It's been a long while since I was on the board. I hope that everyone has been well. After a decade or more of having my 86 2LT LJ70 in the states with a persistent too high EGTs issue I think I finally determined that it is too lean. I've had a 2.5 inch exhaust put on it, replaced the radiator, removed the a/c, done the fan mod, replaced the turbo and had the pump rebuilt to address leaks. It has never made ANY smoke, at least since the injection pump rebuild, yet the EGTs are sky high (1150-1250 mid throttle cruising at 55, 1500 under more load pre-turbo install) while power is quite low. I can't get more than 7-10 psi out of the turbo even with waste gate disconnected. I've futzed with the boost fuel compensator within the past 6 months and I did make limited progress lowering EGTs while increasing power by increasing fuel but the gains were quite limited and I still can't get the truck to make any smoke while driving, just now a puff of black when I start it, even under full throttle. This leads me to the full load fuel screw as I think it needs more fuel across the range. The shop that did the pump didn't road test it and fine tune and I didn't have an EGT then. The screw is a PITA to get at. The shop that rebuilt the pump left the anti tamper collar on it, which I assume will make it even harder to adjust on the car. My instinct is to put a deep socket on it and remove the whole screw assembly from the pump so I can adjust a half turn at a time in a vise. Is there any reason I shouldn't go that route? Thanks, as always, for any advice y'all can provide.
2LT Full load screw adjustment - can I remove completely and adjust out of the pump? (1 Viewer)
- Thread starter richmason
- Start date
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a few general things....
-on a diesel too lean is cooler not hotter, more fuel =more heat
-more boost will cool it down
-generally speaking more fuel helps to spin the turbo
-you should be able to get more boost out of it without upping the fuel tho
-just disconnecting the wastegate accuator doesnt give more boost, you have to clamp or wire the wastegate closed, but then its unregulated and will boost as a function of fuel, on the 2lt i dont think its this simple tho, others will know better
-you dont want it to smoke
-on a diesel too lean is cooler not hotter, more fuel =more heat
-more boost will cool it down
-generally speaking more fuel helps to spin the turbo
-you should be able to get more boost out of it without upping the fuel tho
-just disconnecting the wastegate accuator doesnt give more boost, you have to clamp or wire the wastegate closed, but then its unregulated and will boost as a function of fuel, on the 2lt i dont think its this simple tho, others will know better
-you dont want it to smoke
@GTSSportCoupe is the man with these engines, can you give this guy the run down
GTSSportCoupe
2LTE abuser
My first question is who timed the pump when reinstalled after rebuild? Was it done right ( follow FSM)? Wrong timing can lead to problems.
Second question: is the pyrometer working properly without doubt?
More fuel is definitely not going to fix high egts. Lack of smoke is suspicious, but a car following you might see things differently, LoL
Second question: is the pyrometer working properly without doubt?
More fuel is definitely not going to fix high egts. Lack of smoke is suspicious, but a car following you might see things differently, LoL
- Thread starter
- #5
Greetings GTSSportCoupe. I've spent a lot of time reading your posts and I am sincerely grateful for what you've contributed to all of us with less mechanical ability trying to keep these things going.My first question is who timed the pump when reinstalled after rebuild? Was it done right ( follow FSM)? Wrong timing can lead to problems.
Second question: is the pyrometer working properly without doubt?
More fuel is definitely not going to fix high egts. Lack of smoke is suspicious, but a car following you might see things differently, LoL
On pump timing, a mechanic that I consider to be skilled and proficient with diesels timed it when he handled the rebuild but there is no way of knowing that it was right and there has been no check since then. Sounds like that should be my first check?
For the pyrometer, there is always the chance that it could be faulty somehow but I've had consistent readings since installation. It is a sensor from Spruce Aviation and a VDO mechanical gauge. I believe it is at least roughly accurate because if I leave my foot in it and get the EGTs up, the coolant temps rise very quickly, which, before I had an EGT gauge, was the main issue I was focused on - vehicle gets hot under acceleration or at highway speeds with factory gauge moving from a steady below halfway if speed is kept low enough to keep EGTs around 1050/1150 to over halfway and higher if you let it when EGTs go above 1200. Slowing down gets the coolant temps down very rapidly. I've never checked the coolant temp with a pyrometer to see actual temps and variations but I've replaced the water pump, thermostat, radiator, coolant, fan mod, removed a/c, etc. trying to get it to run cooler to no avail.
In terms of smoke, I've had people follow me and I've followed the truck with someone else driving. There's no or little discernible smoke visible even in the dark in headlights. I've owned dozens of diesels - this is my only Toyota - and all of them, even TDIs, have put out a little smoke i.e. exhaust when you punch it. I'm not looking to roll coal, far from it, and I've always thought that the lack of visible exhaust was a good thing and indicated efficiency. At the same time you need fuel to make boost and boost moves air and cools down the exhaust as you explained so this led me to it could be so lean it is detrimental.
Checks that haven't been performed in past 10 years: timing, valve clearances, injector pop pressure or leakage (I do get some unburned diesel smoke when I start it cold so they are dripping), compression (doesn't start on first click of the key but oil consumption is low), and vacuum pressure leak down on fuel boost solenoid.
It's frustrating because this truck ran nice and cool in Liberia where I bought it, even with a/c on it, and much bigger tires. Of course, it was also hard there at the time to get over 55 mph for any real duration. Once I got it to the US, with less traffic and better roads, I started having hot coolant at speed issues, especially when I would drive to the NC mountains. There is no speed on a steep grade that I can drive where it doesn't get to 3/4 and higher on coolant gauge so that I have to pull over and let it cool down, making it pretty much useless for extended trips on anything but blue highways beyond the coast where I live now.
Sincere thanks again,
Rich
I vote IP timing.
But also... rebuild the fan clutch while you're at it.
But also... rebuild the fan clutch while you're at it.
GTSSportCoupe
2LTE abuser
Hi Rich, sorry for not getting back earlier. Thanks for the kind words about my older posts. Unfortunately these days I don't have as much time to try to help people out.
This is a really tough issue to try to troubleshoot remotely. But generally lack of smoke and being unable to get higher boost does indicate running leaner. So you could start by trying a different pyrometer setup. It takes a certain amount of fuel to generate the exhaust pressures to produce high boost. It sounds like that just isn't happening for you. This explains low power too. But the EGT readings just make this confusing.
The boost compensator can make a lot of difference for better or worse. This is a bit of an art with turning an eccentric pin for different fuel delivery curve, getting the right start point (top cam), and also increasing spring pre-load (bottom adjust) to keep the pin from traveling to quickly (will cut fuel if it thinks boost is too high).
Some of these boost compensators are pretty tricky with two springs above and below a diaphragm etc. Not sure what type yours has.
- Thread starter
- #10
Ok I finally got Beast in the garage and taken apart to check the pump timing. It looks like my timing was off. After locking the LX model cold start lever, I use the dimple on the cam pulley to confirm TDC. I reversed it a bit like the famous video to zero the gauge and then turned back to TDC. I saw .5 mm or so at baseline and the pump line was well off the mark on the case. After loosening the 4 nuts, two at the front and two at the back, the pump wouldn't move enough to reach the correct setting, much less hold it. I had to crack a couple of fuel lines to get it to move enough to get within range. I am leaving the pump gauge in place while I move the pump to confirm I have the correct setting and then will lock it down and rotate crank a few times to confirm the setting is correct. Is that it? Hopefully I can get is all reassembled tonight and see where I am at on performance. Thanks everyone for your help! I can't believe I've driven it so far out of time for so long. I will always check behind any shop that touches it from now on.
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