Slant Six Forum
https://slantsix.org/forum/

Poor gas mileage
https://slantsix.org/forum/viewtopic.php?t=28650
Page 1 of 2

Author:  75scamp [ Mon Apr 28, 2008 9:29 pm ]
Post subject:  Poor gas mileage

Hello all my 75 Scamp is only getting 10 mpg also it pings on acelleration above 65 mph. It seems that it also has no power on acelleration. I have rebuilt the carb and done a complete tune up and also adjusted the valves.

Author:  dank10fenny [ Mon Apr 28, 2008 9:44 pm ]
Post subject: 

your ping is typicaly your dizzy bein too advance or too hot of heat range plugs. some more info on your motor would help. how stock is it?

Author:  75scamp [ Mon Apr 28, 2008 9:58 pm ]
Post subject: 

The motor is totally stock and was recently rebuilt , the plugs are the ngk ones recomended by slantsixdan also this motor has a drool tube head.

Author:  dank10fenny [ Mon Apr 28, 2008 10:18 pm ]
Post subject: 

im sure others will tell you to look into other things, but when my motor pings i just set my dizzy back a lil till it stops. counter clockwise.
check vacuum, and get those vac leaks under control

Author:  kipamore [ Tue Apr 29, 2008 6:09 am ]
Post subject: 

Did we miss-pin the spark plug wires and thus the firing order after a tune up? It's a shot on the dark, but I only mention it because I've done it a million times and it's always a big smack in the face when I finally figure it out.

Or points. Or forgeting to tighten the distributor housing. Or forgeting to put the rotor back on. Or forgeting the carb gasket. Or forgeting the power brake hose. Or forgeting to tighten the lug nuts. I really could go on and on.

Kip on Truckin'

Author:  lincparts [ Tue Apr 29, 2008 9:25 am ]
Post subject:  clockwise?

i thought that counterclockwise ADVANCED the timing...... :shock: Am i wrong :roll:

Author:  DusterIdiot [ Tue Apr 29, 2008 12:35 pm ]
Post subject:  Yep...

Quote:
i thought that counterclockwise ADVANCED the timing......
Yes, it does... the rotor goes clockwise...


I would check your distributors position and reset the timing to spec... I would also check for a vacc. leak (while car is idling spray BrakeKleen/Carb Cleaner at the intake runners and carb and see if the idle changes/speeds up)...

You may also have a problem with your vacc. advance I think, I would check the hoses going from the carb to the distributor and make sure it's in the right spot (AND make sure there's no leaks in the other hoses)...

Also, pull the plugs and check the color on the electrode, the deposits will tell yo where to head... if it's clean you're lean... if it's black it's rich, if they are covered in oil and 'goop' then you have another problem...

-D.Idiot

Author:  Aggressive Ted [ Tue Apr 29, 2008 1:20 pm ]
Post subject: 

75scamp,

Will your engine run at 500 rpm and purr like a kitten?
Is that the stock 1945 Holley carb?

I had the same set up and problem. I fought it for years. I finally bought a new distributor for a 76 and recurved it. Also went back a few years in time and installed a 1920 Holley Economaster. Problems solved! :D
Mileage is very good for the way I drive.

Author:  Slanted Opinion [ Tue Apr 29, 2008 1:31 pm ]
Post subject: 

At 10 mpg I would almost think that you must have a bad carburetor, pouring fuel in like crazy.

10 mpg is hard to do in a stock, Slant A-Body.

My '74 Scamp (long since gone) used to get 23 on a regular basis.

-Mac

Author:  SlantSixDan [ Tue Apr 29, 2008 1:32 pm ]
Post subject: 

Another possible cause for these symptoms is a plugged-up exhaust system. Does this '75 have a catalytic converter? Even if not, mufflers can plug up internally.

Author:  75scamp [ Tue Apr 29, 2008 2:15 pm ]
Post subject: 

It does have a cat converter also it idles smooth in gear even when i turn on the ac. I checked the plugs there all a light brown color. Double checked the distributor vac line to carb and it is hooked to the correct port. I have also replaced all the vacuum lines.

Author:  CARS [ Tue Apr 29, 2008 2:39 pm ]
Post subject: 

Gas leak? :roll:

Author:  SlantSixDan [ Tue Apr 29, 2008 3:13 pm ]
Post subject: 

OK, so exhaust restriction is a possibility worth looking at.

Author:  DusterIdiot [ Tue Apr 29, 2008 3:14 pm ]
Post subject:  Next question...

Quote:
Double checked the distributor vac line to carb and it is hooked to the correct port.
Next question when you unplug this hose from the carb and plug the port on the carb then suck on the hose/use a vacc. hand pump... does it advance? Does it hold vaccuum or does it loose vacc. readily...?

Is the EGR system still intact on the car/and or the 'hockey puck' hooked into the carb...?

Last one, is your choke thermostat and pull off working/ hooked up and have power?

-D.Idiot

Author:  Doc [ Tue Apr 29, 2008 3:27 pm ]
Post subject: 

Quote:
Gas leak? :roll:
Like a bad fuel pump... leaking fuel into the crankcase?
Has your oil level been increasing lately?
DD

Page 1 of 2 All times are UTC-08:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/