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fuel economy and lack of performance
https://www.slantsix.org/forum/viewtopic.php?t=11669		 Page 1 of 1
Author:  madmike [ Tue Feb 08, 2005 12:29 am ]
Post subject:  fuel economy and lack of performance
hi, im from new zealand and have a 69 valiant regal with a super 225. it has a carter 2bbd and headers which were there when i got it. this causes problems with cold starting and wont help my fuel economy. i reckon im getting about 8 miles to the gallon combining city and open road driving, this seems terrible to me. can anyone tell me what kind of mileage i should be getting and what my best options options are to improve it. should i look at a different carb set up to improve economy and performance. the engine is 160hp but seems to lack any real get up and go especially at low revs, when i floor it from stationary or low revs nothing happens for a second like theres no fuel getting thru then it kicks in. is this likely to be a vacuum problem and would this also relate to lack of economy. i had the carb recond. a while ago but i dont know how good a job the guy did , he reckoned the carb was warped?? so if anyone has any ideas on how i can fix these issues or make a few cheapish upgrades
to improve performance and economy i would appreciate it. thanx
Author:  SlantSixDan [ Tue Feb 08, 2005 12:49 pm ]
Post subject: 
Something is way out of line. You should be getting at least double that mileage. Time for some systematic diagnosis and repair. Go through the carby; the step-up piston could be stuck in the "up" position or some other fault(s) equally deleterious to fuel economy. Your dizzy could have faults in the centrifugal and/or vacuum advance systems. Or, it could be something as simple as the fact that the OZ/NZ Carter 2bbl carby uses an integral automatic choke that requires a heat tube, and while the proper exhaust manifold had such provisions (on the 2nd runner from the front) there are no provisions for same with tubular extractors. Could easily be that your choke is staying shut all the time, causing you awful fuel economy and poor power.
Author:  Jeb [ Tue Feb 08, 2005 4:45 pm ]
Post subject: 
Convert it over to a manual choke or just wire it open. What do your plugs look like. They are probably covered with soot. Have you checked your exhaust? The core in the muffler may have shifted.
Author:  SlantSixDan [ Tue Feb 08, 2005 5:09 pm ]
Post subject: 
Quote:
Convert it over to a manual choke or just wire it open.
Jeb, the OZ/NZ choke setup is not the same as the North/South American setup and does not easily lend itself to manual conversion.
Author:  madmike [ Wed Feb 09, 2005 5:58 pm ]
Post subject: 
thanx for the tips. ill check these out
Author:  thejims [ Wed Feb 09, 2005 10:26 pm ]
Post subject: 
you might also want to check your fuel tank, I know mine was having terrible gas mileage and I found a leak or two thousand in my tank
Author:  GuyLR [ Thu Feb 10, 2005 6:46 am ]
Post subject: 
Say Mike, this is bit off topic but where are you in NZ? My son is there now on an internship in Wellington. If you're close maybe he could drop by and get some pics of your setup the we could oogle at and maybe suggest some more fixes!

Guy
Author:  Dart270 [ Wed Feb 23, 2005 2:38 pm ]
Post subject: 
Hey Madmike and GuyLR,

I am living in Wellington until May 1. I would be happy to get together with folks here, and I'm starving for a little wrenching. Would love to check out your car up close, Mike.

Lou, Down Under
Author:  spconnor [ Wed Feb 23, 2005 4:39 pm ]
Post subject:  3 gallons per mile....
I have that same exact problem, So far in the month of February ive filled up (18g) 5 times!! That is within my driving area of no more than 10-15 miles. There is a New gas tank in the car however when i checked it out on the lift, Gas was everywhere on the tank. The rubber hose just above the sending unit was leaking. Also under the hood, gas is all over and around the carb. Yes, the carb is rebuilt but I think that's what messed up my economy so bad. I had origionally rebuilt the carb to try to get rid of that "bog" thats ever so common only to find out the carb was perfectly clean on the inside. Ever since the rebuild, gas flourishes itself on the carb and intake manifold. I replaced all of the hoses under the hood, pcv valve,rebuilt carb(i think thats my economy problem), new gas tank & sending unit/gasket and now it seems that my MPG is that of a Boeing 747 :( . With all the money that i spend on gas, I could get a paintjob. sheesh
Author:  VDART [ Wed Feb 23, 2005 5:03 pm ]
Post subject:  Fuel Mileage!!
#1 why don't you guys down under get together-- fix the ride & post some pics of your adventure. Good luck those guys are more than capable of helping your situation
#2 leaking gas!!! wow!! you need to find the source of your leak(S) pronto, your an accident in waiting. Just make a visual inspection starting with the carb, check your fuel lines, once this leak has stopped --get under your car & check where exactly the tank is leaking , it could be pin holes in the tank , it could be the sending unit gasket is bad, the hard fuel line from the unit could have a break, also don't forget to check the fuel filler area -- most cars have the rubber gasket(between the tank & filler neck) that no longer seals. don't let it torch itself, until you fix the leaks you cannot get an accurate mpg!!
Author:  Rust collector [ Wed Feb 23, 2005 5:11 pm ]
Post subject: 
Be careful! if you try to fix fuel leaks, your car will catch fire.
It is just one of those things.
Author:  spconnor [ Thu Feb 24, 2005 10:47 pm ]
Post subject: 
I had my valiant up on the lift today to find the source of my jetliner like fuel consumption. As for the gas/grime all over the new tank; I removed the sending unit and found out that the weld that holds the hardline to the cover of the unit broke - [On top of the wires inside being broken allowing the unit to work when it chooses, I'm just going to replace it]. As for the other half, I never should've rebuilt that carb. I also need a remanufactured or new carb. Several of the screws that hold it all together are stripped so I replaced them with nuts and bolts temporarily. Every now and then I have to tighten the 2 bolts that hold it to the manifold because for some reason they vibrate loose and make a noticable gap between gasket/manifold.
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