Moarpower

Hey guys.
I have lovely 91 celsior that needs a little TLC. It look amazing and has had the interior completely reupholstered.
I just replace the fuel pump, cleaned the throttle body and the IACV hoping to solve this issue.

When cold she takes about 10 seconds to start and will run and idle great until it reaches its operating temp. Then the idle will bounce from around 600 at idle down to almost stalling, and then bounce back up. As the idle is dropping the Engine light at trac off lights flash on, They turn off when the idle bounces back up.
I have seen the idles hunt up but this is different to what I could find elsewhere. when this starts, if i quickly rev the engine it will stall when i take my foot off suddenly.

Moarpower

Presented a code 31 so I will test the AFM tomorrow and see if it is running. I know it functions to some degree as when removed from the intake it the idle if affected. I the AFM or MAF is working, what would be the next link? Im guessing it could be an ECU issue

dicer

See my post.......
https://www.clublexus.com/forums/ls-...-problems.html

Moarpower

Hi mate.

I did read your thread before posting. I have cleaned my IACV and replaced it. Sure they could both have been bad but Im not too sure.

dicer

Cleaned it? And how where the bearings?

Moarpower

Bearings were spinning well. Just removed carbon build up and reinstalled it; Issue was still happening so I installed another. Same issue.

I have since changed all spark plugs and in doing so removed the throttle body again. Noticed that the air hose on the throttle body to the valve cover on the drivers side has a huge split. Certainly that is contributing. I will replace the AFM as it is throwing a code 31 , replace the hose and go from there. It is a stunning car and needs to be on the road. The interior and wheels alone is what I paid for the car.

dicer

So then you had the little armature out and the little bearings were fine? Could be ecu also any of the hoses cracked etc.

Moarpower

Yea I undid the 3 phillips screws and cleaned the whole thing. The bearings seemed fine to me. This does not prove that it is functioning correctly tho.
I am having a very hard time sourcing replacement hoses.
As for the ECU, it looked perfect upon inspection so I will leave it till last.
Running very well, just not idling at all

Moarpower

some quick images

Moarpower

Curious about the code 31. Removing the afm and running the car affects the idle so I'm assuming it works? What else could it be

Moarpower

Replaced the air hoses today. Still the same issue. Tomorrow I will replace the AFM and hope for the best.

Moarpower

Hi guys. The AFM was replaced today . I purchased that part from A kiwi bloke named George on the GC in Aus. He does a lot of work with these engines. Walking in, the shop was a mess but god was it cool to see so many 1uz's being boosted, charged and built up. Cool guy too and was happy for me to poke my head under hoods and have a look at his work.

The idle issue is now solved. CEL lights are gone and she runs like a dream. Im so glad i decided to ship this car. in usa terms, $1100 for 91 Celsior with 60k miles and fully reupholstered, xyz coilovers.....A steal.

creilly

Man, seems like everywhere but the US is picking these up for pennies. Super jealous, I'd kill for a chance to see Celsiors priced that low!

dicer

I'm surprised the air meter has all that much to do with the idle, thanks for letting us know that it fixed your problem.
I think some people have disconnected them as a check to see if conditions improved. Did you ever do that?
I'd like to see what Yamae says about this, and if the celsior ecu has different programming or other changes from US LS400's.

Moarpower

I actually thought that the AFM was not the issue at all, as when I pulled it out of the body it did in fact change the idle. I guess it is a little more complicated than I was thinking.
I was going to buy an IACV and AFM but went with the codes and it payed off this time. It would only cause issues when at operating temperature.

I assume it contributed to the idle issues as it was not able to detect the correct airflow at idle and caused the wrong volumes to be calculated. Too much or too little fuel etc. Makes sense