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Efi sos!

33K views 254 replies 22 participants last post by  Milt's 68 SS/RS 396 
#1 ·
I am in need of some advice/help. Here is the story.
I decided to install the Holley Sniper EFI on my 68. Car was running fine with a Holley 780 carb on an Edelbrock RPM intake with RPM heads, and a MSD Ready to Run Distributor. But not being able to leave well enough alone I purchased the Holley Sniper EFI unit which I had heard many good things about. I also purchased the Holley in tank fuel pump/sending unit. This allowed me to not have to run a return line. It's an original big block car so I was able to utilize the existing 3/8" fuel line. This is where the battle began. After draining the tank (almost full) I installed the new pump as shown in the Holley video. It went rather well I thought, so I put the gas back in & turned the key on to see if the fuel gauge was working, it didn't. I called Holley. Their advice was to switch the ground wire with the sending unit wire. This made no sense. After much testing & cursing I drained the tank again and dropped it. Pulled the pump assembly out and manually moved the float. The gauge worked, success. I reinstalled the pump, put the tank back in and added 5 gallons of gas. Turn the key on the gauge didn't work. I then gave it the Fonzie slug & to my surprise the gauge registered. Aha! The float needed to be jostled around a bit to be able to move. I then moved on to the EFI installation. This all seemed to go well. Installed the oxygen sensor but one of the provided clamps for the bung locked up & snapped off when I tried to back the nut off. I called Holley & they said they would end a new one
(I received it two weeks later!). I installed the temp sending unit, this seemed to go well, but after getting everything hooked up, I was getting a LOWErr on the CTS sensor. I called Holley. The Tech told me I probably had a bad sending unit & he would send me a new one. He also told me I could get a duplicate from Autozone which I did. Installed that & it worked great. Tried to start car, but it would turn over & and backfire. I called Holley. The tech said I may not be getting adequate Fuel pressure. I doubted this since I am using the Holley in tank fuel pump made for this system, Still to be sure I ordered a fitting & fuel gauge from Summit. After installation I confirmed that I was getting 60 lbs. of fuel pressure at the throttle body. Car still would not start. I called Holley.The tech reviewed the wiring diagram that I had used & the advised me to use the one that did not utilize the yellow wire coming off of the coil and instead hook up the purple wire from the ECU & hook it up to the gray wire out of the Distributor. I did this & car still wouldn't start. I doubled check the timing & it was correct. I called Holley again. The tech told me to increase the fuel prime level from 150 to 200. I did. Car started! Success! Not so fast. After about 5 minutes the car died. I called Holley. Explained what was going on & he seemed to think it was a loose connection somewhere in the rpm signal. I agree because when I turn the car over there is no RPM reading on the LCD screen. I have checked all connections & they seem fine. The car has started a few times & runs for a few minutes, but then dies. I am at my wits end. I think this system is beyond my capabilities. I am done with calling Holley. Hopefully my Camaro compadres have a solution. Does anyone know of a person in the Las Vegas area with Holley Sniper experience that makes automotive house calls?
PS the weather in Vegas right now is great. I should be driving my car & on top of all this it's my birthday! Any help or advice would be greatly appreciated.
 
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#4 ·
Milt - are you using the Sniper for timing control as well or leaving it as-is? Sounds like you have possibly narrowed it down to RMP signal as you should see RPM during cranking.
The yellow wire should connect to coil negative assuming conventional coil or the TACH connection of an HEI type distributor. The green & purple wires that are are only used if you have a CD box such as an MSD 6AL so if you are using these and do not have a CD box then what Holly told you is wrong. See page 13 of this manual.
If you get it wired like this diagram shows and timing is correct and you have 60psi of fuel pressure it should fire right up.
 
#5 ·
Thanks for the advice Travis. The Holley tech told me that my distributor (MSD RTR model 8360) had the equivalent of a CD box inside. Prior to that I hooked up the yellow wire to the negative side of the coil, but I did choose CD box on the set up menu as I was advised by Holley. It would not start in that configuration. I am really at a loss as to what to do next :frown2:
 
#21 ·
The Holley tech told me that my distributor (MSD RTR model 8360) had the equivalent of a CD box inside. Prior to that I hooked up the yellow wire to the negative side of the coil, but I did choose CD box on the set up menu as I was advised by Holley. It would not start in that configuration. I am really at a loss as to what to do next :frown2:
The statement above is what I was referring to in my earlier post.
I think the Holley tech is wrong based on what the MSD tech told me... "the 8360 RTR is not the equivalent of having a CD box inside the distributor".

I’ve used the 8360 RTR on several Sniper installs and select COIL for the set up.
They work fine without issues
This is the same thing that the MSD tech told me.
It's only a guess... but I think the OP's problem is how they originally programed their EFI (selected CD Box instead of selecting COIL).
 
#7 ·
I think this distributor (8360) does function similar to a CD box in that it jumps the spark voltage that is sent to the external coil where as a points type distributor or other does not. In the instructions Holly states

"WARNING! Do NOT use this input if you are using an aftermarket Capacitive Discharge (CD) ignition system such as a MSD, Mallory, or others. The ECU will be damaged if you connect to a capacitive discharge type ignition coil."

Its possible the Sniper ECU is damaged.
 
#8 · (Edited by Moderator)
I called Holley this morning and the tech had me run a system log. I started the car and initiated the log. Car ran for about five minutes then died suddenly. I sent the data log into Holley and called back. In analyzing the log the tech said everything in regards to the Sniper was working perfectly, then there was a RPM signal loss and the Sniper shut down.

He believes the problem is ignition related. I'm running a MSD RTR 8360 with a MSD Blaster SS coil. He suggested I call MSD and see if they can troubleshoot the problem. I told him everything was running fine prior to installing the Sniper.

He said it could have been having momentary dropouts and that would not affect the carb as it does the EFI. This seems to make sense to me, but I have very few miles on this distributor. Thoughts?
 
#9 ·
MSD has had some bashing in recent years to the longevity of coils and other components, and a few members here have had issues with relatively low mileage units going tit's up all of a sudden so it is entirely possible that the tech is right that under the old style carburetor world you never noticed a stumble, but in the digital world it stalls.

But generally the Ready to Run product line is a solid unit. You may just inspect all your wiring for anything a bit dodgy and after the search and destroy see if the issue goes away. The MSD Blaster SS coil on the other hand has some negative posts here and in google searches, and on the Holly forums referring to overheating and burnout issues. https://forums.holley.com/showthread.php?43555-MSD-Coils-Overheating-amp-Burning-Out
 
#11 ·
Holley likes to blame ignition. It’s not the coil their talking about they are usually saying it’s the RPM signal. If the system does not detect RPM it shuts off.

Sounds like it was running fine in open loop before it got to operating temp and went to closed loop/learn

I would run the set up again.

What cam did you select on intitial set up?
 
#15 · (Edited)
That came with my Kit. No one from Holley has mentioned installing that into the system. I called MSD this morning & they suggested Starting the car, waiting for it to stall, then pull the coil wire & see if I have spark. If no spark then the problem is in the distributor. If no spark he suggested running yellow wire form efi to - side of coil. I don't think I should do that.
 
#16 ·
Here is the latest.
I started the car, and it was idling great ran for about five or six minutes, reached a temp of 140 degrees then died like someone pulled the plug. I pulled the coil wire off of the distributor and had my wife turn the car over. There was ample spark. So no I know the distributor is good (according to MSD). I don't know what to do next. I like John's idea of wiring in the efi filter. I'll call Holley in the morning and see what they say. Appreciate all of the ideas and suggestions that have been put forward so far. I still have hope of driving my car before it gets too hot!
 
#17 ·
Spoke with Holley tech this morning & told him what the MSD tech had me try & the results. He now wants me to wire in an external tach and see if it registers after the car dies & I turn it over. If I get a reading on the tach, then it's the ECU in the Sniper. If no signal then it's the distributor. I'm leaning to think it's the ECU, but we'll see.
 
#18 ·
What a PITA.

For future tuning questions the Holley forum is pretty helpful also,.

I would like to go back to EFI on my SBC, but with a multi point efi setup this time,but it just runs sooo good with the 850 right now, I might just wait for an LS or LT to appear under my hood first.
 
#19 ·
It might be worth calling MSD and asking them if the MSD Ready to Run 8360 Distributor is considered a capacitive discharge (CD) ignition system. I always though the MSD Ready to Run distributors functioned about the same a most other types of distributors with self-contained electronic ignition modules.

For my own curiosity, I called MSD and asked them the above question. They told me that the MSD "Ready to Run" distributors were considered an "Inductive Ignition System" and should be wired (and programed) in a similar fashion to a breaker/point or HEI distributor (not like a CD ignition).

I remember you stating that you selected "CD Box” during the programing. I am wondering if you should have selected “Coil (-)”.

Before changing anything, I would recommend you speak to both MSD and Holley techs to confirm the information shown above before altering anything that could harm your system.
 
#23 ·
Holley tech is telling you wrong. The MSD 8360 RTR jade a magnetic pick up module and a conventional coil ie a blaster II.

Unless you’re running an MSD box 6AL or similar do not set up as CD box. Set up as coil.

As I mentioned above I have done several with 8360s this way. Sniper, FAST and Fitech are all the same in this aspect.
 
#24 ·
John, I believe you are correct. It just seems strange that it runs for five or six minutes before it cuts out. I tested it with an external tach wired in. After it died I turned it over an was getting signal on the external tach. So either the ecu is damaged or I need to rewire it and select the negative coil setting in the set up.
 
#25 ·
John has good experience using and setting these systems up. Using his input is a good resource of caution while others are giving you info that could fix or damage your system is a wise move.
With the popularity that these systems has seen recently, I'm surprised that this issue has not surfaced more often, even to the point that the manufacturers have not yet documented this occurrence in their trouble-shooting instructions.
It sounds like you are approaching the solution with a good strategy and hopefully your system will be functioning soon. This post will become a good resource for others experiencing similar issues and will reach their solution much quicker due to your lengthy difficulties.

Brett.....
 
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#27 ·
Why it runs for 5 minutes and then shuts off could be a bad O2 sensor

When you 1st start the engine it runs in open loop until it reaches operating temp. It then goes into closed loop. Closed loop the engine runs and self tunes/learns based on readings from the O2 sensor.

To check. Using the programmer disable closed loop. By doing so the system will not go into closed loop and will not look for O2 reading. If it stays running in open you have a bad O2 sensor.
 
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