Yamae

Quoted above reminds me of the badly clogged throttle body including the air mix passages. Does your car idle 750rpm sharp @ P or N? If lower than 750rpm, simply clean those first.

VolumeToo

Thank you sir,

Yes, the TB could well need attention; I had to remove and clean it on my previous two LS400s. I've only had this car a couple of weeks and have not had a chance to carry out much work, so far. I will do this and report back.

I would also be reassured to have your confirmation that the UCF21 ECU is not known to cause stalling issues.

Kind regards,

Rich

Yamae

The ECU related stalling issue only happens among 95 year models.

CELEXUS84

Hey so I have been lurking here for a little while for info on my build of a 1uzfe swap into a 84 celica. I have a 95 1uzfe (ls400) ecu #89661-50230. Before the motor was removed from the ls400 it had a few quirks. Hard shifting etc. Thought it was just old or maybe a reman trans. So I started the motor up in the car with mocked up wiring (only thing not wired was rear 02 sensors) Started and idled fine for the minute or so. Finalized all wiring and cooling etc and started it. Check light would not go off and could not get it into diagnostics and the idle fluctuates up and down quickly like a 90's honda . Re-checked all wiring that powers ecu (b+,batt,igsw etc) per toyota manual. All checks out. Searched for ls400 computer failures and found this posting. Ordered suggested caps from digikey and cracked ecu open. Found one cap with sticky goo underneath it but no other evidence of any issues. So cleaned the board up and swapped all caps. And it made no difference. Still cannot get the computer into diagnostic mode. Found the ect sensor basically broke in half so I am going to replace that today, but still the not going into diagnostic mode is the problem. Here is some pictures after the repair. Not the best in the world as far as soldering goes but everything has good connection
The fuz is from cleanign with alcohol with ear swabs. Didnt blow them off yet
http://s44.photobucket.com/user/heyitsrj88/ECU/story

jbtvt

This is OBD1? Start with checking the exterior wiring for continuity, like making sure your E1 ground is solid between the check connector and the battery terminal, then check continuity between TE1 at the diag box (or whatever the check terminal is on that one) and the terminal where that plugs into the ECU. You can try hardwiring the ecu terminal to a ground also and see if that forces it. If not it seems to me that it would be an ECU fault.

CELEXUS84

Thanks for the reply. I have checked continuity between E1 and the chassis. Not direct to battery. And it is good. I have pinned TE1 direct to a ground from ECU and it still stays solid. I have been trying not to beat myself up over this and take a break and finish the rest of the car. But I do think about it here and there. I have the battery grounded direct to motor and then motor to chassis. I wonder if it should be grounded to chassis as well, or just to chassis. This is my first full wiring job I have tackled, So I have a feeling there is a issue somewhere I just cant find it.

jbtvt

It's been a while since I've had to chase grounds but if I recall correctly Toyota typically grounds battery to chassis only and engine also grounds to chassis. Shouldn't matter if all connections are clean and tight and wires are large enough gauge. You have continuity between chassis and negative battery terminal I take it? Important to have the car off when jumping TE1 to ground, then turn key to on while leaving it jumpered. On some engines/ECUs the check terminal is T, others have a TE2 which sets the ecu to a more sensitive diagnostic state when jumpered. Maybe play around with that if you have. But if you have power to B+ at the ECU and definite ground to TE1 before you turn the key, and light stays solid it might be time to look for another ECU to try. You should start another thread specific to your issue and maybe someone will know of something else, this thread gets overlooked sometimes.

Sweet looking Celica btw. What's the story with the trans, that the original with an adapter plate? Where'd you find that? And is the trans going to be able to handle the 1UZ torque?

Yamae

Have you checked copper traces and through holes electrically? The leaked QAS liquid damages those and those can't be easily recognized by human eyes. Some boards are not fixable due to the reason that internal traces are damaged and there's no way to connect. I also must inform you that to use a 89661-50230 often causes engine running problems when the engine is aged. See below to know more.
https://www.clublexus.com/forums/ls-...ml#post7540747
If possible you'd better to use a 89661-50234 or 89661-50235-85 instead of a 89661-50230.

CELEXUS84

Thanks for the pointers. I appreciate it. I will check them out. I do have continuity between engine and chassis, engine and battery negative. So everything has good grounds. And the stock w58 trans has been known to handle some torque as long as it is not abused. I am more worried about the rear end though. We just have to be nice.

CELEXUS84

I broke out the magnifying glass and did not see any damage. I did not check the traces for continuity though. Funny thing is...the original comp was the 50230. We picked up a 50231 and it does the same thing. I am just going to quadruple check all wiring and change my ground from engine to chassis and go from there. I will try and find a updated computer as well. Thanks for the pointers.

Saurael

My speedometer and rpm gauge starting going yesterday morning. They stopped working during the am and started working in the pm. I'm wondering after reading a few of these pages if i can find a good shop to take care of this issue asap. I downloaded a speedometer app for my phone just in case it happens again in between now and the actual repair.

Ammorris

Does the capacitor issue exist for a 2006 LS430? I am experiencing intermittent stalling when going from reverse to drive, random !, check engine, check vsc, and trac off lights come on (all at the same time), shuddering at low speeds, jerking and hesitation in stop and go traffic, and intermittently, the rpms will drop almost to zero when going from reverse into drive. All of these problems are intermittent. It seems the car drives either great or terrible.
My poor mechanic is going in circles on this for me, doing everything he can think of to save me money and solve the problem without having to do a new transmission...much of the work at little to no cost. There have been many codes related to solenoids and transmission issues, as well as engine immobilizer codes, and airbag codes. Over the last few weeks we did a new alternator and battery, reset the keys, and replaced 4 new external solenoids on the transmission. Most recently, they added lubegard friction modifier, but today the car stalled again when going from reverse to drive, and the lights came back on about 90 minutes later, followed by low speed shuddering when climbing a hill, so it feels like we are back where we started.
Thanks for any advice you have!

kamileon

Disconnect battery when engine is hot for 10 min. During that 10 min replace the PCV. Reconnect battery with key in hand. Open close drivers door 6 times, turn ignition to on, wait till nav loads. Then start and turn a.c. on. Let it idle for 5 min.

Yamae

I don't think so.

Ammorris

Thank you for your input.