Builds US Spec. February 1990 Poverty 80 2uz/h151f swap (1 Viewer)

[Tank5]

I was making a test run with the other ecu tonight and picked up on something I had not focused much on. I noticed when watching my scan gauge that the TPS starts out at 15 and maxes out at 31. If the sensor is supposed to operate through a range from 1to 31 then it could be topping out halfway through acceleration. This could explain the underpowered feeling.
Time to do some reading.

 

[White Stripe]

I don't think a cylinder running lean would typically create a misfire. When I do a test, and it is successful, I move on. You have smoked it several times, so I would move on. By clearing codes, you reset fuel trims. After that restart the truck with live data on watching stft's specifically for when they go above 5%. Is it at idle or higher rpm or driving and you hit a big hill? As far as tps, you can watch the throttle blade with the intake hose off and pedal at wot to see if it's working.

 

[Tank5]

Over the weekend while trying to test drive it the 80 lost all throttle response it idled but the pedal did nothing. I had to pull it off to the side of the road turn it off and restart the engine. The pedal response came back. I took it home. It tripped a P2121 code. The P2121 code is not identified as a possible cause of my lean condition but it could be why I am experiencing poor throttle response. I am reading about a fail safe mode that limits throttle response and may be why my throttle plate only opens half way.

It had done this before but it was after I installed a new accelerator pedal position switch. I thought the switch was bad. When I reinstalled the old switch it seemed fine no code. This time I ran a bench test on the sensors and they both tested the same and seem to be within spec. New probem to solve.

I also borrowed an injector cleaner and tester.

I had an extra set of injectors, so I tested, cleaned and retested the first set.
First set Tundra injectors

Second set from the LC

The injectors that were in the 80 performed the best, so I reinstalled them with new insulators and o-rings. I didn’t have replacement screens, so I visually inspected them to make sure they were not clogged with debris and resized them. They looked fine except for one that had a large particle in it that I was able to flush out. I got them all reinstalled and there are no leaks.

The injector performance didn’t really change and there were no obvious performance issues, so I will chalk this effort up to possible cause checked off the list.

The search continues.

 

[ryaneddy16]

When your looking at the live data what is the O2 voltage doing?

 

[Tank5]

When your looking at the live data what is the O2 voltage doing?

It looks in spec. to me. I took this picture after I completed the injector work.

 

[Tank5]

This is the other side of the live data test.

 

[Bad Mojo]

I know this post isn’t specifically a 2UZ but they went through the same parts cannon exercise you did and it notes a part I don’t think has been tested or swapped out yet. Their engine also passed a smoke test, but had the same check engine codes. I suspect it has already been removed during the SAI delete. But their explanation to how they troubleshooted it might be helpful if a different valve is having a similar issue.

Air Control Valve Leak

 

[Tank5]

I need to create a record of everything I have done to trouble shoot the potential causes of my lean condition, P0171 and P0174. Referencing the 2005-2006 Tundra Manual diagnostic section for the 2uz VVTI they identify potential causes as:

• Air Induction System
• Injector Blockage
• MAF
• Engine Coolant Temp sensor
• Fuel Pressure
• Gas Leak in Exhaust System
• Open or Short in heated oxygen Sensor (bank 1, 2 sensor 1 Circuit)
• Heated Oxygen Sensor (bank 1, 2 sensor 1)
• Heated Oxygen Sensor heater (bank 1, 2 sensor 1
• EFI relay
• PCV Piping
• ECM

Air induction System

• Installed oem intake to replicate factory intake system
• Individually tested each vacuum port by capping each port for a minimum of 10 seconds while watching Fuel Trim (FT) response using tech stream. No changes in FT or audible engine response during tests.
• Individually tested each vacuum port, planum gaskets, and throttle body gasket by spraying brake cleaner each site while watching Fuel Trim (FT) response using tech stream. No changes in FT or audible engine response during tests.
• I conducted multiple smoke tests using a smoke machine connecting the machine at the intake and also at the brake booster port. The initial test identified two faint leaks that were clamped. The additional tests of 15 minutes each did not identify any leaks.
• The throttle body gasket was removed inspected and reused, the Planum gaskets are new OEM, almost all of the hoses have been replaced with new. The hoses left in place are pliable and don’t have any cracking.

Injector Blockage

• All 8 injectors were removed, tested then cleaned and retested. None of the injectors showed any significant blockage and performed equally before and after the ultra sonic cleaning.
• I cleaned a second set of injectors for the same engine as a comparison. They tested similarly to original injectors but their performance was slightly lower which is why I reinstalled the original injectors
• I installed new oem insulators and o-rings when the injectors were installed. I did not have screens, but was able to visually inspect them and flush them to ensure they were clear of debris.

MAF

• I purchased a new OEM MAF sensor and have also rotated through a used unit for comparison testing.
• Both MAF have been cleaned with MAF cleaner spray
• The MAF is installed in the factor intake and the gasket is intact, no leaks
• I followed the oem diagnostic steps to test the MAF circuit. It tested in spec.
• There was a low voltage on the MAF circuit early in the diagnostic process. The MAF plug was replaced and the symptom has not returned

Engine Coolant Temp Sensor

• The Sensor plug was checked and it is seated all the way.
• The sensor reports a reasonable temp of 192 degrees as viewed in Tech Stream. Believe to be operating as it should.

Fuel Pressure

• The Fuel Pump and filter have been replaced with new oem units.
• The fuel pressure has been tested at idles and underload. With the fuel pressure regulator capped the pressure measured 45-46 psi. With the FPR attached to the intake is running 42-44 psi at idle.
• The fuel pump receives it’s power from the ECU as the trigger

Gas Leak Exhaust System

• The manifolds are Doug Thorgely Headers designed for this engine with the SAI tube deleted. They were installed with new oem manifold gaskets. Upon inspection all header bolts are torqued and I could not locate any leaks upstream of the Air Fuel Sensors.
• Just above the headers on the heads are the port holes for Secondary Air Injection system which I deleted. The port holes were tapped and sealed with a high heat thread sealer. I found 2 on each side that could be torques tighter, so they were. No signs of a leak were obvious. There was no change in the FT after the plugs were torqued.

Open or Short in heated oxygen Sensor (bank 1, 2 sensor 1 Circuit)

• Have not tested for a short in the heater circuit for this sensor
• I identified neither circuit was receiving B+ power and found the circuit was never wired up. I wired both up to the intended sensor circuit. This eliminated the trouble codes I was receiving for the circuit.

Heated Oxygen Sensor (bank 1, 2 sensor 1)

• Both Bank 1 and 2 sensor 1 Air Fuel sensors were replaced with new oem units.
• They are reporting in Tech Stream and appear to be working to and can been seen responding to induced lean conditions using the brake pedal. They appear to be working.

Heated Oxygen Sensor heater (bank 1, 2 sensor 1)

• Both Bank 1 and 2 sensor 1 Air Fuel sensors were replaced with new oem units.

EFI relay

The harness and ecu were customized to build a stand alone harness. My Fuel Pump receives power from the ECU.

PCV Piping

• The PCV and hose has been replaced with new oem units.
• This was tested during various vaccuum leak tests through all methods described previously. It was not identified as a possible leak.

ECM

• The harness and ecu were customized to build a stand alone harness. I purchased a second ECU that has been set up almost exactly the same way.
• I have switched out ECU’s but both perform equally

Timing

• The timing belt was replaced as part of the build. The timing marks were confirmed twice at the time of installation.
• I recently pulled the cam covers and reconfirmed the timing marks are still aligned and they were.

Planum Replaced

• Replaced planum with a clean used planum from a previous running engine.
• Installed new planum gaskets

I will try to update this post as I work through additional tests. I will add in the last two days I have received two new trouble codes, P2121 and P0430. I don't think either relates to the the lean issue, but I will be working to diagnose those at the same time. Keep the ideas coming, I appreciate the help and am really feeling pretty stumped.

 

[Tank5]

I know this post isn’t specifically a 2UZ but they went through the same parts cannon exercise you did and it notes a part I don’t think has been tested or swapped out yet. Their engine also passed a smoke test, but had the same check engine codes. I suspect it has already been removed during the SAI delete. But their explanation to how they troubleshooted it might be helpful if a different valve is having a similar issue.

Air Control Valve Leak

Well there is a part I have not bought! Thanks for the leak that seems very promising and my problem seems to present the same as his. I am going to look into this.

 

[Broski]

Denis, my hat is off to you. You haven’t let this problem get the best of you.
You just keep after it very diligently !!

 

[Tank5]

Well this thing doesn’t seem like it is supposed to be separated from the planum.

I looked the parts diagram on partsouq and I don’t see that I can buy it separately. Looks like. If this is the issue I would have to replace the intake.

 

[ryaneddy16]

Well this thing doesn’t seem like it is supposed to be separated from the planum.
View attachment 3925863
I looked the parts diagram on partsouq and I don’t see that I can buy it separately. Looks like. If this is the issue I would have to replace the intake.

I have a couple of these intakes. Let me know if you need one.

 

[Bad Mojo]

Well this thing doesn’t seem like it is supposed to be separated from the planum.
View attachment 3925863
I looked the parts diagram on partsouq and I don’t see that I can buy it separately. Looks like. If this is the issue I would have to replace the intake.

Unfortunately I think you’re right. Does it have any play in it?

I have a spare non VVT-I 2UZ manifold you are welcome to try.

Not that you want to Frankenstein the engine, but I’ve seen a 3UZ manifold put on a 2UZ. They did that so they could have aluminum manifolds and keep the VVT-I. Also the new design has that actuator as removable.

 

[Tank5]

@ryaneddy16

Thank for that offer, I make take you up on it. I do have a spare hear but it has a little oxidation from sitting out side before I got it. The shaft play in comparison to the one on my engine now. So I really don’t know if it is better or not. I just finished cleaning all the grease off the spare intake, so it is ready to swap tonight maybe.

Before I pull my intake I am going to see if I can identify a leak at the valve with brake cleaner, hoping that maybe if it confirm a leak there. If I cannot I will probably just swap it because why not at this point.

@Bad Mojo The shaft play seemed about the same in comparison to the spare that I have, so I am not sure if it is the problem or not.

I am not sure if the non VVTI planum will work but as you said I have seen the 3uz intake used but it looks shorter and it looks like the injectors might be different, but not sure. I think I would need a complete planum set up to do that. If the plastic planum turns out to be a problem, I will replace it with the 3uz version and figure it out.

Hope to have results tonight.

I was thinkng out loud with a friend as I worked through what I have learned up to this point.

I have been able to achieve good Fuel Trims no lean codes with two tests.

First, I choked the air intake where the MAF sits to 70 mm opposed to the 84mm stock tube. This achieved no lean codes good fuel trims.

Second, I clamped the fuel return line and this resulted in no lean codes and good fuel trims.

We came to the conclusion that there must be unmetered air heating in somewhere. This possible planum leak has potential as the culprite.

 

[White Stripe]

Have you compared stock maf readings at idle with a stock truck vs yours?

 

[Tank5]

Have you compared stock maf readings at idle with a stock truck vs yours?

I did but I didn’t write it down from memory the MAF readings on my other 2uz were similar.

 

[Tank5]

The planum swap is complete but the results are not any better.

I degreased and scrubbed the replacement intake, so I had a clean part going back in.

Swapping parts to the replacement.

I replaced the planum gaskets with new oem because I had them on hand.

I installed the newly dressed planum and ran through a relearn process, that consisted of 6 minutes idling 30 secs off then 3 min idle. It was late, so I did not drive it.

I got lean codes just while it filed. Here a picture of the Fts

I will take it out for a drive tomorrow to see if it changes at all.

The plastic planum bolts are torqued to 15 ft/lbs, should I go tighter?

 

[RivMan]

Just a thought, can you have your Tuner share the file that's loaded in your ECU?

It would be good to look at it's MAF curve, my bet is that it's incorrect for the hardware you have.

-Rob

 

[Tank5]

Just a thought, can you have your Tuner share the file that's loaded in your ECU?

It would be good to look at it's MAF curve, my bet is that it's incorrect for the hardware you have.

-Rob

I don’t think he will share this with me. He is pretty persistent that the ecu is not the issue.

 

[RivMan]

I don’t think he will share this with me. He is pretty persistent that the ecu is not the issue.

It wouldn't be the ECU exactly. It would be a mismatch between what the calibration expects, and what you have for an intake setup.

Did the tuner use the base calibration / MAF curve from the 2005 GX470 (ECU donor) or the 06 LX470 (intake hardware donor)? I'm betting they're different.
You need to make sure that the MAF curve in the ECU matches the intake tube / airbox / MAF hardware.

I'm going to see if I can track down calibration files for those two applications (which may be difficult).

The fact that you can choke down the intake to 70mm and get a good MAF reading leads me to believe the cal might be an issue.

Thanks
-Rob