2jz vvti lean spot
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2jz vvti lean spot
I have tried everything I know to do. Adjusted vr pots got engine to run with no noise filter enabled. That took a 22kohm resistor inline with crank vr+. Without it... to get engine to run good while running i would have to turn trigger pot ccwise to get it to restart after adjustment while running to rev clean with no limiter. after experimenting with resistors and adjusting pots it restarts and runs best. I have ran coil and injector power wires directly to battery. changed ms3 grounding location from block to battery with no change in lean spot. Removed serpentine belt so alternator would not spin to take alt noise out of the equation. Checked over all wiring to make sure I didn't make a mistake somewhere. I don't know what else to do. Injector PW's keep climbing through this lean spot where you can hear engine struggling (sort of a spudder when holding at 2500 and gets worse sounding if you slowing give it more throttle then just takes off after a certain point). Thought it could be TPS but its same rpm no matter the throttle input. Tried playing with moving cam all the way to see if it still does it and yes. My next step is to ditch factory vr and wheel and mount my own. Something tells me it has something to do with this even though I cannot see anything showing up in the trigger log. Maybe I am missing something. Oh and I did a resistance check on plug wires and seem ok. Tried low dwell/high dwell with no change. But I havnt tried a new set. I can get them ordered I guess its worth a try. FYI car revs out fine all the way to rev limiter with no sync losses.
One more thing. the leaner I make idle and low load range the less intermittent pops I get through exhaust. sounds smoothest at 12.5 a/f. 14.0 + gets a lot rougher sounding. Light load cruise in the same way. Lots of popping under very light cruise until a/f is adjusted to about 11.0 then goes away.
Any input or ideas would be helpful.
Attached is a composite log and current tune from me playing with it tonight. Tune is all out of whack due to me frantically trying things to figure this out. But at least you will be able to see the settings.
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- Super MS/Extra'er
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Re: 2jz vvti lean spot
Not seeing any loss of sync issues there. But that's a TINY amount of dwell - what sort of ignition system are you using? You may want to throw more dwell at it.
Are the injectors low or high impedance? If they are low impedance, I would worry about some sort of thermal issue.
Also, consider upgrading from 1.2.4 to 1.4.0 code.
Are the injectors low or high impedance? If they are low impedance, I would worry about some sort of thermal issue.
Also, consider upgrading from 1.2.4 to 1.4.0 code.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Re: 2jz vvti lean spot
I originally had 3.5 for dwell but had turned it down playing with stuff in that msq and it seemed to run the same. I read somewhere to tune the dwell down until it develops a slight miss then increase by .2ms Cannot tell a difference from the lowest 1.0 all the way to 8.0 I think at 3.5 where i had been running it was pulling about 6-7 amps. Injectors are high impedance forgot to mention that. The other night i slid a hall sensor i had laying around off a 392hemi into the crank vr slot temporarily, dont even know what the gap was. Fires up and idles fine but the lean spot is still there holding steady at 2500 so that makes me think it doesnt have anything to do with crank trigger. I did seem to sound smoother holding a steady rpm. going to try that next but need to make an adapter first. Will have new plug wires tonight i will try them but dont think that is the issue since it runs fine up top without a hiccup. Seems spark related to me since everything in the log looks good other than a few degrees plus/minus timing error. Not sure what that is about...
I will get that code upgraded as well!
Thanks for the reply.
I will get that code upgraded as well!
Thanks for the reply.
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- Master MS/Extra'er
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Re: 2jz vvti lean spot
If you do not have sync loss and if the RPM is'nt showing '0' when it shouldn't, then playing with the VR/Hall input (pots, wiring, sensor) can't do anything for you.
Sam
Sam
Re: 2jz vvti lean spot
So I hold throttle steady at 2500 rpm right where this issue is for about 60 seconds and shut it off. Pull all the plugs out and they practically look like new plugs. So this is obviously a fueling issue.
Re: 2jz vvti lean spot
Your firing order is definetly wrong, and probably wired wrong as well. Amazed this runs really
On all JZ engines you use this firing order, connected to the respective outputs: (it's also in the ms3 manual)
You are also pooring in waaay too mutch fuel in that problem area. Very high VE numbers in comparison to the AFR. Take a 3d look on that VE-table. Concider reducing it when you correct the firing order.
On all JZ engines you use this firing order, connected to the respective outputs: (it's also in the ms3 manual)
You are also pooring in waaay too mutch fuel in that problem area. Very high VE numbers in comparison to the AFR. Take a 3d look on that VE-table. Concider reducing it when you correct the firing order.
Toyota JZX90 Mark II drifter
1JZ-GTE, 12+1 on MS3x, 6x LS7 D514's, 510cc, all stock sensors
1JZ-GTE, 12+1 on MS3x, 6x LS7 D514's, 510cc, all stock sensors
Re: 2jz vvti lean spot
I was waiting for someone to catch that. is was correct many tunes ago. VE, Spark and a bunch of setting are out of the ballpark. I will post a street tune tonight. I was playing with stuff trying to figure out the intermittent miss when holding steady throttle or even at idle it pops out the exhaust at random times. Actually when I changed firing order it made zero difference in the way the engine runs so I never changed it back. Also it is wired correctly A=1 B=5 C=3 D=6 E=2 F=4
my normal tune ve is nice and smooth but will not even run at that rpm where I have the fuel dumping in it. with all that fuel it is still like 16.5 a/f until it gets above that. I played with injector curve and required fuel amount to move the pulsewidth around but it still runs lean in that rpm regardless if the pulsewidth is 1.6 or 2.5ms. I was thinking it might be something funky with these large ford injectors needing correction in the curve.
switched to batch injection and wired to mainboard drivers... same thing....
my normal tune ve is nice and smooth but will not even run at that rpm where I have the fuel dumping in it. with all that fuel it is still like 16.5 a/f until it gets above that. I played with injector curve and required fuel amount to move the pulsewidth around but it still runs lean in that rpm regardless if the pulsewidth is 1.6 or 2.5ms. I was thinking it might be something funky with these large ford injectors needing correction in the curve.
switched to batch injection and wired to mainboard drivers... same thing....
Re: 2jz vvti lean spot
Strange.
Firmware corrupted perhaps? Tried to reflash with jumper?
Firmware corrupted perhaps? Tried to reflash with jumper?
Toyota JZX90 Mark II drifter
1JZ-GTE, 12+1 on MS3x, 6x LS7 D514's, 510cc, all stock sensors
1JZ-GTE, 12+1 on MS3x, 6x LS7 D514's, 510cc, all stock sensors
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Re: 2jz vvti lean spot
I see that you don't have vvt setup yet? The hold duty needs to be found and plugged in there at least on these engines.
On my 2j vvti the vvt was wondering around all over the place til i got the hold duty set up. return everything back to the way its supposed to be and try that.
another possibility...I was also having problems with my engine at first. It wouldn't rev up past +/- 3500 rpms. After a Tuner from this forum and I lost a lot of hair, I found both cams was 3 teeth advanced. I was surprised that the engine even ran.
the vvti pulley needs to be on the full clockwise end stop when you put the belt on at BTDC timing mark.
On my 2j vvti the vvt was wondering around all over the place til i got the hold duty set up. return everything back to the way its supposed to be and try that.
another possibility...I was also having problems with my engine at first. It wouldn't rev up past +/- 3500 rpms. After a Tuner from this forum and I lost a lot of hair, I found both cams was 3 teeth advanced. I was surprised that the engine even ran.
the vvti pulley needs to be on the full clockwise end stop when you put the belt on at BTDC timing mark.
Re: 2jz vvti lean spot
Had the vvt working but it was shut off because car seems to run best power wise with it off. Issue is still the same whether on or off, have played with activating it at different rpms but no change to situation.
I did upload the new firmware and got running again with the same issues. I think the intermittent miss has something to do with the 2500rpm thing but I'm not sure. Sometimes it will idle great then a miss every once in a while then goes through a phase where it misses like crazy. It gets worse when I try to lean it out past 13.0 where it should be in the first place... running out of ideas. Possibly a valve being held open or something along those lines... something wrong in the megasquirt? I wish I had a scope to see if the pw's are actually making it to the injector and not just what megatune is saying...
I did upload the new firmware and got running again with the same issues. I think the intermittent miss has something to do with the 2500rpm thing but I'm not sure. Sometimes it will idle great then a miss every once in a while then goes through a phase where it misses like crazy. It gets worse when I try to lean it out past 13.0 where it should be in the first place... running out of ideas. Possibly a valve being held open or something along those lines... something wrong in the megasquirt? I wish I had a scope to see if the pw's are actually making it to the injector and not just what megatune is saying...
Re: 2jz vvti lean spot
How come when I remove serpentine belt and alt is not spinning it runs pig rich off the guage? Even though megatune voltage has not changed.... is there a voltage drop to my injectors somewhere...
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- Super MS/Extra'er
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Re: 2jz vvti lean spot
Please also post a data log.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Re: 2jz vvti lean spot
Here is another datalog. I have rewired some things that I thought could be a cause. All powered items minus fan and pump are now drawing current from the same 8ga wire from batt. I have found that it revs cleanly for the first 30 seconds each day. after that it starts even if you let it cool down to say 100 degrees coolant temp. I have installed a dh61 oem toyota ignitor.
I made another log with it idling and then holding it at rpm. You can see that I am slowly giving it tps but does not accelerate until all of a sudden it desides to take off. If I let it come back down slowly while on throttle through the rpm range it doesn't lean out.
I made another log with it idling and then holding it at rpm. You can see that I am slowly giving it tps but does not accelerate until all of a sudden it desides to take off. If I let it come back down slowly while on throttle through the rpm range it doesn't lean out.
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- Super MS/Extra'er
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Re: 2jz vvti lean spot
Can you check the voltage at the injectors? Maybe some weird voltage drop going on there?
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Re: 2jz vvti lean spot
I have checked voltage drop on everything. I have done everthing I know to do and have learned even more trying to figure this out. Usually when you can't find the answer to something it's probably because you are looking in the wrong place. At least that's usually the case with problems I can't figure out right away or find the urge to seek further help for answers.
Last night laying in bed thinking about what could be wrong... I remembered moving my fuel lines around when I had the motor out. So i had a little spare time this morning so I changed it from "pump flowing to rail, out the regulator and down the return. My aem regulator has 2 pressure ports. It simplified things running pressure to regulator then using other pressure port to feed rail and cap the end. Essentially making it a dead head system. I do alot of systems this way on customer cars upgrading fuel system with turbo or supercharger. Never an issue at all. But never using this aem regulator. Most builds I use a Fore unit. I tune factory pcm's on FI, heads and cam cars and never had this issue.
Car runs like a top now. Absolutely smooth through entire rpm range. Something about the frequency in the fuel rail at that pw making the fuel cavitate? I did notice when I would turn off sequential and go to batch it would happen at a few hundred rpm different. Just weird that if ran good on top end and fuel pressure was dead on, not even a flutter even when misfiring. Guage is even tapped into the rail.
Time to fix all my settings, tables and fine tune this machine.
Hopefully this may help someone in the future
Thanks for the help guys! Any thoughts on this?
Last night laying in bed thinking about what could be wrong... I remembered moving my fuel lines around when I had the motor out. So i had a little spare time this morning so I changed it from "pump flowing to rail, out the regulator and down the return. My aem regulator has 2 pressure ports. It simplified things running pressure to regulator then using other pressure port to feed rail and cap the end. Essentially making it a dead head system. I do alot of systems this way on customer cars upgrading fuel system with turbo or supercharger. Never an issue at all. But never using this aem regulator. Most builds I use a Fore unit. I tune factory pcm's on FI, heads and cam cars and never had this issue.
Car runs like a top now. Absolutely smooth through entire rpm range. Something about the frequency in the fuel rail at that pw making the fuel cavitate? I did notice when I would turn off sequential and go to batch it would happen at a few hundred rpm different. Just weird that if ran good on top end and fuel pressure was dead on, not even a flutter even when misfiring. Guage is even tapped into the rail.
Time to fix all my settings, tables and fine tune this machine.
Hopefully this may help someone in the future
Thanks for the help guys! Any thoughts on this?
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- Super MS/Extra'er
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- Joined: Thu Apr 16, 2009 8:08 pm
Re: 2jz vvti lean spot
That is really odd. All I can think of would be some sort of pressure wave or somehow boiling the fuel in the rail. Glad to hear you stuck with it and got it figured out.
Matt Cramer -1966 Dodge Dart slant six running on MS3X