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I can never win! What the heck?

3K views 16 replies 6 participants last post by  woody31 
#1 ·
Hey guys. Well I have been working and tuning my engine for the longest time. I've run it to see what works, what doesn't. Trying to figure out what the issues are. So I have been unlolugging vacumes in idle to see how it does, testing random crap.

Anyways my new quadrajet carburetor is giving me so much hassle!! It runs so rich at 2 1/2 turns out and at 3 turns out its fun but still rich.

Every time I stop the el camino starves. Heres a video at a stop light. The rpms are so low my alternator Isn't charging and the aftermarket tach doesn't read. So I turned it back out to 3 turns out.
http://s1138.photobucket.com/user/chevykid95/media/IMG_0590_zps07ba6818.mp4.html?sort=3&o=2



What can it be?? I get 9-11mpg on a 305. Something's wrong. Please help.
 
#2 ·
After all the posts and advice from myself and others I am surprised you are still struggling with it. I have asked a few questions that so far were unanswered, so here goes>>

Have you set the idle speed set screw an d idle mixture screws with a manifold vacuum gauge to achieve "best idle"?

Have you done a plug color check by chopping ignition at cruising speed and pulling over ? What was the color ?

Have you checked to ensure the centrifugal advance setup is intact and working?

Have you pulled a main jet to read the jet# ? Same with needles? Have you asked Mountain man for help or to check jet/needles with him?

Initial timing set at lowest possible rpm with vac line disconnected @ 10-12 degrees ?

Gently torqued the carburetor base nuts to make sure they are snug?


My worries is that you are paying too much attention to idle mixture screws, which shouldn't be a source of problems unless idle speed/mixture have NEVER been set accurately with vacuum gauge.
As far as timing, it is possible that timing marks are being misinterpreted, incorrect timing cover/pointer. You don/'t have any cats on the exhaust, right?
Have you swapped out the coil or had it checked for output?
Gas filter is new or clean? No possible kinks or obstructions? Do you smell the ofdor of gas when driving?
:dontknow::dontknow::dontknow::dontknow::dontknow::dontknow::dontknow::dontknow::dontknow::dontknow::dontknow::dontknow::dontknow::dontknow::dontknow:
 
#3 ·
No idea what this is?
"Have you checked to ensure the centrifugal advance setup is intact and working?" Vacume advance?

Timing is 8*, its only a 305 and stock specs were 5*.

Carb is torqued down, no kinks, filler is fine other than surface rust on out side.

But I do smell raw gas when setting at stop lights occasionally.

My neighbor left town and was going to borrow a vacuum gauge from him. Other than that everything I did. New coil, new dizzy, new carb. Didn't take the jets out its brand new????


And no cats or 2nd oxygen sensor.
 
#4 · (Edited)
Lift the dizzy cap up and away, place your hand on the rotor and see if it will easily rotate counter -clockwise and return once you release it. It won't turn very far, maybe 20 degrees rotation. If not, remove rotor and make sure the two small springs are mounted to their perches. This is what gives you spark advance as rpms increase.
Constantly fiddling with idle mixture screws will not rectify whatever problem you are dealing with. That mixture is trumped by intermediate and main metering systems as rpms and speed and load increase. There is a idle speed adjustment screw on drivers side that should allow you to set the idle at least so it won't stall at a light. Mixture and idle speed are interrelated and vital to making your ride streetable. You can buy a vacuum gauge for less than $15.00.
Go to U-tube and search for S"setting idle mixture on carburetor with vacuum gauge. Pleny of visual aids there.
Camm MM up. I don't know him, but so many here swear he is the best. I am sure he will ask you all the same questions.
 
#5 ·
Thank you so, so much.

Alright well I have a $15.00 autozone gift card I haven't used, looks like I know what to spend it on!

I have to say at 3 turns out it runs like a champ. It runs great I just don't know why it needs so much gas and why it starves at 2 1/2 turns out.

I probably won't have time during the week to do this all, probably wait till Saturday.

I guess I didn't realize a vacume gauge was so important.

Not looking forward to pulling the dizzy cap..... Hope I don't knock it or move it out of place I just returned the timing light I borrowed.
 
#6 ·
Removing and replacing cap is cake. No need to pull wires, maybe one or two if there is no slack. Lift it up just far enuff to get your hand on the rotor. If it moves and springs back,replace the cap. The four screws need only be rotated 180 degtrees out of the way to lift cap.

The fact that your idle mixture screws are having such an impact on your performance leads me to wonder if the carb is not running too lean. You really need to speak to MM.I you have a motorhead friend with experience timing motors ask him to double check your work. We all need a second opinion sometimes. It can't hurt!! I am also assuming that when you installed this carb you followed instructions regarding which vacuum port to plug your vac advance into. Make sure every other port is capped!!
 
#8 ·
Have you put a vacuum gauge on it if not get one at harbor frt. $20.00 and here's a link that simulates 15 problems with what's wrong with your engine. Vacuum gauge doesn't lie believe me it's worth trying then take video's of the gauge with the engine running and post them. Seeing is the best way to get the correct help. Also I don't remember do you have the computer hooked up if so check the voltage to the TPS switch the gray wire should show 5v and the blue with the key on not started should show .48v with the engine warmed up. I can walk you through it if you have one. It makes a difference if it's not working.:dontknow::dontknow:



http://www.secondchancegarage.com/public/186.cfm





How to Use and Interpret a Vacuum Gauge

Few tools or test devices are more useful and versatile than a vacuum gauge, yet very few hobbyists own one. A vacuum gauge can tell as much about the internal and external workings of an engine as the combination of a voltmeter, compression gauge, stethoscope and timing light. Really!

An engine's vacuum readings can tell an awful lot about its running parameters, provided you know how to read the gauge in the first place. Unfortunately, most vacuum gauge manufacturers don't provide easy-to-follow instructions and diagrams to help users interpret gauge readings, rendering the gauges themselves virtually useless. We're here to change all that, so follow along with us on a tour of vacuum gauge readings and we'll show you all the neat things you can do with one.
 
#9 ·
Also I read an article that 9 times out of ten it's not the carb at fault.:dontknow::dontknow:
 
#10 ·
Alright, I'm sorry if these questions get old. Just a kid dealing with a Highschool income lol! That's why I borrow a lot because I cant afford my own lol!

I noticed the same trend with the mix screws lockjaw that's another reason why I was confused.

Anybody know why I smell raw gas? Now I'm curious after lockjaw reminded me.
 
#11 ·
#17 ·
Advance your timing..forget the factory specs...quit jacking with it..call the guy who built it. get 15 mpg easy...it is possible the carb builder made a mistake...smelling raw fuel is a indication of to high float level also...
 
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