Need help with no-power 1991 3FE Land Cruiser

[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.

 

[CruiserDM]

Finally moved into our new place and had time to work on the 80. Came back to say that it ended up being the head gasket blown out between cylinders 5 & 6, at least I'm 95% positive this is the reason for my issues.

New HG came in the mail today. I'm going to clean up the head and block and try to get it back together this weekend.

 

[ozarkmud]

Well that explains the low compression on #5 and #6!

I wonder what the actual ratio of head gasket failures between 3FE and 1FZ-FE is.

How hard of a job was it? I wonder if it's easier than the 1FZ-FE head gasket.

 

[CruiserDM]

Well that explains the low compression on #5 and #6!

I wonder what the actual ratio of head gasket failures between 3FE and 1FZ-FE is.

How hard of a job was it? I wonder if it's easier than the 1FZ-FE head gasket.

It took me probably 3-4 hours of fiddling around in 30 minute increments because it's a billion degrees and humid in my garage. I've also been up and down this motor a few times and familiar with it so that helped.

Feel like a big dummy for not checking compression before doing my huge laundry list of stuff. I guess I figured since the truck started and ran fine (apart from the miss and lack of power), and that it never came close to overheating after running for extended periods of time that there's no way it could be the head gasket.

Cleaning off the old gasket material will definitely be the worst part of this job.

 

[CruiserDM]

Well having some less than desirable results. Finished the head gasket change, got everything back together, figured the timing was fine to try and start it and it cranked right up and ran for about 2 minutes before some guests showed up so I shut it off.
Came back to it an hour later and recorded the following video and the truck died after running for 5-10 seconds, then would sputter to life and die after I quit cranking, now it just turns over and doesn’t start at all.


Rechecked all the vacuum lines, set timing back to TDC and set the distributor, still just crank no start. Check engine light says code 51. Open to any advice

TPS?
Old gas? (3/4 tank Been in it for about a year but I did add a big bottle of seafoam when I first filled it)
I can smell gas around the truck and the dipstick smells like gas
Appears to be getting spark. Don’t have anybody here so can’t compression test until tomorrow. Hoping to troubleshoot other things in the meantime if possible

 

[CruiserDM]

Also noticed some disonnected harnesses around the engine bay - these two are far passenger side above the wheel well

These two are just passenger side of the block near the sight hole/cylinder 6 spark plug

 

[CruiserDM]

Closing the loop on this. Had the distributor installed 180 from where it should, didn’t realize two rotations of crank = 1 rotation of dizzy. Started up and ran poorly, added seafoam and topped tank with 93 and it’s running really nice now after idling for a while.

Still some things to sort out like poor shifting and high idle. I believe it needs a new tps then just adjusting cables. Really exciting to see I can accelerate past 30mph going uphill now lol.

Thank you all for your attention and help. Looking forward to having some more 80 series parts available now that I can live in the truck a bit. Overhead consoles and dome lights available and hopefully more in the next two weeks.

 

[jonheld]

Any octane above 87 is a waste of money on these things.

 

[AKHerms]

Closing the loop on this. Had the distributor installed 180 from where it should, didn’t realize two rotations of crank = 1 rotation of dizzy. Started up and ran poorly, added seafoam and topped tank with 93 and it’s running really nice now after idling for a while.

Still some things to sort out like poor shifting and high idle. I believe it needs a new tps then just adjusting cables. Really exciting to see I can accelerate past 30mph going uphill now lol.

Thank you all for your attention and help. Looking forward to having some more 80 series parts available now that I can live in the truck a bit. Overhead consoles and dome lights available and hopefully more in the next two weeks.

View attachment 3758465View attachment 3758466View attachment 3758467View attachment 3758468

High idle may be a dirty Idle Air Controller!