This is a subject that’s been run up the flagpole so much that the information about it has turned to data. Recently on social network sources threads have gone nowhere…. mis-information and simple personal taste has taken over actually giving useful information. The issue I have when trying to delve into important stuff like that is it takes more than 144 characters and even more time than the social netwrk nodes are designed to convey.
I don’t fit into those perameters making explaination probably more involved than most….. I feel if there is information asked that all aspects of the question should be discussed to give enough input that the person asking the question can take away enough to make their own decisions….. so after a really relaxing ride on the Harley I feel it important to spew out what I have discovered over 20 years of trying to get fuel reliably to our motors. It can be a real problem doing that with all the new fuel formulations.
One person on a social network platform commented that all this stuff about fuel formulation is BS. Let me clear that one up right here….. that’s BS! Back in the day when they took lead out of our fuel supply all the engineers were crying our world would end…….. it didn’t so loosing credibility with the automotive community I guess maybe they don’t believe what’s happening today. Please, rethink that……. Ethanol is a stupid chemical to put into fuel.. at least for our older cars and our GMC Motorhomes.
While it does not seem to effect our newer cars that much, the Alchol and water is a leathal mixture for steel fuel tanks. Everything today has plastic tanks…. no problem there but synthetic nitrile rubber is attacked by Alcohol turning the rubber hard causing cracks. the water in Ethanol causes surface rust on our large surface fuel tanks…. then sloshing the stuff around the Alcohol cleans the rust clogging up our filters. The smallest micron filter (in the front of the carb) clogs first. Today I have to tell you if you do not carry and extra WIX 330-48 carb filter you are driving in the breakdown lane or will be.
Ethanol also lowers the boiling point of the fuel… I have west coast customers who do not drive in desert in the heat of the summer….. it’s in-nerving hearing the fuel boiling in the tanks under your feet. Those tanks are so close to that hoe asphalt constantly boiling fuel and vapor lock is almost a way of life for the GMC sporting a bone stock fuel delivery system and Rochester carb.
Another gift these new fuels give us is reduced mileage. You may not notice that much in your car but when you tax a motor the difference become apparent. A well tuned GMC without Ethanol being driven at a descent speed can expect 8.5-9 mpg. Non Ethanol coaches can see 10-11 mpg. That’s because everytime you pull off from a traffic light in our coach is like doing a burnout for a car motor…… whe expect a great deal from our motorhome drive trains…… any small issue make large effects.
So lets call that subject proven, let talk about some other bad Juju in our new fuels. 15 years ago, you could put a pail of gasoline in a barn and find flammable hey and dead rats the next day. The fuel will have been at least partially evaporated (atomized). Now, do that same thing today….. really go try it. You will find the fuel does not exaporate as it did in the past…… Why? Todays fuels are not “hot”. Carbs rely in partial chemical atomization to do their job. Sucking fuel like a Windex spray bottle (how a carb works) is not enough to create a 14.1 air/fuel ratio. The colder fuels today are formulated to be pressurized and mechanically atomized through an injector. This is it….. all cars today are fuel injected and the fuel supply today is formulated for that purpose. When fuels turn to cool aide when E85 is made our standard carbs simply will not work anymore….. and bunky I hope not but my bet it it’s coming!
What can we do? 10 years ago I tried the learning curve on fuel injection. I tried throttle body all the way to sequential direct port……… they were all expensive, reasonably complicated and the diagnostic tree was nothing that most of us could deal with. The first filter I put any new component part or system I use restoring a GMC must not fail and leave you on the side of the road with no options. Breaking down in the “emergency zone” (near a highway) will be expensive…. the thing is too big to push and the tow bull will surley melt your wallet! BTW, stop right now and sign up for AAA Plus towing with an RV ryder……… Good Sam will take you to the nearest “Bubba & Scooter” where you really do not want to do. AAA will take you right to the bank of a lake and help you push it in! Well, don’t do that but you can pick where you want to go and with the “Black List” and the GMC enthusiast community you can find help if you call out.
OK, a tangent… lets move on. As I said I tried fuel injection in the past and was completely unimpressed. The “dumb” systems using a preprogrammed chip of having to be programmed on a chassis dyno all do not give you what you need to go on the open road. They are complicated having sensors and wires going everywhere and connecting to the distributor…….. brother when the system stops you stop and that’s it without help! At least you can spray WD-40 down a carb throat and get safe…… when that hot shot FI system stops…… that’s it! If you call that progress fine… YOU will be the tech, YOU had better know your diagnostic tree and YOU had better know what all the replacement parts in the system are……….. it’s just that simple.
See what I mean, I couldn’t put this much explaination on any social media format but these are the things you MUST consider.
OK so now…. what to do? A crab rebuild must have a tune to match the motor and will probably be retuned when any perameters change in your drive train. The past FI systems were dumb….. if everything is the same they work well but hey… there is nothing in this imperfect world that ever stays the same!
When you picked up you new car, the saleman said the more you drive your new car the more it get used to your driving habits…….. boy, that sure doesn’t sound like the dumb FI systems I’ve been talking about and they aren’t. The new cars use a real time… full time… learning active fuel injection system…… it learns and adjusts to not only your driving habits but also to what the motor needs at all times. THIS is what you need for todays fuels and todays driving styles.
What’s more these new active systems have been designed for Bubba and Scooter to better understand and work with. The FiTech brand systems we are now working with only have 2 sensors…. water temp. and O2…..it will make a baseline set up on the system and will change as needed. No wires running all over…. most of it is self contained in the main fi body. Programming is 5 things… you tell it:
engine size—455 or 403
number of cylinders–8
type of cam– mild
Rev limit– 5000rpm
idle speed– 950rpm
Save that and fire the motor up….. in 5 minutes it adjust to your motor and you are off with as close to 14.1 A/F ratio as it can hold, I got 8mpg first time out with Ethanol fuel…. fired up every time and shut off when the key was turned off…. no dieseling, stumbling and backfiring!
I will say we are having some struggles with adapting the system to our motorhomes…… those will be overcome and from that time on you coach WILL BE adapted to the new fuels we must run on. Non Ethanol fuels will give you a 20% increase in economy but you cannot expect to find that stuff on the road so we need to be able to adapt to the new fuel….. and THAT’S NOT BS….I live3 with it every day and it’s real!
So am I tossing all carbs? No, I do still get good results when a carb is remanufactured (not just rebuilt) to spec….. they run the best the first day but will reduce performace as they age…. it’s hoe it goes. A remanufacture is not a $75 rebuild…… 40 year old carbs (BTW, the definition of a carb is a (series of spring loaded air and fuel leaks…… the fuel must be filtered to less than 5 microns of trash….. the FITeck systems will run fine with only 30 microns of filtration…. that’s shooting rocks compared to a carb! and with that water and Alcohol in the Ethanol….. I rest me case!
Times they are a changing and fuel delivery must keep up. If you keep running a carb, have a second backup electric fuel pump plumbed to your Aux. fuel tank to help push through vapor lock when it happens…. carry that WIX 330-48 carb filter… a 1″ and a 5/8″ wrench and the knowledge of how to change it on the road….. that preparation could save you. Had a customer who picked up a load of bad gas in Georgia which filled 9 carb filters driving home to Canada! This is real and it’s not BS!
Hey, this is America, you can do what you want but that will not change the characteristics needed to deliver fuel to your GMC motorhome drive train…. that will be your responsibility.
So, you see why I really can’t participate in questions that come up on social networking…. they don’t offer enough space to really get into a subject. I am sure there are contrasting opinions on this…. hey, that’s healthy but as for me… after 20 years of doing this… if you ask me yes, I will suggest fi but I will do a great job on your carb and I can tune a GMC like tuning a fish!
Now, base your opinion and taske all this into consideration…. if you feel it’s BS after investigating that’s fine but don’t go off half coacked after reading stuff on the internet…. do all that stuff and your coach will NEVER run again!
Sorry, no pics today…. but this is important information I feel you need to hear. Thanks for hanging with me, I hope there was something in it that is helpful and I’d be happy to talk one on one with you on this….. just give me a call 321.299.5707……
OK, I’mm off to enjoy the rest of this Sunday with Janie…….. go hug your coach… and your wife and thank God for both of them…. see ya later.