Just Plain Stupied

[Dirmaid]

just waitin for the rain to stop so I can crawl under the truck & do the wiring!

I was in the middle of changing sparkplugs in the yard when the bottom fell out here. Talk about a mad scramble to get it into the shop to finish the job

 

[doorgunner]

I ALMOST worked on the truck last night!

Thanks to everyone who keeps checking up on the "build".......

 

[doorgunner]

All right......I finally got the O2 sensor wire up & the sensor lead run into the cab...will try to get some pics of the wiring AND the readings off the multimeter when I do some driving later....

BUT FIRST...I have to troubleshoot the 130 amp alternator....the dash-volt gauge just took a plunge down to 11 volts from 14 volts---meaning the battery isn't getting a charge....

so....the multimeter gets to check the alt first.....as soon as I remeber where I used it last


EDIT: I ACTUALLY FINISHED THE ALTERNATOR REPAIR IN 24 HOURS (23 HOURS TOO LONG!)

Apparrotly.....while I was installing a heavier-gauge power wire from the Alt. to the battery (since the Alt wire was getting fairly hot)...I caused the inline resistor to loosen from the crimp-on connector (too lazy to solder it properly) just enuff to overheat & melt....causing a complete loss of the the 12V signal from the dash-lite to the Alt......the multimeter showed 12V coming out of the firewall Alt sensing wire--but no voltage at the Alt connector---the fried resistor was hidden in the red plastic wire loom (I'll add a resistor at the dash warning lite wiring where it will be safe from engine heat)

pic of the fried inline resistor after the wiring was repaired....

pic of the O2 sensor wired up (I'll shrink the tubing over the connectors once I test the sensor readings)

now....where'd I put that flywheel dust cover?

 

[TheTopher]

Good to see you working again, homie.

When do we get to see Smokey burnouts?

 

[Rowdy Fitzgerald]

I'm real interested in your readings with that sensor. I'm thinking about the same setup since you've already doing a test run on it! Lol so what's your cost so far for the O2 setup?

 

[doorgunner]

Good to see you working again, homie.
When do we get to see Smokey burnouts?

yep Toph_......it's been rough trying to stay sane and stable about my son(the Nam flashbacks don't help either)......burnouts? I'm afraid that I might wring off something since I installed those 2.94? gears (in place of the 3.45's in the 7.5 diff.....Man-those 3.45's would snap your neck on takeoff---after the tires got hot & quit spinning)

I'm real interested in your readings with that sensor. I'm thinking about the same setup since you've already doing a test run on it! Lol so what's your cost so far for the O2 setup?

I'm out of town in the wifes car until Monday night...but I'll post the readings at idle/ 45mph/60mph/70mph when I get back to the house & take it for a spin (no smoke though, Toph).........cost: $40 Bosch O2 sensor (3 wire heated sensor cost more--but the guys said it gave better readings because it held a constant temperature)-------------$10 for two rolls of purdy wires (had plenty left over)------------$2 for a pack of crimp connectors----------$1 for Dr. Pepper at the Sonic Drive-In (I didn't buy a purdy Fuel Economy gauge/I'll use my multimeter to reag the signals from the sensor)

 

[doorgunner]

Good news...........the O2 sensor works.......I cranked up the truck & gave it a few minutes to warm up....

the sensor moved up to 0.9V DC....which is 0.3 to 0.4 volts too rich at idle.....(roughly 30% too rich at idle!)

which means---when I drilled the .060 air holes in the carb butterflies--I drilled them next to the idle circuit jets---WRONG SPOT---I should have drilled them 180* from the idle jets.....(******** meds.....I get a lot of "practice/do-overs because of them!)...that explains the sooty exhaust tips after sitting in traffic......and the way I post comments....

...see "How NOT to do it" below:

anyhow....I will put a drop of solder over each drilled hole & redrill them in the correct spots---this will prevent additional fuel from being drawn into the carb & will allow more AIR at idle (which was my original goal)......AFTER seeing the pic---I'll just unscrew the butterflies/rotate em 180* & & re-install them......

...hence: STUPIeD


AFTER seeing the pic---I'll just unscrew the butterflies/rotate em 180* & & re-install them......

I'll take the truck down the highway later today & get some pics/readings at different speeds....(didn't get time to go down the road.....)

 

[doorgunner]

Got back from a road-trip in my wife's car annoyed.......got ready to take the truck for a spin to check out the 02 sensor readings at highway speeds....


then the bottom felll out (of the sky).......maybe to moorw...tomorrow....

 

[dangerranger83]

Guess you should start work on the carb 2.9 boat thing mentioned some few pages back. And put cup holders in it too.

Sent from my SGH-T499 using Tapatalk 2

 

[doorgunner]

Guess you should start work on the carb 2.9 boat thing mentioned some few pages back. And put cup holders in it too.

Sent from my SGH-T499 using Tapatalk 2

Apparrotly...................you have a memory like an.....ELEPHANT.....

but I really need to repair/rotate the carb butterflies first.....to get a true/accurate reading on the 02 gauge on the highway....

 

[doorgunner]

02 Sensor update:


This pic is a meter reading of 0.9VDC while the engine is idling about 700rpm.......

I drove the truck about 150 miles today:

at 45mph the reading held steady at 0.8VDC

when accelerating the voltage dropped to 0.1VDC

at 60 and 75 mph the voltage stayed at 0.8VDC


Tech Library says: All O2 sensors are vented to the atmosphere which contains Approximately 21% oxygen. The exhaust of a gasoline Powered engine typically contains up to 2% oxygen. The Sensor's output voltage depends on the oxygen content of the exhaust stream. That is, if the exhaust has 2% oxygen, it is lean. This produces a low voltage, below .3 volt (300 millivolts). If the exhaust has near 0% oxygen, it is rich. This produces a high voltage, above .6 volt (600 millivolts).

So......it looks like I need smaller jets to lean-out the mixture(but first I have to repair those butterflys)

 

[TheTopher]

Sounds like yer truck has got butterflies in its stomach.

Must have seen a girl it likes

 

[doorgunner]

Sounds like yer truck has got butterflies in its stomach.

Must have seen a girl it likes

That's the problem with the meds.....sanity has it's price....I can read directions---but somehow stuff ends up getting done backwards....like drilling the butterfly air-holes 180* away from where they should be....putting the lawnmower blade on backwards---for a month!

Running on all 4 barrels with 4 jets reduced in size to match the flow of the two primary jets makes it very hard to take off without spinning the tires---must be the swirling thru 4 butterflys is mixing the fuel/air a lot better?

good news is....it got a solid 20mpg 80% highway 20% in-town....2 mpg better using all 4 butterflys (the tailpipe is still sooty though)

I'm looking forward to "correcting" the improvements....... which will involve removing the carb---which I should be able to do in less than 5 minutes now

(you DO realize that this thread would have only 100 posts had I done everything right the 1st time...................................................)

 

[doorgunner]

Guess you should start work on the carb 2.9 boat thing mentioned some few pages back. And put cup holders in it too.

Sent from my SGH-T499 using Tapatalk 2

I went to the town where the boat was for sale (for a year in the guy's front yard)......

the boat wasn't there!

He moved it next to his house out of the front yard/the windshield & seats are under the carport).....maybe the price will be right if I stop by there when I come into some xtra cash

 

[doorgunner]

CORRECTING THE HOLE MIS-ALIGNMENT IN THE BUTTERFLYS:

I removed the carb (again,,,,,,,5 minutes )

Only the primary butterflys were drilled wrong causing a rich condition at idle (again,,,,,,,, )

I tried just removing the 2 butterflys & rotating them 180* to correct the mistake...............but Holley drilled the bolt-holes in the butterflys off-center..,,so I soldered the bad holes closed and re-drilled them in the correct location......

There....everything is where it ought to be......

Now get out there & I'll reduce the jet size in the secondary metering plate since the O2 sensor readings were nearly maxxed out at 60-70mph...

*******BEING OLD-SCHOOL, I WAS WR----WR-----WRO------WRONG ABOUT THE USEFULLNESS OF 02 SENSORS--THEY'RE SOME HANDY LITTLE DUDES---EVEN ON A CARBED ENGINE**********


Goooood news.....moving the holes 180* in the primary butterflys caused the O2 sensor readings to drop fro 0.9VDC down to 0.7VDC at idle once the engine reached 180*F......

ALSO........by readjusting the idle-air screws I was able to bring the reading down to 0.0VDC,,,,,,,,,,,,,,the recommended reading was 0.5 to 0.6VDC, so I adjusted the air screws until I got a 0.5 reading,,,,,,,,,,,I was able to vary to readings by adjusting the screws 1/8 of a turn to change the 02 sensor output 0.1VDC/per 1/8" turn of the screw ***prurdy sensitive 02 sensor...

Since I installed only one sensor on the passenger's side exhaust---I adjusted the driver's side idle air screw the same number of turns....the 02 sensor is so sensitive that it was varying plus or minus 0.1 VDC with the engine idling (probably because of the varying air/fuel mixture of the carb)

I also took the secondary bowl off and rejetted both jets down 30% from .050" diameter down to .045" diameter (the change in size is about the thickness of a hair)

When i get time I'll take the truck down the highway and get some readings at 60 & 70 mph.



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


(copied from later post)

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.....RATS!

At idle it's reading 0.1VDC 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....



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.