[Gmecm] ethanol

[Tom Prucha]

Many of the later models are already using fuel system components that 
can handle high amounts of Ethanol.  Some of the 5.3L GM truck engines 
are actually FFVs, designed for E85, but I don't think your Cadillac is 
(http://www.e85fuel.com/information/general_motors.php). It would be 
interesting to see of any of the fuel system components, such as 
flexible fuel lines, are different on an FFV 5.3L vs. the Gasoline 6.0L. 
The engines are otherwise the same basic configuration and should have 
the same fuel line routing and sizes. The physically interchangeable 
components might actually be the same part numbers, but I doubt it... GM 
is too cheap to spend any extra money without getting the "credits" for 
the FFV designation. The reason an FFV doesn't usually cost more than 
the gasoline-only equivalent vehicle is because of these "credits", 
which justify absorbing the minor extra cost. The following link shows 
one of the many references you'll find if you go looking for evidence of 
this "fuel system materials upgrade".  The reference is in the "Ethanol" 
section on page 15 :

(http://www.dnr.state.la.us/SEC/EXECDIV/TECHASMT/data/alternative/AltFuelsReport2003.pdf)

I speculate that your Caddy owner's manual recommends a maximum of 10% 
Ethanol, and intentionally exceeding this is likely a cause for 
"permanent warranty invalidation". It is very risky to run E85 if the 
vehicle isn't designed for it, unless you're sure of what parts are 
different on the the FFV equivalent vehicle. Check with your dealer to 
be sure of the warranty concern (you might want to make this inquiry 
anonymously). For example, if a vehicle designated for gasoline-only is 
run on E85 and a fuel leak develops (probably only over a long period of 
time) due to corrosion of a flexible fuel line, not only is it a 
dangerous fire hazard, but GM will probably NOT honor any associated 
warranty claims, and they may win in court in any attempted law suit, as 
the owner's manual specifically states NOT to do run more than 10% alcohol.

The starting problems only occur at colder ambient temperatures. Some 
FFVs have an extra injector for cold-starts.  Others can simply meter 
enough fuel through the normal (or over-size) injectors.  Corrosion 
problems are more of a long-term concern. Limited exposure to E85 on a 
gasoline-only vehicle is said not to be a problem 
(http://www.e85fuel.com/e85101/faqs/misfueling.php). Exposure to an 
aluminum intake manifold, cylinder head, or piston, doesn't "seem" to be 
a problem as the Ethanol doesn't normally "puddle" on the aluminum.  M85 
is much more corrosive than E85.  Here is an interesting paper I found 
on the subject of corrosion.

http://www.hawaii.gov/dbedt/ert/afrw/afrw-07.pdf

?ke Georgsson wrote:

> mroof at nmt.edu wrote:
>
>>>Ethanol is also corrosive, so you'll need to make sure there is no
>>>rubber or aluminum that comes in direct contact with the Ethanol. E85
>>>cars often have Teflon liners in their fuel lines.
>>>
>>>    
>>>
>>
>>This problem with aluminum is something I have been wondering about.  Does
>>this apply to the intake manifold, the cylinder head, and what about the
>>pistons?  I haven't been able to find much information on the corrosive
>>properties of ethanol versus pressure and concentration on aluminum. 
>>Anyone have some links?
>>
>>Thanks Morey.
>>
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>>  
>>
> That is i BS ,,, i run my cadillac esclade esv 2003  on 100%  E85  and 
> havent done ANY modds  .. it runs perfect  and  it?s even easy to 
> start  (witch shoud be an problem  with ethanol )
>
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