'90 ranger no balls

[nesralyrrej]

I've looked into the tach quite a lot but I can't find any issues with it, the only time it's ever worked is when it snows and I lock the brakes up, the abs kicks on and the tach starts working once I let of the bake it stops again lol. I had 33" tires on my 2.3 ranger running 3.73s as well and it would walk all over this truck. I'll replace the 02 sensor and see if it helps anything..

Any other ideas guys?

 

[Spott]

I had 33" tires on my 2.3 ranger running 3.73s as well and it would walk all over this truck.

Aside from the engine problems you're having, your old LL2.3 also had a HP peak at much lower RPM's than your current 2.9. You gotta get this engine spinning much faster to get the power out of it, and you have to use lower gears to accomplish that, for the same ground speed. Really, you want 4.27 or 4.56 gearing to get the most from those tires.

Go look up the Grim Jeeper crawl calculator, and find out what axle gearing gets you closest to 3000 RPM at 75-80 MPH in 5th gear, all else being equal. It'll surprise you.

But get your engine running well first.

 

[nesralyrrej]

Okay, sounds good. I hope to know my problem soon lol. It seems to have plenty on the low side and dog out more in the high rpms

 

[Big Jim M]

Ok so you jacked up only one wheel and kept the other one on the ground? Then when in neutral you turned the wheel one turn and only got 1.9/1,7 out of it? I think you missed the first turn of the driveshaft. If so that would be a 2.73. If not then why not?
At 6,000 feet a 28 inch tire would be about right.
It's all about HP/rpm at highway speeds at altitude. The higher ya go the more rpm ya need. More rpm means different gears SOMEWHERE. I.E. transmission, rear end or tires.
Any one of these can increase or decrease the rpm.
Big Jim

 

[Spott]

Ok so you jacked up only one wheel and kept the other one on the ground? Then when in neutral you turned the wheel one turn and only got 1.9/1,7 out of it? I think you missed the first turn of the driveshaft. If so that would be a 2.73. If not then why not?

Because of the differential. 3.45 revolutions of the driveshaft will turn two wheels exactly once each, or one wheel exactly twice. Therefore, 1.73 revolutions of the driveshaft will turn one wheel once.

Also, for a 2.9l, 28" tires, like I have, work well with 4.10 gearing. 31" tires, like the OP has (plus 1500ft of elevation) need something even lower unless he's pursuing a specialty application.

 

[RonD]

If your spark plugs were black and no CEL then there is at least one of these that's bad:
1. O2 sensor
2. MAP sensor
3. Computer

 

[nesralyrrej]

The truck was just as gutless with my old tires on 27" I'll check again but I'm pretty sure it was only 1.7 rotations

 

[nesralyrrej]

Map is new, I'll replace the o2 and the computer soon

 

[Spott]

Map is new, I'll replace the o2 and the computer soon

Test parts first, before replacing. Also, check the wiring; the sensor(s) and computer may be perfect, but unable to communicate properly.

 

[nesralyrrej]

$60 in parts at most, the wiring looks fine far as I can see

 

[nesralyrrej]

Anyone else have any ideas for me?

 

[Spott]

What are the results of the last several ideas (regarding the fuel/air ratio problem)?

 

[nesralyrrej]

No significant impact on anything

 

[RonD]

So you have new O2 sensor?

And MPG isn't better and spark plugs still show black?
Then it is your computer that is at fault.

When you first turn on the key the computer reads MAP sensor pressure to get local atmospheric pressure, 15psi at sea level, but you are not at sea level so MAP sensor would show that and computer would adjust fuel mix for the lower air volume of higher altitude.
But ultimately the O2 sensor would read lower oxygen levels in exhaust if computer was running engine too rich(black spark plugs) so computer should adjust the mix based on that.
So with new O2 sensor in place the MPG should have gotten better and spark plugs should look clean, if not only conclusion I see is that the computer is not able to use outside sensor data, from MAP or O2 sensors, and is just running Open Loop Sea Level factory program based on engine RPM

 

[Andy D]

Total wild guess is a weak spark caused by a bad coil or something. A bad battery or alternator could do it it too. Does this rig have a cold start injector? Just for grins, replace the 2 wire Coolant temp sensor report back