Need help with no-power 1991 3FE Land Cruiser (2 Viewers)

[CruiserDM]

I bought this truck back in may of last year, and have been wrenching on it ever since. I've done all of the following work below but just can't seem to get it to run right:

New Water Pump, Thermostat, Radiator, and all coolant hoses
New Distributor + Cap
New Spark Plugs and wires
New Valve Cover Gasket + PCV + Valve Adjustment by local shop
Cleaned Fuel Injectors
New Fuel Pump and Fuel Filter (Replaced Today)
New Alternator + Battery
New PS Pump and steering gear
New Air Intake Hoses + Filter
New O2 Sensors + Catted Downpipes (Old cats were cut off before I bought the truck, along with O2 bungs. Truck has had CEL for these since purchase)
New Intake + Exhaust Manifold Gaskets
Adjusted throttle + Trans cables
Full EGR delete with kit from Lerms Customs

I'm hoping for some advice on where to go from here, the truck idles fine, revs freely in park and in neutral, but has almost no power under load.

I can usually rev through first gear but if I'm going uphill I'll have the throttle pinned to the floor and be stuck at 30mph - 2.3k rpm.

I've noticed sometimes when I go from no throttle to full throttle the truck will stumble for just a second before revving, and I am getting some burble/backfires making me think I'm running a bit rich. Truck idles around 850 rpm.

Any advice on where I should look next? Maybe timing or valve adjustment is off?
I read about the TPS sensor causing issues in this thread: 3FE- Loss of power/mild stumbling/at mid RPM range (Fixed it Thread) Whew. - https://forum.ih8mud.com/threads/3fe-loss-of-power-mild-stumbling-at-mid-rpm-range-fixed-it-thread-whew.943942/

And this guy had almost the exact same issue as me but it was due to a kinked fuel line, but I couldn't find any sign of that:

FJ80 3fe new guy with issues

I bought my 80 about a month ago for 6500. I took it out for a drive know there were issues with it but being that it was in decent condition and it had the "bullet proof" 3FE I decided to pull the trigger. On the way home I noticed on hills that it would down shift and fall flat on its face...

forum.ih8mud.com

I haven't performed a smoke test for vacuum leaks, but could vacuum leaks cause such a drastic issue? I can't get this thing over 45-50mph at this point. Any help or lines for me to chase down are greatly appreciated.

 

[jonheld]

This is first gen EFI with 1986 technology. All of the mechanical adjustments have to be correct according to FSM specs first, as the ECU has a very limited window of correction. Below is collection of random thoughts while my wings marinate.

Idle speed is set by the ECU pushing the stepper motor in the ISC and should be 650 RPM at normal operating temperature. If the ECU is getting a false reading from the coolant temp sensor, then it's never going to be correct.
The throttle cable should have slack at idle to allow the TPS to "tell" the ECU that the throttle is at idle. Also, the throttle plate should be resting at the idle end stop and be able to move freely throughout its range with no binding.

The O2 sensors, AFM, TPS, and coolant temp sensor are what the ECU uses for fuel pressure control, injector timing, and idle speed control. Again, the mechanicals must be in spec first.

Any time you change or adjust something under the hood, even a basic tune up, it's a good practice to remove the 15 amp EFI fuse for a while. This essentially reboots the ECU, clears out any stored error codes, and forces the ECU to relearn all sensor inputs.

The fact that the engine idles well tells me that there are no vacuum leaks and no unmetered air is getting into the system. However, this could be a false positive because the engine isn't really at idle speed.

Have you checked fuel pressure according to the FSM?

Is the VSV for the fuel pressure regulator functional? Is the fuel pressure regulator functioning?

 

[CruiserDM]

This is first gen EFI with 1986 technology. All of the mechanical adjustments have to be correct according to FSM specs first, as the ECU has a very limited window of correction. Below is collection of random thoughts while my wings marinate.

Idle speed is set by the ECU pushing the stepper motor in the ISC and should be 650 RPM at normal operating temperature. If the ECU is getting a false reading from the coolant temp sensor, then it's never going to be correct.
The throttle cable should have slack at idle to allow the TPS to "tell" the ECU that the throttle is at idle. Also, the throttle plate should be resting at the idle end stop and be able to move freely throughout its range with no binding.

The O2 sensors, AFM, TPS, and coolant temp sensor are what the ECU uses for fuel pressure control, injector timing, and idle speed control. Again, the mechanicals must be in spec first.

Any time you change or adjust something under the hood, even a basic tune up, it's a good practice to remove the 15 amp EFI fuse for a while. This essentially reboots the ECU, clears out any stored error codes, and forces the ECU to relearn all sensor inputs.

The fact that the engine idles well tells me that there are no vacuum leaks and no unmetered air is getting into the system. However, this could be a false positive because the engine isn't really at idle speed.

Have you checked fuel pressure according to the FSM?

Is the VSV for the fuel pressure regulator functional? Is the fuel pressure regulator functioning?

I haven’t checked the fuel pressure, but will definitely do so. The fuel VSV is removed with vacuum hoses ran between the two ports. I saved the VSV though and can try to put it back in.

One thing I noticed when I was checking check engine light codes was that with te1 and e1 jumped the truck idled lower than when I pulled the wire out. Not sure what the reason for that would be.

 

[jonheld]

I haven’t checked the fuel pressure, but will definitely do so. The fuel VSV is removed with vacuum hoses ran between the two ports. I saved the VSV though and can try to put it back in.

One thing I noticed when I was checking check engine light codes was that with te1 and e1 jumped the truck idled lower than when I pulled the wire out. Not sure what the reason for that would be.

That's because when you jump those 2 pins with the engine running, it disables the ecu from adjusting the ignition timing. That's how you're supposed to adjust the timing.

You check error codes without the engine running, key in the ON position.

Sounds like the timing is misadjusted.

 

[CruiserDM]

That's because when you jump those 2 pins with the engine running, it disables the ecu from adjusting the ignition timing. That's how you're supposed to adjust the timing.

You check error codes without the engine running, key in the ON position.

Sounds like the timing is misadjusted.

Thanks for this, I’ll check timing and report back

 

[jonheld]

Thanks for this, I’ll check timing and report back

Always follow the FSM.

 

[CruiserDM]

Always follow the FSM.

Right, I’m looking at 7 degrees BTCD with TE1 and E1 jumped, and 12 without? I’ve never done timing before but have a light coming.

Looks like there’s just a line that will line up with one of the two dots (7 or 12 degrees) on the flywheel in the inspection window when the light is flashing if timing is correct?

 

[jonheld]

Right, I’m looking at 7 degrees BTCD with TE1 and E1 jumped, and 12 without? I’ve never done timing before but have a light coming.

Looks like there’s just a line that will line up with one of the two dots (7 or 12 degrees) on the flywheel in the inspection window when the light is flashing if timing is correct?

Couple of things here.
On the flexplate/drive plate/flywheel whatever you want to call it, the double dots indicate TDC and the large single dot indicates 7 deg BTDC.
Correct factory ignition timing is 7 deg BTDC at 650 rpm at normal operating temp with the pins shorted on the diag connector.

The FSM specifies MULTIPLE times that static ignition timing should be done at 650 rpm with the terminals shorted on the diagnostic connector. If your idle speed is incorrect, then the static timing will be off.

Getting a timing light into the correct position to eyeball that stupid little timing window can be a real PITA on the 3FE. One of the tricks is to is to remove the inspection plate on the bottom of the bellhousing and fill in the timing marks on the flywheel with white nail polish. This makes finding the timing marks in the tiny window MUCH easier.
Then rotate the engine by hand until the TDC mark is perfectly centered in the window. Paint a a mark on the crank pulley with a line that continues onto the timing gear cover. Then rotate the engine until the 7 deg BTDC is centered in the window. Paint another mark on the crank pulley. This allows you to time the engine in a similar way to the 1FZ, by pointing the timing light at the crank pulley.

 

[CruiserDM]

Couple of things here.
On the flexplate/drive plate/flywheel whatever you want to call it, the double dots indicate TDC and the large single dot indicates 7 deg BTDC.
Correct factory ignition timing is 7 deg BTDC at 650 rpm at normal operating temp with the pins shorted on the diag connector.

The FSM specifies MULTIPLE times that static ignition timing should be done at 650 rpm with the terminals shorted on the diagnostic connector. If your idle speed is incorrect, then the static timing will be off.

Getting a timing light into the correct position to eyeball that stupid little timing window can be a real PITA on the 3FE. One of the tricks is to is to remove the inspection plate on the bottom of the bellhousing and fill in the timing marks on the flywheel with white nail polish. This makes finding the timing marks in the tiny window MUCH easier.
Then rotate the engine by hand until the TDC mark is perfectly centered in the window. Paint a a mark on the crank pulley with a line that continues onto the timing gear cover. Then rotate the engine until the 7 deg BTDC is centered in the window. Paint another mark on the crank pulley. This allows you to time the engine in a similar way to the 1FZ, by pointing the timing light at the crank pulley.

I'll definitely paint those dots, if I were to try and line it up in just the small window - is there a line at the window that I'm trying to line the 7 degree dot up with? or do I just want it to be in the center of the window?

If I'm using this timing light: https://www.amazon.com/gp/product/B000EVYGV4/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 I'll set the advance to 7 degrees and turn the distributor to line up the 7 degree dot (Large Single Dot) in the middle of the window? (Or at the TDC line I would mark on the crank pulley as you mentioned above)

Sorry for the basic questions, just want to make sure I'm thinking along the correct lines here. Really appreciate all of your input.

 

[jonheld]

I'll definitely paint those dots, if I were to try and line it up in just the small window - is there a line at the window that I'm trying to line the 7 degree dot up with? or do I just want it to be in the center of the window?

I think there's a line on the center top of the window, but I honestly don't remember. It's a pretty small window, so visual center should be very close.

If I'm using this timing light: https://www.amazon.com/gp/product/B000EVYGV4/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 I'll set the advance to 7 degrees and turn the distributor to line up the 7 degree dot (Large Single Dot) in the middle of the window? (Or at the TDC line I would mark on the crank pulley as you mentioned above)

I would download the instructions for that timing light and make sure you're doing it correctly.

https://m.media-amazon.com/images/I/91ctdE4PwnL.pdf

This is not going to be accurate until the idle speed is correct first.
If all the mechanicals are in spec according to the FSM and if the throttle plate is resting on the endstop with some slack in the cable and if the temperature sensor is registering properly, then I would try rotating the dissy slightly to see if that lowers the idle to spec. Then adjust timing from there.

 

[CruiserDM]

Just received back from muffler shop, new exhaust + muffler past the new downpipes I just put on so my neighbors can stand for me to own the thing again. Video of it idling in current condition before I mess with anything for records sake.

 

[CruiserDM]

Well my timing window plug is missing, but I did find the window itself. Got the flywheel marked through the inspection plate last night with a paint pen, then marked the crank pulley after pulling TDC then the 7 BTDC mark into the window.

Pulled out the timing light, got TE1 and E1 jumped etc. etc., was idling right around 680-690 rather than 650 so may still have some other issue in hiding, but when I checked timing I was timed right at TDC. I went to adjust the distributor and it seems to be bottomed out to where I can't advance it any more, only retard.

Is this a case of the distributor not being installed correctly? Or could I possibly need to adjust my valves first?

 

[jonheld]

Sounds like you're off by a tooth.

 

[CruiserDM]

Sounds like you're off by a tooth.

Set my timing to the 7 degrees BTDC, 12 BTDC with the diag port jumper removed. There is definitely a bit more power now, I can accelerate while climbing the big hill outside my neighborhood, but just barely. It still is barely creeping past 30mph until the road flattens out.

When I go full throttle there is still a bit of a stumble then it picks back up, but only when slamming foot to floor from no gas at all.

My list right now is to pull the TPS and calibrate, adjust valves, and check wiring on my O2 sensor harness as the bank 2 sensor is throwing a code again.

Video of it running now, pretty noisy around cylinder 5,6:

 

[jonheld]

Set my timing to the 7 degrees BTDC, 12 BTDC with the diag port jumper removed. There is definitely a bit more power now, I can accelerate while climbing the big hill outside my neighborhood, but just barely. It still is barely creeping past 30mph until the road flattens out.

When I go full throttle there is still a bit of a stumble then it picks back up, but only when slamming foot to floor from no gas at all.

My list right now is to pull the TPS and calibrate, adjust valves, and check wiring on my O2 sensor harness as the bank 2 sensor is throwing a code again.

What is your idle speed now?
Does the transmission downshift when you get on the throttle?
Have you adjusted the transmission kickdown cable according the the FSM?

A good running 3FE sounds like ball bearings in a blender. It's a tractor motor.

 

[CruiserDM]

Idle speed seems to be around 750-850 once warmed up. Maybe the O2 sensor not working is the culprit? The transmission does downshift and I've got about a millimeter between the red bobber piece and the black boot on the kickdown cable.

I definitely feel like it's in the correct gear for climbing the hill, it revs all the way to almost redline in first, shifts to second, gets to about 30mph and falls on it's face (less so now after the timing adjustment but still not what I'd expect even out of this old motor)

 

[jonheld]

Idle speed seems to be around 750-850 once warmed up. Maybe the O2 sensor not working is the culprit? The transmission does downshift and I've got about a millimeter between the red bobber piece and the black boot on the kickdown cable.

I definitely feel like it's in the correct gear for climbing the hill, it revs all the way to almost redline in first, shifts to second, gets to about 30mph and falls on it's face (less so now after the timing adjustment but still not what I'd expect even out of this old motor)

It's really bothering me that your idle is still not correct. After resetting the ECU, the idle will typically be higher than normal for the first few drive cycles, but should settle down and remain at 650 rpm.

Is the ISC working correctly? When you shut down the engine, you should hear the ISC get reset by the ECU. You should hear 3 or 4 clicks from the stepper motor. There is no error code for the ISC but there is a test procedure in the FSM. Remember that is a stepper motor and the FSM is asking you to sequentially pulse the individual poles to get the valve to open and close. It moves incrementally with each pulse and the movement is very slight.

If all mechanicals are correct, if the throttle plate is resting on the idle end stop, if the TPS is calibrated correctly, if the temp sensor is accurate, then the ECU should be pushing the ISC to get the correct 650 rpm. Something is still not right here.

 

[CruiserDM]

I've replaced the Coolant temp sensor with this in the past few months: https://www.amazon.com/gp/product/B0013FZYRA/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Cold Start Injector Switch also replaced.

I'll try and listen for the clicks. I've watched a video on taking apart the ISC to clean it, but haven't tried due to fear of dry rot causing it to crumble.

Since it's a stepper motor, vacuum leaks wouldn't have any effect on the ISC would they?

I also haven't driven it very much at all, one 10 minute drive. Guessing that's long enough for the ECU to relearn everything though.

 

[jonheld]

I've replaced the Coolant temp sensor with this in the past few months: https://www.amazon.com/gp/product/B0013FZYRA/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Cold Start Injector Switch also replaced.

I'll try and listen for the clicks. I've watched a video on taking apart the ISC to clean it, but haven't tried due to fear of dry rot causing it to crumble.

Since it's a stepper motor, vacuum leaks wouldn't have any effect on the ISC would they?

I also haven't driven it very much at all, one 10 minute drive. Guessing that's long enough for the ECU to relearn everything though.

It's not the length of the drive, it's drive cycles that allows the ECU to relearn the sensors. 2 or 3 should do it.
The ISC doesn't get vacuum, but it does get coolant. Make sure the coolant lines are not clogged.
There is a test for the coolant temp sensor in the FSM, page FI-37. The FSM calls it a water temp sensor (89422-20010), not to be confused with the water temp sender (83420-20020) which is for the dash temperature gauge. Remember that the ECU is relying on sensor inputs. See the picture below:

 

[CruiserDM]

Well, sorry for wasting your time on all this. Turns out cylinder six just isn’t firing. Pulled the plug cable and nothing changed as far as how it runs.

Made sure the plug and wire are working and they’re good. Going to compression test tomorrow, then probably drive into oncoming.

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.