Just Impulse Bought a LJ78 and Need Some Advice (1 Viewer)

[GTSSportCoupe]

Just reading through your post quickly, it does make me wonder if your EGR system is not working right and totally starving the motor of air supply. I'd recommend removing the whole EGR system. Cap off the main EGR vacuum supply line (hose from vacuum pump). Put block off plates at the exhaust manifold and intake manifold. Remove the main butterfly valve in the throttle body so that the engine can get all the air it wants. Be very sure not to remove or tamper with the throttle position sensor - or you'll create a whole lot of new problems.

My engine had the same problems when I bought my truck, and it ran about as crappy as what you've described yours doing. If I remember correct, I was able to disconnect the vacuum actuator that controls the small bypass throttle plate in the throttle body. Then I forced that little throttle open to give the engine the air it needs at idle. This was the clue to solving the issues mine had.

 

[roscoFJ73]

- Engine smokes white smoke and heavily misfires when starting it for the first time each day for about 30 seconds or until I give it a bunch of gas

If I have the AC on during first start of the day, it seems to idle worse and misfire more.

- If I have the steering wheel cranked all the way left or right when at low speeds, the engine completely stalls

- The speedometer seems to bounce up and down as I speed up or slow down (I don't think it did this before)

- After about 2-3 mins of running, the truck goes back to normal, drives perfectly, great ride on the highway and on future starts seems to be much smoother

Has the compression been tested? You are either not getting fuel on cold starts or your cylinder and rings are worn.
A/C is a parasitic load, so it would do this if the engine is not firing on all 4 cyl evenly. They usually have a fast idle mechanism that comes on with the A/C
Having the steering turned fully also places a load on the engine.
As an engine heats up, particuarly diesels, the pistons and rings expand enough to increase the compression and make it run smoother.
As the engine cools down, the compression drops off ready for the next start.
I would test the compression before spending anymore time or money on it. If the comp is good, you can keep looking for answers.

A bouncing speedo is usually a sign of a bent or dying speedo cable. You can use one off any Toyota if the length is the same, but on road vehicles dont have the heavy. sheathing on the outside of the cable.

 

[1190CruiserLad]

Has the compression been tested? You are either not getting fuel on cold starts or your cylinder and rings are worn.
A/C is a parasitic load, so it would do this if the engine is not firing on all 4 cyl evenly. They usually have a fast idle mechanism that comes on with the A/C
Having the steering turned fully also places a load on the engine.
As an engine heats up, particuarly diesels, the pistons and rings expand enough to increase the compression and make it run smoother.
As the engine cools down, the compression drops off ready for the next start.
I would test the compression before spending anymore time or money on it. If the comp is good, you can keep looking for answers.

A bouncing speedo is usually a sign of a bent or dying speedo cable. You can use one off any Toyota if the length is the same, but on road vehicles dont have the heavy. sheathing on the outside of the cable

Thanks for the advice, I've never tested compression before so I'll have to look up how to do that. Do you know what the typical compression values should be ?

 

[GTSSportCoupe]

Thanks for the advice, I've never tested compression before so I'll have to look up how to do that. Do you know what the typical compression values should be ?

455psi each or so. Start with the easy stuff first.... Checking the EGR system is much easier than checking compression. If you want to be able to service this engine, you should download the manuals for it and your vehicle and read through them. Especially read the Denso manual on the ECD V3 system. Many of the problems people have with these engines could be prevented if they understood how they worked. It's not that hard - just takes reading.

Links to the manuals are in this post at this link:

Help!

Does anyone know the correct torque specs for a Flywheel to crank? LJ78 2Lt-e R-150F (Manual) Single mass flywheel I'm sure it's in the forum somewhere, but I can't find it and the sun is going down here in WI! Thank you Thank you

forum.ih8mud.com

 

[1190CruiserLad]

Okay so I've prepared everything to delete the EGR. I stumbled upon the following mod where you keep the Venturi and feed it with positive pressure which keeps the throttle plates inside the throttle body open so you don't have to drill them out.:

Any thoughts on this? Does the Venturi control both the main and sub throttle plates inside the throttle body? This seems like the ideal solution to keep the smooth shutdown and avoid extra work of drilling out the plates. I was planning to pipe it like this:

 

[1190CruiserLad]

Okay so I removed the EGT system, installed a 2.5 inch straight pipe straight from the dump pipe and also vented the crank case to atmosphere to try to reduce the oil building up in my air intake to the turbo. Things do seem to be running a lot better, with way more power, but still getting a few seconds of smoke at initial cold start. I noticed that one of the coupler hoses on my air intake to the turbo (the one connecting to the throttle body) had a large crack in it so I ordered a new one which is on its way.

Also did a compression test yesterday and took the average of three readings and got:

Cylinder 1: 420 PSI
Cylinder 2: 380 PSI
Cylinder 3: 400 PSI
Cylinder 4: 380 PSI

@GTSSportCoupe I know you said 455 PSI was normal, but do these values still seem okay to you? If so, does this mean my head is okay? I have found oil in my coolant recently but from what I've been reading this could be the oil cooler gaskets failing and fixing with the coolant which isn't a huge deal.

 

[roscoFJ73]

but still getting a few seconds of smoke at initial cold start

You could probably play around with the fuel or glow it longer, but for an old diesel, a few seconds of smoke is not unnormal.
Your compression numbers are within 10$ of each other. The smoke is probably from the 380psi cylinders. Again , its an old engine but some careful driving and maintenance should see some life out of it.

 

[GTSSportCoupe]

Okay so I removed the EGT system, installed a 2.5 inch straight pipe straight from the dump pipe and also vented the crank case to atmosphere to try to reduce the oil building up in my air intake to the turbo. Things do seem to be running a lot better, with way more power, but still getting a few seconds of smoke at initial cold start. I noticed that one of the coupler hoses on my air intake to the turbo (the one connecting to the throttle body) had a large crack in it so I ordered a new one which is on its way.

Also did a compression test yesterday and took the average of three readings and got:

Cylinder 1: 420 PSI
Cylinder 2: 380 PSI
Cylinder 3: 400 PSI
Cylinder 4: 380 PSI

@GTSSportCoupe I know you said 455 PSI was normal, but do these values still seem okay to you? If so, does this mean my head is okay? I have found oil in my coolant recently but from what I've been reading this could be the oil cooler gaskets failing and fixing with the coolant which isn't a huge deal.

I agree with what @roscoFJ73 said above. My old short block had compression similar to yours on the rear most cylinder, as straight water had sat in it when the head cracked in japan, and damaged the bore a bit. It always took two glows to start clean, otherwise it would misfire for a little bit on cold start. It always used some oil too. Like maybe 1 litre for every 1000km or so. Try doing two glows: Key On, wait 7 seconds, or until you hear the glow relay open, Key Off, wait 1 sec, Key On, wait 7 seconds again, or until you hear the glow relay open. Then start.

Glad to hear some of the other stuff is getting sorted out and its running better.

Regarding oil in water, your problem also could be a poor cylinder head replacement job done at some point. The engine in my LJ78 had received a very quick/lazy cylinder head install before I got it. Was not prepped (surfaces/bolt holes cleaned) properly and improper torque. It pressurized the coolant as it was leaking in one spot. I re-did it properly and had no more problems.

Many of the problems with these motors are from poorly done repairs and maintenance in the past. The cylinder head being such a major thing requires a lot of care when replacing.

 

[1190CruiserLad]

@GTSSportCoupe I finally found my problem! Turns out seals in my air intake for the turbo were cracked and the hose clamps had also failed and wouldn't tighten enough. Two new seals, some new hose clamps and a new throttle body gasket and she starts first crank with no misfires or smoke! Just had to adjust the overspill screw to get the fuel ratio right now that the air leak was gone.

Now the next thing I'm addressing is the front brakes, but what should have been an easy job turned into a nightmare because one of the brake pins to hold the pads in place was bent and impossible to remove. 4.5 hours later trying everything imaginable and I was able to drill it out. In the process, I had to remove the front half of the brake caliper. I've never dealt with a fixed caliper before and didn't know the caliper has brake fluid inside of it so when I removed the four screws, brake fluid started pouring out and I let it drain until it stopped. After getting the pin out, I assembled it back together and topped up the brake fluid. When I go to press the brake pedal, it doesn't get hard and if I pop the cap off of the master cylinder and crack the blead valve on the caliper, no fluid comes out. Am I missing something here or did I ruin the master cylinder somehow?

 

[AirheadNut]

@GTSSportCoupe I finally found my problem! Turns out seals in my air intake for the turbo were cracked and the hose clamps had also failed and wouldn't tighten enough. Two new seals, some new hose clamps and a new throttle body gasket and she starts first crank with no misfires or smoke! Just had to adjust the overspill screw to get the fuel ratio right now that the air leak was gone.

Now the next thing I'm addressing is the front brakes, but what should have been an easy job turned into a nightmare because one of the brake pins to hold the pads in place was bent and impossible to remove. 4.5 hours later trying everything imaginable and I was able to drill it out. In the process, I had to remove the front half of the brake caliper. I've never dealt with a fixed caliper before and didn't know the caliper has brake fluid inside of it so when I removed the four screws, brake fluid started pouring out and I let it drain until it stopped. After getting the pin out, I assembled it back together and topped up the brake fluid. When I go to press the brake pedal, it doesn't get hard and if I pop the cap off of the master cylinder and crack the blead valve on the caliper, no fluid comes out. Am I missing something here or did I ruin the master cylinder somehow?

You'll have to bleed the brake system. There are lots of methods for this, but it is a fairly straightforward procedure. A quick internet search will be able to explain it much better than I could here. Best to have someone to help as one person has to hold the pedal down while the other opens the bleed valves.

 

[1190CruiserLad]

You'll have to bleed the brake system. There are lots of methods for this, but it is a fairly straightforward procedure. A quick internet search will be able to explain it much better than I could here. Best to have someone to help as one person has to hold the pedal down while the other opens the bleed valves.

I wedged a piece of wood between my front seat and the pedal so that it stayed compressed, then tried to crack the bleed valve and nothing happens. This is on the front right calipers.

 

[AirheadNut]

It will take several bleed cycles to get any fluid to the caliper if the whole system was allowed to drain. Also, it is wise to bleed the whole braking system, starting from the point furthest from the master cylinder and working forward (i.e. left rear, right rear, left front and finally right front). Bleed each one until you get fresh, clean fluid with no bubbles. It is a good idea to get some clear hose that fits tightly on the bleed valve and run it into a container with a bit of brake fluid in it, that allows you to see what is coming out and prevents air from getting back in. Make sure to keep the reservoir topped up regularly; if you let the fluid run out air bubbles will be introduced to the system and you have to start from scratch again. (Been there, done that!) Doesn't hurt to have all new brake fluid anyway.

 

[AirheadNut]

Here's a good overview of the process:

 

[gmirra1968]

Okay so I've prepared everything to delete the EGR. I stumbled upon the following mod where you keep the Venturi and feed it with positive pressure which keeps the throttle plates inside the throttle body open so you don't have to drill them out.:


View attachment 2749334



Any thoughts on this? Does the Venturi control both the main and sub throttle plates inside the throttle body? This seems like the ideal solution to keep the smooth shutdown and avoid extra work of drilling out the plates. I was planning to pipe it like this:
View attachment 2749338

I did this to mine and it works just fine, I am afraid of doing any unreversible mods in case that I mess something up and I also added the 3 in 1 gage gloshift and I really like to have everything I need in one gage, I also messed around with the boost and now I am getting 13 PSI without intercooler and it works great, my EGT temps with the 82C thermostat do not go beyond 1100 F before turbo ( I fabricated a plate when I removed my EGR and placed the thermocouple there works great) I did the same thing for the boost on the Venturi. I love my truck and I am glad I am not the only impulsive buyer, enjoy it!

 

[simonliew]

For peace of mind I would recommend something along this line. (and yes I realize the photos are lousy). Each gauge has multiple features. I’ve got oil pressure and digital water temp combined (caution features are also programmable .... in this case the gauge turns red to warn of low oil pressure. Boost and EGT can also be combined. View attachment 2608388View attachment 2608391

gun runner what kind of gauges are this?

 

[Gun Runner 5]

gun runner what kind of gauges are this?

Red Arc ….
Oil Pressure / Water Temp.
EGT / Boost.
Dual Battery.

 

[NJ KZJ78]

For peace of mind I would recommend something along this line. (and yes I realize the photos are lousy). Each gauge has multiple features. I’ve got oil pressure and digital water temp combined (caution features are also programmable .... in this case the gauge turns red to warn of low oil pressure. Boost and EGT can also be combined. View attachment 2608388View attachment 2608391

Where did you purchase the combo gauge?

 

[Gun Runner 5]

Where did you purchase the combo gauge?

Red Arc out of Australia.

 

[bj70bc]

So just to add a bit more here. You being a mechanically inclined person is a huge advantage when owning one of these old Toyotas. If you can do a lot of your own work, you'll save a lot, and know that the job was done right.

Some other things to consider with your maintenance are:

- Your truck is probably due for a transmission flush. This can be done yourself (I can explain). These transmissions will go forever if the ATF if flushed at proper intervals. Start by checking the color. Should be bright red. If it's turning brown, it's definitely time for a flush.

- Don't use a Tridon t-stat. Although initially they seem great, the build quality is actually not that good. Mine failed, as did @Nas90tdi 's. The best out there I've tried is a later generation 2LTE OEM T-stat which starts opening at 82C (as opposed to the early 2LTE 88C). This gives more head room, and will help protect your cylinder head. This is the Toyota part number: 16340-54040

- You can order OEM Toyota parts (like that 82C T-stat) from places like Partsouq, Amayama or Megazip. I usually use Megazip EPC drawings to find part numbers, and then use Partsouq for my ordering.

- You can rely on the factory temp gauge too. I don't actually run an aftermarket one. Just know that when the gauge starts passing 1/2, you need to back off on the skinny pedal and take it easy.

- Boost and EGT are very helpful, especially if you eventually tune your motor up a bit. These are the only aftermarket gauges I run.

- Check the state of the oil in your front and rear diffs and t-case also. They might be due for a change.

Anyhow, don't freak out and rush decide to sell the truck. They seem to be holding their value fine at this point despite the reputation of the 2LTE. Yours looks great, has been taken care of from the sounds of it. Take your time and see if the truck is a fit for you. If not, then you can look at selling later.

Other than the engine, these trucks are super well built and rock solid. You simply can't buy this sort of quality new anymore IMHO. Although the LJ78 has the disadvantage of the small 2LTE motor, it does have some advantages in my opinion. It's cheaper than the HZJ77, lol. The coil suspension is comfy, and when properly modified can be very capable off road. The 4.88 diffs suit larger tires perfectly. 33"-35" are great for that ratio. The trucks are well balanced.

There are some great build threads on this forum for these trucks. Read through them to get ideas. Here are a couple gooders:

Builds - 1992 LJ78 build/refresh

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...

forum.ih8mud.com

Builds - My LJ78 build thread...

I have been getting so much helpful information from here I'd thought I'd return the favour in posting up most of the upgrades I have been doing to my truck and a little history of it, seeing as I love reading stories like this on this site.... This is how I bought my truck back in...

forum.ih8mud.com

do you still advocate using evans coolant with these engines for some extra boiling protection?

 

[coldtaco]

do you still advocate using evans coolant with these engines for some extra boiling protection?

Not if you live in cold climates. Evans will gel at below certain temps. I believe on the Evans web site it states what temp limit is. I had to remove it because of this, my first hints of this problem was when my Espar coolant heater wasn’t working anymore when parked outside for extended periods of time but would work in the garage just fine.