Update: Potential Culprit Found? —> 2000 LC Dies, Battery, Check Engine, AT Oil Temp Lights (2 Viewers)

[TheBestCow]

Bumping this back up. Anyone else have thoughts on what I can be testing this weekend?

 

[jpd motorsports]

mine died the other day slowing down to stop, the started again, then same day died again and wouldnt start. I pulled the efi fuse cleaned the contact in the fuse holder and installed a new 25amp fuse with dielectric grease on it (old one looked good and both sides tested good but piece of mind) then removed the efi relay. Cleaned the efi relay contacts(they were not shinny but dull), cleaned the contacts in the sockets. made sure the contacts were tight and pushed the ears in them. Dielectric greased the contacts and re installed relay. vroom up and running. Also noticed my idle has been low (quite some time actually) 400-600rpm. so next day took and cleaned the MAF and throttle body.

 

[Skidoo]

Disconnect your battery cables clean the terminals and posts and make sure they are tight when you reconnect them.
Friend's 100 was stalling, it turns out the battery connections where a little loose.

 

[ramangain]

Check the ground cable ar the top/back of engine block too

 

[TheBestCow]

mine died the other day slowing down to stop, the started again, then same day died again and wouldnt start. I pulled the efi fuse cleaned the contact in the fuse holder and installed a new 25amp fuse with dielectric grease on it (old one looked good and both sides tested good but piece of mind) then removed the efi relay. Cleaned the efi relay contacts(they were not shinny but dull), cleaned the contacts in the sockets. made sure the contacts were tight and pushed the ears in them. Dielectric greased the contacts and re installed relay. vroom up and running. Also noticed my idle has been low (quite some time actually) 400-600rpm. so next day took and cleaned the MAF and throttle body.

Disconnect your battery cables clean the terminals and posts and make sure they are tight when you reconnect them.
Friend's 100 was stalling, it turns out the battery connections where a little loose.

Check the ground cable ar the top/back of engine block too

I guess I will try cleaning the MAF and throttle body as part of this. It is idling close to 600rpm right before it stalls out. But that seems more like a symptom than the disease as I’ve taken this on several 2-3 hour trips without a problem. I’m trying to think of what has changed — nothing that I’ve done. Haven’t touched under the hood leading up to this.

So you think okay, let’s check the connections, the terminals, the grounds. All of it seems fine, took off, cleaned, retightened. Grounds are solid, not loose. (To be clear - I see two grounds, one is on the drivers side quarter panel and connects to the negative on the battery, and one looks to come from a wired connection at the rear of the engine and connects to the body below the windshield area. Those connections were what I checked. I didn’t look under the plastic engine cover to check the actual connection of the ground on the engine.)

I went a few days with it being fine enough to make short trips out. Took another one today and it died on the way home twice today which is when I checked all of the connections and cleaned everything up with baking soda.

I had my Ultragauge plugged in and it was about 13 when it kicked off the first time. I couldn’t tell if it immediately dropped down into the 12s right before or after I stalled, was too busy driving.

Which brings me back to one of the original replies about the voltage regulator. Could that be it? I hate to throw parts at something without knowing for sure.

Here’s what I checked just now after checking all of the battery connections. Restarted with Ultragauge connected, nothing else turned on. Seemed pretty steady in the 13s-14s. Kicked on the ACs, headlights, and the aftermarket fog lights. Did what it originally did - slowly dropped. Low 13s... then into the 12s... then into the low 12s... then into the 11s... then died. This was in park, idling. Voltage would respond if I added revs.

Looking up voltage regulator symptoms it seems like dimming lights, not operational gauge cluster, higher than expected voltage, and lower than expected voltage occasionally are common symptoms. It would appear I’m only getting one of those in the lower voltage sometimes?

Also, my Ultragauge has a error codes section and pulls nothing... should I buy a cheap OBDII port scanner to make sure there aren’t any codes? If so, which one? I will look in the FAQ for throttle body and MAF sensor cleaning guides too.

 

[JunkCrzr89]

Here’s what I checked just now after checking all of the battery connections. Restarted with Ultragauge connected, nothing else turned on. Seemed pretty steady in the 13s-14s. Kicked on the ACs, headlights, and the aftermarket fog lights. Did what it originally did - slowly dropped. Low 13s... then into the 12s... then into the low 12s... then into the 11s... then died. This was in park, idling. Voltage would respond if I added revs.

I maintain my original diagnosis of this being an alternator problem...

 

[TheBestCow]

I maintain my original diagnosis of this being an alternator problem...

How else can I test aside from going to the parts store and them saying it shows as good? Or do I just suck it up and buy a new one and hope for the best?

I did have my multimeter attached to the battery during one of the times it died in the garage. Voltage never dropped below 13 before it stalled. Not sure if that makes a difference.

Edit: Also, anyone have the part number for the two bolt/screws for the MAF? (Looks like 9015940274 on the part diagram but wanted to triple check.) Mine are not budging and I’m going to strip them. Looks like this has never been opened. I was able to spray the cleaner in from the air filter side, but figure a set of $2 screws would be worth investing in so I can get it out correctly in the future. Got the battery disconnected for 30 minutes (really for tonight) to let the ECU reset as well.

 

[TheBestCow]

I believe we have a culprit.

Got the engine cover off to clean the throttle body and to get a better look at everything.

This is what I see:

AC belt has cut through the protective cover of this wiring bundle, which goes up to the top of the engine and into what looks like the black plastic piece that distributes power to the coils.

It looks like it is supposed to be in this metal piece and maybe ‘bounced’ out after maybe hitting a pot hole or something like that?

I had tested it this morning and ran 20 minutes straight with no stall, no major drop in voltage. That was before discovering this.

So the theory is... as it is rubbing into it, it isn’t constantly causing some sort of short. But as the belt moves around laterally a bit or the wire bounces off of it, every so often it runs into it and causes a short, which causes the stall.

Talked to a buddy of mine who recommended:
1. Disconnect battery
2. Cut into wire protective and peel it back a bit to identify which wires are damaged and how badly.
3. Temporary solution: electrical tape over each individual damaged wire
4. Permanent fix: once identifying which individual wires are damaged, buy soldering/wire repair kit, cut out the bad portions of damaged wire, solder in replacement, replace wire cover with heavy amount of electrical tape.
5. Zip tie to the metal tab that I pointed a red arrow to in the picture above to avoid it falling onto the AC belt again

Thoughts? You’d think this is clearly it... but either way, this needs fixing.

 

[Doctor Koko]

Cut out the bad wire, solder in new, cover with heat shrink, and then replace the plastic cover and secure. I would avoid using electrical tape for any of it. You can also simply use butt splice connectors (faster, easier, totally fine). Shorts like this are really common, as are the comments that "it must be a bad alternator" (or bad battery, or bad ________).

 

[medtro]

Look like the harness that should be clipped to the bottom of the plastic timing belt cover. Do you have 2 clips on that cover? I don't believe it goes to the metal tab. That metal tab was bent for timing belt or fan bracket job.

 

[TheBestCow]

Cut out the bad wire, solder in new, cover with heat shrink, and then replace the plastic cover and secure. I would avoid using electrical tape for any of it. You can also simply use butt splice connectors (faster, easier, totally fine). Shorts like this are really common, as are the comments that "it must be a bad alternator" (or bad battery, or bad ________).

I’m a rookie here.

If I go new wire + solder + heat shrink, where’s the easiest place to get all of that? Local parts store?

Or get a butt splice set from Lowes/Home Depot like this? Or, actually, more robustly this kit?

Look like the harness that should be clipped to the bottom of the plastic timing belt cover. Do you have 2 clips on that cover? I don't believe it goes to the metal tab. That metal tab was bent for timing belt or fan bracket job.

Not sure. Still learning the LC. I’ll have to go back out and look

 

[2001LC]

The metal piece is not the hanger. There is a hanger in front of that, that a wire block is on or near (hard to see in pic). That wire block is likely the cam sensor one. . Which has its own hanger on the timing belt cover.

The sheathing cut to wire(s,) that is rubbing on drive belt. Looks like crank sensor and oil sending unit wires. But hard to tell in your pictures. They come from top of engine and go down. Actually start behind the glove box at the ECU and wrap around both side of the engine from the rear. The crank sensor & oil sending unit are the longest wires from the ECU in the main wire harness.

Very often while someone is doing the timing belt job. They'll break the hanger off the timing belt cover, for cam sensor wire block. They'll also route the wire going to crank sensors and oil sending unit wrong. Those wires go between the fan bracket and compressor, back behind sleeve/arm the first or outer bolt that goes through the compressor to hold on fan bracket. They can be rerouted, after fan bracket installed, but very difficult job. Most can not do, as seems not enough room! So pulling fan bracket is solution to rerouting.

If this is your culprit (crank sensor wire cut). I'd expect at least pending code (DTC) in tech stream.

Proper routing!

I use solder shrink wrap butt connectors and high temp electrical tape. Disconnect both wires at sensor and sending unit. Bring up to top of engine where you can work on and splicing more easily.

 

[TheBestCow]

The metal piece is not the hanger. There is a hanger in front of that, that a wire block is on or near (hard to see in pic). That wire block is likely the cam sensor one. . Which has its own hanger on the timing belt cover.

The sheathing cut to wire(s,) that is rubbing on drive belt. Looks like crank sensor and oil sending unit wires. But hard to tell in your pictures. They come from top of engine and go down. Actually start behind the glove box at the ECU and wrap around both side of the engine from the rear. The crank sensor & oil sending unit are the longest wires from the ECU in the main wire harness.

Very often while someone is doing the timing belt job. They'll break the hanger off the timing belt cover, for cam sensor wire block. They'll also route the wire going to crank sensors and oil sending unit wrong. Those wires go between the fan bracket and compressor, back behind sleeve/arm the first or outer bolt that goes through the compressor to hold on fan bracket. They can be rerouted, after fan bracket installed, but very difficult job. Most can not do, as seems not enough room! So pulling fan bracket is solution to rerouting.

If this is your culprit (crank sensor wire cut). I'd expect at least pending code (DTC) in tech stream.

Proper routing!
View attachment 2440165
I use solder shrink wrap butt connectors and high temp electrical tape. Disconnect both wires at sensor and sending unit. Bring up to top of engine where you can work on and splicing more easily.
View attachment 2440171

I think you’re exactly right.

Red arrow pointing the wire going down next to the pulley instead of back behind the bracket like you show in correct routing picture above. I removed the skid plate below and when I wiggle the suspect wire it does seem connected to the oil sending unit.

The brackets on the front of the timing belt cover are broken. There was one still intact, but when I touched it it was so brittle it fell to pieces.

I don’t have tech stream unfortunately. No codes showing in Ultragauge but guessing tech stream shows more.

Again, being a rookie, is there a write up for removing the fan bracket? (Edit: did some Googling, looks like that is part of doing the timing belt and... looks like a ton of work. Is there a way to loosen the two bolts to give myself enough room to route the wire correctly? If not, is it possible to zip tie everything out of the way until next timing belt change in... 75k+ miles? Or am I looking at removing fan and fan shroud, belts, etc. to give myself enough room?)

Overall it seems like a very tight fit in there. Everything is also kind of crusty... afraid I’m going to break the sensor trying to pull it off of the oil sending unit. Not sure I got eyes on the crank sensor either.

Any tips for any of this? I was wondering how I would do the yoga to get down into the engine to cut, splice, etc. I get unplugging and pulling the wire up makes life a lot easier. Just trying not to break the connectors while unplugging everything — making matters worse, obviously.

 

[2001LC]

You can tie it up for now.

I get those butt connectors from Grainger. I do know, Advanced Auto, likey NAPA, etc. have "others" they can order, so does online no doubt! I made the tool to heat, from heat gun and a piece of aluminum roofing flashing. Works very good as you can see. But if you like to buy tools, they have very cool heat guns and attachment made for these. Google is your friend!

If wires and their sheathing not cut, sure tie it up. It's nice to wait until timing belt job to remove a fan bracket. Because when paying for the job, it's just a part (no adding labor cost).

You can "thread the needle" getting both wire blocks back in proper routing, without pulling the fan bracket, as stated above. I did it once with engine on a stand, which made it easy for me to work on. It would be more difficult and may require dropping the compressor (pull 3 bolts) for hand with engine in the bay. Easier to pull fan bracket IMHO.

But if wire sheathing and/or wires cut. Well as DIY, it's just going to add some time to the job of splicing, you need to do anyway. It not that big a deal to pull a fan bracket. You'll also have fan shroud and fan out of the way, which will give more room to do a good job easily on the wires and clips. You may find that fan bracket is not so great, as it looks old to me. So replacing it while in there, if oil on back seal or bearing feels rough. Heck if timing belt near 7 year or 90K, do the job. Likely the "whomever" did the Timing belt job, messed up even more. There is two small pieces plastic (covers), just under fan bracket. Bet one or both missing. Whomever, likely did not use thread sealant on the idler pulley bolts either. Good chance "whomever" did the job without a torque wrench. When I see this stuff, like wire run wrong. I find there is more mistakes 8 out of 10 times.

The crank sensor and oil sending unit wire housing connectors, will come off with care. I like to start with cleaning/degreasing the area very well. If that/those wire(s) cut, even just a few strains of copper. It may affect resistance. This could be your issue. So you do need to splice the wire(s) and re sheath them. So don't think about how to get around for now, just get it done. It just a few extra hours to do the job right once and for all.

If the clips on housing break. You can get new OEM. You can also get pigtails. Most dealerships carry these or can order for you.
These are not the part #'s you may need, just examples of pigtails and housings connectors (knock sensor for 01 IIRC)

 

[TheBestCow]

You can tie it up for now.

I get those butt connectors from Grainger. I do know, Advanced Auto, likey NAPA, etc. have "others" they can order, so does online no doubt! I made the tool to heat, from heat gun and a piece of aluminum roofing flashing. Works very good as you can see. But if you like to buy tools, they have very cool heat guns and attachment made for these. Google is your friend!

If wires and their sheathing not cut, sure tie it up. It's nice to wait until timing belt job to remove a fan bracket. Because when paying for the job, it's just a part (no adding labor cost).

You can "thread the needle" getting both wire blocks back in proper routing, without pulling the fan bracket, as stated above. I did it once with engine on a stand, which made it easy for me to work on. It would be more difficult and may require dropping the compressor (pull 3 bolts) for hand with engine in the bay. Easier to pull fan bracket IMHO.

But if wire sheathing and/or wires cut. Well as DIY, it's just going to add some time to the job of splicing, you need to do anyway. It not that big a deal to pull a fan bracket. You'll also have fan shroud and fan out of the way, which will give more room to do a good job easily on the wires and clips. You may find that fan bracket is not so great, as it looks old to me. So replacing it while in there, if oil on back seal or bearing feels rough. Heck if timing belt near 7 year or 90K, do the job. Likely the "whomever" did the Timing belt job, messed up even more. There is two small pieces plastic (covers), just under fan bracket. Bet one or both missing. Whomever, likely did not use thread sealant on the idler pulley bolts either. Good chance "whomever" did the job without a torque wrench. When I see this stuff, like wire run wrong. I find there is more mistakes 8 out of 10 times.

The crank sensor and oil sending unit wire housing connectors, will come off with care. I like to start with cleaning/degreasing the area very well. If that/those wire(s) cut, even just a few strains of copper. It may affect resistance. This could be your issue. So you do need to splice the wire(s) and re sheath them. So don't think about how to get around for now, just get it done. It just a few extra hours to do the job right once and for all.

If the clips on housing break. You can get new OEM. You can also get pigtails. Most dealerships carry these or can order for you.
These are not the part #'s you may need, just examples of pigtails and housings connectors (knock sensor for 01 IIRC)
View attachment 2440870

Thanks. Good news I work from home and we have another vehicle if needed so not in a rush.

Picked up butt splice connector kit from Lowe’s yesterday. Borrowing the stripping tool and heat gun from father in law.
Planning to tape (painters tape) a thin rope to the bottom wire (not the oil sending unit wire, looks thin) in hopes of being able to help guide the reinstall.

Plan for today is to get everything disconnected and accessible at top of engine for repair. Depending on how long that takes may get it all done today, but if not I’ve got time to take my time and not rush. Thanks for all of the advice.

Edit: re:cleaning and degreasing, is it safe to use something like Simple Green on the connectors and all that?

 

[TheBestCow]

where should I be pulling from? The individual wire (1), the black plastic that wire is going into (2), or the bottom black circle directly next to the metal unit (3)?

is this the crank sensor? What’s the best way to pull this? I’m guessing it goes up toward the top of the engine? Not sure how I’m going to fit my hand in there with the fan in place.

 

[jpd motorsports]

Number 2 in your pic. has a press pull type connector.

Yes Crank sensor. same type plug on it as well.

for the crank sensor, I used a long screwdriver to push on the tab and another to help slide it off. I was able to put my right hand up over the lines below the crank pully and "touch) the sensor to help slide clip off once it moved.

If your removing the sensor as well: The bolt Holding in sensor is a 10mm. I used a shallow socket short extension a swivel and a longer extension to the swivel. took a little bit to get it out.
Note I have 264k on mine and as I was removing the sensor the bolt part basically crumbled apart. Luckly i was completely replacing it.
Also while you have it out check the Ohms on the sensor to see if it is weak and and almost due to replace.

 

[Eicca]

I replaced my fan bracket on my 4.0L V8 a few years ago. It was interesting, but not bad. Have a look at my writeup from ClubLexus:

There may of course be some differences between motors, but given that the timing belt kit is the same for all UZ V8s IIRC, this should get you 90% of the way there.

Fan bracket pulley replacement info - ClubLexus - Lexus Forum Discussion

GS - 2nd Gen (1998-2005) - Fan bracket pulley replacement info - Since there wasn't much helpful info to be found by searching, I am posting some of the tidbits I learned from today's replacement of the fan bracket pulley. The whole job took me about three hours, moving slow and careful. I'd...

www.clublexus.com

 

[TheBestCow]

Welp. Got the oil sensor off.. and the wire ripped out of the back. Fixable? Or am I on a hunt for a part (anyone have the part #)? (looks like 90980-11363 is it, but doesn't necessarily come with pig tail. Can order from Yotashop with pigtail here or Ballinger motorsport here, would need to see which is cheaper for shipping included.)

for crank... do you slide screwdriver up (1) or push on the side (2)?

The learning process continues. Appreciate the help.

I'll probably hold off on ordering replacement pigtail until, you know, I've gotten the other sensors disconnected without breaking those as well...

 

[jpd motorsports]

I pushed in on #2 and had another to push at #1 to help it slide off.

when you get the harness us check to see if that oil sender wire will go back in.