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2005 1mzfe V6 fuel trim issue

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10 months 2 weeks ago #62131 by Morphman
2005 1mzfe V6 fuel trim issue was created by Morphman
Hi all,I have been reading the forum and there is grwat information in here.I have a 2005 1mzfe v6 which I have fitted in my MR2. This is a new build and I am at a loss as to why my fuel trims are all over the place.The stft are alternating on each bank, as are the afr sensors. Bank1 will be -20 while bank 2 will be 20 and then they will reverse.
See screenshot below.
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10 months 2 weeks ago #62132 by Tyler
Replied by Tyler on topic 2005 1mzfe V6 fuel trim issue
After we figure this out, you'll have to show me how you managed to shoehorn a 1MZ into an MR2 engine bay. :ohmy: :lol:

Would it be possible for you to post the video that your fuel trim screenshots were taken from? Might help to see the fuel trim reactions in real time.

With the swings in the fuel trims bank-to-bank, my first thought is that the upstream AFR's are reversed. As in, the bank one sensor is connected to the bank two harness. In that condition, the trims will never be able to get things under control.

I know that on stock 1MZ applications, reversing the AFR connectors is pretty much impossible. But I figure at least a few modifications were needed to the 1MZ harness to make this engine swap work.
The following user(s) said Thank You: Noah

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10 months 2 weeks ago #62133 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
Can I post mp4 files here?

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10 months 2 weeks ago #62134 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
There are only the two upstream afrs in these builds.

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10 months 2 weeks ago #62135 by Tyler
Replied by Tyler on topic 2005 1mzfe V6 fuel trim issue

Can I post mp4 files here?

Unfortunately, the forums aren't set up to allow for MP4's. :(

If you like, email me at wrenchturnsyou@gmail.com and I'll upload it.

There are only the two upstream afrs in these builds.


Right. I'm wondering if the two upstreams are reversed.

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10 months 2 weeks ago #62136 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
I'd say files are too big. I'll Dropbox em or summit.Wouldn't rule out crossed but I don't think so.
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10 months 2 weeks ago #62137 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
youtube.com/shorts/ZZpNuyo0pV4?feature=share3

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10 months 2 weeks ago #62138 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
youtube.com/shorts/5_9YjhGMFnQ?feature=share3

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10 months 2 weeks ago - 10 months 2 weeks ago #62139 by Chad
Replied by Chad on topic 2005 1mzfe V6 fuel trim issue
Both, Bank 1 and Bank 2 Air Fuel sensor voltages are identical, and glitching to 4.99 V. :huh: I don't know what that means, but it's mention-able. :blink: Is it possible that you have a crushed wiring harness, somewhere?
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer."
I have learned more by being wrong, than I have by being right. :-)
Last edit: 10 months 2 weeks ago by Chad.

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10 months 2 weeks ago #62140 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
Harness was modified and built professionally so I doubt it's a crushed harness.
I am completely perplexed, I thought it maybe a vac leak between the maf and the intake but I can't find anything. Several cans of brake cleaner and nothing.

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10 months 2 weeks ago #62146 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
Surely if I disconnected one afr and it shows the correct bank then they are not crossed

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10 months 2 weeks ago #62147 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
I gots updates, I think the PCV is shot. I have one ordered so let's see

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10 months 2 days ago #62334 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
I'm back, can I ask you guys if a restriction in flow in the exhaust of one bank would cause this. After the afr obviously?

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10 months 1 day ago #62356 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
I can confirm the afr sensors are NOT reversed.
This really is giving me a pain now

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10 months 18 hours ago - 10 months 18 hours ago #62361 by STIMECE
Replied by STIMECE on topic 2005 1mzfe V6 fuel trim issue
If i recall correctly the upstreams on that engine....high voltage is lean command. 3.3v is where it needs to be.

Your first order of business is to create rich and lean conditions for the car and see if you can get your upstream to react....report back whenever you get that done.

For a rich condition, I use propane in the intake tube

Edit: Why is your bank 1 sensor sensor 2 showing 0v? that should be your downstream in your cat. That engine doesnt have two cats....so you dont have a voltage reading for bank 2 sensor 2 which makes sense
Last edit: 10 months 18 hours ago by STIMECE.

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10 months 18 hours ago #62363 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
Hi there,
There are only 2 afr sensors on this, no o2 sensors.

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10 months 18 hours ago #62364 by STIMECE
Replied by STIMECE on topic 2005 1mzfe V6 fuel trim issue
The MZFE ECU is going to look for that O2 downstream voltage....if its not there, thats your issue. Tuning that stuff out so the ECU ignores is beyond my scope but I assume you did flash the ECU to account for that yes?

Low voltage on the downstream is lean. I know the upstreams will adjust the LTFT and STFT readings but I am not 100% sure how the downstream will factor in that.

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9 months 4 weeks ago #62370 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
The guy who does these conversions and dud the wiring in mine is puzzled. I bought a vac gauge and it settles on 22 hg and then drops 1 hg and back up. Will post vid on YouTube and link here shortly

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9 months 4 weeks ago #62371 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
youtube.com/shorts/9_xm3gfD5Sc?feature=share3

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9 months 3 weeks ago #62406 by Morphman
Replied by Morphman on topic 2005 1mzfe V6 fuel trim issue
So I removed the cone filter and restricted the air flow somewhat thorough the maf and it seemed to improve things.

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