97 LX450 No Spark, Could use help. (1 Viewer)

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So Iv got a 97 LX450 that I rebuild 2 years ago, haven’t had a single issue till this. How it all started,

I’m driving to work and while I’m at the stop light, I notice a very slight change in idle. I look down, oh the A/C button is on, hence the idle up. Boom, crank it off. All’s good. Didn’t think much of it after that..

I get to work. Less then 5 miles from the stop light I was at and I sat for a minute and then turned it off and a few hours later I go to leave and I turn the key to crank and it does it’s think for 3-4 cranks and I turn the key back and hmmm.. didn’t fire. Ehh it’s a land cruiser. Maybe I needed to hold it one more fire.. nope. Just cranks and cranks and cranks. I don’t hold it over 4 cranks even now that’s it’s not running.

here are my checks. I have a FSM btw.
i am not getting spark from the coil to the distributor. And obviously not spark after that. I am getting 12v to the + pin on the harness side of the coil. So coil is getting power but not sending it out.
I have a BRAND new fuseable link on. I had an extra. Nothing.

Called a buddy and got a coil off a running truck. His checks out resistance wise. I can’t seam to get a good reading on mine with a volt meter but his didn’t work in my truck so mine is probably fine.

I have tried to test resistance at the distributor and I can get a good reading. I cracked the plug on the dizzy when I put the motor in but it’s been working fine since. I did notice that my rotor has a small chip in it but I’m not getting spark to that anyway so.

maybe someone can educate me on what I should check and try next!? I have my FSM but I’d like to hear some other ideas and such.

cheers.
 
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I cracked the plug on the dizzy when I put the motor in but it’s been working fine since.
That would be the first thing I'd replace. That 4 pin connector is what feeds the ECU with the pick up coil pulses and creates spark and ignition timing. If one of those connections is compromised, you will have a large paperweight.
90980-11150 less than $9 from Toyota.
 
Joined
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Messages
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Outer Banks, North Carolina
That would be the first thing I'd replace. That 4 pin connector is what feeds the ECU with the pick up coil pulses and creates spark and ignition timing. If one of those connections is compromised, you will have a large paperweight.
90980-11150 less than $9 from Toyota.
I cracked the connector on the dizzy side. Can you just get the wiring and plug that goes inside the distributor !? I hate the idea of buying a 500$ distributor.
If the distributor connection is not properly working, it will not let the coil fire?? Iv been trying to figure out the process of ignition to start from the beginning and then work my way forward.
 
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I cracked the connector on the dizzy side. Can you just get the wiring and plug that goes inside the distributor !? I hate the idea of buying a 500$ distributor.
If the distributor connection is not properly working, it will not let the coil fire?? Iv been trying to figure out the process of ignition to start from the beginning and then work my way forward.
Rather than trying to guess, all of the Toyota factory service manuals (FSM) and schematics (EWD) are available to download in the resources section.

The pick up coils in the distributor feed pulses to the ECU. The ECU modifies the pulses according to it's mapping and sends them to the igniter. The igniter fires the primary of the ignition coil. The secondary of the ignition coil feeds the distributor rotor.
 

flintknapper

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Rather than trying to guess, all of the Toyota factory service manuals (FSM) and schematics (EWD) are available to download in the resources section.

The pick up coils in the distributor feed pulses to the ECU. The ECU modifies the pulses according to it's mapping and sends them to the igniter. The igniter fires the primary of the ignition coil. The secondary of the ignition coil feeds the distributor rotor.
👍

Yep, that's why I asked him if he had checked his igniter back in post #2.

Check the grounds there too.
 
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I don't think there's an easy way to test it. Given it either outputs a pulse to the coil or it doesn't. Probably could check with a scope to see if there was an input pulse train from the ECU...

Verify the ground connection as mentioned above. To be specific, the igniter gets it ground through the body, i.e. via the bolt(s) that mount it to the bracket. Kind of daft, but it does not have a ground wire. If you lose that mechanical ground connection the igniter wont fire and you get no spark.

cheers,
george.
 

flintknapper

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I don't think there's an easy way to test it. Given it either outputs a pulse to the coil or it doesn't. Probably could check with a scope to see if there was an input pulse train from the ECU...

Verify the ground connection as mentioned above. To be specific, the igniter gets it ground through the body, i.e. via the bolt(s) that mount it to the bracket. Kind of daft, but it does not have a ground wire. If you lose that mechanical ground connection the igniter wont fire and you get no spark.

cheers,
george.

^^^^^

Correct. Not a good way to check the igniter and they tend to be trouble free EXCEPT for losing ground.

It would be a simple matter to remove the igniter, check to see that there is good contact between the mounting bracket base and fender skirt and also the bracket to igniter. Alternately, run a wire from the mounting bracket to a known grounding point.

ALL grounds (battery to chassis, body to chassis) should be checked. And I don't mean just visually. Take them off and clean all mounting surfaces/connectors. That way you start with a 'known' base (grounds are good). Bad grounds cause so many hard to diagnose electrical issues.

I would also have the OP check the harness and connector that plugs into the igniter. None of this might be the problem, but its a good place to start given the symptoms.
 

rdcnj

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Well everyone. I finally got my scan gage back from a buddy and guess what. 1 pending code, p0340. Crankshaft position sensor. I’m going to order this and keep y’all posted.
Thank again for all the info and ideas y’all. Appreciate it!

Check the blue wire and make sure it's not broken, at the distributor, also check the wiring near the EGR to make sure it's not melted.

You have RPM movement on crank with the gauge?
What about with a scan tool, does it show the RPM's moving when you're cranking?

CRANKSHAFT POSITION IS DETECTED BY THE CRANKSHAFT POSITION SENSOR AND THE PICK−UP COIL INSTALLED INSIDE THE DISTRIBUTOR. THE CRANKSHAFT POSITION IS INPUT AS A CONTROL SIGNAL TO TERMINAL NE2+ OF THE ENGINE CONTROL MODULE, AND ENGINE SPEED IS INPUT TO TERMINAL NE
 

flintknapper

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Check the blue wire and make sure it's not broken, at the distributor, also check the wiring near the EGR to make sure it's not melted.

You have RPM movement on crank with the gauge?
What about with a scan tool, does it show the RPM's moving when you're cranking?

CRANKSHAFT POSITION IS DETECTED BY THE CRANKSHAFT POSITION SENSOR AND THE PICK−UP COIL INSTALLED INSIDE THE DISTRIBUTOR. THE CRANKSHAFT POSITION IS INPUT AS A CONTROL SIGNAL TO TERMINAL NE2+ OF THE ENGINE CONTROL MODULE, AND ENGINE SPEED IS INPUT TO TERMINAL NE

Tachometer pulses off of the igniter....but it won't move (that you can perceive) when just cranking the engine....if you were offering that as a diagnostic tool for the igniter being OK?
 

rdcnj

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Tachometer pulses off of the igniter....but it won't move (that you can perceive) when just cranking the engine....if you were offering that as a diagnostic tool for the igniter being OK?
I'm just trying to establish if there is a tach reading at all.

So I did some digging last night and here's what I got so far...

The tach does move when cranking, now does that equal RPM from the crank sensor, it does not appear to. However, I needed to put slow mo on my camera to actually verify the movement.

2021-05-01 13.42.29.png


2021-05-01 13.42.33.png


However, what it does have... is an RPM signal, even in a cheap off the shelf scanner that costs less than $100.

The crank sensor has a brown wire, a blue wire (known to cause problems at ignition coil connector) and a white wire with black tracer.

@ I20 ( apparently behind the glove box ) the blue wire splits from there to the ECM and the distributor.

Hook up a cheap scan tool and see if you have RPM signal.

For reference I disconnected my distributor and had NO RPM signal on cranking.
Video - 2021-05-01 13.53.04-1.mp4 - https://www.dropbox.com/s/2vcmvwiry0p6v5q/2021-05-01%2013.53.04-1.mp4?dl=0

Reconnected distributor, disconnected fuel relay, HAD RPM signal on cranking.
Video - 2021-05-01 13.58.50-1.mp4 - https://www.dropbox.com/s/pj484g08xb54i3y/2021-05-01%2013.58.50-1.mp4?dl=0

Reconnected fuel relay, disconnect crank sensor harness, HAD RPM signal on cranking, vehicle started.
Video - 2021-05-01 14.06.36-1.mp4 - https://www.dropbox.com/s/bj7q4mb9e9xur95/2021-05-01%2014.06.36-1.mp4?dl=0

NO RPM on scanner? My money is on Distributor or broken blue wire or melted wires near EGR.

Being as my truck started with the crank position sensor disconnected completely.... I would say if your truck isn't starting and has no RPM signal, check blue wire @ distributor connector, perform amp load test on wire, all checks out? Replace distributor.
 
Last edited:

flintknapper

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I'm just trying to establish if there is a tach reading at all.

So I did some digging last night and here's what I got so far...

The tach does move when cranking, now does that equal RPM from the crank sensor, it does not appear to. However, I needed to put slow mo on my camera to actually verify the movement.

View attachment 2662080

View attachment 2662079

However, what it does have... is an RPM signal, even in a cheap off the shelf scanner that costs less than $100.

The crank sensor has a brown wire, a blue wire (known to cause problems at ignition coil connector) and a white wire with black tracer.

@ I20 ( apparently behind the glove box ) the blue wire splits from there to the ECM and the distributor.

Hook up a cheap scan tool and see if you have RPM signal.

For reference I disconnected my distributor and had NO RPM signal on cranking.
Video - 2021-05-01 13.53.04-1.mp4 - https://www.dropbox.com/s/2vcmvwiry0p6v5q/2021-05-01%2013.53.04-1.mp4?dl=0

Reconnected distributor, disconnected fuel relay, HAD RPM signal on cranking.
Video - 2021-05-01 13.58.50-1.mp4 - https://www.dropbox.com/s/pj484g08xb54i3y/2021-05-01%2013.58.50-1.mp4?dl=0

Reconnected fuel relay, disconnect crank sensor harness, HAD RPM signal on cranking, vehicle started.
Video - 2021-05-01 14.06.36-1.mp4 - https://www.dropbox.com/s/bj7q4mb9e9xur95/2021-05-01%2014.06.36-1.mp4?dl=0

NO RPM on scanner? My money is on Distributor or broken blue wire or melted wires near EGR.

Being as my truck started with the crank position sensor disconnected completely.... I would say if your truck isn't starting and has no RPM signal, check blue wire @ distributor connector, perform amp load test on wire, all checks out? Replace distributor.


Again, my point being....'visually' you can not perceive the tach needle moving (beyond what looks like needle bounce) when cranking the engine. Which is why I don't suggest it as a diagnostic tool to determine whether or not the igniter, wiring or connections are at fault.


But your investigation is interesting. 👍
 

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