no power (accelerating or going up grades)

[born2drive]

Okay, heres the scoop. I just drove from Los Angeles, CA to Boulder, CO. The elevation gain is about 5000 feet. But while going over the Rocky Mountains, I felt that I had no power. I would be at about ~4500rpm and would be doing really good to be going about 55mph. This would especially happen over Vail and the Tunnel passes. Vail is 10,000feet high and the Tunnel is 11,000 feet high.

Anyway, now that I'm in Boulder, I have a little more power but not as much as I have in LA. The elevation here is about 5000 feet. I know that my car is Fuel Injected, but is there something that I can do. Or is there an adjustment that you have for Fuel Injection like you do a carburerator. (I don't think so, but maybe.)

Also, the shift points seem to be a bit higher than normal and the acceleration STINKS!

So my question(s): Is this elevation related? or is there something wrong with my car? I'm planning to take a couple of trips up to the moutains and I want some more power than I have now.

Thanks A LOT!! - I have a 1993 XLT 4x4 with the 4.0 engine

P.S. Excuse the spelling......

 

[born2drive]

forgot to put this - don't know if it matters much, but while going up the grades the check engine light would go on, then as we started going down hill, it would go off.

Thanks
John

 

[Robb]

You may just need to reset the computer so that it can "re-learn" with the new altitude. Also, you will probably always have a little less power at higher altitude, but not as much as it sounds like you have.

Also, reading the codes from the CEL that you are getting would be a good idea.

Good Luck!!

 

[born2drive]

Hello & thanks

do you reset the computer by disconnecting the battery for 10 mins?

also - Is AutoZone the place where you can get the codes read for free?

Thanks A Lot!

 

[twomedicine]

octane

Other than the obvious shortage of oxygen at higher elevations, 5000 ft is only a bit higher than normal. Timing has to be advanced once above 3000-4000ft but with these X's, they should compensate.

I'll be in the same boat when I return to the rockies in a week or so, about 1000mi north of where you are now, I have never had this vehicle up high and it'll be interesting to see how it does.

But one other item, the only one I can think of other than a restricted fuel filter is the fact that when you are in the mountain states, regular gas is only 85 octane. Our manual for these 4.0 OHV engines say these engines want 87 Octane. So, hopefully a change to the mid - grade may help. Also, I believe the engine light will come on when using too low of an octane.

Hope it's that simple////

twomedicine

 

[Robb]

I am not 100% sure of how long the battery needs to be disconnected. I usually just take it off at night and connect it in the morning. I think it can be done in 20 minutes, but not sure.

Yes, autozone will read the codes for free. But I would call ahead. I have found that a couple of them here have no idea what to do with EEC-IV (OBD1) like you have. They are more used to OBD2.

A code reader for your OBD1 X can be purchased for about $30 from a parts store or wal-mart. It is a great investment for your truck.

 

[born2drive]

Thanks A LOT!!!!

COmplete novice---- where do you plug in a code reader?

Thanks - I'll try resetting the computer tonight.

 

[Glacier991]

Whenever your explorer check engine light comes on, it will save the event data that made the light come on for oh, say, about 65 or so restarts. My advice? READ it. Too valuable to ignore. 4500 RPM? Hmmm. I'd sure as heck want to know why my RPM is about TWICE what it should be!

Try reading this thread on code readers and scanners. It even has a link to a site that will tell you how to read codes without any special reader tools.

http://www.explorerforum.com/forums/showthread.php?s=&threadid=80707

Happy Exploring

Chris

 

[born2drive]

Good Evening - Just got time to post again...

Well heres the scoop. The other night I was driving to Denver and the CEL was on. Nothing to different, but when I started the car to come home, it didn't idle correctly and was belching black smoke.

I didn't want to get stranded on the highway, so I had it towed home. Anyway, I got home and the next day I took it in to the shop expecting some major repair. The mechanic called me and told me that the MAS was loose (the AC shop didn't reconnect it after they fixed my AC.) And my thermostat was bad. The shop fixed both of those things and the car feels a little stronger.

But, it still doesn't feel back to normal. I think that it has something to do with the altitude because I put 91 octane in the last time I filled up and it still feels a bit sluggish.

The mechanic read the codes and said that there wasn't anything worth knowing. (I bet that he would have told me because I asked him to tell me about anything that was broken or may break in the near future.)

THanks
John

 

[twomedicine]

Black smoke

Wondering what happened to you/ Again, I don't have a complicated remedy, but it sounds like a very rich fuel setting for the thinner air.

Although Denver isn't that high, its definitely higher than Pasadena and you could check a few things such as making sure your air filter is clean and unrestricted (sometimes after running real rich an air filter will be loaded with carbon and will not let air pass as easily). When's the last time the fuel filter was changed? And, if the fellow at the garage din't find any noteworthy evidence on his scanner, why don't you try Robb's suggestion about resetting your computer (unhook the battery). The relearning process takes a mixture of city driving, and an uninterupted type of trip mileage of about 15 miles each (going by memory of my manual for a '99). It'll usually run really bad when you first start it after the battery has been disconnected. But it will smooth out.

But, since I lived in Laramie for quite some time @7300 feet, and the pass to Cheyenne is around 8400', when going over the hill I'd see a lot of cars/trucks from sea level blowing the black smoke (partially burned fuel) and reving high too trying to make the pass. Do too much of that and the plugs will load up

Sounds like you are at least moving around now. And 87 octane is plenty good up there/

 

[born2drive]

well......

I bought the computer reader - checked it and it said it was normal - I just got the code that everything was worrking OK.

Then - I thought that I'd check the AirFilter - don't know when that was changed last. It was pretty dirty so i replaced it. THat made quite a difference. Its a little sluggish still but I think that the problem is the altitude.

 

[twomedicine]

Good deal/don't forget to consider that fuel filter either/Yes, altitiude makes for low power for sure, the less restriction the better/Good luck, I aim out that way next week, but quite a bit NW, hoping mine does OK at much higher altitude, like around 10,000'/ Later

 

[twomedicine]

Follow-up Regarding thin air travel

After spending 3 weeks above 8200' with my Explorer I am very impressed with its all around performance.

I am very impressed with the power coming from a 6 cylinder full sized vehicle in the higher altitudes in the Rockies. I experienced less power than at sea level, but nothing like born2drive's experience, thank goodness.

I turned off the overdrive while using the X through the mts and had no problems. My plugs are new, the air filter new, the fuel filter new, and the octane was mid-grade. I also might add that I am loaded with a lot of camping/backpacking/mountaineering gear maybe 400 lbs in total.

I was shocked at the gas mileage. Over 3000miles driven, mostly interstate with A/C and some headwinds, and then a lot of mountain/dirt roads and quite a few 4x4 Low miles too. The average MPG is a whopping 19.44 MPG!!! Unreal

But now it's in the garage with a door latch failure....cannot complain otherwise