8-9 mpg on 2002 Ram 5.9!!!
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Joined: Apr 2007
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RE: 8-9 mpg on 2002 Ram 5.9!!!
ORIGINAL: HankL
If a manual like Haynes or Chilton says that is a valid test
I will give them the benefit of the doubt,
but personally I would be more confident of
a real backpressure test on the highway at full throttle and 4000 rpm.
If a manual like Haynes or Chilton says that is a valid test
I will give them the benefit of the doubt,
but personally I would be more confident of
a real backpressure test on the highway at full throttle and 4000 rpm.
Champion
Joined: Aug 2005
Posts: 3,313
Likes: 8
RE: 8-9 mpg on 2002 Ram 5.9!!!
The easiest way to do a full throttle/max hp rpm
exhaust backpressure test is to either buy a little kit like this:
http://www.sjdiscounttools.com/waebpt01.html
or find a muffler shop that has one.
Temporarily replace one Oxygen sensor with the adapter and then take the vehicle out of a drive where you do a full throttle acceleration in a safe way.
If this first test does show high back presssure
move the adapter between the catalytic converter and the muffler to find which part is restricted.
Getting back to the original problem of low MPG in your vehicle,
keep in mind the prior suggestion to run a few bottles of fuel injector cleaner through the next few tanks. This is relatively cheap at $18-24, and helps eliminate the uncertainty about how good the injector tips are as you do other tests. I still also recommend doing the exact 60 mph test run to see if the MPG really is bad.
exhaust backpressure test is to either buy a little kit like this:
http://www.sjdiscounttools.com/waebpt01.html
or find a muffler shop that has one.
Temporarily replace one Oxygen sensor with the adapter and then take the vehicle out of a drive where you do a full throttle acceleration in a safe way.
If this first test does show high back presssure
move the adapter between the catalytic converter and the muffler to find which part is restricted.
Getting back to the original problem of low MPG in your vehicle,
keep in mind the prior suggestion to run a few bottles of fuel injector cleaner through the next few tanks. This is relatively cheap at $18-24, and helps eliminate the uncertainty about how good the injector tips are as you do other tests. I still also recommend doing the exact 60 mph test run to see if the MPG really is bad.
Champion
Joined: Aug 2005
Posts: 3,313
Likes: 8
RE: 8-9 mpg on 2002 Ram 5.9!!!
The flushes at the dealerships are expensive
but probably work well.
If you are going to go back to the dealership
ask them to check the two fuel adjustment numbers
the engine computer keeps:
the short term fuel trim (AFF)
and long term fuel trim (AAF)
and whether the computer is storing any trouble codes
for cylinder misfire.
but probably work well.
If you are going to go back to the dealership
ask them to check the two fuel adjustment numbers
the engine computer keeps:
the short term fuel trim (AFF)
and long term fuel trim (AAF)
and whether the computer is storing any trouble codes
for cylinder misfire.
Champion
Joined: Aug 2005
Posts: 3,313
Likes: 8
RE: 8-9 mpg on 2002 Ram 5.9!!!
We need the diagnostic trouble code that precedes that info
it is a number like the ones listed here:
http://wjjeeps.com/faultcodes.htm
it is a number like the ones listed here:
http://wjjeeps.com/faultcodes.htm