Abnormally High VE at Idle

[Ben.C]

Hi,

I'm having a problem with abnormally high VE values. I have only started and idled the car but I already know something isn't quite right. As you can see in the map, the VE at idle is around 85% (THAT IS THE ONLY 'TUNED' AREA)

Set up:

• Link G4X Monsoon
• Honda B18C, 12:1 comp, big-ish cams, N/A
• Intake manifold (no ITB's)
• CRANK SENSOR ONLY
• 4 injectors (one per runner) wired to the 4 injector outputs
• Stock K-series injectors from a K24A, injector data taken from the Link G4X K-series plug-in map
• Fuel pressure sensor
• 94 octane pump gas (up to 10%E)
• Link CAN Lambda

The car fires up and idles great, given the obviously wrong VE values. No miss fires or rough running.... I'm not sure if my fuel settings are correct or not? see attached map. Also see attached log of it idling. 

Silver Car 2.4.pclx PC Datalog - 2024-04-21 3;16;23 pm.llgx

[Vaughan]

Your stoich, Fuel density and other fuel related settings are using pure gasoline values, stoich for 10% ethanol for example would be 14.13.

Have you confirmed the flow rate, deadtime and spwa values for the injectors that you are using with the fuel that you are using on Link hardware? different fuels. like ethanol, have different flow rates in the same injectors. If you do get your injectors tested for flow rate, deadtime and spwa be sure to use a G4X or G5 Link ECU as the hardware controlling the injector in that test as the driver chip used affects the deadtime. The K20 sample map was based on a Japanese model DC5 Type R and so I wouldn't be shocked if your injectors are different.

[Adamw]

Your deadtime at 14V is 0.74 Vs 0.9 in the K20 base map, and because you are using multipoint injection with 2 squirts per cycle, you have 2 deadtimes per cycle, so any error due to deadtime is doubled.  Assuming the 0.9ms deadtime was realistic then you would be getting 0.32ms less fuel each cycle than the ECU thinks it is giving you.  Your effective PW at idle is about 1ms so that is more than 30% error in terms of fuel delivered (sorry I had that wrong originally, it is more like 15% error, but still significant).      

[Ben.C]

Bumping this back up.

To eliminate the injectors as an issue, I bought a set of brand new FIC 525cc injectors. FIC has very good injector data and it's in the Link format.

I entered that data to my calibration and made sure my fuel pressure is at 43-44psi even though I have a fuel pressure sensor. 

To get the car to idle at ~14 AFR I had to increase the VE in the fuel table all the way to 90-100%. 

My question is, are my fuel configuration settings correct? I feel like it's injecting 1/2 the amount of fuel I would be expecting. I had the car running last year on my old G4+ atom however the options for injection rate aren't the same in the G4X software.

Silver Car 2.5.pclx

[Adamw]

Can you provide a log of it idling, warmed up with whatever VE it needs to idle with the lambda somewhere close to target.

[Ben.C]

Hi Adam,

See attached.

I turned the closed loop off, just set the ect lockout high. I had it idling close enough to my target. Also attached is the calibration that produced that log so you can see the VE values.

Thanks again!

Silver Car 2.6.pclx PC Datalog - 2024-05-30 6;28;57 pm.llgx

[aerace_fab]

I'm curious why you have it running in group/ wasted. Why not wire it for sequential?

[Ben.C]

9 hours ago, aerace_fab said:

I'm curious why you have it running in group/ wasted. Why not wire it for sequential?

I don't have a cam trigger, crank trigger only. I'm also using 2 of the ignition outputs to control other things.