Intermittent shut off (1 Viewer)

Joined
Jun 13, 2022
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Flagstaff, AZ
Hello, I'm looking for help from the community. I'm fairly knowledgeable on cars, but this is my first off-road vehicle. Thank you in advance.
- 1995 FJ80, 175,000 mi or so
- Engine starts right up, but after about 10 minutes of driving on rough roads, it starts to lose power
- Once power loss begins, the engine shuts off within a minute or two; no amount of throttle can keep it running
- I've checked all fuses and have swapped the EFI relay with two different ones to check with no luck
- All vacuum lines, plugs/connectors, ground wires are intact/connected; no obvious signs in engine bay
- Engine cranks over strong, but won't start
- Very curious that it only seems to die when I drive on rough roads

Do the ECUs go bad on these? I had that happen on a 3000GT from leaking capacitors which corroded the circuit board.

If there's another thread on this, I would appreciate the assist.

- George
 

Road Apple

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Nov 28, 2011
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1,241
Location
Santa Cruz, CA
Here’s a bunch a notes I’ve taken on the issue. A new fusible link would be my first guess.


So the mechanic checked pressure, but did he check volumetric flow?
The fusible links & everything else are now 25-ish yrs old, so UV/ozone damage is real & possible too.

I’d pull the fuse / flip the breaker of whatever hodge-podge the mechanic did while you test all.

-Did the fuel sock get looked at like was suggested?

———————————

In order of operation I’d follow:

Get out the FSM & check your injectors flow & pattern.

Check the holy heck out of the underside of the underhood electrics - see if the hot tap to the EFI relay is discolored.

Buy new fusible links & install - keep the others as spares if they do nothing to your problem.

Swap your fuel filter on the firewall - I know, but your issue sounds exactly like a filter that lets enough fuel past under moderate throttle, but starves at WOT/draw.

If that all checks out & the injectors look awesome & the relay board isn’t showing an issue, and the fusible links aren’t to blame - then go ahead & evil eye / swap fuel pump.
Everything you touch wire-wise, shove dielectric grease at like it’s bedroom lube.

I went in order of cost, but if money is of no concern then go to a better mechanic (IDK who’s local & awesome to you inn Cali) - toss ‘em the keys & wait.



Demand real ‘Yota parts, I’m not rich but I generally never need repeat a job w/ real parts
The wiring to and from the ignition switch is 20 years old, degraded and needs an upgrade.
I solved the issue. Switched a bunch of stuff. Ultimately, the thing that fixed it was removing the original alarm system.”
 
Joined
Feb 23, 2011
Messages
51
Does your dash totally go out when this happens? When I had a short impacting my ECM, I'd hit a bump, and everything would die. Engine stalled, dash went totally dark, no lights. It was instant stall and death. The way you describe it, it almost sounds like you are losing fuel pressure.
 
Joined
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Messages
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Oregon
Do the ECUs go bad on these? I had that happen on a 3000GT from leaking capacitors which corroded the circuit board.

I've heard of that on this era of Japanese vehicle, but I don't think I've yet seen it on a Land Cruiser, for whatever reason.

I'd check the wire harness near the EGR valve and where it passes through the firewall on the passenger side. Not cranking afterwards is weird, but the rough roads make me think of the harness shorting.
 

LandLocked93

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Jun 11, 2018
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Location
Colorado
I'd check the wire harness near the EGR valve and where it passes through the firewall on the passenger side. Not cranking afterwards is weird, but the rough roads make me think of the harness shorting.
+1
 
Joined
Mar 11, 2022
Messages
139
Location
California
Without an actual diagnosis, everyone is going to be throwing darts at any number of causes. You need a spark checker, a noid light, and a fuel pressure gauge. When the engine dies, check for spark, fuel injector pulse, and fuel pressure. Depending on which one(s) are absent, then you can have a better idea where to go.
 
Joined
Nov 9, 2012
Messages
13,240
Location
Olathe, KS, USA
Hello, I'm looking for help from the community. I'm fairly knowledgeable on cars, but this is my first off-road vehicle. Thank you in advance.
- 1995 FJ80, 175,000 mi or so
- Engine starts right up, but after about 10 minutes of driving on rough roads, it starts to lose power
- Once power loss begins, the engine shuts off within a minute or two; no amount of throttle can keep it running
- I've checked all fuses and have swapped the EFI relay with two different ones to check with no luck
- All vacuum lines, plugs/connectors, ground wires are intact/connected; no obvious signs in engine bay
- Engine cranks over strong, but won't start
- Very curious that it only seems to die when I drive on rough roads

Do the ECUs go bad on these? I had that happen on a 3000GT from leaking capacitors which corroded the circuit board.

If there's another thread on this, I would appreciate the assist.

- George
Everything you described points to a fuel system issue. Start at the pump and work forward.

Fuel pump sock
Loose pump clamps
Fuel filter under intake
Change gas cap to new Toyota
Charcoal canister and check valve
 
Joined
Feb 23, 2011
Messages
51
You can also probably rent a fuel pressure tester from an auto parts store if you don’t have one. Connecting it is a little bit of a hassle (you need to remove the banjo bolt from the back of the fuel rail and use an adapter - there is no pre-existing test port) but it will instantly confirm if you have a fuel pressure issue.
 
Joined
Apr 14, 2016
Messages
2,281
Location
Oregon
Does OBD2 on 80s report fuel pressure?

I borrowed an AutoZone fuel pressure test kit and it was a PITA. The banjo is all the way at the back of the fuel rail, the wiring harness gets in the way making it difficult to make sure you're not cross-threading, and technically you should replace the copper washers afterwards.
 

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