2jzgte vvti wont rev past 4000 rpm

[jbjslambert]

this is a new ms3x build using an aristo 2j vvti engine with sequential fuel and wasted spark using Toyotas dh61 igniter. currently trying to understand more about the VVTi system when it was discovered that the engine will not rev past 4000rpm. I have all the VVTi PID set all to 0, min and max at zero, hold duty off. The vvt cam gear is still advancing or retarding when being rev'd up. (can hear it audibly hitting the stops) Its like the engine has hit a limit. Please take a look to see if I am overlooking something or have seen this problem before.

Thanks,

Joe

2015-03-06_20.22.35.csv

2015-03-06_20.23.15.msl

2015-03-07_08.36.43.msq

[Matt Cramer]

Ok, that log is under load. What happens if you free rev it with the clutch in under no load? How high will it go?

[jbjslambert]

Sorry. Yes it was on a dyno when it was discovered. It does the same thing even with the clutch in

[Matt Cramer]

Can you get a data log of that as well? That takes the loading out of the equation.

[jbjslambert]

Sorry again matt. That was a free rev. It was just held at WOT.

[jbjslambert]

was advised that there looks like a false trigger on the cam signal. adjusted the zero crossing on the expansion board. cam signal looks correct, not sure if this is going to correct my problem. hoping so

getting some more fuel and try again today

this is just an attempted start with fuel turned off. I noticed a few things.
1. what is the red line showing some noise or trigger values when I begin to crank?
2. it appears that I am getting a variance in "tooth time" on the crank signal. Most pulses are about 4ms long and some are about 5-6ms. Normal during cranking til engine is at steady rpm?

Thanks

2015-03-10_17.34.57.csv

[jbjslambert]

anyone?

[wes kiser]

The engine will speed up and slow down while cranking depending on where it is in the cycle. The tooth times looks reasonable and as expected.

I have to confess I don't know what the red line is representing. When viewing the logged CSV in excel, nothing corresponding to the red lines displayed in TS exists. I assumed it was triggers or something, but they completely go away after synced. What matters in interpreting the logs is primary level, secondary level, triggers, sync status, tooth time, and total time.

[jbjslambert]

ok thanks, I thought the variance was due to cranking speed. Trying to be on the learning curve.


Update:

Went through the sequential turbo setup today and opened valves manually to see if this was causing the rev issue. It wasnt.

I am beginning to think its a coil/igniter problem.

If I roll the rpms up slowly to the point where it hits the "wall", you can hear it sound like the timing is being retarded. nothing as such is being reported as you can see in the logs posted initially.

Back off the throttle just a touch and back on and the issue is worse with less rpms "allowed". ( initial rev to 4000 then off a little then throttle back up and then the "wall" is 3000-3100 rpm). Its acting like its the speed(dwell) of the output is not keeping up with whats being commanded.

The sound it makes at the "wall", is like a 1974 F100 with a restricted exhaust and glass packed mufflers. very tingy and glass pack sounding. is my best idea of describing the sound. lol

[Matt Cramer]

The red lines at the beginning of the log before it has declared sync. Perfectly normal.

If I roll the rpms up slowly to the point where it hits the "wall", you can hear it sound like the timing is being retarded. nothing as such is being reported as you can see in the logs posted initially.

Check with a timing light: is the timing being retarded?

[jbjslambert]

checked it and timing is being retarded. checked it on multiple cylinders and all are being retarded. tried another DH61 igniter and the same thing happens. tried a value of 1 in the spark latency and it seems less spark retard is happening. I just don't know what each value of latency command does so I didn't try anything higher.

[jbjslambert]

let me add that timing went from about 30 degrees to 10 when I initially checked it and in fixed timing mode it retarded maybe 3-5 degrees

[ekam99]

try to reduce dwell down to 2 ms.

[jbjslambert]

I tried that yesterday and the problem didn't change

[ekam99]

I tried that yesterday and the problem didn't change

OK, ignition trigger capture -> falling edge. Have you tried this?

Also, for "going high" spark output. Are you certain it goes high? Please confirm this with the scope, if "falling edge" ^^ does not make a difference.

[jbjslambert]

Really don't want to.lol. don't want to see metal parts fly

[ekam99]

Really don't want to.lol. don't want to see metal parts fly

What?

[jbjslambert]

Isn't this a dangerous change to make if it's unknown? can someone verify this?

[nathaninwa]

changing from rising to falling is not dangerous at all. You can do both or one or the other and see YOull just need to resync timing on each change

[ekam99]

Isn't this a dangerous change to make if it's unknown? can someone verify this?

if your ignition is being retarded that suggests either the behavior of jz igniter (happens if dwell is too big) or "changing" the positions of the trigger teeth. It happens when your input is "normal" and you try to trigger it with the rising edge. Thus the position of that edge in regards to the tooth will be different with rpm (voltage from sensor rises with rpm and the trigger happens earlier and earlier as rpm rises). On the other hand, triggering on "falling" will be pretty much always at the same place (center of the tooth, where voltage from VR sensor crosses zero) . All this theory depends on a tooth shape as well.

So, nothing's wrong in trying the other edge.