- Thread starter
- #401
Yes, I am not getting any codes for them. I not getting any codes at the moment but from prior experience it takes about 15 miles of driving to trigger the lean codes or least that is what it took last time.
Build US Spec. February 1990 Poverty 80 2uz/h151f swap
- Thread starter Tank5
- Start date
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Yes, I am not getting any codes for them. I not getting any codes at the moment but from prior experience it takes about 15 miles of driving to trigger the lean codes or least that is what it took last time.
- Thread starter
- #402
I am still waiting on the pigtail to replace the MAF plug but I decided to experiment with the vacuum lines.
I purchased a bunch of vacuum line caps and capped all the vacuum ports on the planum and intake. The only lines not capped are the PVC to the throttle body and the valve cover to the intake. They both have brand new hoses and are clamped well.
The FTs are running at 30%+\- after it is warm for 10 minutes. The Short FTs go to -3 to -4% under load but Long FTs go to 31%.
If I unplug the MAF while it is running it dies instantly. I can start it without the MAF plugged in and FTs are exactly the same as stated above no difference at all. The MAF trouble codes show up immediately after it is unplugged. I can see the MAF voltage drop to 1.5 when it is unplugged.
Warmed up 10 min
Just before the MAF is in plugged
After MAF is unplugged
The MAF is communicating voltage referencing intake volume and temperature to the ecu, I gather that from this test. It maybe reporting incorrectly but the ECU is presenting any MAF TCs when it is operating. Could a continuity issue in the circuit cause the reported MAF values to be skewed before reaching the ecu? Seems possible right.
If the MAF plug or circuit is not then the potential that it is vacuum leak is reduced to a few locations. Intake tube, throttle body gasket, planum gaskets. I realize there are other places that could allow in mastered air in but they are unlikely to affect both banks, such as an exhaust manifold leak, injector leak, I would expect those to effect the bank they are located in.
The planum gaskets are new and the throttle body gasket is a clean and good, the intake tube is sealed and inspected for cracks. I have also swapped the planum as a test and the result did not change.
Anyone, What am I missing?
I purchased a bunch of vacuum line caps and capped all the vacuum ports on the planum and intake. The only lines not capped are the PVC to the throttle body and the valve cover to the intake. They both have brand new hoses and are clamped well.
The FTs are running at 30%+\- after it is warm for 10 minutes. The Short FTs go to -3 to -4% under load but Long FTs go to 31%.
If I unplug the MAF while it is running it dies instantly. I can start it without the MAF plugged in and FTs are exactly the same as stated above no difference at all. The MAF trouble codes show up immediately after it is unplugged. I can see the MAF voltage drop to 1.5 when it is unplugged.
Warmed up 10 min
Just before the MAF is in plugged
After MAF is unplugged
The MAF is communicating voltage referencing intake volume and temperature to the ecu, I gather that from this test. It maybe reporting incorrectly but the ECU is presenting any MAF TCs when it is operating. Could a continuity issue in the circuit cause the reported MAF values to be skewed before reaching the ecu? Seems possible right.
If the MAF plug or circuit is not then the potential that it is vacuum leak is reduced to a few locations. Intake tube, throttle body gasket, planum gaskets. I realize there are other places that could allow in mastered air in but they are unlikely to affect both banks, such as an exhaust manifold leak, injector leak, I would expect those to effect the bank they are located in.
The planum gaskets are new and the throttle body gasket is a clean and good, the intake tube is sealed and inspected for cracks. I have also swapped the planum as a test and the result did not change.
Anyone, What am I missing?
The bottom line is that your ECU is expecting X amount of air to be entering the engine at that MAF reading.
The O2 sensors are reading Lean, and telling the telling the ECU that it has 1.3x the air entering the engine, so the ECU is adding 30% more fuel (LTFT of 30%).
Either:
-Rob
The O2 sensors are reading Lean, and telling the telling the ECU that it has 1.3x the air entering the engine, so the ECU is adding 30% more fuel (LTFT of 30%).
Either:
- There is unmetered air coming into the engine
- A vacuum leak after the MAF
- The MAF is reading all the air coming in, but the ECU is interpreting the signal improperly
- ECU is calibrated wrong for the diameter of the intake
- % of air through the MAF vs. %around the MAF
- ECU is calibrated wrong for the diameter of the intake
- The injectors are putting less fuel in the engine than the ECU expects.
- ECU is calibrated wrong OR the fuel pressure is low, causing the injectors to flow less
- An injector is leaking (not likely because one would have to be equally bad on both sides)
- The O2 sensors are bad, and reading wrong
- Not likely because both would have to be bad.
- The O2 sensors are reading air outside the exhaust from the engine
- Exhaust leak before the front O2’s
- De Not likely because there would have to be an equal leak in both banks.
- Exhaust leak before the front O2’s
-Rob
- Thread starter
- #404
Rob, I appreciate the response.
Factory intake and MAF
The only thing I cannot adjust or check is the calibration of systems within the ECU. I can swap out every sensors with a second I have on hand that does not alter the results.
I reached out a local club member that has a GX470. I have ask them if I can meet up to hook my Techstream to capture baseline data in a healthy running vehicle. I can at least use that as a reference to compare all the sensor reading I am seeing in tech stream.
Factory intake and MAF
- I do have the correct intake and MAF on the engine now. The size and equipment is correct.
- I have caped almost ever vacuum port off after the MAF, no change in fuel trims
- I have conducted Smoke tests and found no leak
- I conducted Vacuum tests and no leak was indicated by the results.
- Everything I could not isolate I have replaced with new gaskets and or swapped out know working parts from a running engine to rule them out as the issue.
- The secondary O2 sensors were deleted after the Cats
- The Cats were deleted too
- The Air Fuel Ratio sensors are the only exhaust sensors I have. I did replace them with OEM units.
- I did have to fix a wiring issue where the AFS were never wired with B+ from the battery. I corrected that.
- I confirmed AFS reading properly by monitoring them in TS and using the brake booster to induce a lean conditions and watching the AFS values change.
The only thing I cannot adjust or check is the calibration of systems within the ECU. I can swap out every sensors with a second I have on hand that does not alter the results.
I reached out a local club member that has a GX470. I have ask them if I can meet up to hook my Techstream to capture baseline data in a healthy running vehicle. I can at least use that as a reference to compare all the sensor reading I am seeing in tech stream.
Is it possible to load a speed density tune to the ECU to eliminate the MAF sensor altogether? Speed density tunes are very common in the sand sports world on LS engines, though they usually require a dyno tune of the vehicle to get the tune right. My LS3 is tuned speed density and runs just fine at sea level in Glamis or 5200' in the dunes at St. Anthony Idaho. Just a thought to try and eliminate a variable to help get you past this.
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- #407
I have no idea of this is possible on a 2uz. Definitely outside of my ability and I don’t have anyone that I am aware of close to me that tunes 2uz’s.
I doubt he would send me his programming. It is his proprietary specialty. If he did I wouldn’t know how to read it or manipulate it anyway.
I see that my MAF plug pigtail is arriving today, so I can replace the one I have and see if it changes anything. I will report back after I have got that swapped out.
Have you done a compression test and leak down?
- Thread starter
- #409
Yes, I have done both, the results were shared earlier in this thread. No issues identified with either test.
- Thread starter
- #410
The new MAF pigtails arrived tonight. I ordered deutsch solid pin barrel connectors and the specialized crimping tool for these connectors. I wanted to make sure it went together cleanly.
Pretty crimps
Installed
Started it up and watched the MAF and fuel trim readings in Techstream as it warmed up. I can see the MAF working. It was higher when the idle was high and dropped with the idle as the it warmed up. The FTs are still reading at about 30% and were constant the entire time the engine ran. This does not appear to be my issue.
Where to go from here? Looking back over this thread I have chased every suggestion I could except for ecu programming as I don’t have the tools for that.
The engine sounds smooth, quiet, starts up strong, it wants to run. I am going to dig back into fuel delivery. I have an idea I have not tried yet.
Pretty crimps
Installed
Started it up and watched the MAF and fuel trim readings in Techstream as it warmed up. I can see the MAF working. It was higher when the idle was high and dropped with the idle as the it warmed up. The FTs are still reading at about 30% and were constant the entire time the engine ran. This does not appear to be my issue.
Where to go from here? Looking back over this thread I have chased every suggestion I could except for ecu programming as I don’t have the tools for that.
The engine sounds smooth, quiet, starts up strong, it wants to run. I am going to dig back into fuel delivery. I have an idea I have not tried yet.
- Thread starter
- #411
I revisited the fuel system the fuel pressure holds at 45 psi right at the fuel rail. I went further though and opened up the fuel line at the dampener and in specter it for obstruction and make sure the correct bango washer was in place. I then removed the cross over fuel and blew it out with air and inspected it. Put it all back together and the pressure is the same with in spec.
I don’t believe there is anything wrong with the motor. I am going to reach out to Tim to discuss other options.
I don’t believe there is anything wrong with the motor. I am going to reach out to Tim to discuss other options.
@Tank5 I know you are looking for maybe a shop to check out what is going on it with in NM. I know it's a drive but UMS Tuning in Mesa, AZ tuned a 2UZ that was manual converted and swapped into a Celica recently. That engine was running a Link ECU, but they might be worth a call and seeing if they are an option with the factory ECU. The other option is Overland Cruisers in Montana has been posting a lot of 2UZ swaps into 80s and 40s recently.
- Thread starter
- #413
Thank you I appreciate the leads. I’ll give them a call to see if they can help at all.
Your swap of the MAF plug has ruled out the plug/splice job as a potential issue. But, your MAF is still under-reading air going to the engine. It should be at least 4.5 g/sec for that RPM, and it's hovering around 3.5 g/sec. The O2 sensors recognize this as a lean condition and are dumping in 30% more fuel than the default tables to get you to the 14.7 AFR. The engine will run but not well under these conditions and throw codes. My personal option is that your engine is getting around 4.5 g/sec or higher, but for some reason the computer thinks otherwise.
Unfortunately, I'm running low on ideas as to why MAF is so far off. If you've also ruled out the MAF itself and the intake tube diameter, the only things I could think of would be a vacuum leak (which you seem to have also ruled out). Or, perhaps it's a tune-related/ECU related issue. If you wanted to further rule out wiring, you could pull the ECU out and check the resistance across the pins from the ECU harness inside the cabin and the MAF plug itself - just to verify that you don't have a connection issue further down the harness than the Deutsch plug. Other than that, I'm out of ideas.
Unfortunately, I'm running low on ideas as to why MAF is so far off. If you've also ruled out the MAF itself and the intake tube diameter, the only things I could think of would be a vacuum leak (which you seem to have also ruled out). Or, perhaps it's a tune-related/ECU related issue. If you wanted to further rule out wiring, you could pull the ECU out and check the resistance across the pins from the ECU harness inside the cabin and the MAF plug itself - just to verify that you don't have a connection issue further down the harness than the Deutsch plug. Other than that, I'm out of ideas.
- Thread starter
- #415
Again, I appreciate the help. I do feel that I have rulled out the MAF and plug, vacuum leak, and fuel delivery outside of the ECU.
I had previously tested the MAF circuit to the ECU following the factory trouble shooting manual but I did that by sticking a probe in from the back of the plug. I could test from the face of the plug in the terminal to try and test the connection between the ecu and the plug. I will give it another look.
I have reached a point where I am just going back and rechecking things and tests that I have already done multiple times. Where I can, I try to test slightly different in some cases but the results are the same.
I am going to make a few calls and see if I can find someone who can help. I have a couple of contacts that are Toyota techs
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- #417
I appreciate that!
@Tank5 . I had an issue with the engine in my sand car with hard starts after warming up and running rich and popping & backfiring (LS engine). I bought HP Tuners and I found it showing 0V on one of my 02 sensors. New 02 sensor eventually solved my issue, but not after more issues and figuring out the wiring on the aftermarket 02 sensors had to be re-pinned in the connector to work with my aftermarket harness. In your most recent screen shots in posts above, both 02 Sensor voltage is showing as 0.0V. I apologize for not knowing all the history of your endeavors, but have you absolutely ruled out the 02 sensors or 02 sensor wiring as a possibility?
Isn't there a way to adjust the mass air flow reading? URD used to have a tool to do that.
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- #420
The 02 sensors, specifically the sensors after the cats have been deleted, so they should not show a value. The sensor before the cats Air Fuels sensors are the only sensors needed to run the engine. They are new oem units and I can see them working in Techstream. There was an issue with this circuit early on but I fixed that since.