A new guy with an altitude problem

HB_LC · 05-03-07, 08:14 PM

I've been a reader for a while, but this is my first post. Just had our first kid and moved from UT to soCal. Cherried our FJ62 out before we made the trip--had everything checked (including the sticking driver's side window), but I found a problem once we landed...

The check engine light is on, again, but the truck runs fine. I say again because everytime I have driven it from UT to CA (about 3 times a year) it has given me a check engine light here at sea-level.

I have had two mechanics in the OC look at it. One replaced the oxygen sensor--didn't fix it. The other tried something else (don't remember)--didn't fix it either.

Anyone have any tips? hints? I think I'm gonna have to fix it myself.

Thanks for any advice you can give.

cody c · 05-03-07, 08:40 PM

welcome to the forum!

(newbie salut)

at the top of the 60's section there is a thread to help you find helpful mechanics near you. I cant help you with your 62, because i have a diesel and not a clue about your 3F, or 3FE. But im sure someone here will help soon. You can add the year of your vehicle and any accesories in your signature, this will help others diagnose your problems.

Lots of good info and good guys on here you should get some help soon.
Cheers! And post some Pics of your New to you cruiser!

dfmorse · 05-03-07, 08:48 PM

HB;

Welcome; first off; specify model of LC, mileage; any modifications to said vehicle; and a detail of the problem. This helps the gurus do a quick analysis of problems.

I'm going to guess at possible problems. U probably have over 100k miles on said vehicle ; U have not replace many of the hoses under the hood. If there is Fuel Injection involved , u have not cleaned injectors or do not use a cleaner when fuel up is required (putting gas in the tank).

I am not up on the total specifics of the FJ62; but be assured that people from this group will chimm in/...

...

ellington12 · 05-03-07, 10:37 PM

the 3-FE engine in the FJ62 has an altitude sensor built in to the ECU. this sensor is supposed to sense atmospheric pressure which is directly related to altitude which is directly related to the oxygen content of the air. this signal gets sent to the ECU so that it can alter the air/fuel ratio for optimum driveability regardless of your altitude. the oxygen sensors do play a role for they tell the ECU whether it's compensating appropriately for whatever altitude you're at.

the first thing i would do is pull codes. not sure what year you've got but for an '88 code 35 indicates a problem with the altitude sensor. not sure if all FJ62s have the same codes...

the other possibility is that your ECU hasn't yet adapted itself to sea-level. if you've been running at high altitude, the ECU has self adapted itself for these conditions. it could be a matter of driving around for a while to let the ECU adapt itself to its new home. usually however, this adaptive process happens as conditions change. a drive from say denver to sea-level shouldn't set the "check engine" light which is why i'm leaning towards a problem with the altitude sensor.

you can pull the EFI fuse to clear the code but i believe, (though not positive,) that to reset the adaptive values you'll need to disconnect the battery for a bit.

i'm by no means a FJ62 expert but hopefully some of this helps...

GAS-A-LOT! · 05-03-07, 10:59 PM

Welcome to so-cal. Nice to see more and more Mudd'rs. Down here.

HB_LC · 05-05-07, 07:35 AM

Thanks for the tips. I'll check the codes and look into the altitude sensor. If all else fails, I'll check the list of hopefully decent mechanics.

The LC, by the way, is a 1990. Stock everything. Not modified but babied by me and the two OCD owners before me. 204K when I got it, 235K on it now. And all the mechanics that look at it go off on how clean it is.

She's my backroad Wasatch baby, my soon to be baja surf taxi.

Thanks again for the tips. If you think of anything else, please don't hesitate.

forestdan7 · 05-06-07, 05:25 PM

The opposite sort of thing happened to me in my '87 4Runner. I'm in Kentucky, under 1000' altitude most of the time. I drove it out west back in 2002, and in the middle of Idaho, at pretty good elevation, the check engine light came on.

It kind of freaked me out at first. Then I noticed it usually only happened when I was keeping a constant speed, and that it went off when I acclerated.

Now, back in Kentucky, it's off all the time. It has popped on once or twice in the past five years, on long downhill coasts dropping altitude out of the bigger mountains in SE KY. As soon as I accelerate, it goes off again.

Moral: I wouldn't worry about it. Maybe check the codes for peace of mind, but if it runs fine, it's probably okay.

HB_LC · 05-07-07, 10:43 AM

ellington12,

Thanks a lot for the advice. I disconnected the battery, let her sit for a half day, connected her back up and for three days now, no sign of the check engine light. I think resetting the altitude sensor worked. Many thanks.

Now I need to post some pics. (My wife is a fine art photographer and I convinced her to shoot the Cruiser in back country So. Utah...)

Thanks again.

ellington12 · 05-08-07, 07:58 AM

good to hear...welcome to CA!

Dirty Toad · 05-08-07, 08:49 AM

I am not all that familiar with the 62, but I have been working with cars/trucks for a long time. If you have a mass air flow meter, it may be gunked up. you can try cleaning it. that might help...if you have one