ak diesel driver
6.5 driver
count your gears as it shifts 1234 +lock up which on my truck drops the rs 4-500 rpm
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Fuel Guzzler
- Thread starter Rodd
- Start date
buddy
Active Member
You found the major difference!
A different driver could be considered a major configuration change, unless some of the recent numbers are from your own driving. Driving style, such as around town vice on the highway, or letting it warm up a couple minutes or not allowing it to, or more inconsistent speeds on the highway where you might put cruise on or she doesnt. Although your mileage before was too low, and I expect the odometer just isnt accurate to start with, but the difference is what youre concerned with now.
Like AK said you should notice the shifts and TCC locks. From a start with decent acceleration, 1/2 pedal is more than enough, it will go into 2nd around 25-30mph, then it should shift into 3rd around 50mph, then lock up the torque converter it might feel like its slipping into third, but rather just dropping RPMs from the lockup. Then it should shift into OD when you let up on the accelerator. You may never notice the TCC lock in 4th like you can feel the difference in 3rd. Unless you are cruising while the engine and tranny are still cold, have it in OD and then when the engine gets warm you might feel an RPM drop but youre going the same speed. That would be the TCC locking in OD.
If you mentioned your speed and RPM then we could compare to ours and if yours isnt locked it would be a few hundred too high. Just compare gears and tire heights.
The clutch and fan are together, but you can unscrew the fan from the clutch. You are lucky to have the latest high flow water pump that is thought to be best flow balance. When did you change that pump?
hereismylife
formerly j k auto
I always got that mpg with my 6.5. I checked everything. Also remember the winter blend fuel will drop your mpg
Rodd
Recruit
You found the major difference!
A different driver could be considered a major configuration change, unless some of the recent numbers are from your own driving. Driving style, such as around town vice on the highway, or letting it warm up a couple minutes or not allowing it to, or more inconsistent speeds on the highway where you might put cruise on or she doesnt. Although your mileage before was too low, and I expect the odometer just isnt accurate to start with, but the difference is what youre concerned with now.
Like AK said you should notice the shifts and TCC locks. From a start with decent acceleration, 1/2 pedal is more than enough, it will go into 2nd around 25-30mph, then it should shift into 3rd around 50mph, then lock up the torque converter it might feel like its slipping into third, but rather just dropping RPMs from the lockup. Then it should shift into OD when you let up on the accelerator. You may never notice the TCC lock in 4th like you can feel the difference in 3rd. Unless you are cruising while the engine and tranny are still cold, have it in OD and then when the engine gets warm you might feel an RPM drop but youre going the same speed. That would be the TCC locking in OD.
If you mentioned your speed and RPM then we could compare to ours and if yours isnt locked it would be a few hundred too high. Just compare gears and tire heights.
The clutch and fan are together, but you can unscrew the fan from the clutch. You are lucky to have the latest high flow water pump that is thought to be best flow balance. When did you change that pump?
I will check out when it locks. My wife drives the same now that she did when getting 14 mpg's. She drives it 95% of the time so my driving has minimal impact.
Rodd
Recruit
We don't have winter blend in CA that I know of. Either way I was getting 14 mpg's year round until I swapped my IP 2 years ago.
Matt Bachand
Depends on the 6.5
How is your fuel pressure?
Rodd
Recruit
I just ran some tests to see if the torque converter locked up. It shifted into 2nd around 17 mph, 3rd around 35, 4th or tc at 45 and 55 for the final gear.
ak diesel driver
6.5 driver
was the engine up to temp? unless your accel hard or the engine is cold it should lock up sooner
buddy
Active Member
Well you only have 3 gear shifts, so if you felt 4 drops in RPM then the TCC lock ocurred in 3rd like it was supposed to. You could also just place it in 3rd (Drive) and see how it reacts, if it has that RPM drop following the 2nd shift.
Rodd
Recruit
I didn't notice the RPM drop when driving in 3rd. It may have been there but I didn't notice it. Could this be the problem? I was also thinking does a bad CDR affect fuel economy?
Missy Good Wench
Wild Blonde from Cloud Mt
When were the injectors last changed out??
A set of high mile squirts can really knock the MPG's off into the weeds.
As the injectors wear out the pop pressure falls off and the and ther spray pattern gets sloppy, this results in a very inefficient burn.
Missy
A set of high mile squirts can really knock the MPG's off into the weeds.
As the injectors wear out the pop pressure falls off and the and ther spray pattern gets sloppy, this results in a very inefficient burn.
Missy
Rodd
Recruit
They have about 30k on them. They were rebuilt's from Diesel pro at the place.
Matt Bachand
Depends on the 6.5
You have good fuel pressure at the IP?
Rodd
Recruit
Pressure at the Ip is 4.5 psi at idle. WOT for 2-3 seconds it dropped to 3.5 psi.
Rodd
Recruit
So is my fuel pressure good? An no one said if a bad CDR could cause a drop in fuel economy?
buddy
Active Member
Fuel pressure is low at idle, but decent under load, where are you measuring the pressure?
Bad CDR is unlikely to cause poor fuel economy, but make sure its not plugged, should be fully open at idle and then worst case it causes excessive oil consumption.
Bad CDR is unlikely to cause poor fuel economy, but make sure its not plugged, should be fully open at idle and then worst case it causes excessive oil consumption.
Rodd
Recruit
I am measuring 4 inches from the IP. I have it plumbed for a fuel pressure gauge but there is a wiring prob w/ the sender so the gauge in the truck isn't working. I just tapped into the T going off to the sender.
Rodd
Recruit
Could it be low at idle because the LP is pulling through a racor?
ak diesel driver
6.5 driver
your fuel pressure sounds good even if it is prefilter
buddy
Active Member
If thats post filter and through two filters its alright. More would be better, but not going to cause a problem.