1990 lj78 (1 Viewer)

[Pete B]

HI, new to forum, just purchased a 1990 LJ78g, needs a bit of work and currently has a top speed of 45kph, and is showing a code 12 so from what I'very read I have quite a challenge ahead of me, but I'm sure it will be worth it as its one he'll of a machine. Photos to follow.

Located in the woods in northern Saskatchewan, Canada

 

[GTSSportCoupe]

HI, new to forum, just purchased a 1990 LJ78g, needs a bit of work and currently has a top speed of 45kph, and is showing a code 12 so from what I'very read I have quite a challenge ahead of me, but I'm sure it will be worth it as its one he'll of a machine. Photos to follow.

Located in the woods in northern Saskatchewan, Canada

I think that code has to do with the pick-up sensor on top of the injection pump. If the timing control valve (bottom back of injection pump) can't achieve the desired timing, this will produce an error at the ECU. I don't think your sensor is actually the problem, or the engine probably would not be running. If the injection timing is way out it would significantly reduce your power and give you the severe lack of power you are seeing.

Things I'd look for would be timing belt worn out and skipped a tooth. Injection pump contaminated with water. Injection pump contaminated with sediment or other media.

You can drain the injection pump and 'flush' it out by removing the timing control valve on the bottom back of the injection pump.

Pull the timing belt cover off to inspect the belt.

Good luck.

 

[Pete B]

I think that code has to do with the pick-up sensor on top of the injection pump. If the timing control valve (bottom back of injection pump) can't achieve the desired timing, this will produce an error at the ECU. I don't think your sensor is actually the problem, or the engine probably would not be running. If the injection timing is way out it would significantly reduce your power and give you the severe lack of power you are seeing.

Things I'd look for would be timing belt worn out and skipped a tooth. Injection pump contaminated with water. Injection pump contaminated with sediment or other media.

You can drain the injection pump and 'flush' it out by removing the timing control valve on the bottom back of the injection pump.

Pull the timing belt cover off to inspect the belt.

 

[Pete B]

Thanks for the info, I'll check that next.

 

[GTSSportCoupe]

Thanks for the info, I'll check that next.

Download the manuals linked to in this thread: Ideas for improving the 2LTE. The first one posted (Denso injection pump manual) explains how these diesel engines work. Will help you understand a lot about it which will help you troubleshoot.

I'm happy to help as much as I can. I've learned a lot about these motors of the years.

Oh, and I found a good description of how to pull the codes yourself: 2.4LTE Fault Codes

 

[Pete B]

OK checked the timing, everything is spot on, I have changed the crank sensor and no change, the problem is electrical as I've put the flow control valve ground wire directly to earth and she does Rev up. I have also wiggled the wires behind the glove box, still no better. Anyone got any info on the timer control valve, resistance, removal Etc?

 

[Pete B]

HI, new to forum, just purchased a 1990 LJ78g, needs a bit of work and currently has a top speed of 45kph, and is showing a code 12 so from what I'very read I have quite a challenge ahead of me, but I'm sure it will be worth it as its one he'll of a machine. Photos to follow.

Located in the woods in northern Saskatchewan, Canada

 

[Jim from Idaho]

Giggling the wires got rid of my code 12 problem. If that doesn't work, check the wiring for the connection from the ECU to the injection pump. After that, the try a replacement ECU. I found another used one off of Ebay for about $150 CaD, and that took care of intermittent stalling after the engine got warm. That's a nice looking cruiser for $1500. Manual hubs would indicate someone owned it who cared, at some time in it's past.

 

[Pete B]

I changed the pump and the code has gone, i still have low power but that is looking like a worn out turbo, the bearings are very rough. Im actually thinking of pulling the 2lte out and putting something else in it

 

[JimmyPrado]

Well. I see you posted about an engine swap and that’s a lot of work. IF it is a tired turbo, a $200 turbo is a lot cheaper and might solve your power issue. I think it’s a small price to pay before spending the big ducks on the swap. My two cents.

 

[Pete B]

yeah i know, its a lot cheaper, but its getting frustrating, and the wife isn't too happy either lol, and to add insult to injury ive discovered the alternator isn't putting out either.

 

[JimmyPrado]

Ah, the plot thickens! Kz going for about 4K US not sure about hz’s. Good luck and post up your switch if that’s the direction you go!

 

[GTSSportCoupe]

yeah i know, its a lot cheaper, but its getting frustrating, and the wife isn't too happy either lol, and to add insult to injury ive discovered the alternator isn't putting out either.

The wife's not happy with mine either! I think thats perfectly normal, haha.

In terms of swaps, I've seen gasser swaps to 1UZFE (4.0 lexus v8), 5VZFE (3.4 toyota v6), 22RE (2.4l toyota I4 - gutless in Prado tho), 1JZGTE (2.5l twin turbo I6) and 2JZGTE (3.0l twin turbo I6). All of these will require a lot of custom work and you had better be good with wiring. The thing they all have in common is they share the same transmission series, so it's possible to bolt them to the auto transmission in the Prado.

In terms of diesel swaps, I've seen 1PZ, 1HZ, 1KZ, and 3B swaps. Again all will require a fair amount of work, although much less wiring than the gas motors.

In terms of time and economics, fixing your 2LTE is the best option. As long as it's got good compression and there is nothing fundamentally wrong with it other than the accessories. A few guys have gone with the cheaper Ebay CT20 turbos and have had perfectly good luck. (the $200-300 ones). Rebuilding the alternator is not different than for any other Toyota alternator really. Just leave the vacuum pump part alone.

 

[Pete B]

ive been looking at the turbo options, Postoy on here has a low mile rebuilt CT26 which i might give a try, i got my fuel injection pump off him and it works apart from it loosing prime, which is probably just a small leak in one of the lines, new hoses and clamps should sort that. when it comes to the alternator rebuild, is it just the bushes that need doing normally for does it have a diode pack too

 

[roscoFJ73]

just purchased a 1990 LJ78g, needs a bit of work and currently has a top speed of 45kph

How many klms has it done? I would be doing a compression test before spending any money.

 

[Pete B]

160000km

 

[roscoFJ73]

That's not much for a diesel. L diesels can easily go for 300000klms or more if looked after.