Vintage Mustang Forums banner
1 - 20 of 22 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
Hey Gang,
I have a 70 Mach1 with 351c4v. I did a couple resto mods, including Holly Sniper EFI. I have had some issues with it. The ECU inside the throttle body is having wiring issues, where its not firing right. I was told Holly has a new wire harness that can be installed. Anyone know about this.
 

·
Registered
1965 Coupe C-Code
Joined
·
3,090 Posts
The one thing I learned on this forum about EFI is that they lack shielding and that many issues can be traced back to interference. I have not heard about the new harness but it wouldn't surprise me if they actually started doing a better job at shielding.
 

·
Registered
Joined
·
575 Posts
All these horror stories about the tbi efi systems makes my carb sound better. My driving season is too short as it is.
 

·
Registered
Joined
·
1,799 Posts
I run a Sniper EFI system that was installed EXACTLY as stated in the installation instructions and have never had the slightest issue with it. I took great care in wire routing and made sure that none of the EFI harnesses were bundled along side other wire runs. I've run Holley and Edelbrock carbs on the same 302 and would say that the Sniper is by far, the best system.
 

·
Registered
Joined
·
575 Posts
Cheapness is definitely part of it. With the short driving system I just can't justify spending the money to improve the drivability of a car with no air, no power steering, no power brakes, no radio, and a hood scoop. Plus my next build is going to have a grumpier cam, more cubes and more compression. I am going to splurge on a manual choke, though. You have to have a few luxuries!
 

·
Registered
Joined
·
1,766 Posts
Precisely why I went Edelbrock Pro-Flo 4.

The ProFlo is by most accounts a step above the TBI EFIs, having less electrical interference problems (and less heat soak) because the brain isn't sitting on the engine, its separate. However, the system doesn't fit under all the classic Mustang hoods- a 69 with 351w needs a hole in the hood to make it fit. That's not my opinion, its in a post on the Edelbrock forum, and dropped air cleaners did not help. I would get it instead of a Sniper if it would fit.
 

·
Registered
Joined
·
2,658 Posts
I read all the negitave post about the Sniper's & it makes me wonder. I have a 2300 installed on the 200/6 cyl in my 67. When i installed it the Sniper control wires were coiled up under the hood . I did try to keep the sniper ecu wires secured & away from anything close to the dist, coil or spark plug wires . I also made a particular effort to wire it exactley as the instructions said . Its ran/ runs fine other than o2 issues caused by exhaust leaks .

Then when I was trying to make the underhood wireing a little neater I purchased some split wire loom and bundled Sniper wires ,msd wires to the coil & everything else under the hood together .
Would'nt you know it still ran fine. Even mounted over the header on the stock intake over that huge #3&4 exhaust port . Maybe I just got lucky who knows.

If mine crapped out now I'd buy another one as soon as I had the money . Putting that thing on my six was like getting an engine transplant.
 

·
Registered
Joined
·
1,297 Posts
Sonic,
As others have noted, be sure the wiring is properly routed. Also, sometimes air gets stuck right at the fuel inlet at the TB, be sure to purge there. I presume you have a good fuel filter installed where the injectors haven't got debris?
 

·
VMF Ambassador
Joined
·
7,243 Posts
A number of people here have found that the Sniper has issues with EMI interference - basically the computer isn't shielded from the distributor, and apparently some types of distributor make the issue worse. Not an issue on other makes of car because their distributors are in the back.

A guy here on VMF, @JohnnyK , got a piece of lead shielding and found that placing it between the TBI and the distributor cleaned the issue up completely, confirming that it is indeed an interference issue with the distributor. His solution was to get a totally different EFI system because keeping a sheet of lead between two components isn't really viable and speaks to a lack of engineering on Holley's part that made him (and me) uncomfortable.

Many people do run a Sniper with no issue on their small block Fords, so that's what leads me to believe that some distributors are more prone to causing issues than others.

Myself, I went for a Holley Terminator which has an external computer, allowing me to circumvent any potential issues by putting the computer in the dash.
 

·
Registered
Joined
·
1,964 Posts
A number of people here have found that the Sniper has issues with EMI interference - basically the computer isn't shielded from the distributor, and apparently some types of distributor make the issue worse. Not an issue on other makes of car because their distributors are in the back.

A guy here on VMF, @JohnnyK , got a piece of lead shielding and found that placing it between the TBI and the distributor cleaned the issue up completely, confirming that it is indeed an interference issue with the distributor. His solution was to get a totally different EFI system because keeping a sheet of lead between two components isn't really viable and speaks to a lack of engineering on Holley's part that made him (and me) uncomfortable.

Many people do run a Sniper with no issue on their small block Fords, so that's what leads me to believe that some distributors are more prone to causing issues than others.

Myself, I went for a Holley Terminator which has an external computer, allowing me to circumvent any potential issues by putting the computer in the dash.
I may have to pick your brains when I finally get my engine back from this machinist, Kelly! I got the Terminator X Max (so it could run my 4R70W) to control my new 8 stack EFI setup. I'm stoked.
 

·
Registered
Joined
·
3,785 Posts
These problems with electromagnetic interference and just bad ECUs are part of the reason I have not pulled the trigger on a Sniper setup, even though it has been what I have been wanting to do for a few years now.

I've know half a dozen people that had to send theirs back for a whole new unit. The heat I think also is tough on the ECU because of where it's mounted. It's nice for ease of installation and overall simplicity but not sure it's the best idea.

I've heard that some of it was solder that would let go related to getting hot.

I keep reconsidering going with EEC IV factory fox body EFI which I originally thought about doing a decade ago, but the look is not what I really want to see when opening the hood.

Here are some tips from my friend Pete that had some interference issues with Holley EFI. The first thing I would do is try running the car in the dark and watching for electricity jumping or arcing.

Holley EFI - For those chasing EMI/RFI issues
 

·
Registered
Joined
·
246 Posts
The new harness from Holley includes a relay for the switched power pink lead for the ECU. Many people (myself included) had EMI/RFI problems until installing a relay for this wire. There may be other minor changes like wiring length, but that is the major change. I spent countless hours troubleshooting my problem and resolved a number of install or preexisting problems contributing to my EMI, namely poor grounds. My Sniper is running like a top now and would never go back to carb.


Sent from my iPad using Tapatalk
 
  • Like
Reactions: Wayne clark
1 - 20 of 22 Posts
Top