LJ78 high altitude overheating woes

[disco voador]

Hi all,

I'm one week in on a roadtrip around the USA and now that I'm at a high altitude (wyoming-utah) 2L-TE in my Prado is giving me grief - higher than normal EGTs on the hwy and I'm basically unable to go up any decently sized hill without overheating.

Basically I'll enter a hill doing 90 kph or so and hold the egt at or just below 1000f and the car will gradually slow down up any hill and I'll downshift to the point where I'm in 2nd going at about 50 kph, and by that point there's not enough air flow into the rad and it'll overheat. Pretty ridiculous.... Air temp is also not hot, 10-20°C. I've had no problems of this sort in Ontario (basically all sea level) but we also don't have hills of this calibre near me.

Research so far has lead me to guess that my problems are twofold-
1. The e-fan that the previous owner installed doesn't pull enough air at low speeds when the engine is under load (-> overheats when going slow)

2. There is no altitude compensation (again this is my guess - I could not download that Denso manual) on the 2L-te which is causing it to run rich and hot at altitude. In Wyoming where I was, I was around 2500m altitude, so the atmospheric pressure would be about 4 psi less than sea level. If the engine is seeing 10 psi boost and fuelling accordingly but there's really "6 psi" of air going into the intake I could understand why the EGTs are so high all the time.

So, I understand there's a bleed valve mod I can install between the boost line and the boost sensor (I've already tried to replicate this by poking small holes in that line near the sensor... I think it has helped, but not solved the issue) but other than that, any suggestions or spiritual guidance? Preferably something I can do "in the field" as I'm quite far from my workshop.

Or is there a bigger problem with my car? This seems pretty absurd that the car barely works at high altitude, and I couldn't find reference to anyone else having similar issues....

Thanks,
Eugene
Currently near Ogden, UT


(Background info-
2L-te LJ78, 3L head swap reportedly done
Head is not yet cracked (I keep checking)
Automatic
33" tires, 2" lift
Snorkel and cheesy looking k&n filter, EGR delete
2" exhaust (that's all I could scrounge at the last minute)
Stock rad with e-fan
Roof box and a ton of crap in the back of the car, maybe 4-500 lb? )

 

[mcmarshing]

Hey, I live in Ogden. If you want to swing by to get more eyes and more tools to use, message me and feel free to come by.

are you intercooled? One thing that has worked on the 3L i’ve been working on that the PO installed was a 5L fan and a bigger aluminum radiator. Some people also suggest using waterless coolant as well to at least avoid water boiling even when it gets hot.

are you slowing down out of trying to keep engine temp down or just because the engine isnt generating enough power?

 

[disco voador]

Hey, I live in Ogden. If you want to swing by to get more eyes and more tools to use, message me and feel free to come by.

are you intercooled? One thing that has worked on the 3L i’ve been working on that the PO installed was a 5L fan and a bigger aluminum radiator. Some people also suggest using waterless coolant as well to at least avoid water boiling even when it gets hot.

are you slowing down out of trying to keep engine temp down or just because the engine isnt generating enough power?

Oh hey that could be cool, I'll send ya a message

No intercooler unfortunately, got started on putting one in and didn't have the time to get it done before the trip

Slowing down because the egt hits 1000f. Not enough power to maintain any reasonable speed up a hill. Engine temp goes up after a while at high egts

 

[AirheadNut]

Sorry to hear of your issues! The electric fan could easily be part of the problem, even high power fans will only move around 3000cfm while a good mechanical fan can easily do twice that.

Is your pyrometer pre-turbo or post-turbo?

 

[disco voador]

Sorry to hear of your issues! The electric fan could easily be part of the problem, even high power fans will only move around 3000cfm while a good mechanical fan can easily do twice that.

Is your pyrometer pre-turbo or post-turbo?

Pyro is pre-turbo,

 

[Waikato Willy]

plus 1 for the viscous fan ,get your hands on some silicon oil 10,000cst from a hobby shop , pull it apart and adjust the valve inside up, before my rig got written off under load the fan would engage so had it would actually suck power from the engine but it certainly cooled it down no matter how hard the load , you should hear the fan engage with a massive whirring noise , I could always hear mine engaging, you could always cut the exhaust halfway to help with back pressure and crank up the boost , a bit hard to do and exhaust when your in the middle of traveling I guess , adding boost with out a nice free flowing exhaust can be almost counteractive , as an experiment you could pull the wastegate pipe all together but would will need to do a fuel cut defense mod of the bleedoff mod on this forum - be the same for both 1KZTE and 2LT

 

[GTSSportCoupe]

Hi all,

I'm one week in on a roadtrip around the USA and now that I'm at a high altitude (wyoming-utah) 2L-TE in my Prado is giving me grief - higher than normal EGTs on the hwy and I'm basically unable to go up any decently sized hill without overheating.

Basically I'll enter a hill doing 90 kph or so and hold the egt at or just below 1000f and the car will gradually slow down up any hill and I'll downshift to the point where I'm in 2nd going at about 50 kph, and by that point there's not enough air flow into the rad and it'll overheat. Pretty ridiculous.... Air temp is also not hot, 10-20°C. I've had no problems of this sort in Ontario (basically all sea level) but we also don't have hills of this calibre near me.

Research so far has lead me to guess that my problems are twofold-
1. The e-fan that the previous owner installed doesn't pull enough air at low speeds when the engine is under load (-> overheats when going slow)

2. There is no altitude compensation (again this is my guess - I could not download that Denso manual) on the 2L-te which is causing it to run rich and hot at altitude. In Wyoming where I was, I was around 2500m altitude, so the atmospheric pressure would be about 4 psi less than sea level. If the engine is seeing 10 psi boost and fuelling accordingly but there's really "6 psi" of air going into the intake I could understand why the EGTs are so high all the time.

So, I understand there's a bleed valve mod I can install between the boost line and the boost sensor (I've already tried to replicate this by poking small holes in that line near the sensor... I think it has helped, but not solved the issue) but other than that, any suggestions or spiritual guidance? Preferably something I can do "in the field" as I'm quite far from my workshop.

Or is there a bigger problem with my car? This seems pretty absurd that the car barely works at high altitude, and I couldn't find reference to anyone else having similar issues....

Thanks,
Eugene
Currently near Ogden, UT


(Background info-
2L-te LJ78, 3L head swap reportedly done
Head is not yet cracked (I keep checking)
Automatic
33" tires, 2" lift
Snorkel and cheesy looking k&n filter, EGR delete
2" exhaust (that's all I could scrounge at the last minute)
Stock rad with e-fan
Roof box and a ton of crap in the back of the car, maybe 4-500 lb? )

As the other guys have pointed out, the e-fan is the likely culprit. Mechanical fan with a new OEM hub (or serviced original) will be best. The e-fan is hard on the LJ78 55A alternator too, and will lead to earlier failure.

The 2LTE was made through to 2002. Shortly after the head cracking 2LTE's of the early 90's, Toyota spec'ed a new 82C thermostat instead of the original 88C. Make sure you run that newer type.

I found recently that the A/C condensor in these trucks can gradually get stuffed up with bugs/seeds/debris that really feeds into airflow issues. Make sure it's clean.

The 2LTE ECU does definitely compensate for altitutude. It does this by measuring air pressure in the manifold. Long hills will cause EGT's to rise, that is to be expected.

These motors are very happy around 3000rpm or even more under load, and will run lower EGT's there. I recommend that when you're going up those hills. Don't lug it. 2LTE by bore/stroke geometry and IDI technology is actually designed to burn diesel faster and run high rpms ok.

You could pickup a manual boost controller for your turbo waste gate. Tune for up to 12psi (without intercooler). After 10psi, the computer pulls fuel a little bit. This means you'll run leaner at 12psi. But you'll also make a bit more power. win/win.

 

[disco voador]

As the other guys have pointed out, the e-fan is the likely culprit. Mechanical fan with a new OEM hub (or serviced original) will be best. The e-fan is hard on the LJ78 55A alternator too, and will lead to earlier failure.

The 2LTE was made through to 2002. Shortly after the head cracking 2LTE's of the early 90's, Toyota spec'ed a new 82C thermostat instead of the original 88C. Make sure you run that newer type.

I found recently that the A/C condensor in these trucks can gradually get stuffed up with bugs/seeds/debris that really feeds into airflow issues. Make sure it's clean.

The 2LTE ECU does definitely compensate for altitutude. It does this by measuring air pressure in the manifold. Long hills will cause EGT's to rise, that is to be expected.

These motors are very happy around 3000rpm or even more under load, and will run lower EGT's there. I recommend that when you're going up those hills. Don't lug it. 2LTE by bore/stroke geometry and IDI technology is actually designed to burn diesel faster and run high rpms ok.

You could pickup a manual boost controller for your turbo waste gate. Tune for up to 12psi (without intercooler). After 10psi, the computer pulls fuel a little bit. This means you'll run leaner at 12psi. But you'll also make a bit more power. win/win.

Ah just the guy I was hoping would see this! Your posts have been very valuable to me in the past and lately...

Interesting that the e fan could hurt the alternator. Ive got this redarc bcdc charger for my hotel power and it used to charge the hotel battery with the alternator but I don't think it does anymore - which implies that the alternator never makes more than 13.5 or whatever it is volts. Ive got a volt meter at the dash too and it never goes above 13 v I think... not sure if there's voltage drop between where I'm measuring it and the battery though.

Thermostat - I read a post of yours stating the 88°c one is better for fuel economy and me being a cheapo, I opted to leave it in. Well that and I didn't have overheating issues before...

A few bugs in the condenser, I should give it a wash or something I guess


Update on my end:

Between advice here and discussions with my friends I guess yeah, the engine is working fine but my car being pretty well loaded with junk and with big tires, I've hit the power / cooling limit. The 2" exhaust certainly isn't ideal and neither was the fan.

Not so much I could do about the exhaust (oh actually, I could remove half of it??) But today I went to cruiser outfitters here in Salt Lake City and to my surprise they had a 2L fan hub and a 1hz fan (again, thanks to gtssportcoupe for the thread with the part numbers). Cost came out to 220 USD - 60 for the fan and 140 for the hub, pretty reasonable I think. They didn't have a shroud but I went to a junkyard and a gen 2 Chevy tracker one is a pretty close match - mostly the lateral offset is a bit off. I installed it in a parking lot of an empty office building here (lol) and despite forgetting that the engine moves relative to the rad I think it doesn't rub (or not much at least? It's pretty close ) .
I added some water wetter as well into the coolant. Tomorrow I'm gonna make a run for the mountains and try to get to Moab the day after or something - hope my engine doesn't blow up haha.

Thanks everyone for the support, I really appreciate it!!