Engine leaning out at 3000rpm

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I have a 100micron pre filter before the pump and a canister filter on the frame rail i have a brand new painless harness no bulkhead but i will check for proper voltage at the coil just to make sure
 
Remember its going lean on my a/f meter like its sucking air if it wasnt getting spark it would show up way fat 9:1 or so
 
It has a pre filter and a canister filter on the frame rail brand new harness wihout a bulkhead allthough i will check the voltage to the coil to insure it is good it seems because if it going lean on my a/f ratio guage it has some kind of vacuum leak in the intake or something like that
 
I'd check the filters and even remove them just to make sure.
 
What does the fuel pressure read on the carb line when this happens?
 
moparwillybb said:
Hello guys it seems my engine has developed a problem now when i mash the gas my engine goes way lean like 16-17:1 pops out the exhaust and makes a hollow kinda bbbbbeeeerrrrrrrrvvvvvvvv sound ive cahanged intake gaskets 3 carbs jetted the thing as big as it can go no change its a 493 with a performer rpm intake 440 source heads checked the vac port for power brakes its good put brand new carb gaskets torqued to 80inlbs it does not idle funny runs good if i keep it under 3000rpm what the heck is going on its driving me crazy im switching to a single plane intake this weekend got the expensive hughes engines intake gaskets and a new pan and some hylomar blue so im gonna seal the crap out of it hopefully last time i took the intake off i had a little oil i the intake runners of the heads and oil in the intake bolt holes is my engine sucking air from the valley? Any help would be appreciated
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I run single plane intakes on 99% of the motors I`ve built and the cars I build carbs for ESPECIALLY a stroker..............better distribution and consistent booster signal and easier to tune imo. Something is amiss here having tried different carbs w/the same results. You need to SEE your fuel pressure when it acts up to at least take that out of the equation and if you`re sucking that much oil the dilution percentage COULD cause it to detonate and lean out. Where are your float levels? I thought I read that you`ve been having ign. problems also so that can`t help matters..............
 
He doesn't know, the pressure gauge is under the hood.
 
All good stuff im gonna try to put a camera on the gauge when i am driving im at work right now im going home this afternoon to swap intakes and gaskets no ignition problems so far gonna try all these things when i get home just collecting things to check thanks a bunch guys keep it coming
 
moparwillybb said:
All good stuff im gonna try to put a camera on the gauge when i am driving im at work right now im going home this afternoon to swap intakes and gaskets no ignition problems so far gonna try all these things when i get home just collecting things to check thanks a bunch guys keep it coming
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You stated the digital 6+ was giving you problems on page 1 unless I misinterpreted ..............
 
Lol thats just my bad punctuation i was just listing what was in the car digital programable 6 plus. Its been plagueing me.......... sorry
 
moparwillybb said:
Remember its going lean on my a/f meter like its sucking air if it wasnt getting spark it would show up way fat 9:1 or so
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If you're having a misfire, the A/F meter can read a false lean condition. The O2 sensor can read the unburned oxygen and think it's lean when it's realy not. I'd check plugs, wires, cap, rotor, and coil first. Just to be sure it's not a false lean reading.
 
Probably not your problem, but I had the same symptoms when I wiped the cam on my 318. Thought it was a fuel problem for the longest time.
 
I was wondering about the exhaust. Is something restricting the exhaust-like the muffler, bent or kinked exhaust pipe. If the exhaust is restricted to flow-the engine will not have good vacuum especially as intake air flow will cause the engine to lean out as the throttle opening is increased. You may want to check this?
 
If you think the pump is running it lean, get on a back road and hammer it, when it starts to stumble throw it in nuetral and shut it off at the same time. Pull over and check the fuel bowls, if they are empty you will know that is the problem.
 
ChrisPerry said:
If you're having a misfire, the A/F meter can read a false lean condition. The O2 sensor can read the unburned oxygen and think it's lean when it's realy not. I'd check plugs, wires, cap, rotor, and coil first. Just to be sure it's not a false lean reading.
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This is a good and valid point as well and would love to see the plugs as they tell a good part of what`s going on in the combustion chamber...........
 
Very true those msd caps dont hold up to well i need to check that one and everything else again guys thanks a bunch for the suggestions i will check all of them! I het home in about 2 hours and its thrash time!
 
Well i changed the valley pan and gaskets upgraded to a single plane m1 and nothing changed so i got to looking at the timing and lo and behold i took the distributor cap off and it had white corosion on all the terminals i scraped it all off and it ran great that cap dont have 3000 miles on it! But i guess they dont last to long i ordered a new cap and rotor so i will see tomorrow if it fixes the problem for good oh and i love the single plane that thing pulls like an animal i didnt perceive any loss on the low end at all the thing is a monster but i guess when you make 609ftlbs @4400 rpm you can afford to loose 15-20 lol
 
If you continue to get the corrosion, you can tap a small hole in the side of the distributor and run a vacuum line up to the air cleaner. It will give just enough vacuum to keep the gases from building up in the cap and causing the corrosion.
 
moparwillybb said:
Hmmmmm that sounds fancy there is gases in there where are thay coming from?
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Ozone, caused from the electrical sparks from the rotor to the terminals. That's what the small vent on the cap or the side of the distributor is sopposed to be for. It's just not always enough with a high power ignition system.
 
ChrisPerry said:
If you continue to get the corrosion, you can tap a small hole in the side of the distributor and run a vacuum line up to the air cleaner. It will give just enough vacuum to keep the gases from building up in the cap and causing the corrosion.
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THIS is a great idea . Thanks .
 
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