high rpm weak low rpm power

[Guest drunken_rice]

:help: i just got a 1990 Pathfinder a several months ago and im happy to find this site... i wish i woulda found it a lot earlier to save me money... oh well....

 

ok my question to all of you is... how much gas do you use up on the freeway???

i seem to be using more gas when i drive on the freeway then when i drive streets which i kno for every other car is the opposite... i do have smaller tires on it then were initially only cuz i didn't have the money to get 30x10's (i think thats right) so i put 235/75s since they were about $200 cheaper....

 

i noticed that when i drive on the freeway my rpm's are between 2500 and 3000 when im just coasting at normal freeway speeds.... also sometimes when i start her up she guzzles gas and i end up with less gas then when i turned her off which is really weird.... i think my speedometer is off since i put smaller tires on her but im not sure if it is and if that would nething to do with it since it did all this before i put smaller tires on....

 

my friend has a tokoma trd and i noticed when he drives on the freeway his rpm's are at about 1500 ro 2000 not 2500 to 3000+ so ne help u can offer would be much appreciated.... thnx all

[88pathoffroad]

Holy runaway sentences, Batman! Heh.

 

There's an ongoing thread about gas mileage that you can look through for that subject. A lot of Pathfinders came with 235/75/15's to begin with, so you're fine there. Your speedo should be real close to correct.

 

Which transmission do you have? If you drive around with the auto tranny in Power mode it'll keep the torque converter from locking up and you'll be at a lot higher RPM's on the freeway than you would be if it were allowed to lock up into overdrive.

 

The faster you drive, the higher your RPM's will naturally be. How fast do you usually drive on the freeway?

 

You can't compare a newer Toyota to a 1990 Nissan, man. I don't know why you even thought it should be the same.

 

Gas guage needle differentiation is normal also. Not a whole lot, but if you're noticing a big difference in needle position between the time you shut it off and the next time you turn it on, your voltage regulator for the guages might be going out on you. Might be a good idea to look into that before it dies on you...

[94extreme]

if the tires are any different then the ones printed on the driver's door pillar or door then your actual speed will differ a bit from what you see on your speedo. If they are smaller then you are actually going slower then what's showing.

 

My tk turns about 3k rpm @ 70mph. That's what my 89 did too.

[88pathoffroad]

Mine has a listing for both 31's and 235's on the door and in the owner's manual. *shrug*

[MrJim]

The older Pathfinders had the smaller hp engines so naturally they would be geared lower to ensure that we had enough power. This means that our low end power is pretty good, but the rig is no high end speed vehicle. That is why we are seeing 3,000 rpms at around 70 mph. The Toyotas had more hp so they can sacrifice some of their low end gearing that would translate to their engines running at lower rpms than ours at hwy speeds. If we somehow managed to setup our gears so that our stock 153hp engines were only hitting 1,500 rpms at 70 mph, I do not think we would be able to maintain a steady speed even going downhill. It is all relevant. We have smaller hp engines, so Nissan geared them lower to deal with it.

[n0cturne74]

I personally like how my Nissan engine winds itself down with OD off, especially going downhill in the winter. I've driven alot of other cars that don't have any wind-down at all, resulting in massive use of brakes...which some of us know doesn't mix well with an icey hill!

[Guest drunken_rice]

Thnx a lot for the info.. yea i know cant compare the 2 vehicles;just wondering is all....

 

so how does one go about checking the voltage regulators??? it does that when i turn it off and come back and turn it back on and it also does that if im driving... if i hit the gas the fuel just drops like crazy sometimes... i was driving on the freeway just yesterday was going about 70 (im guessing cuz of the whole tires thing) dropped down to 30 cuz of a turn, was marking between 3/4 and a full tank, sped back up to 70 and went down to 3/4 a tank..... so im sure if the voltage regulator would do that... also i do have the auto tranny (unfortunately, rather have manual) and i dont use the power mode since it does rev a lot higher...

 

it sounds like im hitting the same rmps as everyone else so i guess im cool. this is my first Nissan and Pathfinder so im still trying to learn what i need to...

 

also i have a fluttering sound and im guess it might be the minifold problem that i read somewhere in here... what do u guys think???

 

im also awaiting a k&n cone filter so i can mod my air intake so we'll see what that does..

[88pathoffroad]

Mine runs at about 2300 @ 70 MPH on the freeway. Your auto tranny might not be working properly. Fluttering sound? Probably a leaking exhaust manifold.

[MrJim]

Yours seems to be the odd one out 88. I wonder if your larger tires are effecting that, because that would raise your gear ratio too.

[Guest drunken_rice]

my tranny seems to be fine.... sometimes i get a hard shift from 1st to 2nd.... i think i might have too much tranny fluid... would that cause a major problem??? hmm... i dunno what else to say... i ran codes and all i got was 13 when i ran mode 3.... i dont think that would matter towars this prob.... does neone know how i can fix a code 13????

[Mr. Pickles]

I get about 2600 RPM's at 65 or so, closer to 3000 at 70mph. That's with 31x10.5 BFG MT's. 88, did you change your gearing with your 33's?

[88pathoffroad]

Not a bit. The auto OD setup lowers the RPM's a lot when I'm on the freeway. The only way I can get it to run at 3000+ RPM's at 70 MPH is by leaving Power mode on. *shrug*

[Mr. Pickles]

Huh, so its an auto-thing. Guess us 5sp'ers just wouldn't understand. I imagine if I was turning any lower RPM's, I'd probably have to shift on any hill or acceleration. That would be just a tad annoying when trying to roll in cruise control.

[n0cturne74]

That would be just a tad annoying when trying to roll in cruise control.

 

cruise control...what's that?? :sniff:

[Mr. Pickles]

Its what keeps us west-coasters sane (& ticket-free) in our several-hundred mile road trips all over hell and back.