mbonne

Have seen, read, the comments on your youtube posts?

MattLS400

Thanks Finn... Yamae sent a link so i purchased that one....

Is this the Engine Coolant Temperature Sensor ? If so, I changed this already...


Interesting, is this closed and open loop that you are referring to has to deal with the IACV ? As suggested by Yamae's post;


I have purchased an IACV with part number 22070-50010 . Even though my IACV with part number 22070-50020 was serviced 2 months ago, my IACV cannot be opened to inspect the coil and bearings due to the sealed nature of this part. ( My faith lies in the fact that when it was serviced it was merely cleaned since it cannot be properly inspected....) However, the 22070-50010 which I purchased can be opened, inspected and bearings can be changed.. I sincerely trust that my issue is faulty bearings/ coil of my IACV...Sigh....Fingers crossed, waiting on shipment guys.

LScowboyLS

no, that is the sender for the temperature gauge on the cluster, so you know more accurately where the temp really is - when I say should be at 40%, that is assuming your cluster temp gauge is reading correctly!

besides, it's dirt cheap for piece of mind!

mbonne

WAIT!

If the IACV stepper motor can open up the aperture enough for high idle airflow then it most certainly can open up enough to provide (the proper) low idle airflow. Think about what might cause the ECU to restrict the idle airflow below the "target" , 600 RPM?

Improper A/F mixture ratio...

Forced to make a choice, what might be the higher priority for the engine control ECU?

A. Proper/correct idle speed....600 RPM..

B. Proper/correct A/F mixture.

Since the catalyst can have long term damage with improper A/F mixture I vote for "B".

So the IACV must "throttle down" the engine intake airflow to maintain the correct A/F mixture.

The engine ECU "wants" to maintain the idle speed at 600 PM but that results in a too lean idle mixture.

Throttle plate is closed, so intake airflow level is strictly a function of IACV opening....

But here we are with, seemingly, not enough fuel getting to the engine to support 600 RPM.

Maybe not enough fuel from the injectors, pintle "STICTION", injector PWM dutycycle so low at idle that some of the injector(s) don't always open..

Can the ECU supply unique PWM drive for/to each individual injector?

Can the ECU even detect how well each individual injector is working, or not?

mbonne

At the "cold" video time stamp 1:05-7 we can see that the radiator cap
is NOT installed. If the coolant fluid cannot be pressurized (~12-15
PSI ?) it might not have a adequate radiator heat transfer
coefficient, plus the engine will be operating below it's operational
design temperature.

Water boils at 212F (coolant F ?) sea level pressures, pressurizing
below sea level allows the engine and coolant to operate well above
212F, while that also results in improved radiator heat transfer.

Got it, FINALLY...

Initially puzzled as to why the PS pump only produces the "cavitating"
sound once you turn on the A/C.

But just as with the electric radiator cooling fans being turned on
automatically with the need to provide adequate airflow for cooling
the A/C condenser, the same is true for the hydraulically operated
fan. Open the PS fluid flows to the fan, the fluid level in the PS
reservoir drops, the pump starts ingesting AIR.

The air and fluid mixture simply cannot drive the fan, the air
(bubbles) compress, NOT the fluid....

MattLS400

Interesting....that is a lot to digest...So basically you are saying that My IACV is fine and my problem is my injectors ?

If you would kindly have a look at post #1,my injectors were previously dribbling and as such were changed to Re-manufactured OEM Injectors....Furthermore, if the problem were injectors, wouldn't the problem occur all the time, irregardless of when the temperature is cold or hot ?

MattLS400

Members,
I have received my purchased IACV! Decided to unmount and inspect and clean as outlined in the tutorial some of you sent in prior posts....

MattLS400

I do however, need confirmation as to how this Ring is to be placed.
1st Picture -- Facing Up
2 nd Picture 2 - Facing Downward

LScowboyLS

'96 LS400 is known to have a problem with IACV bearings - it does not have a problem with injectors - try to focus on members such as Yamae for advice on this car

MattLS400

Members,
I have changed my 96 IACV to a cleaned/inspected 94 IACV..I must say I have seen an improvement in performance/ power of the engine !!

But....The Problem still persists "Hunt of the Idle at Half temperature and thereby shutting off"
....I honestly dont know what else to do...sigh

LScowboyLS

I am still not convinced that you have a properly rebuilt ECU that uses the exact capacitors I specified in post #1 ordered from the links in that post to ensure using authorized source and prevent counterfeits - please post pics of ECU repaired this way.

If you have not done this, then you cannot say "I honestly dont know what else to do...sigh"

python

iTrader: (4)

elaborate on this cuz it sounds like ur saying he is the only one on this forum who knows anything which is a direct insult to those who preceded. its a wonder how this place survived so many years then huh?

LScowboyLS

yes, Yamae did bring a whole other level of knowledge to Club Lexus - never before have we had someone here that holds over 100 U.S. patents, kind of like having Einstein in your Physics club!

never before has Club Lexus had someone in Japan with very close ties to Toyota and Nippon Denso and who lives a short drive from the Tahara plant where your LS400 was built.

It was his insight that got my brain working and solved the last big frustrating problem with LS400, which was ECU failure! - just happy that he and I happened to stumble across this place just in time to help the 100,000 visitors to our famous ECU thread, which is now one of the most seen threads in Club Lexus history, and stunningly, all of this happened in only 1.5 years!

Life has been good to both Yamae and I, and saving people $2000 on an ECU replacement is our way of giving something back to folks who realize just how special this car is!

python

iTrader: (4)

goes right along with this statement I got in a pm from you:

the point is, I have troubleshot and rebuilt, more LS400 ECU's than anyone on planet Earth

so therefore, unless you are a Nippon Denso ECU engineer, or a consultant to them with over 100 U.S. patents (like Yamae), neither you, nor any other member of CL including PD are qualified to question my ECU diagnosis!

sha4000

iTrader: (1)

Wow that's some real internet dislike from the both of you. Most times it's kind of entertaining and it seems like both you guys really know a lot about the cars, their problems as well as many other things. It's one thing to think your smarter and more knowledgeable than EVERYONE else on the forum ( which may be true ) but it's another thing to state that out loud in so many words! This forum has been a great resource for me ever since I joined as well as LOC and there have been some ppl including myself who have felt that they were right and someone else was totally wrong but never have I seen the type of comments displayed in such a condescending manner as those above. I might not like the way you guys state some things but I do believe the information is always reliable for the most part. End rant...