87caprice318

iTrader: (1)

Hey there guys, Im having major issues with my carb setup. It is fouling plugs INSTANTLY. This just started happening when I added the nitrous plate to it and the guy who set it up for me took out the NGK plugs for Autolite 104 on a 100shot. What gives??? so confused and cant enjoy the car anymore.

The carb I'm running is a Quickfuel 780vs...I recently installed a AEM wideband and at idle my AF ratio is hoovering around 11.7-12.2.....When I touch the gas it drops down to 10.0 which is pegging the wideband RICH then shoots up too LEAN...basically the plugs are dead fouled now. If I attempt to take it around the corner it pops/bangs bad. Ive pulled all my hair out.

My timing is 0rpm=14* to 500=17* THEN to 1000=24*THEN 2000=20* all the way out. MAP sensor adds 6* so it'll be 6* added to those numbers......WHO WANTS TO TUNE THIS DARN CARB.... ENGINE is a LY6, heads milled 40, 230/242 cam, Holley dual plane, NX nitrous kit now on 150....I have a carb jet kit also. The guy who did my nitrous also removed my PV from the front of carb and blocked it off as the rear PV come blocked off.

Doug G

First....do NOT run projected tipped plugs with N2O.
How is the fuel routed to the fuel noid ? Could it be leaking by ?
When he had the carb apart to block the front PV, was it re-jetted ? Betting a torn gasket at PV easy to fix...And, really not sure why it was done if this car is driven on the street
Maybe another issue with carb since it was taken apart and unsure what all else he did. Did he mess with the idle speed ? Did he turn out the A/F screws ?

This is why I learned long ago to work on my own stuff....been down this road having to rely on others SUCKS.
Not putting you down. Just some things you need to know and learn....there is some pride that comes with it.
I've actually stopped working on my car when someone showed up and wanted to help...LOL

ZONES89RS

iTrader: (25)

Get a NGK Br7ef for the nitrous. And do everything mentioned above.timing seems low as it sits though.

WTF?

Sounds like an old school guy with old school ways of thinking. Put the carb back to stock first. If he blocked the PV, then he upped the jetting 8-10 jet sizes to compensate. That is where you are getting you rich tip in, that or he raised the float level too high. BR7eF's, carb back to stock, and if the car has a good mph tune up in it, then pull the timing from there. Don't let a hack work on your car. It is frustrating and expensive.

87caprice318

iTrader: (1)

Thanks for the response Doug. This is also on Motor, without even arming the nitrous it's killing plugs instantly. Yes he's an old school sbc/bbc guy, nothing LS. I don't know what he did with carb but I do know he took the pv out, don't think he re-jet it because he never used my jets and when asked, he said no you don't have to do it. The plugs he recommended, were the 104s, projected, sprayed once in a 100 shot and melted the tip a little on #2 plug. So yesterday I pulled them, and replaced with some more and instantly fouled them out. Not going to spray until I get my car right.

My car ran so much better when I did everything to it myself vs listening to recommendations on so called carb "tuners". Normally no one has ever touched my car until recently when I was wanting to grab every bit of power from the carb and I hate I messed up and did it. And hate is a word I prefer not being in my vocabulary.

I really need guidance or help on this asap because I want to race my buddy tuned 13 5.0 on 100 shot xmas weekend

87caprice318

iTrader: (1)

Thanks also Zone, yes Im on my way to O'Reilly now to hopefully get a set of those plugs for when I spray. I will do all mentioned above or just swap my cousin new quickfuel I have sitting here (same carb as mine) for his ls swap in a couple weeks to see what gives.

As far as my timing, the numbers above is what's on the table. The Map sensor adds 6 to each of the numbers listed above. So it's roughly 20, 23, etc in the timing dials in the software. Still too low, I'm so frustrated it has me lost. I was about to call u bro but didn't want to bother you

87caprice318

iTrader: (1)

Yes he is one of those guys. I will go back stock and go from there. I've learned my lesson there not continuing to do it alone. Need to learn more about carbs and these engines with timing. Thank you!

TTur1996

I would try disconnecting the fuel line going to the Nitrous fuel solenoid first. Like Doug said it sounds like it could be a leaking. I'm not sure about the old school crap. But carbs haven't change all that much. Lol

87caprice318

iTrader: (1)

Checked everything, no leaks anywhere. I can't seem to get the wideband to read above 12.3 at idle adjusting the mixture screws. Hit the gas, still goes rich. Wtf I'm tired of buying freaking plugs

TTur1996

The only way to see if its leaking would be to physically pull the carb off to see. That's why I said to disconnect the fuel line going to the nitrous fuel solenoid. Then see what your wide band says. This is assuming your nitrous fuel solenoid is under constant fuel pressure. If its not, then this will not apply.

TXsilverado

iTrader: (18)

It seems odd that you cannot get it to run lean with the idle screws. You should be able to shut off fuel completely with those screws. Are the idle screws hyper sensitive when making adjustments?

87caprice318

iTrader: (1)

No leaks coming from the Fuel side of the nitrous noid.

TXsilverado, thats whats getting me. When i adjust the idle mixture screws, the cars really does nothing even if I screw them all the way in. Fuel sights are at half way like recommended. Check for fuel leaks. Tried the new quickfuel on, same model etc, SAME THING. killing plugs.

Could it be my timing is entirely too low or something? Are you guys running your map 0'd out until you get everything squared away or letting the map add the timing as normal?

TTur1996

The real strange thing is the fact, the motor ran fine before you put the nitrous on.

87caprice318

iTrader: (1)

That's what got me so confused. It ran perfect before I added the NX plate. Once I added the plate, plugs didn't last at all. I've removed it and replaced with new gaskets. Checked everything. I never sprayed the car before this btw. I know it's that freaking carb. Even tho I have a wideband, I'll buying a vacuum gauge tomorrow to adjust the I/M screws

WTF?

Start it up and see if it is dripping fuel from the boosters at idle. I would bet the floats are too high now. It' might be getting pullover. That or the floats are not sealing since it's been apart.

TXsilverado

iTrader: (18)

fuel is coming from somewhere if you can completely close the idle screws and it keeps running...

raceman14

I am an old school Carb guy with efi skills too. I have had a SuperFlow chassis dyno for 25 years and have tuned from 15hp to 2500hp.

I am guessing floats .030- .090" too high. Did he have wrench and screwdriver to float bowls???

Also power valves are for tuning and only folks that don't know how to tune them in leave them out. I have built 50 Nascar style SB-2s in 7 50-1100hp N/A and I have never left out power valves. Just to let u know I made 750 hp on BGN358" with 390 carb and she book over 200 mph in practice at Charlotte.
Anyway do u know anything about working on a carb??? Got any gaskets and parts cause them Blu gaskets go to $hit when u take carb apart.
What jets are in it?
You got a vacuum gauge to tune with, u don't need no stinking laptop.
Are ur 02 sensors heated and where they located for ur rich / lean?
I will wait on ur responses and we go from there...

WTF?

Nice resume, who cares? Basically you just stated what I've already said after you beat your chest about it. You're great, we get it.

OP, place the carb back to stock settings FIRST. Then pull your timing. Timing affects afr's. But honestly, you are over thinking it.

87caprice318

iTrader: (1)

Update: I was about to tackle this after reading you guys replies but came to a conclusion if I went about this and it didn't turn out good, I was throwing this car back in storage until next summer....

I checked with a LS dyno running place, but they only deal with efi and he recommended a carb tuner close by the area that builds Nascar engines. So I got his name and asked my unc from Texas did he know him and he said yea I know him, I've sold many of my 4 sec race cars to him and he's legit/knows his stuff. Finally called the guy told him what I had and what the problem was. He said come on and get the car over here so I can get you right. After about 2 hours, car is running great, NO MORE burning eyes at idle, NO MORE smoking from excessive RICHness, and pulls like it did at first. Cranks so much better.

It was about to rain, luckily we finished it before it did and made a few test runs. At WOT, it reads about 13.8....at idle is reading around 10.9-11.2...but the guy also suggested to take out the autolite plugs and said when the track reopens we'll tune in it some more to get it all the way right because how he say he have it now, it's pretty close but he wants it dead on. Also suggested to make a couple street passes with the 80 jets in the rear and try 82s to see if it gets a lil quicker, SOTP, if not put them back and wait for the track.

He changed primary jets to a 70 and rear jets to a 80 from a 72 and 86...adjusted floats, put power valve back in, adjusted mixture screws. But car runs great now and he also said to change my nitrous fuel pressure from 12psi to around 8. Stated he didn't know why on earth the nitrous guy put it at 12psi on just 150 shot.

TXsilverado

iTrader: (18)

You dont get a fuel smell at 10.9 afr at idle?