Engine/Transmission (1994 - 1998) 11 Mpg's!!!!

[budctdca]

when its cold and i rev it up, it does stutter, i was wondering what that was. so its probalby the timing right? i am going to do the KDP in about a month (don't have my tools at school), and i am hoping to get some help with the timing, but where should i set it? i'll check the delivery valve while i am there, with 224K, im sure shes a little out of whack.

 

[JGK]

Personally, I'd be real surprised if your timing has slipped if it has never been changed since the factory. That's pretty rare. Much greater chance its something else, like air in the fuel line, weak overflow valve, pump needs tuning (still rare), etc. However, it could be set on the retarded side from the factory. So its still worth checking. If you were in my area, I'd check it for you, but alas...



Seems to me at one time Ted Jannetty from Jannetty Racing posted all the possible things to look at when chasing a mileage problem. But that was years ago. Can't remember the list. I'd have to dig through my hardcopy file. I'll see if I have it.



Wait... try this link.



-Jay

 

[budctdca]

heres my dilemna, I havent had the truck for long, only about a year, and it was a one owner truck. so im not sure if the timing was ever checked.



but with my mods, do you think I should bump the timing? to where? 15. 5-16. 5?

I am going to the KDP in a month, so Ill be able to check the fuel lines and the overflow valve then.



I heard that the timing can be off quite often, but then again Ive heard all sort of things... .

 

[budctdca]

might have found problem

I looked under the hood today and noticed my fuel filter canister was wet. so i took it for a drive and then stopped and looked again, seems a bit of fuel has been seeping from the banjo fitting on the top of canister. i tightened it up, but i don't know if this would cause the fuel problem... ?

 

[Kirwin]

Have you checked you speedometer calibration

Since you changed your tires have to corrected your speedometer? Its done on the 97 using different size (# teeth) pinion gears that are put in the tail stock of the transfer case. Your fuel milage will depend on how FAR you drive as well as how much fuel you use. Just my $0. 02. Ken Irwin

 

[budctdca]

my tires are the same size as the ones i took off (265/75/16) now they are 265/70/17, so i dont think it should make a big difference... .

 

[Kirwin]

The stock tire in 97 was...

The stock tire in 97 was 245/75R-16 E. If you use a 265/75R-16 you introduce nearly 10% speedometer error. I would check this as you should be able in a STOCK truck to achieve 16-20 MPG if you drive it carefully. Maybe a little less with the 4. 10 ratio. I have the fuel records from my 97 since new to prove it. Using my mods I didn't see a change in MPG as long as you don't use all the extra power. Now if I want to I can get less than 10 MPG But that's not how I NORMALLY drive. I just don't believe that a truck suddenly slips time. Unless you have done something to make it happen. The P7100 is a pretty good setup. My $0. 02. Ken Irwin

 

[AMink]

(# teeth) pinion gears that are put in the tail stock of the transfer case

Kirwin-is this something that I can do myself? I asked the dealer to correct for my 255's, then 285's, but I don't know if it was done right. Whenever I go past one of those "your speed" deals, I'm about 3-4 mph low. Gets worse as speed increases. Any good place to get the pinion gears? Thanks

 

[Kirwin]

changing the pinnion gear is easy

You can change it. The tail stock can use a large variety of gears. Depending on how many teeth you have you just rotate the "plug' that the gear goes into to set the clearance. Each position is good for a range of pinion sizes and I think that the pinion is held in with a snap ring. The speedometer drive gear is plastic. The tailshaft of the transfer case has a worm style thread that drives the plastic speedometer drive gear. The calibration should not change with speed. It will be off some % of actual. I. E. if you are off 10% then you would be going 66 MPH when the speedometer said 60 and 33 MPH when the speedometer said 30. That said these speedometers are NOT very accurate and I wouldn't be surprised that that error is not linear. Ken Irwin



PS The actual gears may be listed with either the transfer case, transmission or even the speedometer cables in Dodge's parts book. The last 2 digits of the part number is the number of teeth on the gear. I can probably look these up for you at home if you can't get the dealer to help you search. Note that the 98 and later Dodge's no longer use the speedometer drive pinnion to drive the speedometer, they use the RWAL speed sensor on the rear differential to provide speed input to the ECM and the instrument cluster.

 

[AMink]

Thanks, Kirwin. I'll check on that at the dealer.