Team Chevelle banner

HOLLEY SNIPER EFI TUNING tips, info sharing, ideas, settings, etc...

159K views 428 replies 49 participants last post by  Dkar26 
#1 ·
I wanted to follow suite with the popular FiTech tuning tips thread but being more specific with Holley information.

ENGINE SIZE:
350

HOLLEY SETUP USED:
600 HP Sniper in shinny finish

ENGINE VACUUM:
Thinking it's around 13.

CAM SETTING (Stock/Mild | Street/Strip | Race) AND YOUR CAM SPECS:
Stock/Mild settings
Comp Cam 280/494

IAC COUNTS @ idle and cruise
????

TIMING CONTROL: Y/N?

Not at the moment but plan to soon.

IDLE RPM:
950

TARGET IDLE AFR:
???

ANY ADJUSTED PARAMETERS AND WHY?:
No setting changes yet. Looking for any suggestions.

ADDITIONAL NOTES:
I'm using a Tanks Inc. tank with a 255 LPH in-tank pump.
3/8" supply and return line.


I just fired mine up earlier today but have not driven it yet. I had an issue with a vacuum leak and then too high of an idle. I'll be going back tomorrow to do some idle adjustments and hopefully get it on the road for a little while.

Any suggestions on settings I should look at or change right off the bat?
 
See less See more
#2 ·
I would not adjust or play around with ANYTHING until you've given it some actual driving time to learn.

Just double check ALL "needed" parameters that you have ser and entered, then once fully warm, set IAC with the idle screw, and drive it.

It won't start to learn until it's at 160 degrees, as measured by the Holley supplied coolant temp sensor...I had to change mine to an aftermarket one since mine read upwards of 20 degrees lower than actual....and since it's gotten much colder, mine was reading in the 150's so not learning at all.

I've also 100% POSITIVELY found that mine has an issue regarding running Timing Control.
I had done everything that the Holley manual said to do, and done the other things that were never even mentioned and still have a random, loss of power, which caused an intermittent stalling with no pattern to it whatsoever....
Since the Sniper datalogs are inaccessible until they finally release their software, there's nothing to check.
Distributor was locked out.
Holley required tuning parameter changes done.
Distributor/Computer Timing matched at all RPMs.
Rotor was phased perfectly
Reference Angle set 10 degrees above highest timing commanded
Inductive Delay set to allow timing match and steady reading
Timing parameters set as close as possible to previous mechanical/vacuum settings that have been proven over the last few years.
Idle was smoother, but extended idling or light throttle cruise, my car would randomly die, IAC would go full open, and act as if key was shut off, and engine restarted...

After this happening AGAIN about 10 times yesterday...I decided to AGAIN switch the EFI back to NON Timing Control, and AGAIN the car runs 100% fine like that, with no stalling whatsoever...I removed distributor, reinstalled the weights, springs, 11 degree advance bushing, and vacuum can. Set total timing at 44 degrees, and good to go again...Very pissed about this....

Anyway, hooked up sans Timing Control, the efi works, and car runs, great. What sucks is I had planned to use the Holley to control ALL nitrous functions, including timing retard, and now that's not going to be an option, evidently... :(
 
#3 ·
I was able to get the idle down and get the car out on the road. There will be some tweaking I need to do but here are the two things I need to address first if anyone has any suggestions.

1. When switching through gears (it's a manual trans) or coming up to a stop light/sign, the idle stays high. It stays around 1,800 RPM until I whip the throttle. Then it will return to the normal idle. I but a slightly stiffer throttle return spring on it trying to make sure that wasn't the issue. I then read through some of the touch screen manual and saw where it talked about an IAC Decay. From what I understood from that was the time that it took to go back down to idle. It was initially set as 4.0 but I then changed it to 2.0 and then down to 1.0. It didn't seem to affect it either way.


2. When I initially start it up it doesn't start as soon as I think it should plus when it does start the idle is fairly high (~1,300 RPM) for about 2 - 3 seconds and then it settles down to closer to what I have set.

BTW: my hot idle is set at 650 but it still stays around 680 - 700 RPM.


I'm sure it probably needs more drive time but I don't know that these issues will get fixed on their own through just self learning.

As a side note, I've owned this car for just over 31 years and it's had the same motor for approximately 30 of those years. This by far has been the best it has ever run on the top end. I was able to get out a 6 lane country road with a long stretch with no cars. So I decided to lay in to it for some WOT learning. It continued to pull like it never has before. It put a nice smile back on my face.
 
#11 ·
I was able to get the idle down and get the car out on the road. There will be some tweaking I need to do but here are the two things I need to address first if anyone has any suggestions.

1. When switching through gears (it's a manual trans) or coming up to a stop light/sign, the idle stays high. It stays around 1,800 RPM until I whip the throttle. Then it will return to the normal idle. I but a slightly stiffer throttle return spring on it trying to make sure that wasn't the issue. I then read through some of the touch screen manual and saw where it talked about an IAC Decay. From what I understood from that was the time that it took to go back down to idle. It was initially set as 4.0 but I then changed it to 2.0 and then down to 1.0. It didn't seem to affect it either way.

If it didn't affect it in anyway, I'd put it back where it was. You absolutely NEED to drive the car, and let it learn. If you just got the car running, there's no way it has learned enough to reasonably compensate for your combo. The biggest mistake many people make with these throttle body efi setups is to (A.) start changing stuff before it's had nearly enough time to adjust itself, and (B.) Change multiple things at once....

Just get the basic parameters set, get your IDLE/IAC set, once fully warmed up, and DRIVE it. From the main "Monitor" screen, on the AFR screen, the middle gauge on left side (CL COMP %) will tell you when it's got adequate learn time. The closer that reading stays to zero, the more it has "learned". Once you've gotten a decent amount of driving done, and CL COMP % is near zero most everywhere, you can ADD this learned info to the BASE FUELING.
Go to: TUNING > ADVANCED > ADV. LEARN > Transfer Learned Data....This will transfer the learned data to the base fuel map


2. When I initially start it up it doesn't start as soon as I think it should plus when it does start the idle is fairly high (~1,300 RPM) for about 2 - 3 seconds and then it settles down to closer to what I have set.

BTW: my hot idle is set at 650 but it still stays around 680 - 700 RPM.

It's normal to remain slightly higher for just a few seconds. I'd bet you do not have the IDLE SCREW/IAC Counts dialed in yet.

I'm sure it probably needs more drive time but I don't know that these issues will get fixed on their own through just self learning.

DEFINITELY needs a lot more LEARN TIME. :thumbsup:

As a side note, I've owned this car for just over 31 years and it's had the same motor for approximately 30 of those years. This by far has been the best it has ever run on the top end. I was able to get out a 6 lane country road with a long stretch with no cars. So I decided to lay in to it for some WOT learning. It continued to pull like it never has before. It put a nice smile back on my face.

That's awesome! Idle and overall driveability will also get better and better for you, as it's driven in various temperatures, and conditions.
RED highlighted above...
 
#4 ·
Just received my sniper 550-511. Right now reading through instructions, and planning out my system. Waiting on my PowerSurge from RobbMc. One thing I've been thinking about is the coolant temp sensor. The one available port in the intake has the sensor for my Dakota VHX temp gauge. I see a threaded plug in the head, but don't really want to mess with that. Plus thinking my headers are going to heat soak the crap out of it. Anyone have any suggestions on what I could do? Is it possible to combine the wires to feed off the one sensor? If my only choice is the head, would it be best to put the sensor for the Sniper or the VHX gauge there?
 
#7 ·
I have been running the Sensor for my FiTech in the Head for a several months with no issues, placed a tube of Insulation around it to protect plastic housing from ambient heat, it will read hotter than the Gauge Probe mounted in Thermostat Housing initially however once engine up to operating temperature & cruising they are near identical.
 
  • Like
Reactions: 70CHEVELLE396
#5 ·
Do you have a stock intake or aftermarket one? Are you sure you only have one port on your manifold? I had the same issues trying to find a place for my coolant sensor. I have two ports, one on each side of the t-stat housing, one was being used by a heater hose and the other was being covered up by the radiator hose. I went round and round about what to do and ultimately what I did was put the Sniper sensor to the left of my t-stat then added a 1" t-stat housing spacer which gave me enough room to move the heater hose to the right side of the t-stat housing. My driver side head port is where my aftermarket temp sensor is and my driver side port hasn't had it's plug out in over 30 years so I know it's not coming out easily.

Now, one option you'll come across is to use the port in your manifold for the Sniper sensor and then get the Holley water temp gauge that will hook to the EFI. So, the EFI will let you know what the temp is. It's cool and I would love to go that route but it's something like $80 for the gauge and then $100 for the harness to hook it to the EFI. I didn't want to spend that kind of money right now.
 
#6 ·
It's an Edelbrock perf rpm. Left port has heater hose, right port has temp sensor for my Dakota VHX gauge. So I definitely don't want to add another gauge. I have no idea how long the plug in the head has been untouched, and I'm not sure I want to mess with it. It's not like I use the heat in the car, but if I removed the heater hoses, I feel it would look unfinished, unless I went all the way and removed heater core all together, and covered it up. But I don't want to do that. Wondering if the Sniper just uses the sensor to kick into learn mode, and if I could tie in both (sniper and VHX temp gauge) to the one sensor.
 
#8 ·
One option that I was going to do and would probably work for you is to put the Sniper sensor where your heater hose is currently, then use the 1" t-stat adapter which has two 3/8" NPT ports, then use a 3/8" NPT to 1/2" barb. Relocate your heater hose to the 1" spacer. It might take your heater a little longer to warm up but it should work.

https://www.summitracing.com/int/pa...gle-_-shopping-_-srese1-_-meziere-enterprises (you can get them in chrome as well)

Earl's 984408: NPT to Hose Barb Adapter Fitting 3/8" NPT Male to 1/2" Hose Barb | JEGS (should be able to get this in black as well)

I've attached a picture where I was going to put the sensor in the adapter but that won't work because the t-stat is below the adapter. However, imagine the sensor and heater hose switched in this scenario. I would just use the driver's side port on the adapter with that 45* barb.
 

Attachments

#9 ·
@70CHEVELLE396...another thing you need to think about that I didn't until it actually came time is how you will attach your EFI to the battery terminals. You're supposed to go straight to the battery terminals for both the positive and negative. My terminals were not the type that would accept an add on wire. I ended up cutting off my ends, buying some marine terminals, and then added some battery terminal lugs to connect them all. It was a pain to find some silver (tinned) lugs but I did find some and once it was all said and done I'm happy with the way it turned out. I'm going to eventually do an install thread on what I did and I'll post some pictures there.
 
  • Like
Reactions: 70CHEVELLE396
#10 ·
Thanks a lot for the info. I am also having connections stack up at the battery too. I want to make my own custom battery cables. Have a junction for all the connections. Try to make it clean.
 
  • Like
Reactions: rel3rd
#12 ·
ENGINE SIZE:
439 BBC

HOLLEY SETUP USED:
600 HP Sniper in shinny finish

ENGINE VACUUM:
8-9"

CAM SETTING (Stock/Mild | Street/Strip | Race) AND YOUR CAM SPECS:
Street/Strip
.233/.243@.050", 620.600 lift, 107 LSA

IAC COUNTS @ IDLE
7-8

TIMING CONTROL: Y/N?
NO.
Tried to run it on 2 separate occasions. I need to contact Holley Tech to determine if mine needs to be sent back, or needs some sort of an upgrade/update. Car randomly stalls (loses voltage/power) whenever Timing Control was enabled.

IDLE RPM:
900

TARGET IDLE AFR:
14.7

ANY ADJUSTED PARAMETERS AND WHY?:
Target Idle and Cruise AFR changed from default of 13.5/14.0 to 14.7/14.5 respectively. Smoother idle and very smooth cruise. If cruise AFR is set leaner, I get misfire at low rpm/low load. WOT AFR set at 12.5, as it was out of the box.
I also lowered CLOSED LOOP enable temperature, to 120 degrees to prevent any OPEN LOOP/CLOSED LOOP crossovers at the dragstrip.

ADDITIONAL NOTES:
TanksInc tank, 255lph pump, stock 3/8" feed line, 3/8" return,
I also had to replace the original coolant temperature sensor, to a STANDARD part# TX3T to get handheld screen temperatures to match my Autometer gauge temperature readings...Factory sensor read much lower than actual (150's instead of 170's) which kept car out of Learn Mode.
 
#16 ·
I run a 2/0 cable from the battery in the trunk to a junction block on the chassis at the starter, 1 gauge to the starter and a 4 gauge to a high current fuse block I made up that will mount on the firewall next to the A/C box. I'll be running the power feed to the EFI unit from a fuse in this block. I hope I''ll have no problems. That same 4 gauge cable will loop from the fuse block (uncut) to a 140 amp alternator.
 
  • Like
Reactions: 70CHEVELLE396
#18 ·
As mentioned above. My temp sender is in the intake below the stat as in the picture above and the gauge sending unit is in the t stat housing on the top.
Both read almost exactly the same.
Works fan just fine too
 
#21 ·
Thanks, I'll re-check these things.

First I will say that I switched from a working 650 carb and although that doesn't mean a whole lot what I do know is that I didn't have issues with things like the throttle arm sticking in the firewall or a loose distributor.

I can't 100% guarantee I got rid of every little vacuum leak but I've done what I can think of. The biggest culprit was a manifold fitting I had behind the carb. The one I had in there was too high. I had to switch it out and of course found one in a bucket of fittings. When I first started my Sniper the RPM was in excess of 2,400 RPM constantly. So, checked things and ended up putting on another fitting. I got the RPM down to about 1,400 and from there I backed out the idle screw. That got me to a manageable RPM.

I did have to back out the screw a bit. I started worrying that it was getting too far out.

I think 650 or even 700 is pretty low but when I set it to much higher than that and it RPM sounded too high. It too me setting it down into that low of an RPM to get it to where I could hear the lope of the cam like I used with my carb.
 
#23 ·
Here are some quick pictures off of my phone. In the first pic you can see my original style terminal that didn't allow for any add on wires. In the bottom of the first pic you can see where I have a battery terminal lug on the end of the cable. You can find them at just about any auto part store if you are okay with copper color but I ordered them in tinned copper so they look better. I think you can get in a solder style but I used a crimp on mine. My large crimping tool barely fit the 4 gauge wire.

In the second picture you can see the marine style terminals that allow for lugs on them. They usually come with wing nuts but I replaced them with a nut and a lock washer. You can also see where I put heat shrink over the lug and cable. The two other wires on each terminal have a standard round end on them. I cut the casing off of those ends, crimped them, solder them, and then heat shrinked them. One wire is for he EFI and the other supplies a junction box (positive) and grounds the body (negative).

I will eventually put some nice sheathing over the wires but haven't gotten to that point yet.

The only thing to watch out for is that I guess marine batteries have the same size posts on each side where auto batteries have slightly bigger positive post. So, I had to work on spreading the positive side and it was very tight going on.
 

Attachments

  • Like
Reactions: 70CHEVELLE396
#24 ·
Thanks. That's a lot better than what I currently am doing. I'll look into that, and see what I can come up with. My buddy told me about a marine shop that sells a lot of electrical parts like that. I guess one of the few benefits living near the shore on the east coast.
 
#27 ·
@70CHEVELLE396 ...this is how I've got mine run now. I used the 1" t-stat adapter to raise my housing so the radiator hose would clear. I turned the ports to the back and put plugs in them. I taped off the actual sensor and wires and then painted the outer brass and installed it where my heater hose was originally installed.

My other option was going to be using a 90* port under the radiator and putting the coolant sensor there. My only concern was that it would have taken the sensor somewhat out of the flow of coolant plus there could always be a slight chance of an air pocket in the 90* fitting.
 

Attachments

  • Like
Reactions: 70CHEVELLE396
#28 ·
A 15 degree rotatable water neck housing like shown below might also give enough clearance for the sensor installed on the driver's side of the intake. You should be able to move the upper hose angle enough to get a reasonably straight shot down to the sensor connector. I used a Billet Specialties part, but would not buy another one. Overpriced, and I don't like the way it is constructed. I felt the need to modify it internally to improve flow. The link below shows one for about half the price that I think would flow properly as designed. That's just my opinion though.

Water neck

 
#30 ·
I say you're either going to have to use one of the ports in your head or use one of the t-stat adapters and put the heater hose on it or you can spend the money and get the Holley gauge that connects to the EFI. If it were me, I would try out the t-stat adapter and move the heater hose there. That's a fairly cheap option that's not hard to implement.
 
  • Like
Reactions: 70CHEVELLE396
#35 ·
Yes, in fact I have a JEGS vacuum canister, and it looked identical. This second gen is now a stainless tank, and the new mount allows for it to be spun 360deg to mount how you need it. Mine is the 500hp level unit with a 255lp Walbro pump. You can swap out the pump if you ever need more pressure. In fact RobbMc will do the work for you, if you send it yourself them. You just pay for the pump. Once I get it going I will let everyone know. However winter is here, so it may be awhile.
 
#36 ·
I just checked their web site.........still shows the old version. How did you find that one?
 
#37 ·
Yes, just talked with Robb today. Website will be updated soon (by the weekend) is what he told me. Said the text on the site describes the new one from what I understand. I just ordered about 10 days ago. They were waiting for the machine shop to CNC some more top plates. So I placed an order to secure a spot. Evidently I got one of the first ten produced. I didn't know about the second gen until I opened the box!
 
#38 ·
Have you found any reviews on the RobbMC Power Surge? Just wondering because the FiTech FCC which is similar to the Power Surge is, according to others, a hit and miss....mostly a miss.

From what I understand it works well until the fuel inside gets hot and fuel comes out the vent. I would like the simplicity of using one of those set ups and actually like the looks of the FiTech unit but don't want all the problems.
 
#39 ·
Forgetting about the FCC is the right thing to do.

I've yet to read anything bad about the RobbMC tank on this site. Edelbrock makes one too, but it's over priced IMO.

Spectra Premium EFI fuel tanks with in-tank pump are actually as inexpensive as the surge tanks. I would imagine the tanks themselves are as good as the stock tanks popular name brand tank vendors sell.

Food for thought
 
#40 ·
I really like my Tanks Inc tank. It was about $40 - $50 cheaper than the Holley Sniper fuel tank and looked to be the same thing. Even Holley said either their tank or Tanks would work just fine. I got my tank, 255 LPH pump, straps, vent/rollover valve and sending shipped to my door for $540. Then I spent about $85 for new fuel line and fittings to hook it all up to my Sniper EFI. I can slightly hear it only when I initially turn the key on and it primes the unit. Once the car starts you can't hear it at all.
 

Attachments

#41 · (Edited)
I agree with you on the tank. Right now I could get a Holley Sniper tank (P/N 19-106) for my Chevelle under 500.00 which is really the way I should go. I guess I would have to add about another 200.00 for hoses, fittings and a filter. So the whole EFI conversion would be around 1700.00.

My car now has an AED 950 HO carburetor (bought new in June 16) and runs great and has tons of power........except during warm-up due to not having a choke.
 
#42 ·
I agree with you on the tank. Right now I could get a Holley Sniper tank (P/N 19-106) for my Chevelle under 500.00 which is really the way I should go. I guess I would have to add about another 200.00 for hoses, fittings and a filter. SO the whole EFI conversion would be around 1700.00.

My car now has an AED 950 HO carburetor (bought new in June 16) and runs great and has tons of power........except during warm-up do to not having a choke.
That's about right. I think my setup cost right at $1,650 and that was when the Sniper was on sale for $890 shipped.

Depending on what hoses you want you can get by with cheaper than $200. I already had a return line so I only had to do a supply line. I mostly used 3/8" hard line which is cheap (~$11 for 10') and then some Earls Vapor guard to do the connections of the hard line to the pump and EFI. My filter was only $12 and it's the same one that comes in the Sniper Master Kit.

Call Chris over at HolleyInjection.com and talk to him about your fuel plans. He is a good guy and will take the time to talk through your whole setup. His prices matched or were cheaper than Holley or Jegs. He also has a couple good articles explaining install and tuning. Let him know we sent you over.
 
#43 ·
If I was starting with an old system, I would indeed go with a intank pump set up. I however just replaced my entire system. Tank, sender, mech pump, filters, and all lines. Everything is new, except my Holley 750dp carb. So when I got the itch to try the Sniper, I remembered seeing the PowerSurge while on the RobbMc site. Like I stated before, it's a beautiful piece, everything they make is top notch, and it has a Walbro pump submerged in fuel. They state to keep it away from any major heat sources, and you could wrap it with heat shielding. However I think this would be in extreme cases only. I believe I read if the temp of the fuel reaches 150deg, it could create a problem. Right now, I'm thinking of mounting it in the washer fl tank spot on my 70 Chevelle.
 
#45 ·
Maybe consider adding an electric fuel pump like what comes with the Master Kit. I don't think the Master Kit is out officially yet but the guys at HolleyFuelInjection can put one together for you for probably the same price or maybe even a little cheaper. Again, I recommend calling them and at least talk to him about your plans. It doesn't cost anything and you might get something put together that is cheaper like he did for me.


I know what you mean. Everything mechanical on my car has less then 1500 miles, including my entire fuel system which I would have to throw out.

I was even thinking about removing my tank and install a supply fitting at the bottom to gravity feed a frame mounted pump. I already have an unused 1/4 barbed fitting on my current sending unit that I could use as a return.

Going that way I could just buy the Sniper master kit and save about 450.00 but wouldn't have any baffles in my tank.
1/4" return line is going to be too small. I already checked with Holley on that because my stock return line was 1/4". They want you to use at least 5/16" for a return. What I did was used my stock 3/8" supply line for my return and then I added a new 3/8" hard line with and in-line filter and connected it up with rubber EFI line. That saved me quite a bit of move over going down my original route of suing Stainless line with 6AN fittings. Those fittings start adding up real fast.
 
#44 ·
I know what you mean. Everything mechanical on my car has less then 1500 miles, including my entire fuel system which I would have to throw out.

I was even thinking about removing my tank and install a supply fitting at the bottom to gravity feed a frame mounted pump. I already have an unused 1/4 barbed fitting on my current sending unit that I could use as a return.

Going that way I could just buy the Sniper master kit and save about 450.00 but wouldn't have any baffles in my tank.
 

Attachments

#46 ·
70chevelle396

Here's some hindsight

I built my own external pump fuel supply kit based on the 255 lph 60 psi Walbro pump Holley has pictured in the master kit, and used my old brand new tank with a new sender assembly that included a return. Would not do that again. I saved maybe $100 over doing it with a Tanks Inc tank by the time I was finished. I didn't save a penny over doing it with a Spectra Premium tank.

Anywho, if you build your own EFI fuel supply or have someone else put it together for you, do whatever it takes to remove any dips in the return line to the tank. I used the original 3/8ths fuel supply line for return from the throttle body, and I'm relatively certain my return line does not clear fuel out properly due to the hump in the line over the chassis over the rear axle and my tank and sender unit not being designed for fuel injection. I've removed the return line at the tank and there is always some fuel in it. To address this sometime in the spring 2017, I'm going to use the Corvette style filter regulator right after the external pump as close to the tank as possible, and run the return to a return fitting I installed in the fuel tank filler tube. Macgyver engineering to say the least.

Obviously the RobbMc surge tank is the easiest way to put together a reliable EFI fuel supply with what you have now. If he had been using the new tank 3 months ago, I would have used that most likely.

I might be repeating myself. My apologies to anyone who actually reads anything I type in a message box. :D
 
#48 ·
70chevelle396

Here's some hindsight..................

Obviously the RobbMc surge tank is the easiest way to put together a reliable EFI fuel supply with what you have now. If he had been using the new tank 3 months ago, I would have used that most likely........................
The RobbMc surge tank would be, no doubt, the easiest way; just like the FiTech or Edelbrock units, all of similar design (the Edelbrock is ugly though).

The big question is do the RobbMc or Edelbrock units work or will they have the same problems like the FiTech FCC. I sure couldn't find any reviews on either. I would love to use any of those units if they would work as intended!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top