Done with EFI, back to carb

[KQQL IT]

Analog ftw or

K.I.S.S

[fdbdw]

Parts came today
AVS 2 650cfm , performer intake, mechanical fuel pump, went ahead and purchased a new cam to match, since the O2 bung is in place I’m adding an A/F gauge ( which is handy at 6000 feet. Gotta work this weekend but I should be done with the swap sometime next week.

[weq92f]

Originally Posted by dan42

<snip>...First start up it cranks a bit, but after that it kicks right over...

I solve this issue by allowing the fuel pump to prime for a full cycle, usually about 5 seconds, before I attempt to crank it over on a cold start. On warm starts, I a crank the motor over in the middle of the fuel pump prime.


-klb

[El Dorado Jim]

Originally Posted by dtkarst

Anytime I have a Holley on anything it goes away. PO switched the Quadra jet off my 402 and put a Holley on. I rebuilt the QJ and put it back on, runs much better. I’ve just never had luck long term with a Holley. Just my two cents

x2 Holley is junk

[zicc1835]

I was about to jump into this Sniper Kit saving my nickles , you guys just saved me a sizeable amount of cash and more important the stress and time wasted ...thanks to all ill stay old school until I do the LS swap on the next one

[jaros44sr]

Originally Posted by AussieinNC

The "Electrical" sub forum lists EFI swaps as a component thats permitted to be posted.....perhaps a sub forum listed under Electrical would be the easiest to deploy....

BTW...best practice is to always run dedicated ground feeds back to ground bus....

When I built my shop...I ran all power feeds thru EMT plus dedicated ground return wires back to the panel, along with grounding the EMT to the panel....makes certain the circuits work correctly...

just dropped down to the electrical forum, didn't see any listing for EFI, any help?

[jamyers]

Originally Posted by fdbdw

Parts came today
AVS 2 650cfm , performer intake, mechanical fuel pump, went ahead and purchased a new cam to match, since the O2 bung is in place I’m adding an A/F gauge ( which is handy at 6000 feet. Gotta work this weekend but I should be done with the swap sometime next week.

What you going to do with the Sniper stuff? Wanna sell it?

[fdbdw]

Originally Posted by jamyers

What you going to do with the Sniper stuff? Wanna sell it?

Already sold

[fdbdw]

So glad to be done, AVS 2 carb

[toolboxchev]

Curious on your setup, What are you running with both vac lines hooked up?

[BlouDon]

Originally Posted by fdbdw

Holley sniper EFI has been nothing but problems.

My 2c worth:

I have extensive experience with Megasquirt on V8 and V12 engines.

Many DIY EFI tuners rely too heavily on the O2 sensors doing tuning for them. When I tune my engines, I use a wideband sensor to tune my fuel maps so well that the engine can run very well "open loop" - without O2 sensor. In some cases I leave the O2 sensor active for "closed loop" but then the O2 sensor only has to do the last 3% or so fine tuning.

The other mistake often made is that current limit resistors are used with low impedance injectors. This is fine for racing but very bad practice for road cars that spends a lot of time at partial throttle (small pulsewidths).

The effect of intake air temperature is often also underestimated (ignored), not to even mention barometric pressure (latter plays a massive role on normally aspirated engines).

Bottom line: If you DON'T know your stuff with EFI, you most likely WILL be better off with Carb.

Now here's a curved ball....?

Most carbed engines are more in need of mapped ignition than EFI (Something like Megajolt) ....

[davepl]

The only thing worse than a misconfigured EFI is a Q-Jet missing a few parts! :-)

My Sniper runs really well. I do have to dial in the "accelerator pump" after changing my linkage, but otherwise it's perfect.

My blue truck runs the factory Q-Jet with ALL factory equipment (heat risers, thermac, etc) and it runs well enough. A good carb or good EFI is great, but living with a bad version of either sucks.

[fdbdw]

Originally Posted by toolboxchev

Curious on your setup, What are you running with both vac lines hooked up?

Driver side to the distributor, center PCV, passenger side to the transmission
because I didn’t have a fitting at the time that one has been moved to the rear manifold port.

[toolboxchev]

Thanks for the info, I kinda figured it was something simple. I was hoping to figure out some tidbit of gold that no one else knew about!

Eddy wanted me to buy one of those last time I spoke with their tech department. It has been 10 years since I put one on my truck and has been trouble free since install. Granted its not a AVS.

And thats with ethanol! Yikes!

[67ranchhand]

Originally Posted by liftlawssuck

Where are you running your grounds? A ground bus is the best way to go but the very least all grounds should go back to the battery. If not then they are susceptible in picking up stray voltage. I cannot stress that enough with the grounds. Grounds to chassis aren't good enough. Also shielding from the distributor is also crucial. Running wire harness near plug wires or distributor is also just as important.

I have the sniper setup on my Monte Carlo and I like it but know nothing about it as far as tuning. I’m not going to give up on it because it cost me money and I like the idea of it. I know how to tune a carb very well but tuning this is a little different like you mentioned. What do you use to shield the distributor? What do you use to shield the wires? I do have issues with mine and think it will run great after all the bugs are out of it. Thanks.