Build US Spec. February 1990 Poverty 80 2uz/h151f swap

[Tank5]

Isn't there a way to adjust the mass air flow reading? URD used to have a tool to do that.

Never heard of it but I will do some research.

I looked it up, it they do make something. My hesitation in jumping on this is it seems like a bandaid for an issue I shouldn’t have. My engine isn’t supercharged or using an aftermarket intake. I don’t want to deviate farther from stock than I already am to avoid introducing another variable.

 

[Cruiserlab]

I have not read through all of this thread, so pardon my ignorance, but a dumb?/long shot idea comes to mind.

Am I correct in my understanding that the engine is running lean?

Did you end up deleting SAI? I don't know exactly how that works, but are there any holes (air injectors) that were plugged? If so, was sealant used?

Also, not trying to say this was a bad idea or that this can't be done, but wasn't there a reason why Slee never swapped a VVTI? I honestly don't know and am curious.

 

[Tank5]

I have not read through all of this thread, so pardon my ignorance, but a dumb?/long shot idea comes to mind.

Am I correct in my understanding that the engine is running lean?

Did you end up deleting SAI? I don't know exactly how that works, but are there any holes (air injectors) that were plugged? If so, was sealant used?

Also, not trying to say this was a bad idea or that this can't be done, but wasn't there a reason why Slee never swapped a VVTI? I honestly don't know and am curious.

The issue at hand is that it is running lean with observing the fuel trims at about 30%. It doesn’t eventually produce trouble codes for the lean condition for both banks.

The SAI was deleted but the harness build/ ecu programmer. The entire SAI system has been removed from the engine except for the air injection controller which still plays a role in the delete wiring for the ecu. The only holes to plug are in the heads which were tapped and sealed with stainless steel plugs with a high temp sealant. I have checked these as a possible leak and found no indication that any of them leak.

I can’t speak to why Slee didn’t do VVTI swaps. I don’t know for sure that they didn’t.

 

[Scheefdog]

It seems to me that your ECU is in limp mode from the SAI system - or in limp mode from something else that was "deleted" in the ECU programming. Based on what I have read it is possible to turn off the SAI codes from triggering the check engine light, but the limp mode condition still prevails.

Have you considered ordering a flashed ECU from Quantum Auto to give that a try? Or you could send in one of your ECUs to have them look at it and reflash with their recipe. That would be an easy and quick option that would at least verify if the issue is in the ECU programming.

 

[Tank5]

It seems to me that your ECU is in limp mode from the SAI system - or in limp mode from something else that was "deleted" in the ECU programming. Based on what I have read it is possible to turn off the SAI codes from triggering the check engine light, but the limp mode condition still prevails.

Have you considered ordering a flashed ECU from Quantum Auto to give that a try? Or you could send in one of your ECUs to have them look at it and reflash with their recipe. That would be an easy and quick option that would at least verify if the issue is in the ECU programming.

I have talked to the owner of Quantum Auto and his opinion is it is very unlikely that there is an issue with the ecu especially since I have two to test with and they both perform equally. He advised against the issue being in the ecu.

I had reached out to to Tim and outlined my issues. He is going to build me a new harness. This will be my next step I will just have to wait until I get the new harness.

 

[mrsleeve]

Tim seem like a very helpful and responsive and does a good business. He’s doing my harness and ecu, we had a little snag but he’s made it right and I have nothing but good things to say.

Maybe I missed it or forgot, Did you ohm out the wire harness between the connector at the maf and the pin on the connector at the ecu. Perhaps there is something causing a higher resistance in that leg?

 

[Tank5]

Tim seem like a very helpful and responsive and does a good business. He’s doing my harness and ecu, we had a little snag but he’s made it right and I have nothing but good things to say.

Maybe I missed it or forgot, Did you ohm out the wire harness between the connector at the maf and the pin on the connector at the ecu. Perhaps there is something causing a higher resistance in that leg?

I have done a resistance test earlier in this process.

This is the second 2uz harness Tim has done for me. The first worked with out issue. This current build has drug on for three years and had issues. Tim is replacing the harness now, so I feel like he working to resolve the issues I have been dealing with.

 

[Rednexus]

A harness issue certainly seems like a feasible root of the problems here. Good luck!

 

[mrsleeve]

what if you were to connect the MAF to the ECU conector with 4 new wires and just run externally, this would eliminate any data transmision isssues with a paritaly broken wire a bad splice or something partialy conected. I know its a bit of pain to run wire and repin some stuff but it would tell you if that leg of the harness has issues outside of just conitniutiy and resistance, I know what else is there? Kinda the last thing there is left it seems

 

[Tank5]

what if you were to connect the MAF to the ECU conector with 4 new wires and just run externally, this would eliminate any data transmision isssues with a paritaly broken wire a bad splice or something partialy conected. I know its a bit of pain to run wire and repin some stuff but it would tell you if that leg of the harness has issues outside of just conitniutiy and resistance, I know what else is there? Kinda the last thing there is left it seems

I did not try this but I don’t see the need at this point. This harness has had multiple issues and we have reached a point where even Tim recognizes we should start with a new harness. I am in favor of this and will wait for the new harness to arrive.

Tim did let me know he has a few orders in the shop he needs to finish first and said it would be a couple weeks before he could start on the new harness. I will update after it arrives and gets installed.

Tim has said he has built harnesses and ecus for other manual conversion 2uz VVTI builds and that they work, so I know this can be done.

I can’t say why this harness has been problematic and I don’t care to dig into the why. I really just want to push forward with the next logical step that will get this swap running properly and reliably. I think we are doing that with a new harness. In the meantime I have a new booster to install and some interior work to finish up.

 

[mrsleeve]

I did not try this but I don’t see the need at this point. This harness has had multiple issues and we have reached a point where even Tim recognizes we should start with a new harness. I am in favor of this and will wait for the new harness to arrive.

Tim did let me know he has a few orders in the shop he needs to finish first and said it would be a couple weeks before he could start on the new harness. I will update after it arrives and gets installed.

Tim has said he has built harnesses and ecus for other manual conversion 2uz VVTI builds and that they work, so I know this can be done.

I can’t say why this harness has been problematic and I don’t care to dig into the why. I really just want to push forward with the next logical step that will get this swap running properly and reliably. I think we are doing that with a new harness. In the meantime I have a new booster to install and some interior work to finish up.

Oh I totally would be where you are to, you can only chase your tail ane beat your head aginst a wall for so long before your concussed and exhausted. It was just a thought I had this afternoon staring at my wireing and trying to decide on what to start clipping out of the 80s harness and how to get my charging wire routed and just what I can eliminate from the Evap system since I am attempting to run a pasive GM/1fz style EVAP sytem.

 

[thepinktaco]

I may have missed it if you have tried but under active test in techstream there is a test that says control injection volume for a/f sensor or something similar. This allows you to richen or lean out the fuel mixture to test the a/f sensors and make sure they are responding correctly. Whats interesting with your data is fuel trims are maxed but A/F signal looks normal.

 

[Tank5]

I may have missed it if you have tried but under active test in techstream there is a test that says control injection volume for a/f sensor or something similar. This allows you to richen or lean out the fuel mixture to test the a/f sensors and make sure they are responding correctly. Whats interesting with your data is fuel trims are maxed but A/F signal looks normal.

I am a beginner Techstream user and have not tried using to run any tests or manipulate any systems. I will look and see if that test is available to me. My version of Techstream is not registered and can only be used in offline mode, so I cannot access all the features it offers.

Interesting observation about the FT and AF sensor readings relationship. What would allow the AF sensors to read normal while the FTs are maxed out?

 

[Tank5]

I may have missed it if you have tried but under active test in techstream there is a test that says control injection volume for a/f sensor or something similar. This allows you to richen or lean out the fuel mixture to test the a/f sensors and make sure they are responding correctly. Whats interesting with your data is fuel trims are maxed but A/F signal looks normal.

I figured out the active test feature, which was not hard. I could not adjust the MAF in the system but I could test the AFS and injector column.

I ran a test on both of those and can see the the AFS fluctuations with the test but the Fuel Trims never changed.

The injector column test I can hear the vehicle idle change but the Fuel Trims never change.

The MAF on both test adjusts some with the idle change.

I gather from this the AFS are working as they should. The MAF is reading and adjusting as well. I know @Rednexus said my MAF reads were compared to his, so maybe something is skewing the MAF reading. I don’t know.

I would expect that if the AFS provide input to manage fuel input then the fuel trims should change during these tests if that is true then something is not communicating the way it should.

 

[mrsleeve]

Have you checked your EVAP and purge valve for leaks and or being stuck?

Sure you thought of that already but I just was thinking about it planing my evap system out last night. As a sticky purge valve or if your using the factory 2uz set up is more complicated.

 

[Tank5]

Have you checked your EVAP and purge valve for leaks and or being stuck?

Sure you thought of that already but I just was thinking about planing my evap system out last night

I have and even capped the entire system and separated and capped the port in the intake. It has no effect on the FTs.

 

[Tank5]

Last night I installed nutserts in the cab to attach the cargo cover mount trim parts. Then added the cover. It does not seem as satisfying as I thought it might but living in the desert I think it will be useful. I have it, so I will try it out for a while.

 

[Tank5]

I asked a club member to scan their gx470 with tech stream so I would have a local data set from a good running 2uz VVTI and as a bonus they also are running headers and deleted cats, so it is a very similar set up as mine.

The biggest difference in the test is I am at 7800 feet elevation and they are at 7100 feet elevation. Their data set was taken at 793 rpms and mine at 703 rpms.

I was focusing on the MAF and atmosphere pressure readings.
Their MAF was at 5 mine at 3.34
Their atmosphere pressure was -3 mine is 3.
It seems like these should not be this far off for only 700 feet in elevation.

If you have followed along you may have seen that I went down the atmosphere pressure rabbit hole already. The MAP sensor which is under the manifold is what measures the AP. I replaced the map sensor and added a new filter and reinstalled at that time it did not change this reading at all. I “moved on” thinking this was not the issue.

The last time I sent the harness back to Tim he deleted the wiring to the MAP sensor all together as part of the SAI delete. Yet without the sensor the reading is still the same. How?

Further reading the map sensor supposedly does provide information that is used to correct Fuel Trims. I am also guessing that if the air density (AP) measurement is off this probably skews the MAF calculation which could explain why it is off.

I need to talk to Tim to see how his ecu is receiving the MAP sensor input and calculating AP for the FT mixture.

I have gotten my hopes up in the past thinking I figured it out, I am not holding my breath this time either but it seems like there is something to this.

 

[Tank5]

Tim says, the Map sensor should not affect my issue. The plan now is for me to send one of the ECUs back to him to get flashed and reprogrammed. The replacement harness is on hold at the moment.

I did have something new happen, unrelated to anything I was doing I got a P2121 Accelerator pedal sensor trouble code and the pedal had no response. I tried clearing it in Techstream and it would not clear. I ended up disconnecting the battery for a little bit and hooking it back up. This cleared the code and the pedal worked again. I had this same thing occur much earlier in the build but after swapping in a brand new sensor the pedal would not work. I put the old sensor back in and it worked fine until this happened. It is working now but it seems there is an intermittent problem.

 

[Tank5]

I have pulled the complete harness to send back to Tim. He is going to open it up and rebuild it. He is also going to read the fuel trims on his engine when he runs it with the new harness. Looking forward to what Tim finds.

Anyone who has changed the starter in a 2UZ knows this job sucks. The job is the same every time I have had to pull the engine harness back off the engine for which I have lost count of how many times I have done this. I will add that having an H151F bellhousing mounted to the 2UZ makes the job slightly for frustrating because the housing is raised and in the path of where you would normally access the two starter bolts. Still accessible with a short turns of a wrench but no sockets, adds a little more suck to this job. I hope this is the last time.

Pictures of what I am talking about.