Sorry for your troubles Denis. Man you have done you’re due diligence on this and it still persists
Build US Spec. February 1990 Poverty 80 2uz/h151f swap
- Thread starter Tank5
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Your MAF is reading really low. I have the same engine/ECU as you (2007 VVTI GX470). My MAF usually reads around ~4.0-4.5 g/sec at around a ~550 rpm idle. Yours is reading 3.32 g/sec at a 713 rpm idel. So your reading should be 5-6 g/sec or even higher at that RPM. Your fuel trims of +29% indicate the ECU is having to add a ton of fuel to make up for the extra air the MAF is not reading.
I have had lots of MAF problems on my GX470 with a aFe cold air intake. Most of them have been due to the physical MAF plug itself. I've had to replace the plug (with an aftermarket pigtail) only to have to replace it again due to my crappy crimping job on the replacement plug. That one got replaced with a Amazon plug that worked for a bit, but then that plug cracked. The rig would start running weird, after which plugging/unplugging the MAF would make it run better for a bit, then it would start up again. Toyota MAF plugs are very fragile. BUT, since you have a DIY intake, I am not sure if your issue is plug related or intake-related.
What ended up working for me (at least for now) is a Ballanger Motorsports MAF pigtail spliced into a Deutsch connector. I then spliced another Deutsch connector into the OEM harness leading up to the MAF. So if this MAF plug craps out, I can easily replace it w/o slicing up the OEM harness more. See below (note this also has a DIY SAIS bypass added in, which you do not need).
I have had lots of MAF problems on my GX470 with a aFe cold air intake. Most of them have been due to the physical MAF plug itself. I've had to replace the plug (with an aftermarket pigtail) only to have to replace it again due to my crappy crimping job on the replacement plug. That one got replaced with a Amazon plug that worked for a bit, but then that plug cracked. The rig would start running weird, after which plugging/unplugging the MAF would make it run better for a bit, then it would start up again. Toyota MAF plugs are very fragile. BUT, since you have a DIY intake, I am not sure if your issue is plug related or intake-related.
What ended up working for me (at least for now) is a Ballanger Motorsports MAF pigtail spliced into a Deutsch connector. I then spliced another Deutsch connector into the OEM harness leading up to the MAF. So if this MAF plug craps out, I can easily replace it w/o slicing up the OEM harness more. See below (note this also has a DIY SAIS bypass added in, which you do not need).
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- #363
It has been challenging but there is a solution. I will figure it. Hopefully sooner thank than later.Sorry for your troubles Denis. Man you have done you’re due diligence on this and it still persists
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- #364
@Rednexus
I have replaced the MAF plug twice, the original plug when I received it came with non oem wiring and would not allow the pins to seat in the plug completely, so I replaced it with an oem plug and crimped new terminals. I was not convinced they seated well again because on the wire gauge, so I bought another plug with a pigtail and soldered the pigtail into the harness.
Maybe something about my splice job is causing an issue but I did trouble shoot the circuit following the service manual and it was within spec.
I am open to anything though, so I may try you solution and see if it makes a difference. If anything it will make replacing the plug in the future easier.
I also really appreciate the MAF reading specs. Without another yo compare it to I am not sure what some of that should be. I am going to swap out the plug and cut out my earlier splice and use a plug to attach the pigtail as you suggested. See if my readings change.
I am currently running an oem intake, so my 80 series modified intake is not part of the equation any more.
Thanks for the suggestion.
I have replaced the MAF plug twice, the original plug when I received it came with non oem wiring and would not allow the pins to seat in the plug completely, so I replaced it with an oem plug and crimped new terminals. I was not convinced they seated well again because on the wire gauge, so I bought another plug with a pigtail and soldered the pigtail into the harness.
Maybe something about my splice job is causing an issue but I did trouble shoot the circuit following the service manual and it was within spec.
I am open to anything though, so I may try you solution and see if it makes a difference. If anything it will make replacing the plug in the future easier.
I also really appreciate the MAF reading specs. Without another yo compare it to I am not sure what some of that should be. I am going to swap out the plug and cut out my earlier splice and use a plug to attach the pigtail as you suggested. See if my readings change.
I am currently running an oem intake, so my 80 series modified intake is not part of the equation any more.
Thanks for the suggestion.
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Does the OEM intake you are running match the donor ECU? Meaning, both the ECU and air intake assembly are from a VVTi 100 series?
The reason I ask is because there might be a difference in the diameter of the MAF tube between a 100 series and GX470/4runner and the correct diameter is needed even if the MAF part number is the same. A quick Ebay search shows the configuration on where the MAF is mounted on the airbox is significantly different.
there’s poverty spec… but this may be on another level. Prob make a decent currier whip in snow states, how sick would it have been if they made high roof panel 80’s with manual trans, part time locked with manual hubs and LSD rear diff ( my cross faded thought of the night )
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- #367
Short answer no, the ECU keeps changing.
This VVTI motor came in the Tundra, 100 series, LX and GX 470 and 4runner. The MAF was shared across these versions with two part numbers and I have both. The air box and intakes are configured differently to fit the engine compartments for the given model but I have so far found that the MAF tube mounting location is the same. I have concluded that as long as the complete intake is built from a 4.7 VVTI model then it should be fine. The airbox I am running is from a Lx470 and the intake tube is from a Gx470 both VVTI models. I have this configuration because it fits in the engine bay.
Tim who built the harness is has sent me different programmed ECUs from VVTI models. The original Land Cruiser ECU I sent for the build got fried during the programming, so he replaced it with a GX470 ecu and I bought a second ecu as a spare that came from a 4runner. The ECU I just got back may be different again but is from a 4Runner. I expect that Tim knows more about the interchangeability than I since he is programming them. I will ask him to see what he says.
It may be the plastic part plug itself. The plugs are very thin/fragile, if it is 15+ years old OEM plug is used I would expect the plug to be damaged inside and causing a poor connection. When mine would act up it would often show super-low MAF readings as well and run pretty lean when in closed loop.
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- #369
Last night I ordered some solid pin Deutsch connectors and a couple MAF pigtails from Ballenger Motor sports. I am going to do just as you suggested and make an extra jumper as a back up to keep in the rig should it fail. I will the update as soon as I get it all installed.
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It seems worthwhile in my opinion to do the easy troubleshooting step of measuring the inside diameter of the air tube where the MAF mounts for both a VVTi Land Cruiser/GX470 and a VVTi 4runner/LX470. They are probably the same, but what if they are not? For a data point comparison my 05 Tundra measures about 85mm inside diameter where the MAF mounts.
I know Rivman made this same point few pages back in your thread in post #320 and your reply was that the MAF is the same part number. It isn't about the MAF sensor, it is about the air intake tube diameter that the sensor is positioned in.
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- #371
I don’t disagree with your thinking and I have spent the last couple hours comparing part numbers and the various 4.7 VVTI air boxes. I unfortunately only have the LX470 box to measure the MAF housing tube. If anyone out there has a gx470/4runner (VVTI version) air boxe that can take a diameter measurement for me I would appreciate it.
The ecu I am using now is out of a 2007 4runner which uses the same airbox as the GX470. I can see in pictures that the MAF is positioned differently in the LX box (horizontal ) compared to the GX box (vertical). Earlier on I actually tried orienting the MAF vertically and it did not change anything but I had other other issues that could have clouded the result.
I researched the MAF part number more as well and Toyota shows the same MAF is fitted in 98 different vehicles ranging from 1.8 liters to 5.7 liter engines. I don’t expect they all have the same MAF housing diameter. There may very well be well be a difference in the diameter of the tube in the GX and LX housings. Could be that simple.
I was talking to a Toyota tech tech today and said what ever my issue is it is probably going to be something simple. This could be it.
@Rednexus you said you have a gx470 could you measure the diameter of the tube that the MAF sensor sits in and post it up here?
The ecu I am using now is out of a 2007 4runner which uses the same airbox as the GX470. I can see in pictures that the MAF is positioned differently in the LX box (horizontal ) compared to the GX box (vertical). Earlier on I actually tried orienting the MAF vertically and it did not change anything but I had other other issues that could have clouded the result.
I researched the MAF part number more as well and Toyota shows the same MAF is fitted in 98 different vehicles ranging from 1.8 liters to 5.7 liter engines. I don’t expect they all have the same MAF housing diameter. There may very well be well be a difference in the diameter of the tube in the GX and LX housings. Could be that simple.
I was talking to a Toyota tech tech today and said what ever my issue is it is probably going to be something simple. This could be it.
@Rednexus you said you have a gx470 could you measure the diameter of the tube that the MAF sensor sits in and post it up here?
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- #372
The same guy that told me this was going to be something simple also suggested I consider the brake booster as the source of vacuum leak causing my lean issue. I checked it again this time separating the vacuum line from the booster and plugging it. I ran it for about 10 minutes idling in the garage and it showed significant improvement in the Fuel Trims. I am going to buy a booster. I believe the booster is the original booster.
Here is the live data with the booster line plugged.
Here is the live data with the booster line plugged.
Glad to hear a promising update! I'm a bit invested in this story now and want to hear a happy ending!
I'm also going to refer to this thread as Exhibit A the next time someone asks me why I prefer my all-mechanical 1HZ diesel engine.
I'm also going to refer to this thread as Exhibit A the next time someone asks me why I prefer my all-mechanical 1HZ diesel engine.
VAC leak that will do it too, sounds like you might be on your way.
back to MAF discussion. I think I might have an insight for you, did you say you have been using factory air boxes with this last bout of trouble?
If your using using some of the cutom ones you have built your MAF is in backwards I think. I cant remember where I read it, ( Its on here somewhere) when reseaching this project myself, where someone said its very important to have your MAF plug facing to the back of the truck to make sure its flowing the right dirrection.
your post here shows the white MAF tube and the cut and welded one in the oppsit configuration. If you accounted for this with how you built those set ups or if I am mistaken and getting some things mixed up form all my reading I could very well be wrong. But its something simple that could be over looked for bigger ideas. I find I mess up simple s*** and spend hours chasing something.
back to MAF discussion. I think I might have an insight for you, did you say you have been using factory air boxes with this last bout of trouble?
If your using using some of the cutom ones you have built your MAF is in backwards I think. I cant remember where I read it, ( Its on here somewhere) when reseaching this project myself, where someone said its very important to have your MAF plug facing to the back of the truck to make sure its flowing the right dirrection.
This project keeps going, it seems every time I solve an issue it presents a new one.
I was able to confirm the issue with the P0031 and P0051 codes. After pulling the harness off and opening it up I found the Air Fuel sensors battery power was never wired. It apparently got missed when the harness got built.
I after wiring it up and putting it all back together. Sure enough, no more P0031 and P0051codes.
Wiring it up.
With that solved I focused on what I believe was my last issue, the intake. What I have learned is that the...
I was able to confirm the issue with the P0031 and P0051 codes. After pulling the harness off and opening it up I found the Air Fuel sensors battery power was never wired. It apparently got missed when the harness got built.
I after wiring it up and putting it all back together. Sure enough, no more P0031 and P0051codes.
Wiring it up.
With that solved I focused on what I believe was my last issue, the intake. What I have learned is that the...
your post here shows the white MAF tube and the cut and welded one in the oppsit configuration. If you accounted for this with how you built those set ups or if I am mistaken and getting some things mixed up form all my reading I could very well be wrong. But its something simple that could be over looked for bigger ideas. I find I mess up simple s*** and spend hours chasing something.
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- #375
VAC leak that will do it too, sounds like you might be on your way.
back to MAF discussion. I think I might have an insight for you, did you say you have been using factory air boxes with this last bout of trouble?
If your using using some of the cutom ones you have built your MAF is in backwards I think. I cant remember where I read it, ( Its on here somewhere) when reseaching this project myself, where someone said its very important to have your MAF plug facing to the back of the truck to make sure its flowing the right dirrection.
This project keeps going, it seems every time I solve an issue it presents a new one.
I was able to confirm the issue with the P0031 and P0051 codes. After pulling the harness off and opening it up I found the Air Fuel sensors battery power was never wired. It apparently got missed when the harness got built.
I after wiring it up and putting it all back together. Sure enough, no more P0031 and P0051codes.
Wiring it up.
With that solved I focused on what I believe was my last issue, the intake. What I have learned is that the...
your post here shows the white MAF tube and the cut and welded one in the oppsit configuration. If you accounted for this with how you built those set ups or if I am mistaken and getting some things mixed up form all my reading I could very well be wrong. But its something simple that could be over looked for bigger ideas. I find I mess up simple s*** and spend hours chasing something.
Thank you, finding the booster leak feels like progress but I will wait to celebrate until I get a new booster installed and drive it to see if solves the power issue too.
I put my custom intake on the shelf months ago and have been using a factory LX470 air box which is where the MAF mounts. The MAF will only mount in the housing one way. If I try to put it in backwards the bolt holes do not line up, so there is only one way to install in the oem location. I did find in my research that the MAF is mounted differently in some models such as I described in an earlier post.
Your MAF readings are still pretty low however, and 20% fuel trims are quite high. You may have a vacuum leak in the booster, but with a stock intake, your fuel trims should be within +/- 5%. So, IMO it's still under-estimating the amount of air getting into the motor.
COS80
SILVER Star
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- #378
@Rednexus I agree, I FTs are not perfecto but they improve. Which is progress
I am trying get a measurement on the inside diameter of the tube where the MAF sits on a GX470, can you help me with that. I want to compare it to the LX470 version I am using.
I am trying get a measurement on the inside diameter of the tube where the MAF sits on a GX470, can you help me with that. I want to compare it to the LX470 version I am using.
Luckily I had the OEM airbox sitting around. The tube flares out just past the MAF where the intake tube connects to it. My caliper was just deep enough to get in past the flare.
It also wasn't perfectly round, but seemed ~84 mm ID on average (just below 84 mm in some areas, just above in others).
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- #380
Thanks @Rednexus for the measurement. I measured my LX version and will also add the measurements that @Broski took from his MAF tube on a Tundra VVTI air box.
MAF Tube inside diameter measurements:
MAF Tube inside diameter measurements:
- Tundra 4.7 VTTI = 85MM
- GX470 4.7 VVTI = 84MM
- LX470 4.7 VVTI = 84MM