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highwaystar
06-19-2007, 09:57 AM
My truck (yota 3.0) runs like a top but at about 6500ft elevation or so usually starts to stumble and doesnt want to idle well.

Are there any tips on how to get your engine running well high up without messing around too much?

UU
06-19-2007, 11:52 AM
Is it carburated ?

Carburetors run some where around 4 - 7 psi and atmospheric pressure is 14.7, so the more altitude you gain the less fuel pressure to the carb.

If you're injected :dontknow:

highwaystar
06-19-2007, 12:51 PM
yea its fuel injected, older system probably designed in 1987.

Smurf131
06-19-2007, 01:35 PM
you also lose compression at higher altitudes

epic3
06-19-2007, 01:58 PM
You probably need a new O2 sensor its out of range and your runnin way lean causin your knock sensor to retard your timing

epic3
06-19-2007, 01:59 PM
you also lose compression at higher altitudes

NO just oxygen

B
06-19-2007, 02:41 PM
on the front of the trottle body there is a idle mixture ajustment screw right above the throttle cable might help it out ?

85_GMC_4x4
06-19-2007, 02:47 PM
Fuel injected vehicles usually handle evevation changes better than carbed.

Could be a faulty O2, but since you mention idle and startup (when the ECU ignores the O2 sensor) I kinda doubt it.

If there is an adjustment screw, that'll help but you'll end up running leaner at normal elevation. Could also look into the MAP sensor (if the yota uses speed density) most vehicles take a barometric correction measurement when you 1st turn on the key.

Stetson
06-19-2007, 02:55 PM
Is it carburated ?

Carburetors run some where around 4 - 7 psi and atmospheric pressure is 14.7, so the more altitude you gain the less fuel pressure to the carb.

If you're injected :dontknow:


toyota 3.0L are all fuel injected .......... .. . [16] silly jeep owner [f]











:D

Smurf131
06-19-2007, 04:11 PM
NO just oxygen

if the altitude in the area where the vehicle is driven is significantly higher than sea level, then the compression ratios will vary. to determin the effects of the altitude on a calculated compression ratio use the following formula:

corrected compression ratio = FRC minus [(altitude/1000)x 0.2]

that will give you your actual compression ratio

meaning you lose compression at higher altitudes...

that's why they say the mission quarter mile is one of the fastest, cuz i's so close to sea level.

85_GMC_4x4
06-19-2007, 05:05 PM
if the altitude in the area where the vehicle is driven is significantly higher than sea level, then the compression ratios will vary. to determin the effects of the altitude on a calculated compression ratio use the following formula:

corrected compression ratio = FRC minus [(altitude/1000)x 0.2]

that will give you your actual compression ratio

meaning you lose compression at higher altitudes...

that's why they say the mission quarter mile is one of the fastest, cuz i's so close to sea level.

Lol... compression RATIO will NOT change. The compression ratio is a mechanical property of the engine and does not change without changing engine parts.

However, As altitude increases the amount of cylinder pressure during the compression stroke will drop as a result of the thinner air.

It really boils down to the fact that at higher altitudes the air is thinner and contains less oxygen. Less oxygen means less fuel is required for engine to run properly, and less horespower is made. Same thing as cold vs hot air.

highwaystar
06-19-2007, 05:19 PM
[cheers] ok well thanks for the info guys

I shouldnt have said stumbling, really the problem was that it didnt want to idle. The engines always idled really low like 4-500 rpm anyways. Ill just keep my foot on the gas a bit. thanks.

Stetson
06-19-2007, 06:21 PM
[cheers] ok well thanks for the info guys

I shouldnt have said stumbling, really the problem was that it didnt want to idle. The engines always idled really low like 4-500 rpm anyways. Ill just keep my foot on the gas a bit. thanks.

ON THOSE 3'S, YOUR ISSUE IS USUALLY A RESULT OF A DEAD CYLINDER. AS THOSE 3'S ALL HAD HEAD ISSUES. CHECK EACH CYLINDERS COMPRESSION. YOUR IDLE ISSUE IS HOW ALOT OF THEM BEGIN TO SHOW THEIR HEADS LEAKING.

UU
06-19-2007, 06:21 PM
toyota 3.0L are all fuel injected .......... .. . [16] silly jeep owner [f]





I own 2 jeeps [wako]

highwaystar
06-19-2007, 07:27 PM
ON THOSE 3'S, YOUR ISSUE IS USUALLY A RESULT OF A DEAD CYLINDER. AS THOSE 3'S ALL HAD HEAD ISSUES. CHECK EACH CYLINDERS COMPRESSION. YOUR IDLE ISSUE IS HOW ALOT OF THEM BEGIN TO SHOW THEIR HEADS LEAKING.

The idle has been exactly the same for over 10 years since my dad bought it. I dont think its an issue. Thats the first thing I noticed years back was how low it idled. But my friend had one that idled higher?

oh well if it aint broke dont fix it.:dontknow:

Trooper
06-19-2007, 08:13 PM
Dont you have an altitude adjustment thing around the throttle linkage? or is it only a diesel yota thing.
I would check your o2 sensors

highwaystar
06-19-2007, 09:23 PM
O2 sensor is not even a year old. Ill clean out my MAF maybe before next trip

kootenaycat
06-19-2007, 09:36 PM
Have you checked codes? Could have a MAF code in it even if it is not triggering the light all the time. In the Diag connector under the hood, I believe it's E1 and TE1 you short together, turn ignition on engine off, watch and count check eng light flashes. I'm sure someone on here can decipher the codes for ya. ;)

And yah, I'd clean the MAF if possible. Some you can access the heated wire and carefully clean with a cue tip with throttle body cleaner.