11 mpg....

Topic: 11 mpg.... (Read 1744 times) previous topic - next topic

11 mpg....

June 13, 2005, 12:38:44 AM

My 3.8 is getting low mileage. Usually i have 19 Mpg in highway at normal speeds (no more than 55mph) and today i tested my car to get the economy. I was traveling at 50 mph and after calculations and measures i get 5.02 km/l, and all was highway miles....

Any help ?

Remember, my car is carbed. ....

Re: 11 mpg....

Reply #1 – June 13, 2005, 01:21:46 AM

have your tweeked the air and gas mix? is it running rich out the tail pipe?

have you tweeked the foat any at all?

Re: 11 mpg....

Reply #2 – June 13, 2005, 02:14:27 AM

mmm, really not. I adjusted the carb one year ago and was fine. But i adjusted the Mixture without a gas buttstuffizer. I choose a simple method (but not technically correct). I tightened the two screws of the Mixture under the carb. After, i count two and half turns to each screw and started the car. Put the car in D and the idle was aceptable and i checked the tail pipe (using HB) and was ok. Some mechanics told me about a "magical number of turns" where the car "gets the best mileage". mmm,ambigous veracity, maybe true, but sound like BS....

Mr. Cassity. How much MPG does your cougar get ?

Re: 11 mpg....

Reply #3 – June 13, 2005, 06:30:31 AM

Two and half turns is going to be approx a turn too much... Adj them back in, then out two turns. Next with the engine warm(and running) turn each one in till the engine starts to stumble, then back out for the smoothest idle.

Also If you're still running that TFI distributor, the engine doesn't have any iginition advance. Need to advance the timing as much as possible and not cause hard starting when hot(or get the correct dist installed)...

Re: 11 mpg....

Reply #4 – June 19, 2005, 06:34:24 PM

Thanks for the Info. I readjusted the carb, but i did not have chance to test the car again (its raining). But seems to run fine....

Í´m going to change the spark plugs. Here is an old question....

Every time i have used "AWSF 44C" motorcraft plugs on my car. I dont know if these are the correct plugs. I had good results with these. But I wanted to buy another brand, and see the NGK site . I checked the application chart, and looked that the correct plugs for my car are NOT the "AWSF 44C".

I Want to know what type of plugs do you use in your 3.8 engines, carbed and CFI (and even SEFI). Preferably, with "motorcraft numbers" but any other brands will be fine....

And i want to know if i am using the correct type of spark plugs in my cougar (remember its a 3.8 carbed with and attached TFI ....but runs fine)

Re: 11 mpg....

Reply #5 – June 20, 2005, 07:12:38 PM

I use Champion RS14YC, gapped at .044" in my '83 T-Bird 3.8L. Those screws should be 1 & 1/2 turns from bottomed out. If it doesn't run at that setting then the carb may have a vacuum leak. Check for cracked hoses or some such. Also the factory main jet size was #53 and you may go to a #51 if at altitudes above 4000 feet. Make sure the choke is operating correctly, I.E. when warm it is fully open. The idle jets control only the idle circuit, above 1000 RPM's they aren't in the picture, thus unless it's really screwed-up should not effect gas milage that much. Recheck for a vacuum leak! Good Luck, Fred

Re: 11 mpg....

Reply #6 – June 20, 2005, 09:43:35 PM

This may seem too simple, but did you check the choke? On my old carb's '85 T-Bird the heater that works the choke burned up (literally - made a nice stain, too) and the ran hella rich and got bad mileage. I ended up putting a manual choke in it.

Re: 11 mpg....

Reply #7 – June 23, 2005, 12:20:23 AM

im not carbed,, but i get 26highway and just standing by waiting or it to blow up any day now.

as mentioned,, good idea on the choke thunderchicken.....

Does your carb have the vac choke or the roundy sideways mounted one? If you have the roundy looking one with a wire going to it,, make sure the motor is bone cold before you adjust it. Having a choke out of range will make you suck down the juice. You should loosen the choke screws a little then rotate it till you see the trottle plates just start to barely open,, snug the screws back down.

if i got that wrong,, someone correct me but thats how i get the choke back in line on carb'd cars. as for the turns,, i agree with tom,, but the rule is about 1 1/2 to 2 turns out on each then tweek them from there by listening to how your engine likes its air / gas mix. In reality, carbs of the same type/size/model/part number will act differently to adjustments because there are so many mechanical moving parts inside them. You may end up changing your settings later on due to the changes in the season. Carbs are wierd like that ,, its like they are alive or something.

I would not be running 10deg BTDC for sure so tweek the timing if you can and see if you can hook up with someone that ***knows** how to use a dwell meter.

Re: 11 mpg....

Reply #8 – June 23, 2005, 04:02:45 PM

I second that choke heater suggestion!
The last carb'd Ford I owned was a '78 Pinto. I left the choke heater wire disconnected after working on it one day and man did it run rich!!
I believe the heater wire comes from the stator connection on the alternator.

Re: 11 mpg....

Reply #9 – June 23, 2005, 06:52:19 PM

Whoa ! Thread Printed !!!!!

I need all the info for future reference. Tomorrow i am going to do some new tests. Thank your very much guys !