Builds 1992 LJ78 build/refresh

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Joined
Dec 3, 2017
Threads
4
Messages
462
Location
Tulalip, WA
Thought I would start a thread and try to keep all my stupid questions in one place.
I just bought a LJ78 because I need another project about like I need scurvy.
1992 LJ78 with 179k kilometers. Auto trans. LWB.

I will be doing all the EGR removal , fuel tweaking and most likely intercooler on this. But, first I want to establish the maintenance on it. And, I won't tweak a diesel until it has an EGT gauge , so that will need done.

Front swivels are a mess. So, Kurt helped me out with an entire kit to rebuild the front hubs. I am retaining the auto hubs for the time being as they work. If they give me trouble down the road I will dump them for manuals.

Truck has a touch of death wobble at about 50mph. Tires aren't great. So next project will be front end bushings and new shoes.

Now the stupid questions.

Truck is a hard start from cold. Glow plug indicator pops on for maybe 2 seconds regardless of engine temp. I have seen several threads about testing the plugs, relay, ect, so I will get to that in the next bit. But ,my question is; how does that light function. Does it stay on for different interval at different times. I probably just missed it, but couldn't find that answer.

Next is the idle adjustment knob. Mine just turns a bit. CW snugs it down and seems to raise RPM a bit. CCW losens and drops RPM slightly. How much variance is that designed to give? I am seeing maybe a 50-100 RPM change.

As you can see in the background of my picture, I have a far more insidious hobby than Toyotas. Hopefully Toyotas can replace that hobby after over 20 years. Not sure it will take but I am hopeful.

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Sweet looking Prado! Looking forward to seeing what you do with it.

With regard to the manual throttle knob, there should be a lot more RPM change than what you are seeing, more like +1000rpm from idle. How many turns does it take to raise the idle? My guess is that the cable is stiff. Mine is currently seized and the knob is off, so I will be digging into it soon too. On my old Prado I could hit over 2000rpm with no load. It could provide enough throttle to cruise at 80kph, too.

Oh, the glow plug light should vary depending on how warm the engine is. However, I don't know what determines that, probably coolant temp sensor (underneath the intake manifold on the engine block).
 
Thanks.
I suspected that was the case with the throttle knob. I didn't want to force it if it was working as intended. I will take it apart and see if my cable is seized as well.

I also suspected the glow plug light was variable. I guess I need to get to the root of that as well. I wondered about the temp sensor. I would assume if it were bad, it would always give one reading and throw the plug timing off for what was actually needed.
 
Best way to use the throttle knob is to depress the pedal until you are at the rpm you want then adjust clockwise until it meets resistance and holds rpms there. Then it's easy to dial it CCW to adjust rpms down.

Makes morning warm up easy. I don't even sit in the truck...I make sure it's in neutral, turn the key with my left hand and hold the accel pedal down with my right. Get rpms where you want, turn knob to hold it there, then go inside and make coffee. When the coffees done in a few minutes I come out and the truck is warm and the windshield is clear and I dial it down to a regular idle.

I should say my truck is RHD. Would be less convenient with LHD.
 
I can redline my motor with the manual throttle adjust. So, as the others said, you should be seeing more.

Don't go by the glow light indicator when you start. Listen for the main glow relay in the engine bay instead. Takes a little while to learn the sound, but it should open after about 7-8 seconds in this weather we've been having. That little dash glow indicator is pretty useless. Not sure what Toyota's idea was with that. If you have a healthy glow system and good compression etc., the motor should start no problem after 8 seconds of glow at freezing.

Great looking truck. I'm excited to see what you do with it.

Here is a great build thread with lots of ideas if you have not read it already: My LJ78 build thread... Most of the same stuff I did.
 
Great to see another LJ78 here in NW Wa. Looking forward to seeing your progress. I need to address my throttle knob and cable. The PO lost the knob. I have a new one but am stumped on finding a key to fit it on with. Anyway, it seems I’ve read and also experience easier start ups if I run the glow plugs twice in weather like this.
 
I should add, with my LJ78 I do have to glow twice in cold weather to get a perfect clean start. My motor did suffer some abuse back in Japan, so I've always attributed it to imperfect compression.

I bought an LN130 Hilux Surf a month ago to drive while I give my LJ78 some TLC. The LN130 I have has a 2LT-II (mechanical injection, not electronic) with manual transmission, and that thing starts perfectly after one glow every single time no matter how cold it is. Makes me wonder if the 2LTE electronic injection is just not as effective for cold starts. Or perhaps the Hilux just has that much better compression... The engine does seem to have been very well maintained it's entire life.
 
I haven't actually pulled a glow plug to check them, yet. But, the rest of the system checks out fine. I am getting 11.7V to the glow plug rail and the relay seems to be working as intended. So, I am guessing the glow plugs are the issue as the engine starts fine as soon as it is even slightly warmed up. I think I will just replace them anyway. I hate to do the work of pulling them and not replacing while I am in there.

I am a tad fuzzy on the 2 stage system. I just haven't researched it much.
 
OK, both swivel balls rebuilt. I decided to replace my rotors. Closer inspection when I removed them revealed they weren't in as good of shape as I believed inspecting them with the tire and dust shield in place. I opted for th Napa Premium rotors. I suspect they will serve my needs as well as an OEM.
So, I am waiting on those and the Moly-Silicone grease for the auto hubs. Should see those Wednesday. I will wrap up the front end and then do the back bearings,rotors, and pads. Next on the list for that stuff is tie-rods and bushings.

Also found the outer jacket of the short brake hoses are starting to degrade, so those are on the way as well.

Glow plugs are in fact bad. I have new ones on the way. I figured they would be a lot easier to get to if the throttle body wasn't in the way. I have the EGT system out. Throttle plates removed.Still need to fab one of the 2 blanking plates. I am leaving the pipe around behind the engine until I pull the turbo to do the EGT probe. The nuts on the manifold at a bit crusty. I really don't want to bugger one when it's so hard to access. So, I will just blank off the other end until then.

Over all everything is going smooth and I am really happy with the condition I am finding things in when I disassemble. No surprises yet. Just pretty standard 25 year old vehicle stuff.

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Any suggestions for sourcing a snorkel? I can find about 9 million 70 series snorkels, but not a tremendous amount specifically stating they fit the LJ front end. I have spent a small fortune over the years on Land Rover snorkels and would really like to find one for less than 400 bucks for the Cruiser.
 
I think this is the parent company of that auction. Slightly cheaper. About 175.00 USD. That is really the only reasonably priced one I have found. Maybe I will shoot them an email and get a shipping quote.

SNORKEL 4x4 TOYOTA LC PRADO LJ71 / LJ78 WIDE FRONT #80

My rotors actually came in today. So, good job NAPA. I am working on a definite US part number cross reference for various parts. There is an unbelievable amount of good info out there, but it's sort of spread out and we are just starting to get these trucks down here. Which sometimes makes it hard to find the exact part numbers it seems.
I live in a small town, so I know the guys at NAPA a bit. They will usually go that extra mile for me sourcing and researching parts.
So, hopefully I can start putting together a cross reference of parts that makes it a bit easier to order the correct parts the first time.
 
Here's the answer on that one. Quick answer though.

Hi Kris,

Thanks for your interest in our products, sorry we don't ship internationally at this stage. We're not setup for it.

We have had one UK customer get his friend in NZ to buy one from us then the friend sent the snorkel to the UK. Please note our warranties only apply to NZ customers.

Best regards,
Pat.
 
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I will check him out. That's sort of a back burner project, but I am always shopping for some part or another.

Front end all wrapped up without incident.... Hubs tested and I am calling that project done.

Friday the new glow plugs come in and I will put the intake back together and see how the EGR delete worked out. I have no question its better. That is the first thing I do to all my Land Rover diesels. Ditch the EGR. They are 100% mechanical however, so this will be the first one I have pulled off of an ECU controlled truck.

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I am making a real effort to take and post pictures.
I am terrible about it. I did a ground up rebuild of a truck once that I have maybe 30 pictures of. Always pisses me off. Complete frame off,galvanized chassis. Every nut and bolt replaced. And, hardly a decent picture of the entire process.
 
My oil gauge needle is buried at the bottom. Never moves. I pulled the dash apart last night to see if it was actually attached. It's so far down it is completely behind the plastic shroud. Even with no power to it, it strenuously wants to be down there. If you have ever moved a gauge,you know how it has a tiny bit of resistance to return to home if you gently move it? The oil gauge is not like that. It has about twice the tension as the other gauges and springs back down quickly.
Is that a replace the entire oil/voltage cluster? Or can a portion of that section be replaced? I didn't take the entire instrument cluster out as I didn't see the need. The gauge is, fairly obviously, done for unless someone can lead me down a different path.
 
Not looking to start a tire debate. We have plenty of those already.:rofl: Just wanting some observations from people actually running a couple of size tires.
I am trying to decide between a 33" VS 31" tall tire. I will be running either in a 10.5" width.

If you are running the 33" tires, how has that effected the performance of your 2LTE?
 

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