Attention Sniper Owners...

[007]

Two things I learned recently and really want to share...

Last Sunday I was out wheeling and having a blast. About 2/3 of the way through I developed a miss. I figured it was a plug as I knew my plugs were in need of replacement.

I finished the trail and hobbled home on 7 cylinders and pulled it in the garage and out a fan on it and went straight to the parts store and got plugs. Sure enough, #3 looked A LOT different than the rest. Put them all in, fired it up. I It idled smooth, but as soon as I touched the throttle, the miss came back.

Naturally I thought, well it's gotta be wires then right? Picked up a set of wires at Summit (thank God we have a store here) and replaced #3 - made no difference. So I replaced ALL the wires, no difference.

Pulled off the cap, inspected it, cleaned the contacts with a rotary wire brush, no difference.

Changed tunes on the Sniper to an older one, no difference. Put the current one back.

Finally I got on the Sniper forums on the Holley site and when through all this there, and not long after I got a response that it could be a bad injector OR perhaps just a loose connection on the injector. They said to pull the air cleaner, fire it up and see if all injectors were firing.

I did just that and BAM - the front passenger side injector was dry!



Finally a root cause! So I went back to the forum and reported my findings and asked - what do I do now?

What you do is unscrew whatever side the problem is on and the injectors are housed in those sides. I pulled my passenger side off nervous as can be, and gently snuck a flat head screwdriver inside between the housing and the back of the plug and sort of pried it downward and sure enough it slid down about 1/8". I quickly pulled out the screwdriver, reattached the side and fired it up and voila - problem solved!

I also noticed that this is the injector that would feed the #3 cylinder.



The second thing I learned, I learned by accident in searching for solutions to the first problem. This topic is under some debate, but for me it's a no-brainer. Many (myself included) have found a noticeable improvement in throttle response and performance in raising the throttle body up an inch, particularly on dual-plane intakes like the Edelbrock Performer. Doing so creates the ability for the fuel mixture to flow differently (similar to what you find in open-plenum intakes EDITED due to TeamRush's correction below - which I appreciate!) and perhaps of equal importance, it leaves the MAP sensor completely uncovered and exposed for better metering/measurements.

I added a 1" phenolic spacer to mine and I like the results, plus it will keep the throttle body a tad cooler, and that's always good.




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[TeamRush]

Um....
Knit picking here,
'Air Gap' intakes have a literal air gap between baseplate (bottom of intake) and intake runners.

I *Think* you probably intended to say 'Open Plenum' intakes, little or no divider between 'Sides' of the intake.

High rise, open plenum intakes are often have an 'Air Gap' between the base plate/bolt flanges and plenum,
And they often have open plenum.

.

Great for Idle & Wide Open Throttle (WOT).
Sucks at mid range RPM, particularly when emissions controls are involved.
Divided plenums allow for greater control, particularly when it comes to cylinders firing one right after the other, say 5-7 on Chevy engines,

5 is in full draft, pulling charge mix (fuel/air) when 7 opens and gets starved until 5 intake valve closes. 7 always runs lean with an open plenum...

A lean cylinder, bundled spark plug wires creating induction fire in #7 or multi-fire in the distributor fires #7 up to 90° too soon, the connecting rod is no where near ready to break over center of the crank,
#7 gets hammered out of the engine...

Things compound, and that's one of the drawbacks when 5-7 firing order is used.

---------------------

SOME intakes have a notch cut in the center divider, it doesn't take much, 3/4" square is usually plenty to equalize the intake vacuum signal.

Spacers do the same thing, BUT they can also kill the midrange draft separation, raise emissions & reduce fuel economy.

One thing we do for part throttle race cars (for tuning) is drill the plenum side, through the center divider,
We use plugs in the divider and plenum wall, removing internal divider plugs as needed to equalize vacuum signal without overdoing things (controllable & reverseable with threaded plugs).

We figured this out with the old nitrous oxide systems that had fuel & nitrous spray bars that crossed the plenum, so we kind of stumbled into the holes/plugs.
I can't take credit for it, kind of something that evolved as we were driving to/from the drag strip and got better throttle response & fuel economy, and could still pass the tail pipe 'Sniffer' test when we had those here.
(If you are old enough to remember Marv Miller nitrous systems, you will know exactly what I'm talking about with cross plenum spray tubes)

Just an idea, if it makes sense feel free to use it.

 

[007]

Um....
Knit picking here,
'Air Gap' intakes have a literal air gap between baseplate (bottom of intake) and intake runners.

I *Think* you probably intended to say 'Open Plenum' intakes, little or no divider between 'Sides' of the intake.

High rise, open plenum intakes are often have a gap between the base plate/bolt flanges and plenum,
And they often have open plenum.

Thank you! I edited my post above and indicated why I changed it. That was indeed what I was referring to.

I'll find out on the trail how midrange is when I'm in it, but opening up the MAP sensor area seems to be the more important improvement. Folks who have done this report better economy due to better measurements, they see less jumping around in the AFR measurements and that improves the fuel learn table substantially.

I've always felt my EFI didn't give much of an economy boost, and to be fair - I don't care as there's not much room to improve that aspect of this engine/vehicle combination - it's a streetable tractor. But it's something that I expected and perhaps I shouldn't have.

 

[gert]

it's a streetable tractor.

OMG that’s so funny and so true for the older Willy’s


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[TeamRush]

Everyone asks why I keep the old rusting '73 above all others,
Manual steering (skinny column), brakes, shift, lockouts, etc.
No Air Conditioner, the heater just squeals so much the annoyance makes you forget about being cold, and it didn't even come with a radio option.

It has a drawbar, I plowed the gardens the first 3 years I owned my property with a CJ.
The winch raised the barn walls and set roof trusses,
The dual batteries & jumper cables did all the welding around here the first year.
The extra battery on Anderson connectors powered my camp, tent fans, lights, battery powered tools when the Ni-Cad batteries quit, etc.

It hauled water, rock, (composting), pulled stumps & logs, plowed/disked, pulled, pushed and generally did everything I needed to build the homestead from dirt up.
It's as much a part of this place as any tractor,

It's basically a gocart sized V-8 tractor with some mountain goat DNA,

But it still requires a clean underwear change when you try and go interstate speeds!