fuel starvation or ignition issues?

[charger2fast4u]

i'm having some engine problems with my 73 challenger has a 440 in it pretty much stock 6pack 440 except for the carb is a holley 4 barrel double pumper my problems im having are i have a holley rich/lean fuel indicator with 3 lights middle means its right left is lean and right side light is rich it was running good until one day it started to read lean at idle then as you drive and got  around 2,500 RPM it read it was good. couldn't tell any difference in performance. now my issues got worse it has a slight stutter as im pulling out of somewhere and after 3,000 RPM it falls on its face if you give it gas has no power and seems like its misfiring or starving for fuel i get it home after replacing the spark plugs and notice the fuel pressure was reading about 3 PSI on my liquid filled gauge at the carb tried adjusting the regulator and no difference would not get higher so i replaced my fuel pump, fuel pump pushrod, inline filter right before the pump and cleaned the filter after the pump right before the carb i tried running it and same thing gets 6PSI at first startup and idle then you go around the block and stop it and its down to 3PSI or lower again also the fuel should be up to the middle of the sight on the carb beside the fuel inlet line right? here's pictures of my carb. any guesses i'm thinking possible clog at the gas tank? or would the sympoms say different don't want to drop a almost full tank of gas if i don't have to

[FLG]

Maybe a bad regulator? Have you tried it without the regulator?

You can also run fuel line to a small gas can and start her up and see what you get for fuel pressure.

[charger2fast4u]

haven't thought about the regulator it does work some as i was turning it both ways and it changed the pressure so i dont think it's that as for running a gas can i'd need it to be able to be driven with it. as i idle the pressure was staying around 6PSI and after 5 mins of idling from startup i took it around the block and checked it snd it was around 3PSI and wouldn't gain so i was thinking something in the tank there is a sock filter on the sending unit right?

[FLG]

I would just slowly eliminate variables, the pressure reg and a clogged filter sock in the tank or clogged line are the 2 last choices. You could easily put gas in a pepsi bottle, put a hole in the cap just big enough for the line and secure it somewhere by the front headlights away from heat and take a easy spin around the block.

[firefighter3931]

If it's a liquid filled guage be warned that the pressure will be "off" after it becomes warm. This is a common issue with liquid filled guages. Don't trust what they are telling you ! 


Ron

[charger2fast4u]

Thanks for the heads up Ron ill have to get a regular gauge then ill hold off on dropping   the tank until I get another gauge on my carb should I see the sight glasses beside the fuel inlet ports half full with gas?  I've read some threads on carb adjusting and always says the sight should be filled half way for best tuning I haven't messed with carbs and timing so this is a learning experience for me

[firefighter3931]

Holley recommends the bowls at the bottom of the sight glass with the engine running 

Definately get a non-liquid guage before doing any type of diagnostic work or teardown ! 



Ron

[charger2fast4u]

just ordered a new fuel gauge and some other needed parts. i didn't see any fuel in the sight glasses on the carb since i'm new to adjusting carbs how would i go about adjusting the floats?

[firefighter3931]

how would i go about adjusting the floats?

From the Holley website :

http://www.holley.com/data/TechService/Technical/Adjusting%20Your%20Carburetor.pdf



Ron

[charger2fast4u]

I got a new non liquid filled fuel pressure gauge and installed it started up and ran at 6PSI idling took it out the road acouple miles and pulled over and checked it was at 6 1/2 - 7 PSI engine still backfires though the exhaust it sounds like after 3,000 Rpm and falls on its face got it home and looked again its running at 6PSI so it isn't the fuel pressure so what would be the next thing to check? 

[firefighter3931]

Good news on the fuel pressure  I hate those liquid filled guages 

Usually a backfire indicates a lean condition but it could also be ignition related. 

Where is your timing set ? How much at idle and how much advance ? What rpm does it stop advancing at ? Is the vacuum advance connected ?


Ron

[charger2fast4u]

I'm kind of leaning towards it being lean as I have a holley lean/rich fuel indicator and the problems started not long after the light was reading lean not sure how accurate they really are I don't see any fuel in the sights on the carb I haven't checked the timing yet I am a noob when it comes to carb/timing

[firefighter3931]

If you can't see any fuel in the sight glass then start by adjusting the float level....it should be visible at the bottom of the sight.

How do the plugs look ? What color are you seeing on them ; white ? Tan ? dark brown ? Black ?



Ron

[oldschool]

also, you have a vacuum secondary carb, not a double pummper....