High RPM's

[FrFghtrBRET]

I received an 02 Discovery that had a bad motor. I did an engine swap on it and everything seems to be working fine. Ive just been keeping it in town until yesterday, I finally took it out on the highway. At 70 mph its running around 3000 RPM's. That seems high to me. Can someone tell me if thats normal? Thanks.........Bret

[drowssap]

mine sits right around 2500 @ 70mph. what size rubber do you have on it?

[Disco Mike]

That is high if you are running stock size tires and no gears.
Are you sure you had the tranny in 4th. gear?

[Savannah Buzz]

Or perhaps you had the tranny selector in "sport" mode which moves the shift points.

[Disco Mike]

Sport Mode will not cause high RPM's just change the shift points.

[FrFghtrBRET]

Everything is stock includiing the tires. The selector was in 4th gear and showed "D" on the display. Want me to check the exact tire size??

[DiscoKline]

The tire size will not affect the relationship from the speedo to the tach on the dash. It will only affect the actual road speed. Were you just watching the dash, or a GPS? It sounds like the torque convertor is not locking up, or you are not getting to 4th gear. Try counting the number of shifts next time you take it for a drive and get up to highway speeds. You should count 4 shifts total with 3 gear shifts and the TQ lockup.

[drowssap]

the tire size will absolutley effect your RPM at a give speed. In your case your are using 70 mph as a base, a smaller will have to spin faster therefore increasing the rpm.

[grandkodiak]

i think he ment in relation to the speedo reading... if you throw in gears or tires, you will read the same speed to rpm on the dash, but your actual speed will vary because of the different gears/tires. a stock tire vs big tire will read the same rpm at INDICATED 70mph on the dash, but the bigger tire truck at 70mph dash will actally be going 72-75mph measure by gps/radar gun. the only way the rpm would be at 3k and only doing 70mph is if the speed was properly recalibrated to accomadate gear/tire change or far more likely since he thinks its stock, the tranny either being in 3rd while indicating D or in D but without getting to 4th lockup. if he had small gears or smaller tires hed certainly need more rpm to get to 70mph but unless the comp was recalibrated, the car would be indicating that hes actually doing 85mph (or whatever) when his ROAD speed would be 70mph.

[FrFghtrBRET]

I had a friend of mine with an OBD2 scanner hook up to my Disco. It showed a code of P0734. From what he told me its a bad mass air flow sensor. Any opinions on that? Havent had it back out on the highway to actually count the shifts yet.......Bret