LX450 starting problems (1 Viewer)

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thanks. i'll go pick some up tomorrow. appreciate the help.
You can use a tool as simple as a screwdriver to check for spark, it just depends on what you have on hand. A timing light, screw driver, an extra spark plug.

You can pull the #1 spark plug, set it on a bare metal part of the engine, make sure it's plugged into the wire from the distributor then watch it while you try to start it, you can see the spark. Might require an extra person to try to start it while you watch it.
 
The CEL illuminated with the key in the ON position before cranking the starter is telling you that the ECU is in a "ready" state and all systems go.
Without the CEL illuminated, the ECU is not in a ready state, and the engine will not fire.
The first thing to check are the fusible links off the positive battery terminal. There are 3.
Check them with a meter, not your eyeballs.
 
In my experience, these issues are almost always the fusible link. Even when they aren't the fusible link, and the OP is 100% certain that isn't the issue, it turns out to be the fusible link.

Don't sweat all the curmudgeonly replies; it's par for the course here lately. The important info is what @jonheld posted: the sequence of the check engine lights. If something is amiss, the engine will absolutely turn over without the ECU sending a spark or fuel signal. I strongly recommend using the Toyota manual to troubleshoot these things. Its on the forum if you don't already have a copy. (FYSA @jonheld put it there...)

Lexus FSM
 
does anyone see the fuel pump relay in here? i thought i saw a pic showing it in Drivers Side up by the hood mount but i'm not seeing it on mine?



View attachment 3674510
It's in this photo, if I've selected the right one. Second photo in the group of 4 you posted. Has the numbers 66010 on it. But if I were to guess-don't do that!- it's most likely not your issue. Sounds like you're good with the CEL coming on. 👍
 
You can use a tool as simple as a screwdriver to check for spark, it just depends on what you have on hand. A timing light, screw driver, an extra spark plug.

You can pull the #1 spark plug, set it on a bare metal part of the engine, make sure it's plugged into the wire from the distributor then watch it while you try to start it, you can see the spark. Might require an extra person to try to start it while you watch it.
hey. thanks i was thinking to do this. just lay the electrode on bare metal?
also apologies for all the extraneous stuff and the multiple questions. there's been a lot of confusing stuff.
one thing i am starting to hear is that the alarm could be draining the battery. i've never had this problem so i've found it confusing.
i had heard someone mention ECU for this kind of problem.
someone else on a thread here mentioned some frayed wire on a power steering mounting bracket. supposedly they said it's the B+ into the ECU.
i can try to read electrical diagrams but can i be do bold as to ask if you know if the fuel relay is still in play as being a problem?
i need to find all 3 above - ECU, fuel relay and the B+ wire on the power steering reservoir - so just trying to get my head around things some more here...

IMG_7509.png
 
In my experience, these issues are almost always the fusible link. Even when they aren't the fusible link, and the OP is 100% certain that isn't the issue, it turns out to be the fusible link.

Don't sweat all the curmudgeonly replies; it's par for the course here lately. The important info is what @jonheld posted: the sequence of the check engine lights. If something is amiss, the engine will absolutely turn over without the ECU sending a spark or fuel signal. I strongly recommend using the Toyota manual to troubleshoot these things. Its on the forum if you don't already have a copy. (FYSA @jonheld put it there...)

Lexus FSM
hey. thanks for the nice post here. it's appreciated. it's a bit of a tall order for some of us to keep up with just what things are called. i've been at it awhile. i imagine there are a lot of others that are starting with even less.
can you help me with a /hopefully/ 95-97 or even better LX450 FSM link. i have a hard copy and i have the charm.io but my PDF on dropbox is coming up as corrupted.
also are you saying there is a separate document explaining order of the CEL/Check Engine light or other lights for diagnostics. what i got from a poster her is that if i do see the Check Engine light On when key is On then i know it is not relays and not fuses and not if ignition.
i also understand that what i am hearing is the starter spinning causing the flywheel and crankshaft to spin.
so i am understand this preventing it from firing and i am looking at fuel or spark.
spark could be no power to the ECU.
not sure if this means fuel could be a bad fuel relay.
and i am also not totally sure if check engine light means it's not fusible link. mines pretty new which is sort of why i ask but i suppose i could have fried it charging it somehow.
anyway is there some document that explains the CEL diagnostic steps? or i need to go to FSM for this in Diagnostics i guess.
 
It's in this photo, if I've selected the right one. Second photo in the group of 4 you posted. Has the numbers 66010 on it. But if I were to guess-don't do that!- it's most likely not your issue. Sounds like you're good with the CEL coming on. 👍
hey boss. thanks for this.
wondering if anyone can help me find some parts.
i accidentally posted someone else's photo pointing out the fuel relay in their rig like a dope.
A. so i am still looking for the fuel relay in my truck.
B. i am looking for the ECU. is it the silver wafer looking thing in front of the steering fluid reservoir?
C. also supposedly there is a wire that is the "B+ to the ECU". and supposedly it is on top or in front of the steering fluid reservoir? can anyone see that here?
THANKS

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here is what i am trying to check for spark tomorrow.
not totally sure what i do to check for furl troubleshooting if i get spark?

View attachment 3674821
That will certainly work and the diagnostic tree here is great if you don't have spark.

I never liked hand holding 25K+ volts, you get it a bit wrong and it bites you. I prefer to pull a plug wire off the first spark plug, insert a spare spark plug into it and set it on some metal or use a squeeze clamp to clamp it to some metal.

I've gotten really lazy now though and usually just give it a quick squirt of the starting fluid into the intake as an initial diagnostic tool. If it's got spark, it will run just great for a few seconds with that quick shot and you can move on to other potential issues. If it doesn't run then you still have to double check for spark more properly as you show here.
 
so i am understand this preventing it from firing and i am looking at fuel or spark.
spark could be no power to the ECU.
not sure if this means fuel could be a bad fuel relay.
and i am also not totally sure if check engine light means it's not fusible link. mines pretty new which is sort of why i ask but i suppose i could have fried it charging it somehow.
anyway is there some document that explains the CEL diagnostic steps? or i need to go to FSM for this in Diagnostics i guess.
OK, this is my last post on this matter, so pay attention.
THIS ENGINE WILL NOT RUN WITHOUT THE CEL ILLUMINATED WITH THE KEY IN THE ON POSITION BEFORE CRANKING THE STARTER.
THIS ENGINE WILL NOT RUN WITHOUT THE CEL ILLUMINATED WITH THE KEY IN THE ON POSITION BEFORE CRANKING THE STARTER.
THIS ENGINE WILL NOT RUN WITHOUT THE CEL ILLUMINATED WITH THE KEY IN THE ON POSITION BEFORE CRANKING THE STARTER.

THE ECU IS NOT IN A READY STATE.
THE ECU IS NOT IN A READY STATE.
THE ECU IS NOT IN A READY STATE.

On an OBD2 FZJ80, the ECU controls spark and fuel delivery.
You can try starting fluid, check for spark, check for fuel, all while standing on one leg facing east while swinging a live chicken over your head, and it will all be POINTLESS.

THE ECU IS NOT IN A READY STATE. THE ECU IS NOT IN A READY STATE. THE ECU IS NOT IN A READY STATE.
Let me say this again.
THE ECU IS NOT IN A READY STATE. THIS ENGINE WILL NOT RUN.

Your ONLY CONCERN at this point should be figuring out why the CEL is not illuminated. Anything else you do is a waste of time and effort.
As previously stated, your VERY FIRST STEP should be verifying that all 3 fusible links off the positive battery terminal are intact.
You had a discharged battery and were messing around with terminals.
YOU CAN'T CHECK FUSIBLE LINKS OR FUSES WITH YOUR EYEBALLS.
Use a meter.
 
That will certainly work and the diagnostic tree here is great if you don't have spark.

I never liked hand holding 25K+ volts, you get it a bit wrong and it bites you. I prefer to pull a plug wire off the first spark plug, insert a spare spark plug into it and set it on some metal or use a squeeze clamp to clamp it to some metal.

I've gotten really lazy now though and usually just give it a quick squirt of the starting fluid into the intake as an initial diagnostic tool. If it's got spark, it will run just great for a few seconds with that quick shot and you can move on to other potential issues. If it doesn't run then you still have to double check for spark more properly as you show here.
hey. thanks a ton for that.
i've been slowly trying to move to a more deliberate set of steps but of course it's a lot and also it helps to have an old hand to guide you.
can you remind me why i am leaving the spark plug in and using a spare spark plug? meaning and not pulling the plug and using it? any reason? is it just easier?
in part i ask because on my two cylinder motorcycle i can pull both plugs (thinking out loud here) and i can alligator clip the electrode to the cylinders and i test - well i guess i test without the risk of it starting.
so how does that work here? i DO see that if i use a clip like you suggested (THANKS) i can look for spark while i crank it and not worry - well i would worry about it bouncing around and not being able to see it?
do i "worry" about it starting? do i worry about stray voltage drying something if it is not grounded?
also please - can you help me understand if there is any kind of diagnostic difference between spraying starter fluid into the throttle body and doing this electrical test with a spare spark plug?
or are they basically the same test?
THANK YOU
 
OK, this is my last post on this matter, so pay attention.
THIS ENGINE WILL NOT RUN WITHOUT THE CEL ILLUMINATED WITH THE KEY IN THE ON POSITION BEFORE CRANKING THE STARTER.
THIS ENGINE WILL NOT RUN WITHOUT THE CEL ILLUMINATED WITH THE KEY IN THE ON POSITION BEFORE CRANKING THE STARTER.
THIS ENGINE WILL NOT RUN WITHOUT THE CEL ILLUMINATED WITH THE KEY IN THE ON POSITION BEFORE CRANKING THE STARTER.

THE ECU IS NOT IN A READY STATE.
THE ECU IS NOT IN A READY STATE.
THE ECU IS NOT IN A READY STATE.

On an OBD2 FZJ80, the ECU controls spark and fuel delivery.
You can try starting fluid, check for spark, check for fuel, all while standing on one leg facing east while swinging a live chicken over your head, and it will all be POINTLESS.

THE ECU IS NOT IN A READY STATE. THE ECU IS NOT IN A READY STATE. THE ECU IS NOT IN A READY STATE.
Let me say this again.
THE ECU IS NOT IN A READY STATE. THIS ENGINE WILL NOT RUN.

Your ONLY CONCERN at this point should be figuring out why the CEL is not illuminated. Anything else you do is a waste of time and effort.
As previously stated, your VERY FIRST STEP should be verifying that all 3 fusible links off the positive battery terminal are intact.
You had a discharged battery and were messing around with terminals.
YOU CAN'T CHECK FUSIBLE LINKS OR FUSES WITH YOUR EYEBALLS.
Use a meter.

See post #15.

I understand that working with new amateurs can be frustrating, but you might read the entire thread before giving the OP a hard time about completing step 1. It's been completed.
 
hey. thanks a ton for that.
i've been slowly trying to move to a more deliberate set of steps but of course it's a lot and also it helps to have an old hand to guide you.
can you remind me why i am leaving the spark plug in and using a spare spark plug? meaning and not pulling the plug and using it? any reason? is it just easier?
in part i ask because on my two cylinder motorcycle i can pull both plugs (thinking out loud here) and i can alligator clip the electrode to the cylinders and i test - well i guess i test without the risk of it starting.
so how does that work here? i DO see that if i use a clip like you suggested (THANKS) i can look for spark while i crank it and not worry - well i would worry about it bouncing around and not being able to see it?
do i "worry" about it starting? do i worry about stray voltage drying something if it is not grounded?
also please - can you help me understand if there is any kind of diagnostic difference between spraying starter fluid into the throttle body and doing this electrical test with a spare spark plug?
or are they basically the same test?
THANK YOU

It's just easier and faster if you have spare plug and you don't risk the engine starting with an empty spark plug hole which can be noisy and messy, shooting fuel all over the place. The starting fluid process is just the easiest, quickest way to see if the engine is ready to run and has everything it needs except fuel. It's great when you are in the desert on the side of the freeway on a 109 degree day and you want answers, fast. There's nothing special here, you just want to find out if the spark plugs are sparking, that's it. As @jonheld has pointed out multiple times, we've verified the computer is ready the (CEL/MIL/check engine light) is on when the key is in the ON position (post #15) and now we wonder why it won't start. Is it lacking ignition (spark) or fuel? Spark test is first because it's easiest.
 
See post #15.

I understand that working with new amateurs can be frustrating, but you might read the entire thread before giving the OP a hard time about completing step 1. It's been completed.
From the OP.
"mines pretty new which is sort of why i ask but i suppose i could have fried it charging it somehow."
 
OK, this is my last post on this matter, so pay attention.
THIS ENGINE WILL NOT RUN WITHOUT THE CEL ILLUMINATED WITH THE KEY IN THE ON POSITION BEFORE CRANKING THE STARTER.
THIS ENGINE WILL NOT RUN WITHOUT THE CEL ILLUMINATED WITH THE KEY IN THE ON POSITION BEFORE CRANKING THE STARTER.
THIS ENGINE WILL NOT RUN WITHOUT THE CEL ILLUMINATED WITH THE KEY IN THE ON POSITION BEFORE CRANKING THE STARTER.

THE ECU IS NOT IN A READY STATE.
THE ECU IS NOT IN A READY STATE.
THE ECU IS NOT IN A READY STATE.

On an OBD2 FZJ80, the ECU controls spark and fuel delivery.
You can try starting fluid, check for spark, check for fuel, all while standing on one leg facing east while swinging a live chicken over your head, and it will all be POINTLESS.

THE ECU IS NOT IN A READY STATE. THE ECU IS NOT IN A READY STATE. THE ECU IS NOT IN A READY STATE.
Let me say this again.
THE ECU IS NOT IN A READY STATE. THIS ENGINE WILL NOT RUN.

Your ONLY CONCERN at this point should be figuring out why the CEL is not illuminated. Anything else you do is a waste of time and effort.
As previously stated, your VERY FIRST STEP should be verifying that all 3 fusible links off the positive battery terminal are intact.
You had a discharged battery and were messing around with terminals.
YOU CAN'T CHECK FUSIBLE LINKS OR FUSES WITH YOUR EYEBALLS.
Use a meter.
hi jon, i apologize. it's been confusing on my end and i probably had a confusing original post in trying to explain things and then jump right in to checking fuses and replacing a relay. i'm new to this despite spending a lot of time on it. i also realize it can be frustrating.
if i am not mistaken rhe CEL/MIL/check engine light for my truck is On when key is in the On position. i admit i was unaware that this was so important for diagnostics (again i am learning) or i wouldn't have covered it up with my ultragauge. actually in retrospect i am not sure why i covered it up since it's important otherwise. maybe i got sick of seeing it.
am i right in thinking i can move down to spark and duel at this point and ignore fusible link etc etc? or am i still missing something?
this is what i see with key On. should i try to find anything else aside form trying to get the ultra gauge to show me if there are any codes (it's scanning extremely slowly).
again apologies. i know you put in a huge amount of effort in helping posters here.

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It's just easier and faster if you have spare plug and you don't risk the engine starting with an empty spark plug hole which can be noisy and messy, shooting fuel all over the place. The starting fluid process is just the easiest, quickest way to see if the engine is ready to run and has everything it needs except fuel. It's great when you are in the desert on the side of the freeway on a 109 degree day and you want answers, fast. There's nothing special here, you just want to find out if the spark plugs are sparking, that's it. As @jonheld has pointed out multiple times, we've verified the computer is ready the (CEL/MIL/check engine light) is on when the key is in the ON position (post #15) and now we wonder why it won't start. Is it lacking ignition (spark) or fuel? Spark test is first because it's easiest.
hey. thanks.
so learning here and again thanks to all for feeding me good info. i found the FAQ.
for testing spark i can
1. squirt starter fluid into intake and crank it (no extra hands needed)
2. pull the plug from the coil off the distributor and hold it with a pair of welding gloves 12cm (?) which is like three or four inches or something away from the aluminum in the engine block?
3. hook up a timing light to each plug wire (make sure to point it the right way) and crank the engine (no extra hands needed if you can reach)?
4. on this one i am pulling the lead on one spark plug, insert a spark plug an then clipping it to the aluminum engine block somewhere and cranking (no extra hands needed)
5. not totally clear in this one but i can make (would kind of like to do this) or buy a spark plug tester that would test each cylinder?
does that sound right?
> i think i wasn't totally sure i admit about grounding plugs. i guess i can ground to the body of the frame or i can ground to a metal clip attached the engine?
🙏 THANKS

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@johheld point is that the CEL light needs to be on and that the three fusible links have to be good and in tact for the engine to start. He is 100% right on those. There are three fusible links that connect the battery to everything in the entire vehicle. They have names, odd ones, but they do have names.

#1 FLMain 1.25B
Runs the Horn/Dome Light/Ignition switch

#2 FLAM2.03P
Runs the EFI computer (CEL Light)

#3 FLMAIN 2.0L
Runs the Headlights, alternator, EFI 15A (fuel pump cutoff)

So you can put a meter on each of the three links and see if they are in tact, if you have a meter, and if you know what you are looking for. Looking at them visually is not good enough.

If your horn works, dome light works, then the #1 is OK. If the CEL light comes on, #2 is OK. If your headlights work, #3 is working.
 
It's just easier and faster if you have spare plug and you don't risk the engine starting with an empty spark plug hole which can be noisy and messy, shooting fuel all over the place. The starting fluid process is just the easiest, quickest way to see if the engine is ready to run and has everything it needs except fuel. It's great when you are in the desert on the side of the freeway on a 109 degree day and you want answers, fast. There's nothing special here, you just want to find out if the spark plugs are sparking, that's it. As @jonheld has pointed out multiple times, we've verified the computer is ready the (CEL/MIL/check engine light) is on when the key is in the ON position (post #15) and now we wonder why it won't start. Is it lacking ignition (spark) or fuel? Spark test is first because it's easiest.
hey man. probably a two day affair or weekend work here so trying to get it together.
do you mind if i ask about FUEL tests as i learn here? i'm going to find the FSM diagnostic in case i need to go deep but i have two tests here for FUEL?
1. rhis one is kind of easy and empirical. i crack open the gas cap to lessen the pressure and then i unclip this hose and i put it into the end of a bottle or something? then i crank the engine? and if fuels spits into the bottle i am getting fuel to the engine?
2. i wasn't clear on this one exactly but if i DON'T see fuel at that point i move up to the fuel relay? i unclip it from the sheet metal. well at the bottom of the FAQ "TrickyT" seems to suggest - well A. to check the voltage from a terminal in this relay? and i do this with the key in On position i guess? or B. i could connect the same terminal inside the fuel pump relay to the POS pole and see if fuel shoots out of that fuel pump "return hose"?

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@johheld point is that the CEL light needs to be on and that the three fusible links have to be good and in tact for the engine to start. He is 100% right on those. There are three fusible links that connect the battery to everything in the entire vehicle. They have names, odd ones, but they do have names.

#1 FLMain 1.25B
Runs the Horn/Dome Light/Ignition switch

#2 FLAM2.03P
Runs the EFI computer (CEL Light)

#3 FLMAIN 2.0L
Runs the Headlights, alternator, EFI 15A (fuel pump cutoff)

So you can put a meter on each of the three links and see if they are in tact, if you have a meter, and if you know what you are looking for. Looking at them visually is not good enough.

If your horn works, dome light works, then the #1 is OK. If the CEL light comes on, #2 is OK. If your headlights work, #3 is working.
i am trying to find my meter. i can't figure out if i misplaced it - hmm maybe i check the kennedy - or if someone jacked it. my lawnmower was upside down and spitting fuel last night like someone tried to snatch it when i went out to the garage...
i have a spare fusible link in the glovebox.
i'll try to find the FSM to see if i can find something for testing the fusible links with a multimeter in the meantime?
i've learned a lot here already so i want to thank everyone again.
am i correct in understanding i can test the #1 and #3 portions of the fusible link by turning on the interior dome light and by turning on the headlights? but that if #2 path in the fusible link is bad it will kill the - i see if i see CEL than i know the computer - or the EFI portion of the computer - is getting power since CEL is On with key On?
THANKS

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