ms2 1jz lean misfire

[robinpipers]

Hello!

I'm a tuner newbie, was at a tuner some months ago to tune my car, or give it a touch up after upgrading to a faster spooling turbo,
and fixing exhaust leaks etc.
We had issues with it stalling and running lean on dyno, didn't respond to increase in VE.
Taught the injectors were bad, sent them in for testing with ok result, changed fuelpump with no difference,
increased the size of fuel lines didn't change anything, new filters, tested my 1.8t vag cop on a friends car with no difference,
new fuel pressure regulator also no difference, new battery, new grounds, measured volt and ampere to pump, connected fuel pressure meter and it measures alright.

Car spec:
1jz-gte, e85
walbro gst 450 pump
an6 feed, an 5 ish return.
1600 cc injectors RC engineering Peak n hold.
Megasquirt 2 v3
1.8t vag cop.

Running without boost pipe connected to turbo (to not exceed 100 kpa).

So after the initial test at my tuner I've been trying to fix things and trying the car in a short slope I have where I live. And the pull I do is in first gear with handbrake pulled to create load.
The car starts to run lean & stalls when reaching around 4000-4200 rpm. It also stalls and sound like launch control if I free rev the engine, like step on the pedal. and it gets stuck at around the same rpm, sounding like it builds boost. And the only way to get out of it is to take the load off or to get of the throttle.

Am i supposed to be able to free rev the engine like that when EGO is not enabled, or when AE is not tuned?
I'm running a tune from last year when the car was tuned for a bigger turob, but with boost pipes disconnected.

Anyway later today I took the car for a longer drive up a longer hill. A 2nd gear pull and here the car started to run rich instead.

When i look at the long pull it looks like pw is stable and its going rich, I richened the VE table after the shorter pulls. After this pull I went back to do another pull in the shorter slope but here it stalled after changing. Does this have something to do with AE or EGO begin disabled?

Another thing I've tried is to mount the fuelpump connected to the fuelrail 60cm from engine without a filter. The free revs recorded looks so much richer in mixture.
Just don't understand, Changed filters, Upgraded size of fuellines, new fuel pressure regulator tried a different pump, opening the fueltank for more ventilation.

Upgrades since last season was turbo + fixing exhaust leaks.


Best regards

[tryingbe]

It does looks strange. Given your fuel pump and injectors, it should not be out of fuel.

Have you done a fuel volume test?

Take the fuel hose between fuel regulator and tank off, put it in a gallon jug, run the pump for 30 seconds and take note of how may litre you have. Multiply what you have by 120 and you'll get your litre per hour.

[robinpipers]

It does looks strange. Given your fuel pump and injectors, it should not be out of fuel.

Have you done a fuel volume test?

Take the fuel hose between fuel regulator and tank off, put it in a gallon jug, run the pump for 30 seconds and take note of how may litre you have. Multiply what you have by 120 and you'll get your litre per hour.

2.75l in 30s = 330l /h at 43,5 psi

[rickb794]

Where are the injectors getting power? Full 12v?

Any sync loss?

[robinpipers]

I have the flyback circuit, Injectors are getting full 12v from fuse and then wired back to box.
Injectors are PnH.

No sync losses in any logs.

[rickb794]

Do you have Peak & Hold drivers for the injectors or are you using PWM current control?

Injector power should come from the fuel pump relay or an aux relay triggered by the fuel pump relay that gets power directly from the battery (no vehicle harness used).

[robinpipers]

Im using PWM for current control, it has been working good last year.
Injector power is through FP relay and from battery to relay.

Noticed something. What is the timing err % in the log for? Added a screenshot of log

[robinpipers]

Just a question first, Am I testing the wrong way, I'm driving in a slope on first gear with handbrake pulled to create load, and then I try to be careful not to increase throttle too much.
Car stalls or hesitates at around 4000 rpm, always. Shows super lean 19,9.

I don't know if its the box, if its my triggers, But I cant see any reported sync loss. Only timing err where the hesitation occurs. Should I try log the sync instead when driving?
Havn't tried inspecting my crank sensor wiring or other parts of triggers since theres no sync losses reported in my datalogs (when normal logging).

I have access to oscilloscopes and other equipments so if theres anything you want me to scope to aid or anything just ask I'm running out of ideas.

Attached a picture of current going to my injectors. theres some ripples, are these normal, 100mv = 1a.

[rickb794]

Lean indication can be rich misfires..... (or ignition misfires)
The O2 does not measure fuel it measures the difference between O2 levels in the exhaust and outside air.
Any misfires will increase O2 level in the exhaust which is then converted to AFR (lean).

Perhaps your plug gaps are too big for the boost level or you have some weakness in the ignition secondary.

Don't some of the VAG COP coils require a driver to properly trigger?
5.3.1.3 Logic spark outputs - FET driver method.

[robinpipers]

Ok, but its strange it would go from 14 to 19 like that if it would be rich or maybe not?

Yes VAG cops with fet is how its running today, worked great last year, COP's where tested on my friends supra with no issues.

I've changed to new plugs and also gapped them down. No difference.

And theoretically if my lambda would be the problem it should still run fine with the tune since theres no EGO activated?

I've been thinking if it can be something timing related..?

Added a log from monday, afr really jumps straight up like a misfire.

[robinpipers]

Tried some more pulls today.

The misfire is always coming at 4000 rpm,
Tried increasing advance by 5deg with no difference, Then Lowered VE by 10 in affected cells no difference,
Lower dwell settings, Tried logging sync, can't see anything different.

Attached log and pic of region

[Tjabo]

Did you ever find any improvement for this condition? Or for that matter, did you ever find any good information about what "Timing err" really is or represents?

[dakin.engineering]

JUst guessing, but the error tells you the wheel doesn't have enough teeth.
My 45 deg seperation got plus and minus 12.7 error.
The prediction wants less than 25.4 degrees between signals.

Hope this helps.
Sam

[Matt Cramer]

Timing error is a percentage difference between the expected time between teeth and the measured time. It's sampled at a rate that is too slow to make it a really useful number, but it does tend to increase when the engine is running roughly.

I see this one is using PWM current limiting on the injectors. This can be very sensitive to grounding, and it's also possible that a 20% current limit may cause the injectors to start "creeping back shut" if it is set too low.

[mdlimy]

OP may have already fixed the issue, either way, I am curious to hear his fix.

I can almost bet I know what the issue is/was, but no one will believe me until they see it with their own eyes.


I completed a big single turbo upgrade on my brothers 1jz car a while back and ended up with a very very similar issue. Started tuning the car and it would just hit a brick wall, going lean, almost like there was a massive drop off in the VE table when coming into boost.

The fix was to reinstall the fuel pressure pulse damper that I removed when I upgraded to the top feed rail, fpr, -6an lines etc... Once the stock pressure damper was reinstalled the issue completely disappeared.

For reference heres a brief spec list of things that matter.

1jz non vvti
aem v2 ems
id1000s
driftmotion top feed fuel rail
aeromotive fpr
aem 340lph
stock fuel lines to the firewall, -6an to the motor
Pump gas