Hiya! Just finished the install of the Holley Sniper EFI system on my 12A Street Port. It’s runs if I keep giving the throttle little blips, but ai can’t seem to get it to idle. Has anyone had any luck tuning these systems? Can I get a config file or at least some advice on getting it to idle?

 

i know nothing about the system, but try adding fuel, and if that doesn't work remove some. (sounds dumb i know) if you have a wideband O2, you're shooting for about 12:1 at idle, and then when you have the timing all dialed and stuff, you should be able to lean it out, how much depends but 12.2-12.8 is reasonable

once its over ~1100 rpm or so it can be 14.5:1, and then when you get over ~50% throttle you want it to be about 13:1

 

Hello Workaholic,

Looking at EFI as well. What specific model do you have? have you worked out the issue?

 

I got the 550-511K , went with an in-tank pump and re-ran my fuel line and return in 3/8" NiCu alloy. With a little tweaking I got it running decent. It starts so much easier than carb and idles nice; but I'm leaning out when I decel in gear (sometimes to the point of stalling). If I knew an iota about tuning EFI systems, I'm sure I could get that worked out easily.
I did see someone on youtube have a good go with the 2bbl version with an adapter plate. Might be a better bet. I'm going to try a progressive linkage to try to smooth things out (I accidentally chirp tire sometimes at stop signs).
If your carb is in great working order, keep it for now; otherwise with a bit of tuning the Holley kit ain't a bad deal.

 

If you have not already, you guys should check out RAD Potential on YouTube. Erich did a series on the Sniper EFI. Currently the playlist has 10 videos
https://youtube.com/playlist?list=PL...ilQJXrMq2FNwbh

 

I second this. RAD Potential is an amazing resource for many things first gen for those who are visual learners, myself included. He is also great with responding to questions in video form, which is also an awesome help.

 

The progressive linkage won't do any good. The fuel injectors will meter The fuel like secondarys. I had to raise the idle screw so the butterflies were open enough for it to idle. Then the computer will tune the rest. Make sure the learning percentage is 100%. Mine was at 50% even though the default was 100%. Once it learns the map u can lower the idle.

 

New to the club. Have been playing with a street ported 12a that I had installed in a porsche 914 back in the 1990's because the Rx-7s were blowing my doors off at the autocrosses. Put on the pole barn around 2000 and pulled it out last year and have been tweeking on it ever since. Installed A/fF ratio guage last week and found that I have been running 18.5:1 and higher. added more jet sized and still way lean, but a LOT stronger. Better idle, more mid range pull and top end is awesomely better. But a bad cruising gurgle at high vacuum cruising between 3000 and 3500 fixed by pushing for more gas. Using Elderbrock 600 cfm vacuum secondardary carb. 410 main jets with 65-37 metering rods and the stronger springs. was thinking running lean at high vacuum but bigger jet made it worse. Any ideas are definitely appreciated!!!!!!

Also the main reason to be posting on here. May just give up on the elderbrocks and go to the Sniper EFI. I watch the Rad videos with the 2 barrel Sniper, but while buying would like to know if going with the 4 barrel fixed his 3000 rpm stumble which is what I am having with the Elderbrock. This has been the first site in a year of looking that asks and answers technical questions on these awesome engines. Thank you for sharing your learning experiences!!!!!!

 

Bought the 4 bbl 800CFM. Had a few issues to figure out, but now is idling at 1300 ( Street port ) with smooth acceleration and nice power curve. Have a race beat Intake manifold to arrive Friday, but VERY pleased so far with stock manifold and a Nikki to Holley open port adaptor. Will do some 0 to 60 runs before switching to the Race Beat manifold. to see if there is a difference. Also isolating the primaries from the secondaries to see if the settles down the low end like the Nikki. Anyone ahead of me on all of this.??? Still in a nice learning curve.

 

A quick question (sorry to hijack the tread), I have been thinking about getting a sniper but, I know some EFI turns off all fuel under no throttle coasting to conserve fuel, does the sniper do this? as I premix I'm worrying about oil starve under deceleration.

 

It does go lean on deceleration. I premix too but also have a little from the OMP..The OPM puts in about 3 1/2 oz per 5 gallons. Use 5 oz/ 5 gallons.

Drove the car today the best feel of acceleration was between 40and 60 % TPS. Most of my cruising is between 3 and 8% on the TPS

 

was watching a vid on an older Vette conversion and he was having a lot of problems and it turned out to be ignition noise interfering with the electronics. It was stated they’re finding this to be a common issue with older vehicles using this system. So it seemed worth mentioning.
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Screwed up with saving ECU to transfer to Base Map. It down loaded the 2x4 sniper file. That is for a duel 4barrel sniper system. Started over with the base. I had it running great and idling at about 1300 rpm smoothly. then would not idle below 1800after the screw up. Now back to smooth at 1600 and will try lower as the base map works in.

Page 15 of the EFI Manual handles to factors.
" Fuel Control Decel wait time" Normal 0.5 to 2.0 seconds " Higher number can hope manual transmition cars abd improve Driviblility"
"Fuel Control RPM Added to the Idle for fuel Reactivation" 300 is a good starting point for a manual car.

Have not found how to get to those setting yet, but I think that could be one of the answers for the dying on decelaration.
I added more Idle screw to open the butterflies slightly more to see if that works tomorrow.

Race beat intake manifold came in today. Also ordered the 40% secondary delay linkage. Want to see how running on just the primary port helps out low end and Idle.

 

Added Racebeat Street ported intake manifold last week. Start over on the tuning from fresh wizard. Too cold to do much tuning on it so far, but seems to be strong in mid range. The RB manifold is slightly wider and rearward than stock with Holley adapter. I have a 1" 4 hole spacer. The Sniper butterflies are 1.74" and the RB manifold is sized for a 465 CFM Holley carb. So a spacer or milling of the Manifold is required to allow the butterflies to open. Ordered a 1/4" spacer to see if that is tall enough to allow the butterflies to open freely.

27 degrees this morning and the car started IMPRESSED!!!!

 

Still putting together more pieces of information. A utube talking about starting issues. Says the older starters were slower 250 rpm and the newer stronger ones turn at 300 + rpms. My first start requires throttle and about 10 seconds of turning. My porsche conversion uses the stock starter and only turns at 153 RPM until It starts firing. The 1/4" spacer came in today but a winter freeze is almost here. So may be a week or two. to put it on and checking it out

Watching EFI tuning videos several good ones. A good idea is to tune Rotary engines by exhaust gas temperature. The Hotter the exhaust gas the hotter the engine chamber and the engine itself.

Off subject question :::: 12A NA 1983 Length of the dip stick to the ledge on the rubber that sit against the engine. The rubber started sliding around. 10 1/4" is my guess at where it was. Could anyone measure to see if that is correct.

 

With the Sniper installed I was able to cold start the engine to about. 20 degrees. Tried Yesterday at about 0 degrees but the starter would only turn the engine at 103 RPM and would not start. Tested the battery CCA of 880 but only putting out 200 amps. Replaced Battery and Spun over like a top and started at 9 degrees. I have a mine mounted to a 915 Transaxle with the stock Porsche starter. Not as strong as a Mazda starter. will try again in the morning at 3 degrees. Just impressed that I have not fouled the plugs yet.!!!!

 

Cold start the last couple of mornings.. Temps in the 15 to 20 range. Would have never started with my old Elderbrock set up!!!! Cold start takes about 15 to 20 seconds of grinding with 257 rpm with butterflies closed and a little over 300 rpms open. . Starts very rich 9.1 AFR and leans out in about a second or two. Will not drive until it rains and washes the salt off of the roadway.

 

How is the tuning going on the sniper? I just installed a super sniper on a 12a and I am looking for some help on decel stalling.

 

I Found that if u turn down the idle air control valve all the way. Helps with that. Unplugging works too. I could never get iac to be consistent.

 

Increasing the minimum injector open time helped alot with decel. I think I bumped it up to 2ms? The option wasn’t on my handheld, only on the software on the computer.

 

Re- ran Wizard 110 cu in with mild cam settings was much closer the needed setting.12 A street port engine

 

i wonder if that got the injector opening enough it was more consistent? the FC Tweak for the PFC looks for injector duty that is too low to be controlled, its interesting because its not something you'd normally think of

 

Thank you will look into that. Knew I would not exceed thew max. Have not looked into too low. Will to get the laptop hook up cord to set the min time for the decel issues. too

 

I am the owner of the car that RAD Potential used in the video. I had similar stumble with car (Erich talks about this in couple of the videos); this spring I decided to stop being lazy and change the plugs/wires; and now there is no more stumble at all. Cars start cold and hot easy. Only issue I have is that the IAC is at 20% while cruising; and it sticks some coming off cruise to a stop but blip the gas and IAC goes to lower 5%. So the stumble was related to less than fresh plugs/wires and not having the 2bbl Sniper. Extremely pleased with Sniper set-up.

 

THANK YOU so much for having RAD do your car !!!!! Learned several things from it. I went with the 4 barrel due to the stumbling issue. Thinking that it could be the Reducing plate from the 4 barrel to the 2 barrel. And the option to run on only the primary ports if I wished.(Have not tried that yet.). Even disconnecting the secondaries completely is not a bad option

Cold Starts are possible even in 20 degrees morning without fouling spark plugs !!! I need about 250 to 300 rpms to get the compression good so I changed to thinner oil and then discovered the battery was only putting out about half the amperage. Will change back to 20-50 in a month or so. My Sniper temp gauge reads hotter than my older Gauges, which is lucky since if it did not it would be hard to get it up to temp to learn.

What Air/ Fuel ratios are you finding to work best? What Vacuum does your read at Idle. Mine is 45 to 53 ( 100 is full open butterflies )