Just Plain Stupied

[Rowdy Fitzgerald]

Very cool! I think I'm gonna do the same since you're getting so accurate readings!

 

[doorgunner]

Very cool! I think I'm gonna do the same since you're getting so accurate readings!

10-four......I'm amazed that 1/8 of a turn on the idle air screws actually move the voltmeter needle.....

and that drilling a 0.060 Diameter hole in eachbutterfly will change the reading by 20-30%!

I still havn't highway driven the truck yet......

UPDATE SUNDAY: The idle reading of 0.5 VDC was good when the engine reached 180*F........so I drove the truck 60-70mph......the meter never registered more than 0.1VDC.....which means that I jetteted the main jets down too much causing the truck to run lean & stumble when I go to WOT.

sooooo......I removed the two rear jets and drilled them out to 0.050 &n re-installed them.....I'll test drive it again tonight to see what the readings do at highway speed



UPDATE 9/30/2012: I drilled the secondary holes out to .055" since the drill (bit) was handy. Bad news is---the meter shows only 0.01 VDC at 60mph...considering that the two secondary jets are now 20% larger. The GOOD news is---at 70mph the voltmeter registers 0.4 VDC, but the voltage drops to 0.2 VDC while cruising at 70 mph.

At least the larger jet-size is getting some response from the O2 sensor now.

NEVER try to modify a vacuum secondary carb.....LOL.

 

[Rowdy Fitzgerald]

So what is the point of drilling the homes in the butterfly? What carb are you using?

 

[doorgunner]

So what is the point of drilling the homes in the butterfly? What carb are you using?

I UPDATED SUNDAY #3443.....

I have a Holley 600CFM 4 barrel carb (which isn't designed for good mpg's) it's more for street racing (but I knew that I could tinker with it & get what I wanted out of it)

Holley carbs are designed to run very rich at idle and at highway speed so when you floor em--there's LOTS of fuel already available.........

drillings holes in the butterflys is the only way to "de-rich" the carb at idle....there's not enuff adjustment in the idle air screws to lean it out correctly at idle....right now the adjusting screws are turned out exactly where they should be on any carb (out of the carton--I had to turn them out 2 extra turns on the out-of-the-carton-carb to get the idle right which caused the sooty exhaust)

more later in post #3443 so all the info will be in ONE POST....

 

[Rowdy Fitzgerald]

Oh I see.

 

[doorgunner]

I got home too late to test drive it/watch the voltmeter/stay on the road....

I enlarged the main jets to .050" diameter(back to where I previously had them drilled)

I'll try to drive it Tuesday and get some good readings at 45-60-70mph & post em......


UPDATE: I drove it about 40 miles today....but I put a "cold air" intake on it and it thru off the readings/they all dropped to near 0.00VDC.....RATS!

At idle it's reading 0.1 to 0.3VDC and at 60mph it's reading 0.0V to 0.01VDC........looks like 1/8 turn on each idle-air screw will solve the lean-idle....

and drilling the main jets out 0.002 per jet will richen the cruising mixture just enough (but I have to find a 0.052 drill(bit) first/I only have a .050" drill(bit) and a 0.050" (0.005 increments.....RATS....) will have to go to a specialty drill store for the correct drill(bit))

 

[Rowdy Fitzgerald]

Sweet sounds like a plan!

 

[dangerranger83]

I may consider doing the O2 sensor mod someday.

Sent from my SGH-T499 using Tapatalk 2

 

[doorgunner]

I may consider doing the O2 sensor mod someday.

Sent from my SGH-T499 using Tapatalk 2

I updated my last post....

If your getting decent gas mileage and the tailpipe isn't sooty--don't spend the time/money on an 02 sensor mod..


UPDATE: I got 290 miles on 15 gallons of gas-----70% highway/30% in-town traffic

(including some nice take-offs from traffic lights/Man--it's got some GO using all 4 barrels @ 20 mpg
gonna hafta put a set of old-school traction bars on it/can't afford positive traction )

 

[Rowdy Fitzgerald]

I just got mine drivable and the tailpipe is very sooty. I prob need to wire brush it and drive it between adjustments first. I have a 4 wire O2 sensor already would that work? I know absolutely nothing about them.

 

[doorgunner]

Me either....TRS members gave me the idea and some knowledge about which direction to take....then i searched the web....

here's one set of diagrams that might help you connect the sensor that you have...

the wire labeled (signal to computer) will be the wire that you run to the dash & hook the positive lead of your voltmeter to/the negative lead of the voltmeter gets connected to the metal ground under the dash)

the two heater wires (one wire connects to a wire with 12VDC/with key on (so the heated sensor won't run down your battery when you're not using the truck)....the other heater wire goes to the frame ground)

 

[Rowdy Fitzgerald]

Heck it ain't that hard! Thanks that just made me feel a lot better about doing this!

 

[doorgunner]

10-fo........the worst part was doing a 2 hour search on the net to make sure my meds undrstood everything that I ReD before doing the /any mod ........



UPDATE added to post #3441 to keep it organized....

 

[doorgunner]

Haven't been doing anything with the truck lately....(sadness about my son & war memories seem to be too strong to get anything accomplished)


waitng to "snap out of it" and get back to things.......

 

[Rowdy Fitzgerald]

Sorry to hear they DG. Just try to think about all the good times you guys had together! How's the Son In Law doing lately?