1991 FJ80 starts and then immediately dies at seemingly random times

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evicta

evicta

Joined
Sep 17, 2023
Threads
7
Messages
13
Location
Carson City, NV
I’ve got a 1991 FJ80 which I’ve had for a few months and know very little history about.

I would say that I have done most of the general maintenance or suggestions that I have seen throughout this forum/FSM & tried to use OEM Toyota parts as much as I could. Spark plugs, wires, distributor, rotor, ignition coil, vacuum lines, fuel filter, fuel pump sock, fusible links, EFI relay and so on are all OEM. The FPR and the damper were also replaced but these parts came from RockAuto.

Recently I am facing an issue where if I start the FJ80 in the middle of the day, it cranks and starts but it immediately dies. I see the tachometer climb in RPM and then it drops to 0 over a period of a second. I am getting the CEL light and I have also tried jumpering the diagnostic port so that the fuel pump is constantly running. I am still getting the same problem where it just dies. However, if I start it in the morning, it stays running and drives great. I find this pretty odd.

One thing to note is that before this starting issue occurred, I noticed that my battery voltage would spike over 16.0V while the FJ80 is running. I let the FJ80 sit for about three weeks while I was out of town. I just replaced the alternator with a remanufactured one from Toyota. I am now at a stable 14.4V but I am still experiencing the starting & dying issue. Any ideas?
 
evicta said:
I’ve got a 1991 FJ80 which I’ve had for a few months and know very little history about.

I would say that I have done most of the general maintenance or suggestions that I have seen throughout this forum/FSM & tried to use OEM Toyota parts as much as I could. Spark plugs, wires, distributor, rotor, ignition coil, vacuum lines, fuel filter, fuel pump sock, fusible links, EFI relay and so on are all OEM. The FPR and the damper were also replaced but these parts came from RockAuto.

Recently I am facing an issue where if I start the FJ80 in the middle of the day, it cranks and starts but it immediately dies. I see the tachometer climb in RPM and then it drops to 0 over a period of a second. I am getting the CEL light and I have also tried jumpering the diagnostic port so that the fuel pump is constantly running. I am still getting the same problem where it just dies. However, if I start it in the morning, it stays running and drives great. I find this pretty odd.

One thing to note is that before this starting issue occurred, I noticed that my battery voltage would spike over 16.0V while the FJ80 is running. I let the FJ80 sit for about three weeks while I was out of town. I just replaced the alternator with a remanufactured one from Toyota. I am now at a stable 14.4V but I am still experiencing the starting & dying issue. Any ideas?
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When you're experiencing this issue, try loosening the banjo bolt on the cold start injector and make sure you have fuel spraying out when you're cranking the motor or by jumping the pins on the diagnostic port to get the fuel pump to run.
This could be a stuck check valve in the fuel pump that releases itself after it's been sitting for a while and the pressure alleviates.
This is pretty common after having a failed fuel pressure regulator.
 
jonheld said:
When you're experiencing this issue, try loosening the banjo bolt on the cold start injector and make sure you have fuel spraying out when you're cranking the motor or by jumping the pins on the diagnostic port to get the fuel pump to run.
This could be a stuck check valve in the fuel pump that releases itself after it's been sitting for a while and the pressure alleviates.
This is pretty common after having a failed fuel pressure regulator.
Click to expand...
I've been traveling for work lately so I haven't been able to put as much time troubleshooting.

The issue seems pretty consistent. Starts and drives great first thing in the morning. Then when the sun starts coming out, the LC cranks, starts up, tachometer goes a few hairs over 1000 rpm, and then dies out after running for a second. I can come back to the LC later in the evening and it'll start normally again.

I changed out the fuel pump with some made in Japan part from CruiserTeq. Previously there was a Delphi fuel pump. I slightly misspoke in my original post. I had only done the ignition coil but now I bought an igniter from eBay and installed it. Still having the same issues.

I cracked the banjo bolt on the cold start injector and observed a good stream of fuel coming out. Would it be helpful to monitor fuel pressure from the cold start injector? I have an 1/8" NPT fuel pressure gauge but I'm not sure how to adapt it to the banjo bolt.

I have a theory that changing out the charcoal canister might be causing this. I wasn't having any starting issues previously but I changed out the OEM charcoal canister with one recommended on here to troubleshoot my pressurized gas tank. Then the following days is when I started observing the mysterious starting issue. Could the charcoal canister be the issue or is it an entirely unrelated component?
 
evicta said:
I have a theory that changing out the charcoal canister might be causing this
Click to expand...
Is it plumbed in correctly?
Is there excessive pressure in the tank?
Is the tank under negative pressure?

"I cracked the banjo bolt on the cold start injector and observed a good stream of fuel coming out."
Was this when you were having the hot crank no start issue?

This sounds like an AFM/fuel pump logic issue. The circuit opening relay that fires the fuel pump has 2 coils. The primary coil is fired from the starter circuit. The secondary is fired from the flap in the AFM when the motor starts to suck air. If it fires briefly then dies, it could be related to the AFM.
The next time you have the issue, jump terminals 1-8 (FP-B+) in the diagnostic connector. This bypasses all fuel pump logic.
 
jonheld said:
Is it plumbed in correctly?
Is there excessive pressure in the tank?
Is the tank under negative pressure?

"I cracked the banjo bolt on the cold start injector and observed a good stream of fuel coming out."
Was this when you were having the hot crank no start issue?

This sounds like an AFM/fuel pump logic issue. The circuit opening relay that fires the fuel pump has 2 coils. The primary coil is fired from the starter circuit. The secondary is fired from the flap in the AFM when the motor starts to suck air. If it fires briefly then dies, it could be related to the AFM.
The next time you have the issue, jump terminals 1-8 (FP-B+) in the diagnostic connector. This bypasses all fuel pump logic.
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99% sure it is plumbed correctly. "Tank" is the line going along the frame and "Purge" is the line going to the VCV? When I open the gas cap, there is no form of differential pressure anymore. I've also tried starting it with the gas cap on or off.

Banjo bolt was opened when I was having the start issue.

I am able to measure +12V DC coming out of B+ with the key in the On position. Jumpering FP- and B+ starts the fuel pump and I can hear it whirring. Then trying to start it causes it to fire up and then die shortly. Similar issue.

Worked more on the landcruiser early this morning. Installed brand new OEM air intake hoses, an AFM from a Lexus, and a PCV valve (this must have slipped by me otherwise I would have done it earlier). Wrapped up by 8 AM and took it for a drive around town and it drove great. Let it sit for a few hours, weather's warming up, and now at 11 AM it goes back to the start up and die issue.

Is there some issue related to the weather or having it sit for a while? When I drove it around this morning, the engine warmed up to operating temperature and it all looked happy.
 
I would check spark and fuel pressure at the no start situation. Here's a post I did a decade ago that explains how to check fuel pressure. Truck now has 440K and this specific issue has not happened since then.

forum.ih8mud.com

Intermittent Starting Problem Solved

Vehicle 92 3FE with 350K. About a year ago we noticed it would sometimes take 3 swings of the key to get the motor started. Lately it has even taken as many as 7 attempts. In the last 30 days it has failed to start completely 3 times (about once/week). After an hour or so, it would always...
forum.ih8mud.com forum.ih8mud.com
 
Haven't made more progress but I have some more things to report.

I installed a pressure gauge on the cold start injector. It's always getting 40 psi whenever I try to start it whether it's the starting issue or not. I have not had a chance to check for spark yet. I dropped off the land cruiser at a local mechanic since I needed to go through surgery this week.

I did pull codes from the diagnostic port which was code 14. There wasn't much information on these forums but reading up on Code 14 on the Toyota Pickup/4Runner forums seems to give a similar problem to mine. It's the loss of the IGF signal and apparently it will kill the injectors if this occur causing the start & die issue.

Are there any troubleshooting steps for the IGF signal and maybe any relation to the weather warming up? I've replac
 
evicta said:
Haven't made more progress but I have some more things to report.

I installed a pressure gauge on the cold start injector. It's always getting 40 psi whenever I try to start it whether it's the starting issue or not. I have not had a chance to check for spark yet. I dropped off the land cruiser at a local mechanic since I needed to go through surgery this week.

I did pull codes from the diagnostic port which was code 14. There wasn't much information on these forums but reading up on Code 14 on the Toyota Pickup/4Runner forums seems to give a similar problem to mine. It's the loss of the IGF signal and apparently it will kill the injectors if this occur causing the start & die issue.

Are there any troubleshooting steps for the IGF signal and maybe any relation to the weather warming up? I've replac
Click to expand...
Fuel pressure is within spec.
The IGF signal comes from the igniter.
Igniters do fail over time. They typically become intermittent before complete failure. AFAIK, there is no FSM test for the igniter.
 
Since you've had the fuel pump in and out, here's another thing to check. The connector on top of the tank can be flaky. I recently diagnosed a fuel pump failure, so R&Red it with an OEM one. This ran great for about 3 hours. Then it started chugging and died. I R&Red the fuel filter under the intake manifold, a major PITA, Still no start. Decided to start over on the trouble shooting list.

The first thing that came up was the fuel pump. WTF?? Further checking showed the problem was the connector at the tank. Although I was careful to get it seated together, I remembered the lack of the usual click when I reassembled it. Inspection showed some of the contacts were less that optimal, so I cleaned them up, then gave them a light spray of CRC 2-26. I reassembled still with no click, but it fired up and hasn't shown any signs of further problems.

As these trucks age, I think such connection issues are going to to appear more frequently,.
 
jonheld said:
Fuel pressure is within spec.
The IGF signal comes from the igniter.
Igniters do fail over time. They typically become intermittent before complete failure. AFAIK, there is no FSM test for the igniter.
Click to expand...
I replaced the igniter with a used eBay part 89621-12010 a few weeks ago. However, the one that originally came with my 1991 Land Cruiser was the 89621-30010. A quick search mentioned that the 12010 was compatible. Did I screw the pooch by using a different part number for the igniter? I'm experiencing the start and die issue with either one though.

I did pick up my Land Cruiser from the local mechanic today. They verified there was spark and tightened the belts but I didn't see much progress past that. Last Friday was a warmer day and they experienced the start & die issue and honestly it puzzled them too. Luckily today was a colder overcast day so I just drove it back home.

Thanks for the suggestion above. I'll try going through all the connectors and wiring. Is it possible the ECU might be faulty? It's the one thing I haven't checked at all. I seem to be experiencing the start and die issue when the cab starts to warm up. My running theory is the heat is affecting the ECU.
 
FYI, the latest on my issues. Got through the Culvers drive up window Saturday and was at the front of the Wait line when the LX gave a familiar chug and died. At least I soon had a shrimp basket and cold root beer to wait on the tow home. :p :beer:

I now had the job at getting to the fuel pump simplified, because I found pulling the water tank was all that was needed to access the top of the fuel tank. Going by the FSM I got several mixed signals about the fuel pump, so finally decided to pull it again. It ran fine on it's own, don't you know? But the path from the connector down to it was definitely having issues. I finally found this...
IMG_6408 2.webp

IMG_6408 2.webp

That's the positive power lead to the fuel pump. It's a rivet so you can't take it apart. I bathed it in vinegar and cleaned it up, while rotating it in the plastic insulation insert. Started right up and has been OK since, but that's only 2 days.
 
evicta said:
Is it possible the ECU might be faulty? It's the one thing I haven't checked at all. I seem to be experiencing the start and die issue when the cab starts to warm up. My running theory is the heat is affecting the ECU.
Click to expand...
Although it is a possibility, it is very unlikely to be the ECU.
I would certainly reseat the 3 connectors and make certain there is no corrosion.
Look for abrasions on the ECU harness that passes through the firewall.
I would also look very carefully at the inside of the distributor and the 2 pickup coils. They have been known to corrode if the breathers are plugged or hooked up incorrectly.

Again, during the no start condition, have you verified spark and fuel?
 
jonheld said:
Although it is a possibility, it is very unlikely to be the ECU.
I would certainly reseat the 3 connectors and make certain there is no corrosion.
Look for abrasions on the ECU harness that passes through the firewall.
I would also look very carefully at the inside of the distributor and the 2 pickup coils. They have been known to corrode if the breathers are plugged or hooked up incorrectly.

Again, during the no start condition, have you verified spark and fuel?
Click to expand...
Inside the distributor looked clean and the pickup coil resistances were within the FSM specs.

Unfortunately this entire week the weather has been nice, cloudy, and a little rainy so the landcruiser has been starting up. I can confirm that there is fuel during the no start condition from a prior test but I have not had a chance to check for spark.

I had the landcruiser started and idling last night. Started pulling and shifting wires around in the engine bay. Everything checked out and I didn't experience any odd behaviors. I got to the ECU, poked one of the connectors, and the landcruiser immediately died out in a similar fashion to what I've been having issues with. You could lightly touch the connector with your pinky finger and the engine would react poorly. I am not sure if it is the connector itself or the slight tension on the wires causing it to die out. It was getting late at night and I decided to call it a night. I'll pick this up after the Memorial Day weekend but I wanted to report my findings.
 
evicta said:
I got to the ECU, poked one of the connectors, and the landcruiser immediately died out in a similar fashion to what I've been having issues with. You could lightly touch the connector with your pinky finger and the engine would react poorly.
Click to expand...
Well it looks like you have identified the issue, because that is certainly not normal.
I would carefully inspect the connector in question and start with a simple reseat. If there are no abnormalities with the connector or associated wires, it's possible that a pin has broken loose on the PCB inside the ECU. You can remove the cover and carefully inspect.
 
evicta said:
Inside the distributor looked clean and the pickup coil resistances were within the FSM specs.
Click to expand...
Hey Evicta I noticed your location and I have the strangest feeling that I may have inherited this FJ80 as I also reside in Carson City.

Was your 91’ two tone with beige and cedar brown?? It’s my profile picture!

No joke I’m having the same issue and feel like this might be your old FJ lol
 
Youngypsy said:
Hey Evicta I noticed your location and I have the strangest feeling that I may have inherited this FJ80 as I also reside in Carson City.

Was your 91’ two tone with beige and cedar brown?? It’s my profile picture!

No joke I’m having the same issue and feel like this might be your old FJ lol
Click to expand...
Were you able to diagnose this issue? I am currently experience the same issue.
 
Dexter said:
Were you able to diagnose this issue? I am currently experience the same issue.
Click to expand...
Youngypsy

Thread '91’ FJ80 3FE won’t start (No Spark)'

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...
  • Like

Here's my thread on this problem; lots of good info and step by step incase your issue isn't as obscure as mine!
 
Youngypsy said:
Youngypsy

Thread '91’ FJ80 3FE won’t start (No Spark)'

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...
  • Like

Here's my thread on this problem; lots of good info and step by step incase your issue isn't as obscure as mine!
Click to expand...
Thank you for responding! After several months, I stumbled upon the issue this morning. I had a faulty wiring on the MAF connector.
 
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