classik90s

i picked up a 1990 LS400 back in september 2013 with around 120,000 odd miles on the clock and when i went to get it smogged it passed with decent results

this test took place on 10-22-15, so far so good.

the following year i transferred the title to my own name and had to come up with another smog test. A few months prior i flushed the coolant because the previous owner was running Dex Cool for reasons i could not say, and i refilled with toyota's factory red coolant, but like an idiot i had the bright idea of running 60% coolant and 40% water( ignoring the fact that it's called "anti-freeze", and not "anti-heat"). the sweet sound of pre-detonation and two months later the results would be obvious.

(This test took place on 12-23-2016) The all wise smog technician informed me something was causing the engine to run hotter than normal and advised me to clean the EGR valve.
After cleaning the egr valve and the vacuum modulator filter i realized my mistake a few months prior and proceeded to drain the radiator and refill with a gallon of distilled water

yeah this crusty bastard had seen better days

notice the charred spot(it was face down over the down pipe on the vacuum mod.

nice and clean
on 12-28-16 i went back to retest and passed with flying colors

now that's what im talking about!(although it is important to note the hydrocarbons almost flunked the test because i had run a bit of marvels mystery oil in the fuel in some delirious attempt to help pass this test, w/e it worked)

considering i had the appropriate coolant ratio and after changing the thermostat months prior, discovered the previous owner had the jiggle valve upside down i went on to the bi-annual smog test with high hopes.
on 11-20-18 i went to pass smog but failed, with epic proportions

obviously, this star certified station was using a soviet era printer built in a gulag somewhere, you cant read much except for the noX levels being above 1000 ppm, not good.

now at this point i figured i should just clean the egr valve and the vacuum mod filter , unfortunately none of that really worked....
(11-27-18),

noX emissions actually ran higher than the week before.
so what went south this time ?
-while cleaning the egr valve i did break the filter on the vacuum switching valve, because engine bay plastics dont have infinite shelf life
-and my vacuum mod filter has the texture of a stale potato crisp

oops. nothing some good ol' glue cant fix, WRONG !(evidently)

more crusty-ness, note that charred spot from before, prior to the test i did inspect it and figured i should probably flip it over as the upside still felt like a filter, now i know i should just replace it.
-also note the CEL turned up in the middle of the second smog test, not good, not good at all.
after jumping Te1 and E1 with a primary wire and reading CEL morse code i got a code 71 , obviously something egr related has failed.
Now ive been scouring the forums finding a plethora of diagnostic procedures on the egr components and checking local listings for replacement parts, obviously i want to track the malfunction because as an amateur tech i dont believe in throwing parts at problems. If anyone has any info or experience chasing these issues feel free to chime in, any help is always appreciated. As i move on to diagnostic procedures i will keep on updating this post.
-Until next time.


update 1,

i tested vacuum on the egr valve, with 15 in.hg the rpms dropped a little but the engine didnt bog out


i also removed the vacuum mod and blew compressed air through the lines to check air flow, when i blast air through the highlighted vacuum line the modulator just pops right off, away from its vacuum hose, is that normal ?

RA40

iTrader: (6)

Doing a good job on this! I've not had to hunt it that hard being a good clean of the EGR valve and pipe has been my encounters. That coolant mix is still mild so that's not as big a contributing factor for heat IMO. A lean A/F ratio would be. The vacuum lines and O2 sensors check out?