91’ FJ80 3FE won’t start (No Spark) (2 Viewers)

[Youngypsy]

Hey everyone!

First and foremost I would like to say thanks to everyone who helped build this awesome community, although I’m a new member I have already found so much great information and looking forward to seeing if I could resolve some pesky issues occurring with my FJ80!

Recently I had the chance to save a 1991 fj80 Land Cruiser from a local pick n pull and ultimately pulled the trigger! Very excited for this project as I have always wanted a Land Cruiser but ultimately was priced out so I am very much looking forward to upgrading and making this become an awesome machine with the support and connections from everyone here! Being a 91' it comes with the formidable 3FE and I seem to have come across some issues getting it to run.

Here is some previous information to help understand what the underlying issues may be because quite frankly this LC was missing a bunch of components and really want to make sure I'm not overlooking something obvious.

-Parts missing that I replaced with used/new OEM: Starter, Alternator, Clutch fan, Ignition coil and Igniter, Throttle body, Thermostat & all sensor on thermostat housing, Intake hoses, Circuit opening relay, fuel pump relay, fusible link x2, and fuel pump 6-pin connector ( Clip that connects fuel pump harness to chassis harness; wires were broken and fixed to OEM standard )

-Parts missing that I have NOT replaced: AC compressor, Center diff lock interior switch, Antenna

Prior to purchasing this Land cruiser, I had never owned a Toyota so being a whole new manufacturer I was a little weary to dive into such a big project, but I got the FSM and started chipping away. About a month after I initially purchased, I finally had the car back together to the point of starting and decided to give it a crank and it cranked extremely strong but ultimately no spark.

After some digging on here, I was blessed with all the instances of Jon Held helping fellow 91-92 owners diagnose their pesky no-start issues and with the information I found I was able to rule out everything down to some sort of underlying issue within the Ignition System (I believe).

I found Jon Helds diagnosis sheet and went to work and here is the status currently: I am confident the issue is within the ignition system from two key aspects;

1. I have CEL when key is powered ON, I have A/T light on, I have dome lights, I have working brake lights, and I have charge lamp.
2. Fuel pump works and have fuel at the rail. I was still skeptical so I pulled the fuel pressure regulator and checked and I have fuel at the rail so ultimately I ruled that out.

From this point forward I trouble shot everything in the ignition system from resistance on the distributor, resistance on the ignition coil, tested for 12v on the IC power wire, cleanliness of the distributor cap and rotor, continuity of the wires and high-tension cord, and even checked the CEL and only had one code: 14 and that is ignition signal. Everything checked within FSM specs using the correct meter so ultimately, I thought my igniter was bad as it cannot be tested unless paired against a working unit, so I went ahead and bought a new one and threw it in. I pulled the 15amp fuse from my panel box for approximately 15 minutes to let codes clear and when I threw it back in to attempt to start and still had no spark. The charge lamp stayed on for a few cranks but then shut off. By this time I went ahead and replaced the ignition coil with a new unit and also cleaned all grounding points just to ensure it was not that causing issues and low and behold the charge lamp has stayed on and hasn’t turned off since. (verified that it does indeed turn off as well) with all light indicators working correctly, ECU in ready state, and new ignition components is possible I could have a ECU issue?

Also wanted to add that I believe this vehicle was running and driving at some point as fluids looked good throughout the vehicle, has new tires, and had plates that are still currently registered through the end of this year just seems like somebody had this same issue occurring and it derailed them into letting it go. Being that it was at pick n pull and showed up with missing components I truly cannot say if it did run prior though but with somewhat of a mechanical background I feel my prognosis is close.

I feel I am so close to getting this thing back on the road and cannot wait to hear it fire over!

Thanks in advance for any help provided! Glad to officially be part of the group and hope I can help conquer this with the support of the Ih8mud members!

 

[jonheld]

is possible I could have a ECU issue?

We're not going to know if the ECU is faulty until we can verify that the ECU is getting the information it needs first. You have a CEL, so you're already in good shape.
Since this vehicle is an unknown, the first thing I would do is inspect and reseat all 3 of the ECU connectors and inspect the harness where it passes through the firewall. It is a known pinch point.
This truck has been sitting, so you're also looking for rodent damage to any wiring.

I am also sceptical of the "new" igniter and ignition coil that you installed, as these parts have been out of production for at least the last 15 years.

 

[Old Nick]

Hey everyone!

First and foremost I would like to say thanks to everyone who helped build this awesome community, although I’m a new member I have already found so much great information and looking forward to seeing if I could resolve some pesky issues occurring with my FJ80!

Recently I had the chance to save a 1991 fj80 Land Cruiser from a local pick n pull and ultimately pulled the trigger! Very excited for this project as I have always wanted a Land Cruiser but ultimately was priced out so I am very much looking forward to upgrading and making this become an awesome machine with the support and connections from everyone here! Being a 91' it comes with the formidable 3FE and I seem to have come across some issues getting it to run.

Here is some previous information to help understand what the underlying issues may be because quite frankly this LC was missing a bunch of components and really want to make sure I'm not overlooking something obvious.

-Parts missing that I replaced with used/new OEM: Starter, Alternator, Clutch fan, Ignition coil and Igniter, Throttle body, Thermostat & all sensor on thermostat housing, Intake hoses, Circuit opening relay, fuel pump relay, fusible link x2, and fuel pump 6-pin connector ( Clip that connects fuel pump harness to chassis harness; wires were broken and fixed to OEM standard )

-Parts missing that I have NOT replaced: AC compressor, Center diff lock interior switch, Antenna

Prior to purchasing this Land cruiser, I had never owned a Toyota so being a whole new manufacturer I was a little weary to dive into such a big project, but I got the FSM and started chipping away. About a month after I initially purchased, I finally had the car back together to the point of starting and decided to give it a crank and it cranked extremely strong but ultimately no spark.

After some digging on here, I was blessed with all the instances of Jon Held helping fellow 91-92 owners diagnose their pesky no-start issues and with the information I found I was able to rule out everything down to some sort of underlying issue within the Ignition System (I believe).

I found Jon Helds diagnosis sheet and went to work and here is the status currently: I am confident the issue is within the ignition system from two key aspects;

1. I have CEL when key is powered ON, I have A/T light on, I have dome lights, I have working brake lights, and I have charge lamp.
2. Fuel pump works and have fuel at the rail. I was still skeptical so I pulled the fuel pressure regulator and checked and I have fuel at the rail so ultimately I ruled that out.

From this point forward I trouble shot everything in the ignition system from resistance on the distributor, resistance on the ignition coil, tested for 12v on the IC power wire, cleanliness of the distributor cap and rotor, continuity of the wires and high-tension cord, and even checked the CEL and only had one code: 14 and that is ignition signal. Everything checked within FSM specs using the correct meter so ultimately, I thought my igniter was bad as it cannot be tested unless paired against a working unit, so I went ahead and bought a new one and threw it in. I pulled the 15amp fuse from my panel box for approximately 15 minutes to let codes clear and when I threw it back in to attempt to start and still had no spark. The charge lamp stayed on for a few cranks but then shut off. By this time I went ahead and replaced the ignition coil with a new unit and also cleaned all grounding points just to ensure it was not that causing issues and low and behold the charge lamp has stayed on and hasn’t turned off since. (verified that it does indeed turn off as well) with all light indicators working correctly, ECU in ready state, and new ignition components is possible I could have a ECU issue?

Also wanted to add that I believe this vehicle was running and driving at some point as fluids looked good throughout the vehicle, has new tires, and had plates that are still currently registered through the end of this year just seems like somebody had this same issue occurring and it derailed them into letting it go. Being that it was at pick n pull and showed up with missing components I truly cannot say if it did run prior though but with somewhat of a mechanical background I feel my prognosis is close.

I feel I am so close to getting this thing back on the road and cannot wait to hear it fire over!

Thanks in advance for any help provided! Glad to officially be part of the group and hope I can help conquer this with the support of the Ih8mud members!

I'm still relatively new to the 80 series. But, learning a lot as I've been building one for my wife ('94 factory triple locked).

Did the '91 80s come with the factory immobilizer/security system?

If it fails (or if it is disconnected), the engine will crank all dang day, but it won't fire up.

Just a thought.

 

[jonheld]

I'm still relatively new to the 80 series. But, learning a lot as I've been building one for my wife ('94 factory triple locked).

Did the '91 80s come with the factory immobilizer/security system?

If it fails (or if it is disconnected), the engine will crank all dang day, but it won't fire up.

Just a thought.

Not available in 1991. The dealer installed or port installed alarm systems on later 80s like the RS3000 won't allow the starter to crank as they interrupt the starter logic circuit.

 

[Youngypsy]

We're not going to know if the ECU is faulty until we can verify that the ECU is getting the information it needs first. You have a CEL, so you're already in good shape.
Since this vehicle is an unknown, the first thing I would do is inspect and reseat all 3 of the ECU connectors and inspect the harness where it passes through the firewall. It is a known pinch point.
This truck has been sitting, so you're also looking for rodent damage to any wiring.

I am also sceptical of the "new" igniter and ignition coil that you installed, as these parts have been out of production for at least the last 15 years.

Thanks for following up Jon! Really do appreciate your time on this!

Finally had time to tear into this LC some more and definitely have promising updates as far as finding issues!

So after inspection of the ECU and connectors everything seems in good working fashion, even took my boroscope and inspected the harness where it enters the firewall and all looks very good with no signs of damage or unexpected wear. I had only ever seen one other person with an ECU issue so I thought it may have been a little extraordinary.

I completely agree with your skepticism on the ignition coil and igniter not being new OEM, I actually bought two other igniters and ignition coils that are used Denso OEM parts but to reassure they weren’t bad I had bought remanned OEM units just so I could check that off the list of what’s good (atleast for now)

After that I decided to do a full undercarriage inspection of wiring and I believe I may have found my issue. Once I got to the transfer case I noticed a lot of debris tucked up between the transfer case and trans tunnel and low and behold a damn rats nest..

After cleaning out all the crap and debris I noticed the nest was lying right next to a wiring harness that runs atop the transfer case so I took my boroscope and inspected the harness. Strangely enough the loom is in tact but I have a feeling those little bastards definitely have chewed into it because once I cleaned everything I decided to turn the key and see what the cluster looked like. Everything was as normal until I started moving transfer case shifter…

After shifting the transfer case gear selector I noticed my center diff lock light came on, my A/T park light came on, and my charge lamp came back on but after a few cycles of the key and just moving the shifter back and forth the charge lamp is now off again but this is where things get interesting. I thought to myself maybe I’ll just take another look into the dash except behind the radio this time and I found yet another nest and exposed wiring from the radio harness and antenna. All I did was wiggle the harness and my charge lamp came back on so I’m going to more than likely pull the dash and dig deeper to find all the damaged wiring.

Attached are some photos, the different lights and exposed wiring in the dash (looks like antenna and stereo harness)

Going to dive into the FSM and see what exact harness that is and what’s going to entail on intial replacement! Feeling confident this may be my ultimate issues but I’ll keep moving forward


If anyone knows what this replacement harness is or where I could find a used section to ultimately replace that I would greatly appreciate that as there isn’t much for used parts near me.

 

[jonheld]

Finally had time to tear into this LC some more and definitely have promising updates as far as finding issues!

Couple of thoughts before coffee.
Nothing on the transfer case will effect ignition.
The AT/P lamp should only illuminate when the transmission is in PARK and the transfer case is in neutral. No effect on ignition.
The CDL lamp should only illuminate when the CDL is locked. The CDL should lock by pushing the dash switch or shifting the transfer case into low range. No effect on ignition.
The oil pressure sender/gauge is simply a variable resistance to ground. No effect on ignition.
The intermittent CHARGE warning lamp could be as simple as a loose fuse connection in the fusebox by the driver's left knee (the ECU needs to see the signal from the 7.5 amp IGN fuse and this fuse powers the CHARGE lamp) or in the relay box on the left fender or a loose connection on the alternator. Or possibly more rodent damage.

 

[Marco Lau]

check NSS.

 

[jonheld]

check NSS.

If the NSS was an issue, the starter wouldn't crank.

 

[Youngypsy]

Couple of thoughts before coffee.
Nothing on the transfer case will effect ignition.
The AT/P lamp should only illuminate when the transmission is in PARK and the transfer case is in neutral. No effect on ignition.
The CDL lamp should only illuminate when the CDL is locked. The CDL should lock by pushing the dash switch or shifting the transfer case into low range. No effect on ignition.
The oil pressure sender/gauge is simply a variable resistance to ground. No effect on ignition.
The intermittent CHARGE warning lamp could be as simple as a loose fuse connection in the fusebox by the driver's left knee (the ECU needs to see the signal from the 7.5 amp IGN fuse and this fuse powers the CHARGE lamp) or in the relay box on the left fender or a loose connection on the alternator. Or possibly more rodent damage.

after a second look the transmission harness it seems to be good and no shorts through the harness, the outer loom is pretty beat up but no glaring issues with the harness itslef. I’ve yet to check continuity but figured if I cannot find answers I’ll return to it later. The lights not being on prior to first power on was particularly odd but with all lights working as they should I’m going to shift my focus to the glaring issues within the dash.

CDL light is on primarily because I don’t have the physical switch, ordered one so it should be here soon! (P.O. Tried to part out the vehicle so some components were missing) if the CDL is engaged would that prevent start for any reason??

What’s odd about the Oil pressure gauge is I have not even messed with that particular unit whatsoever (physical unit or guage) The only wiring I have messed with that has initiated the intermittent lights is the harness in the dash that connects the radio and the antenna. No particular handling of the wiring kind of just moving it around. Although I understand it’s not tied into ignition could a short or bad ground comprise electrical current to allow these systems to function correctly?

I did replace the fuse for the ignition on the fuse block ( wasn’t blown, I just replaced for the sake of crossing potential issues off my list) and even tested continuity to FSM specs on the ignition switch and that all checked out fine but for the sake of troubleshooting I will double check the physical connection on the back of the fuse block in the cab and on the fuse block in the engine bay to assure the relay & fuse is getting proper power. I’ll follow up after these!

 

[jonheld]

after a second look the transmission harness it seems to be good and no shorts through the harness, the outer loom is pretty beat up but no glaring issues with the harness itslef. I’ve yet to check continuity but figured if I cannot find answers I’ll return to it later. The lights not being on prior to first power on was particularly odd but with all lights working as they should I’m going to shift my focus to the glaring issues within the dash.

CDL light is on primarily because I don’t have the physical switch, ordered one so it should be here soon! (P.O. Tried to part out the vehicle so some components were missing) if the CDL is engaged would that prevent start for any reason??

What’s odd about the Oil pressure gauge is I have not even messed with that particular unit whatsoever (physical unit or guage) The only wiring I have messed with that has initiated the intermittent lights is the harness in the dash that connects the radio and the antenna. No particular handling of the wiring kind of just moving it around. Although I understand it’s not tied into ignition could a short or bad ground comprise electrical current to allow these systems to function correctly?

I did replace the fuse for the ignition on the fuse block ( wasn’t blown, I just replaced for the sake of crossing potential issues off my list) and even tested continuity to FSM specs on the ignition switch and that all checked out fine but for the sake of troubleshooting I will double check the physical connection on the back of the fuse block in the cab and on the fuse block in the engine bay to assure the relay & fuse is getting proper power. I’ll follow up after these!

Nothing related to the transfer case will have any effect on ignition.
If the oil pressure sender/gauge had a short, the GAUGE fuse would pop. If there was a faulty ground, the gauge wouldn't work.

What I would be checking is proper signals to and from the ECU that are spark related. The rest of this stuff is fluff if the engine won't run.

With the key in the ON position:
Are you getting +12 to ECU connector E6 pin 6?
Are you getting +12 to pin 3 of the igniter?
Are you getting +12 to pin 1 of the ignition coil?
The igniter is grounded through the mounting bracket. It MUST BE MOUNTED TO THE FENDER (ground) for the igniter to work.

Have you checked the pick up coils in the distributor for proper resistance values according to the FSM?
Have you verified continuity between the distributor pickup coils and the ECU?
Have you verified continuity between the ECU and igniter?
Have you verified continuity between the igniter and ignition coil?

 

[Youngypsy]

Alright finally back with some updates! Weather and work has delayed me a bit but here’s what I’ve got now:

I have 12+ to connector E6 pin 6
I have 12+ to pin 3 on the igniter connector
I have 12+ to pin 1 on the ignition coil

The ignition coil/ igniter bracket is indeed grounded and even removed and cleaned all point of contact including the ground wire that connects to the block just to ensure cleanliness

Resistance on the IGN coil reads .50 from + & - terminals
Resistance on the distributor reads 280 on G pickup coil; 440 on NE pickup coil

Figured I would check the ignition switch as well and it has continuity on every setting of the lock tumbler (BE section of FSM)

Going to pick up a longer wire for my multimeter to test continuity from ECU to all points of the ignition system. Or would you recommend pulling the harness through the firewall?

Also one last thing I wanted to note was my Charge lamp relay is good, and the 7.5a fuse is good. I pulled the fuse block in the cab to inspect connections from the back and everything was nice and tight, and same for the fuse box in the engine bay so I don’t think it’s loose fuse or connection. Really starting to feel like there is a bad ground or short as the light was intermittent and even came on with the distributor completely unplugged. I thought maybe it was my fusible link but I have a brand new spare and still same intermittence regardless of which one is on.

Believe I noted it earlier but for what it’s worth the only code is 14: ignition signal

Also TGIF! Ready to have the full weekend to tear into this some more!

 

[jonheld]

Resistance on the IGN coil reads .50 from + & - terminals

That's the primary coil. Did you measure the secondary according to the FSM? Should be 10.2K – 13.8K ohms.

Resistance on the distributor reads 280 on G pickup coil; 440 on NE pickup coil

Those readings are higher than expected and should be closer in resistance to each other. Both coils should read closer to 200 ohms.

Going to pick up a longer wire for my multimeter to test continuity from ECU to all points of the ignition system. Or would you recommend pulling the harness through the firewall?

I wouldn't disturb a 30+ year old harness.

Really starting to feel like there is a bad ground or short as the light was intermittent and even came on with the distributor completely unplugged.

Charge lamp/relay has nothing to do with the distributor. It is alternator related.

Believe I noted it earlier but for what it’s worth the only code is 14: ignition signal

Code 14 is telling you that the ECU is not seeing the IGF signal from the igniter.
Ignition pulses are generated from the pickup coils in the distributor and fed to the ECU to adjust ignition timing based on mapped parameters.
The ECU then feeds the igniter IGT pulses.
The igniter then feeds pulses to the primary of the ignition coil which then feeds spark from the secondary to the distributor rotor.

You need to verify that the pickup coils in the distributor are making it to the ECU.
You need to verify that the ECU is feeding pulses to the igniter.
You need to verify that the igniter is feeding pulses back to the ECU.
You need to verify that the igniter is sending pulses to the primary of the ignition coil.

 

[Youngypsy]

Finally back with some updates!

Checked secondary coil on the ignition coil read 12.46 so that unit is still within FSM specs

Tested continuity on the wiring from the distributor to the ECU (thanks to your 3FE diag sheet) and all connections are solid to the ECU! (Connector E-4 pin 4,17,18) So with everything checking out I decided to double check my distributor since my readings were a bit skewed last time

Distributor resistance:
G-G: 235
NE-G: 241

Still within FSM specs

I have not tested live current pulses yet as I’m still trying to figure out how I’m going to do that as a sole individual lol going to get the correct pointers that will get in from the back of the connectors and see if I can get some buddies to assist. Would the vehicle need to be cranked to see pulses through a meter or just key at ON position?

Bit of a side note but when pulling the ECU down I noticed it had been covered in something at some point (old stains just not sure if water or something else) given with everything reading correctly I figured I’d at least share to see what your thoughts are, even opening the case it looks okay maybe one small portion of the board had gotten something but the other side looks flawless. At this point I’m not opposed to pulling the dash off but if I can avoid it I would like to

 

[Youngypsy]

That's the primary coil. Did you measure the secondary according to the FSM? Should be 10.2K – 13.8K ohms.

Apologies Jon forgot to reply to your comment when posting!

 

[Youngypsy]

Ok so big update!

My LC fired up and ran for about 30-40 seconds! I crank to start and it fires on but only runs for a few seconds

Should note fuel is old and plugs are looking pretty dark so I am going to replace those both and come back with an update

 

[Youngypsy]

So thought I’d come back to this thread to as I found my issue that ultimately wasn’t anything I was expecting

So thanks to the help of Jon I went through everything possible in terms of troubleshooting for my no spark issue and ended up discovering my issue at the point of ECU doing continuity testing of the wiring. After testing continuity I was completely stumped, all points of ignition were solid so i decided something had to be up and keep digging.

After searching through MUD I actually found a thread from a member who had the exact same symptoms and issues and even had replaced a lot of the components that were changed in mine. His thread simply ended on him discovering that the connection to the ECU was faulty causing the truck to randomly die so I figured what the hell I’ll see if I have a similar issue. When I removed the ECU I cleaned the connectors and reconnected and the truck started for about a minute then sputtered out and died so I had my buddy lightly apply pressure to back of the connectors and low and behold it stayed on and kept running!

I thought to myself how strange it was that I have the the same exact issue as this member, so reluctantly I tried to reach out but had no reply. So I checked out there posts and it turns out we are in the same exact town and he ended up getting rid of his LC 2 months before i ultimately purchased.

Unfortunately the PO has chosen to not reply which sucks and for respect I will not tag but if you look up the same non-spark issue you can ultimately piece it together.

The truck starts and drives when the ECU is not in the factory location (resting on the bottom edge of the dash where the glovebox connects, NOT hanging) when I connect and put back in the factory location it won’t start. I am still not 100% what the underlying issue is but I am going to test each connectors pins as I believe maybe it’s not getting full contact to the ECU’s or is still a chance the ECU is no good or damaged.

 

[ColoradoBoy]

So thought I’d come back to this thread to as I found my issue that ultimately wasn’t anything I was expecting

So thanks to the help of Jon I went through everything possible in terms of troubleshooting for my no spark issue and ended up discovering my issue at the point of ECU doing continuity testing of the wiring. After testing continuity I was completely stumped, all points of ignition were solid so i decided something had to be up and keep digging.

After searching through MUD I actually found a thread from a member who had the exact same symptoms and issues and even had replaced a lot of the components that were changed in mine. His thread simply ended on him discovering that the connection to the ECU was faulty causing the truck to randomly die so I figured what the hell I’ll see if I have a similar issue. When I removed the ECU I cleaned the connectors and reconnected and the truck started for about a minute then sputtered out and died so I had my buddy lightly apply pressure to back of the connectors and low and behold it stayed on and kept running!

I thought to myself how strange it was that I have the the same exact issue as this member, so reluctantly I tried to reach out but had no reply. So I checked out there posts and it turns out we are in the same exact town and he ended up getting rid of his LC 2 months before i ultimately purchased.

Unfortunately the PO has chosen to not reply which sucks and for respect I will not tag but if you look up the same non-spark issue you can ultimately piece it together.

The truck starts and drives when the ECU is not in the factory location (resting on the bottom edge of the dash where the glovebox connects, NOT hanging) when I connect and put back in the factory location it won’t start. I am still not 100% what the underlying issue is but I am going to test each connectors pins as I believe maybe it’s not getting full contact to the ECU’s or is still a chance the ECU is no good or damaged.

Nice job on troubleshooting! Keep up the good work, & hope you have it sorted soon.
Cheers!