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Since replacing the head gasket, MAF pigtail and TPS pigtail my 22re has been running a lot better. At less than about 5k ft, i'm getting 15-17 mpg whereas before I was getting 13-14.

Both before and since the gasket, at about 7k ft I begin to notice slight power loss - no misfiring, but it just seems to take a bit more pedal the get going. Once I get to +9k ft, I'm having to mash the pedal pretty well, and there have been a few times on about a 9% grade I was afraid I might not make it even in 1st gear.

When I did the head gasket, I also replaced the water pump, radiator, and fan clutch. Before the new parts, I would regularly see 1/2 to 2/3 on the gauge. Now, regardless of how I work it, the temp guage never goes over about 1/3, so I'm sure it's not overheating.

Many years ago I had an old 1955 Dodge pickup w/ a flathead 6. When I was living in Denver for a time, I had to advance the timing and adjust the carb to run a bit richer to make it run right. Then, when I headed back East, I had to reset the timing and carb to factory specs - otherwise, it would ping.

The engine doesn't miss or ping (at least noticeably) or "sound funny" at altitude - the only symptom I've been able to detect is a gradual loss of power as the altitude increases.

Timing is factory spec at 5deg BTDC w/ jumper and 12deg BTDC w/o jumper. New plugs, wires, cap, rotor shortly before the new head gasket. The TPS has been adjusted following the "feeler gauge" procedure at http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml. I also changed the fuel filter.

Can anyone tell me how the 22re's EFI system compensates for altitude changes, or if it even does? Do I need to make any manual adjustments to compensate for high altitude? Is my ECU failing? Any other thoughts, suggestions appreciated.

Thanks

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Your not going to like this answer :shit:

At 9000 ft your power loss is around 35%. Your engine is running just fine. The EFI should be good to 12,000ft.

The EFI will lean out the fuel mix as you gain altitude, so the engine won't go rich and lose even more power.

If you want to play go here...........http://www.wallaceracing.com/braking-hp.php

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Dang - I was afraid of that. Anyone know anything about a "high altitude compensator"? How to ID, troubleshoot, etc? I don't know if I have one, but it seems to me that if I could get my timing a bit more advanced at higher altitude, the fuel/air would have a bit longer time to combust.

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A turbo charger is about the only way to reduce altitude loss of power. HP declines at only about 1.5% per thousand feet compared to non turbo charged engine declines at about 3% per thousand feet

Linda S.

Not universally true in reference to a turbocharged engine. If setup correctly a turbocharged engine virtually loses no power, regardless of altitude, on planet earth. I say "planet earth" because some airplane engines can lose some power when they fly over 4-5 miles high. Exhaust-driven superchargers, i.e. "turbochargers" were more commonly called "altitude compensators" when first used in the trucking industry, mostly on diesels. Granted - if someone has a wimpy turbo system with a very small turbo, no low-end boost - or a wastegate not set up for change with altitude, there might be loss. But a good turbo system on a car or truck will allow steady power regardless of altitude. A non-electronic Dodge truck with a 5.9 Cummins diesel will lose around 2.5% power when driving at 5000' above sea-level. A non-turbo engine (gas or diesel) at the same height would lose around 17% power. I've been told that the newest diesel pickup trucks with electronic controls lose no power when driven at a mile high.

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a normally aspirated engine loses power with elevation increase. With the 4 cylinder (IMHO) you are under powered at sea level except on really flat land. As for adding a turbocharger r supercharger, I think you would be better off selling your unit & buying something that does what you want.

I can report that the V6 will operate at those elevations but it is working hard.

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Just drive and enjoy the scenery. All the fiddling will only gain 3-5hp at the most. If you really need to go faster then remember the old hot rod saying.

Speed cost money how fast is your wallet???

A turbocharger or supercharger is in the $3,000 range

http://www.lceperformance.com/Pro-Turbo-Kit-Low-Boost-22RE-Non-Turbo-Block-p/1071012.htm

http://www.lceperformance.com/22RE-Supercharger-Kit-High-Boost-10psi-p/1073004.htm

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Not universally true in reference to a turbocharged engine. If setup correctly a turbocharged engine virtually loses no power, regardless of altitude, on planet earth. I say "planet earth" because some airplane engines can lose some power when they fly over 4-5 miles high. Exhaust-driven superchargers, i.e. "turbochargers" were more commonly called "altitude compensators" when first used in the trucking industry, mostly on diesels. Granted - if someone has a wimpy turbo system with a very small turbo, no low-end boost - or a wastegate not set up for change with altitude, there might be loss. But a good turbo system on a car or truck will allow steady power regardless of altitude. A non-electronic Dodge truck with a 5.9 Cummins diesel will lose around 2.5% power when driving at 5000' above sea-level. A non-turbo engine (gas or diesel) at the same height would lose around 17% power. I've been told that the newest diesel pickup trucks with electronic controls lose no power when driven at a mile high.

Hmm. I think I was talking about Toyota trucks. Not airplanes or diesels

Linda S

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FWIW I had my 22RE over several 12,000ft passes. 10,000ft is very common and 7,000ft is the low lands and 5000ft is the flat lands.

Just go and when you get there your are there. The difference between a v-6 and a 22RE on a 400mi day is only about 30 min in the mountains and 0 in the flat lands.

Remember we travel at the speed of smell.

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I have also driven over 10,000 ft many times. I have a 22 Re oin my '88 Escaper. When I bought the RV, I knew that I was buying one of the most underpowered vehicles on the road. I bought it anyway and my wife and I just enjoy the "slow" side of life. We rarely drive on the interstate highways. We get there when we get there. I love being retired (semi-retired actually)

Next summer our planned trip will take us up The Old River Road in Rocky Mountain NP (12,143 ft), over Independence Pass (12, 093 ft), up and over The Beartooth Highway (10,947 ft), and up the Bighorn Mountains on 14A (9,430 ft) from the west.

Slow is a state of mind and we love it.

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We've been living in our Escaper since April - so it's home to us, not a vacation <g>.

The issue isn't being able to move fast - we took 3 months to cross the US because we actually enjoy going slow on back roads, exploring and meeting people. Compared to our sailboat, the Escaper moves at the speed of light!

My concern is that the little 22re might just not be able to pull us over the next hill. A couple of weeks ago we were at about 10k ft going up the mountain at Great Basin National Park in 1st gear and I wasn't sure if we'd be able to make it. It's a narrow steep winding road and I was uncomfortable with the thought of having to stop and turn around in the middle of it.

Maybe I need to add a nitrous system just for big hills <g>.

Seriously, though, we're not even considering adding turbo or anything big or expensive. We're just wanting to squeeze out a bit more power at higher altitudes.

I looked at Google images for "22re high altitude compensator" and then at our engine, and I don't think we have one. I'm just wondering if a bit of extra timing advance might help, and if so, how to implement it.

Thanks all, this list has been invaluable!

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I looked at Google images for "22re high altitude compensator" and then at our engine, and I don't think we have one. I'm just wondering if a bit of extra timing advance might help, and if so, how to implement it.

Thanks all, this list has been invaluable!

Advancing the timing approx. 1 degree for every 1000 feet above sea-level is a general rule-of-thumb to restore some of the power and also lower emissions. I'm talking about an engine with electronic fuel injection that automatically takes care of the over-rich fuel situation - unlike a carbed vehicle. So the timing change is the only thing you can do easily. Too bad you didn't have a 1918 Ford Model T and you'd have a timing advance lever on the steering column. You could put the advance timing for "mile high" driving by adding 5 degrees more advance by moving the distributor. I'd do it at home and mark the distributor base in two places. This way you can easily see the normal-driving mark and the "one mile up" mark. Then leave the distributor clamp-down bolt just tight/loose enough that you can twist the distributor by hand when you want to change in hurry (no tools needed). Mine has been like that for years. That is one simple method. Also make damn sure you fill the tank with the cheapest, lowest octane gas you can find when driving in high places. Never never use mid-grade or high-test since they burn too slow. The reason why you want to advance the timing in high places is to get the fuel-air mixture to burn faster. High-test just makes it that much worse.

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The HAC is on 22R carbed engine. Its basically a controlled vacuum leak. It also advances the timing a bit. You can do the timing advance but the efi eliminates the need for the HAC

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I would suggest a complete tune up. News plugs, plug wires, distributor cap, new PCV, adjust the valves, & change the fuel filter. I can tell the difference between 700 ft at home and anything above 6000 ft but I have never come close to putting the gas pedal to the floor. Even at 12, 000 ft I had plenty of pedal travel left. I just watch the tack and enjoy the sound of that little 4 banger play its music.

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Now I'm confused. Are we talking about a 22R or a 22RE? I was responding to the post from "mustrmrk" that mentioned the controls on a 22RE.

We are talking about a 22RE. The OP keeps talking about an altitude compensator. Which is only on carbed engines. Just trying to keep him from going down rabbit trails.

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BobC - As previously stated: 22re, new cap, rotor, plugs, wires, timing set to factory specs. TPS and MAF both test fine, both have new pigtails, and, as far as I've been able to determine, the TPS is adjusted correctly.

WME - I didn't know the HAC was only available on carbureted vehicles - thanks for the clarification - I'll drop that line of inquiry.

So, if the ECU automagically advances the timing for higher altitude / lower oxygen levels, is the manual adjustment suggested by JD, above, rendered moot?

Is it possible my O2 sensor is sending an erroneous signal to the ECU? Guess I should test that, too.

Maybe I just have too much crap aboard....

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B

So, if the ECU automagically advances the timing for higher altitude / lower oxygen levels, is the manual adjustment suggested by JD, above, rendered moot?

Is it possible my O2 sensor is sending an erroneous signal to the ECU? Guess I should test that, too.

I think the 22RE has a barometic air pressure sensor inside the air-flow-meter. So assuming it is working - your timing is adjusted automatically. If it didn't work - I don't think it would trip the "check engine light" and you'd likely never know. But - I'm just guessing. There are several things about the EFI system used in these older Toyotas I'm not sure about. My 1988 22RE has a "knock sensor" yet I assume it does not work. My engine starting pinging pretty bad on steep hill climbs unless I used high-octane gas. So to fix it - I just loosened the distributor a bit and retarded the timing just enough to stop it from knocking. So much for the on-board "knock sensor." One thing I know for sure. NEVER use mid-grade of high-test gas at high altitudes. Just get the lowest cheapest gas you can find.

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I don't know about every where else, but in Wy regular gas is 85 Octane. I THINK it changes around 4000 ft.

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87 octane is regular anywhere I've been in New York, Vermont, and Michigan. When driving in high altitudes - the lower the octane the better since it burns faster then the more expensive stuff.

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Well, shoot - that could have been my problem. I made a point of buying mid-grade since I didn't want no steenkin' 85 octane fuel in MY rig..... I guess I know better, now.

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Jumping out shorting the timing pins advancing the timing jumping back in only to do it again on the other side of the mountain sounds like a lot of useless effort to gain a couple of HP.

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