Need help with no-power 1991 3FE Land Cruiser (1 Viewer)

[jonheld]

Strangely enough the plug has soot/oil blackness on it but I just recently changed them. Hopefully something is just wrong with the injector wiring but I’m not super hopeful.

Possibly clogged/faulty injector.
3FE fires injectors in 2 groups of 3. All injectors get a +12 on pin2 (black/green stripe) and are pulsed to ground on pin 1 by the ECU to energize the coils. White/light blue stripe for injectors 1-3 and solid yellow for injectors 4-6. Connector 90980−10720. Pins 82998-12270.

 

[CruiserDM]

Possibly clogged/faulty injector.
3FE fires injectors in 2 groups of 3. All injectors get a +12 on pin2 (black/green stripe) and are pulsed to ground on pin 1 by the ECU to energize the coils. White/light blue stripe for injectors 1-3 and solid yellow for injectors 4-6. Connector 90980−10720. Pins 82998-12270.

Will definitely tap that one with the multimeter tomorrow too. Just had them all sent out to be cleaned while the intake was off and spray tests looked good on all of them. Hoping for bad harness or connector. Thank you for the info

 

[CruiserDM]

Possibly clogged/faulty injector.
3FE fires injectors in 2 groups of 3. All injectors get a +12 on pin2 (black/green stripe) and are pulsed to ground on pin 1 by the ECU to energize the coils. White/light blue stripe for injectors 1-3 and solid yellow for injectors 4-6. Connector 90980−10720. Pins 82998-12270.

Compression test results:
#1 176psi
#2 150psi
#3 140psi
#4 150psi
#5 35psi
#6 36psi

Cylinder 5 still seems to be running though, noticeable change when spark plug wire is pulled while the engine is running. 6 seems to be completely dead.

 

[ozarkmud]

Ouch!

Did you make any typos there? 35PSI and 36PSI?

Curious what's causing this. I wonder if the #5 value is much higher if you add some oil to it during testing.

 

[CruiserDM]

Ouch!

Did you make any typos there? 35PSI and 36PSI?

Curious what's causing this. I wonder if the #5 value is much higher if you add some oil to it during testing.

Unfortunately no typos. I’m going to try that then a leak down test hopefully this coming weekend. The truck is currently way up on jack stands as I’m in the middle of an axle job. Once that’s finished up I’ll determine if I’m looking at a 3FE repair or an LS swap lol

 

[jonheld]

Unfortunately no typos. I’m going to try that then a leak down test hopefully this coming weekend. The truck is currently way up on jack stands as I’m in the middle of an axle job. Once that’s finished up I’ll determine if I’m looking at a 3FE repair or an LS swap lol

The FSM specs 149+ PSI with a minimum of 114 PSI.
Difference between each cylinder should be 7 PSI max, but all these readings are assuming a new engine.
In any case, before making any rash decisions, remember it's a pushrod engine. Be certain you have checked valve clearances according to the FSM, don't have a sticking valve or 3, or deformed pushrods.