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Discussion Starter #1
Hi all,

Build: 408w, large cam, Holley Super Sniper, Hyperspark Distributor, MSD digital 6al (pn 6425), dual fuel pumps (58psi), battery located in trunk.

Settings: Hyperspark ignition setting, 57.5* reference angle, clear cap used to phase rotor while engine was at 0* top dead center (verified with finger in #1 spark plug hole)

Problem 1: Engine will start and run rough, must keep foot on gas (~10% throttle) to keep the engine running for a short while, then it may idle on its own. Although, it will idle very low (500-600rpm) with tons of IAC. My Idle timing is set to 20* and idle rpm set to 1000rpm. Engine will eventually sputter and die, may cough out of throttle body after about a minute.

Problem 2: Occasionally engine will flash "no data" or negative throttle position, leading me to believe I may have EMI/RFI. Vehicle initially only had the battery grounded to body in trunk. Since then I have added the following grounds in addition: battery to frame, timing cover to frame, passenger cylinder head to body. Still will have those codes flash occasionally.

I have called Holley multiple times with no insight and they haven't answered 2 emails I sent weeks ago. I have a couple datalogs as well, but I can't figure out how to add them to this post o_O
 

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The Holley forum is probably the best place to ask.

Did the engine run before the efi install or was this all put together on a new engine?
 

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Hi all,

Build: 408w, large cam, Holley Super Sniper, Hyperspark Distributor, MSD digital 6al (pn 6425), dual fuel pumps (58psi), battery located in trunk.

Settings: Hyperspark ignition setting, 57.5* reference angle, clear cap used to phase rotor while engine was at 0* top dead center (verified with finger in #1 spark plug hole)

Problem 1: Engine will start and run rough, must keep foot on gas (~10% throttle) to keep the engine running for a short while, then it may idle on its own. Although, it will idle very low (500-600rpm) with tons of IAC. My Idle timing is set to 20* and idle rpm set to 1000rpm. Engine will eventually sputter and die, may cough out of throttle body after about a minute.

Problem 2: Occasionally engine will flash "no data" or negative throttle position, leading me to believe I may have EMI/RFI. Vehicle initially only had the battery grounded to body in trunk. Since then I have added the following grounds in addition: battery to frame, timing cover to frame, passenger cylinder head to body. Still will have those codes flash occasionally.

I have called Holley multiple times with no insight and they haven't answered 2 emails I sent weeks ago. I have a couple datalogs as well, but I can't figure out how to add them to this post o_O
I replaced my Throttle Position Sensor and it fixed a similar issue to what you mentions about your problem 2.

For Problem 1. I have a high idle (900rpm) as well and I was having some issues. I pulled the unit and examined. Overall made pretty nice. one issue (at least for mine) is there is play in the primary-secondary linkage, so first thing I did to try to improve idle and throttle response was open up my secondaries a little to compensate for this play. If you pull the sniper and play with the throttle you'll see that the primary blades open quite a bit before the play is taken up, noting they need this play/tolerance for manufacturing reasons so only way to eliminate is to change to a different type of linkage, anyways, so I dialed down the idle adjustment screw on the primaries, opened up the secondaries a crack then readjusted the system so the IAC is around 5% when it's warmed up. Throttle response is better and idles really nice now.

My electrical setup is similar, my battery is in trunk and is grounded to the frame as well. In my engine bay I have alternator and engine grounded to the frame with 2 gauge. For the sniper, running directly to the positive and negative battery terminals using 10 gauge.
 

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Discussion Starter #5
I'm not sure about an answer for you. But have you posted on the Sniper forum?

I have attempted to make a profile to post on there weeks ago and performed the "email verification" after which it emailed me again stating I would recieve an email upon my approval so I may post on their forums. I have not received a verification email.
 

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Discussion Starter #6
I replaced my Throttle Position Sensor and it fixed a similar issue to what you mentions about your problem 2.

For Problem 1. I have a high idle (900rpm) as well and I was having some issues. I pulled the unit and examined. Overall made pretty nice. one issue (at least for mine) is there is play in the primary-secondary linkage, so first thing I did to try to improve idle and throttle response was open up my secondaries a little to compensate for this play. If you pull the sniper and play with the throttle you'll see that the primary blades open quite a bit before the play is taken up, noting they need this play/tolerance for manufacturing reasons so only way to eliminate is to change to a different type of linkage, anyways, so I dialed down the idle adjustment screw on the primaries, opened up the secondaries a crack then readjusted the system so the IAC is around 5% when it's warmed up. Throttle response is better and idles really nice now.

My electrical setup is similar, my battery is in trunk and is grounded to the frame as well. In my engine bay I have alternator and engine grounded to the frame with 2 gauge. For the sniper, running directly to the positive and negative battery terminals using 10 gauge.
I am interested in how you adjusted the primaries and the secondaries on the Holley separately. I will look into that. Since my initial posting, I have rerouted some wires away from each other which has seemed to help. Only had one "no data" flash today, and it occurred right as my car hit 160 degrees. After which it was able to start again. Now a new problem has began.

The Holley either will not idle without ~10% throttle, or it will idle really low ~250-500 with 100% IAC. Ugh.

I have adjusted the throttle blades all the way open and it will still create 100% IAC.
 

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questions...

Have you logged the issues and looked at data on the pc software?

how clean is your voltage? TPS?

Are you running power to efi direct to battery terminals?
 

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Discussion Starter #8
questions...

Have you logged the issues and looked at data on the pc software?

how clean is your voltage? TPS?

Are you running power to efi direct to battery terminals?
I have a data log. Don't know how to post it on this forum. I'm no expert at reading these graphs unfortunately. Not really sure what I am looking at.

Holley positive and negative are going to the battery. I just bought a brand new battery for it the other day.
 

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Discussion Starter #11
Here is what I have done so far to update this thread as to what has helped, and my current problem.

I previously also had the MSD's Orange/black coil wires ran parallel to my white trigger wire, I have since ran them apart and that has solved many of my EMI problems. The car will start and idle mostly on its own now. I must still give the car throttle to start it and the IAC still runs 100% even with the butterflys opened all the way, but will now idle at the target 1000rpm. I have also moved my coil mount off the accessory bracket to the body but that has not made an EMI difference.

Now, whenever I shut my hood, the Holley immediately shuts off. I have re-mounted my air cleaner to see if that will cause it to shut off, but the air cleaner by itself is fine.
 

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Program says that the dlz. file does not have an allowed extension
make sure you download the sniper software from the website. there is two versions, one doesn't read the sniper files. I made that same mistake. Scroll down a bit on the site and you'll see the sniper specific software.....
 

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Here is what I have done so far to update this thread as to what has helped, and my current problem.

I previously also had the MSD's Orange/black coil wires ran parallel to my white trigger wire, I have since ran them apart and that has solved many of my EMI problems. The car will start and idle mostly on its own now. I must still give the car throttle to start it and the IAC still runs 100% even with the butterflys opened all the way, but will now idle at the target 1000rpm. I have also moved my coil mount off the accessory bracket to the body but that has not made an EMI difference.

Now, whenever I shut my hood, the Holley immediately shuts off. I have re-mounted my air cleaner to see if that will cause it to shut off, but the air cleaner by itself is fine.
Do you mind sharing you .dlz file that is logged during what you describe. I am no expert but spoke a bunch with the tech at EFIsystempro which is where I bought mine from....
 

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Discussion Starter #15
I can open the Sniper file and it will show me charts that I do not comprehend. Still wont let me upload to this website.
 

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Here is what I have done so far to update this thread as to what has helped, and my current problem.

I previously also had the MSD's Orange/black coil wires ran parallel to my white trigger wire, I have since ran them apart and that has solved many of my EMI problems. The car will start and idle mostly on its own now. I must still give the car throttle to start it and the IAC still runs 100% even with the butterflys opened all the way, but will now idle at the target 1000rpm. I have also moved my coil mount off the accessory bracket to the body but that has not made an EMI difference.

Now, whenever I shut my hood, the Holley immediately shuts off. I have re-mounted my air cleaner to see if that will cause it to shut off, but the air cleaner by itself is fine.
I have a FiTech but have had similar issues. The hood comment was something that caught my eye. Shielding the MSD cables helped my situation a lot. I also found that my repro oval air cleaner contacted the coil wire on my distributor and the hood which caused the ECU to shut down stranding me. Got the car towed home and for some reason the fuel pump was still running with the key off. By the time I had this issue I had put about 600 miles on the car. I disconnected the battery to shut down the fuel pump. Next morning I pulled the air cleaner, reconnected the battery and the car fired right up. Confused but happy I dropped the air cleaner on and as I was tightening the wingnut I got lit up as the air cleaner compressed the coil wire boot on the distributor. Sold that air cleaner and that problem went away.
 

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Grounding the air cleaner base can help. Having a ground strap from the body to the hood will also help. If you find that you need to open the throttle to get it to start, you need to increase the IAC Park Position. The combination of IAC Park and the cranking fuel is what determines your AFR as the car is cranking to start.

Andrew
 
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