local performance shop in Gilbert that is listed on the Holly site and chatted with them about the Sniper. They confirmed that 95% of the time it works fine but that 5% is a major hassle. For that reason they recommend the Terminator X over the Sniper as the ECU is remote located on the Terminator system. While that would be nice at over $2K for the Terminator it is outside my budget, plus its for a much higher performance level than I'm at.

I encountered intermittent RFI/EMI issues with my install.....would be running great and then all of a sudden stall for no reason. It ended up being my plug wires, I guess there was something wrong with my 10 year old MSD wires. Swapped the wires out and everything is good to go and runs great. I really like the system, car has never started so well and has great throttle response...super easy to tune with data logging etc.

The shop I buy from also mentioned to me that they install the regulators (LS style I think he said) back by the tank, but I think that is just due to faster install time. He also said they have removed a few systems and put them back to carburetor because people didn't understand that you might have to hook a laptop up and do some tuning on them...

[gassman_67]

for a few more $$ get the pro flow 4

[Formulajones]

Originally Posted by ID67goat

The shop I buy from also mentioned to me that they install the regulators (LS style I think he said) back by the tank, but I think that is just due to faster install time. He also said they have removed a few systems and put them back to carburetor because people didn't understand that you might have to hook a laptop up and do some tuning on them...

You would be correct in your thinking that shops are doing it for faster install time, also for cheaper price quotes to get customers in the door. But it's by no means the best way.

That's the other issue not being expressed enough. Just because they advertise these units as self tuning doesn't mean you won't have to do any tuning on your own.. I've had to do A LOT of tuning on both of our units just on the fueling side alone. The base maps are very generic, they'll get you going, and in some cases may run fine on nearly stock type engines, but they are no where near optimum for even a mild performance application.

I do like the target AFR aspect of it, as it does try to adjust for the elevation changes I see around here, which is the reason I bought it, but even that I have dummied down just a bit in the lower rpm ranges.

[darbikrash]

There are many different ways to wire, plumb, and tune EFI systems. I’ve tried several approaches, and had some failures as well as some success.

One of the EFI cars, the ’69 GTO has a Terminator system which is a throttle body EFI with remote ECU. This worked out pretty well, but as mentioned has a great deal more wiring harness than the throttle body mounted ECU’s. Because it is more or less a generic unit, the harness is way too long for most cars and you have to somehow hide or deal with this extra length.

Also not wanting to drill big holes in my firewall, after several tries I opted to mount the ECU behind the headlight on the passenger side, and route the harness behind the wheel well so its not visible. Another tip is buy a battery that has both top and side terminals, such as the Odyssey 1500, which gives you dedicated terminals (I use the side terminals) for the ECU without sharing the connection with any other loads.

For fuel lines, I mounted my regulator back by the tank and importantly, bought an extra 0-5v Holley pressure sensor to mount right at the throttle body. I have another EFI car with a firewall mounted return regulator, and a full car length return line also with a fuel rail pressure sensor.

I data mapped both systems and I see no difference in pressure drop from the tank mounted short return line system versus the firewall mounted fuel length system.

While the full length return line system with engine compartment regulator is no doubt “better” in theory, I can’t say that the car runs any better and the tank located system is easier to install. Just make sure you have a TB mounted pressure sensor to tell you exactly what the line pressure is, you can enter this value in the tune and get accurate injector performance- as long as the pressure drop is managed.

I’m not saying this is better than a conventional firewall mounted return regulator, but installed properly it does work just fine.

[HWYSTR455]

Originally Posted by ID67goat

I encountered intermittent RFI/EMI issues with my install.....would be running great and then all of a sudden stall for no reason. It ended up being my plug wires, I guess there was something wrong with my 10 year old MSD wires. Swapped the wires out and everything is good to go and runs great....

People argue with me all the time when I say plug wires are only good for like 3-5 years max, and tell me to send them my old wires. Crazy. MSD boxes and HEI put an incredible load on plug wires, just because they test out via resistance doesn't mean the jackets are good. IMO if you don't change them at regular intervals, you will chase gremlins until you do.

Same with tires.

There's frugal, and then there's 'cheap'. In the long run, everyone pays.


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[lamans71]

Originally Posted by HWYSTR455

True about the ALTs, but most do not cause issues. At one point, early in the EFI game, many recommended CS130 type ALTs to combat the potential EMI issues.

Most that I hear complain about EMI on the Sniper setups are Ford & Mopar installs, because the dizzy is right there. That's straight up spark scatter for those folks.

If you want ideas to run lines, look at the thread I put together for fuel line install, or either of the 2 build threads I have. All 3 give ideas of line routing.

Here's the one thread, other 2 are in my sig:

https://forums.maxperformanceinc.com...2+line+install


.

Thanks for that link, I may have read it but never hurts to reread and find some info that you may have overlooked. Case in point is the Tanks Inc. sending unit, I decided on the floatless unit from the get go and have it mocked up in place with the rubber gasket, however I was concerned about it sealing well enough. I see that you had that issue and went to the cork gasket to solve the problem, great tip that I will change before I place the tank in position.

[HWYSTR455]

Yeah, the rubber gaskets I could never get to seal, not to mention they grew from gas additives. They may have fixed that issue, but the cork is a sure-fire solution.

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