Engine stalls out after start with MAF connected

[hooda66]

Hey all, my car has been at United Speed Racing in Atlanta for the past couple months getting the engine built and adding a PRL P600. I scoped it up late Friday (03/18/22) and headed back to Tennessee. After about 50 miles in, the car spuddered for a bit and then died before I came to a complete stop on the side of the highway. Got the car towed back to USR after troubleshooting all that I (thought) I could without any tools. The code being thrown was P0560: System Voltage Malfunction. Next morning we troubleshot just about everything. Swapped a fully charged battery. Coils. Spark plugs and checked gaps. Potential disconnected sensors. All grounds. Checked compression. Fuel pumps. Uploaded Factory tune. We also followed the Honda diagnostic troubleshooting guide for that code and checked for continuity between sensors and ECU. Swapped MAF sensor with known working one. All of these came up with dead ends. Until we unplugged the MAF sensor, tried starting the car and it started perfectly fine. We left the car running for a bit and tried plugging it back in and and car died. When I dropped the car off, the car had the following firmware version: 3.8.5. Before leaving USR, it had been updated to 3.9.0.

Attaching two datalogs and Kefi's tune. hoonda66_log1 shows me starting the car with MAF plugged in and car immediately dying. hoonda66_log2 shows car being started with MAF unplugged and around 40 seconds into the datalog, I plugged the sensor back in and car dies.

My mods:
Hondata Fuel System Upgrade
Hondata MAF 500
Flex Fuel kit
PRL Race MAF + HVI
PRL P600
PRL Charge Pipes, Intercooler, Inlet pipe, HF exhaust, frontpipe

Let me know if I can provide anything else for you all.

Thanks,
-Ben

[Hondata]

None of the datalogs show lambda so it is not possible to see what the AFM calibration is like nor the fuel trims.

But why are you using the MAF 500 and the PRL race MAF? You only need to use one or the other. You can get the it run using both, but that is going to take some AFM table tuning.

[hooda66]

The Hondata MAF was a last resort effort. I get the same results from OEM MAF.

[Hondata]

Put the stock MAF in. Change the calibration to use the AFM table for the PRL HVI. Re-test.

[hooda66]

Attaching now (hoonda66_log3). Same result. Car stalls out around 10 second marker when MAF is plugged in.

[Hondata]

That datalog was made with the AFM unplugged, so it's not going to give useful information. It doesn't show lambda (perhaps from the error code) so it is not possible to see what the fuel trims are.
Go back to the stock intake and stock AFM and then verify the car is running with normal fuel trims, then start changing one thing at a time until the problem is isolated.

[hooda66]

So I tinkered around a bit, updated flashpro manager to 3.9.1.0, uploaded to the car and was able to start the car with the sensor unplugged but this time, the car stayed on long enough to get AFM readings. The car idled for about 30 seconds before it shut off.

I haven't changed to stock airbox yet. Wanted to see if this was sufficient data.

[Hondata]

Any datalog made with the AFM unplugged is not helpful. Any datalog made without closed loop operation is not helpful.

[hooda66]

That's the kicker, the car will not start with the MAF plugged up. I've tested that with the OEM MAF sensor and the PRL HVI (Street MAF housing) and I still get the same result. If you believe results would be different by installing the OEM airbox/MAF housing I will do so now. To note, USR and I even installed OEM HPFP with appropriate calibration and still the car would not start with the OEM MAF sensor plugged up.

[hooda66]

I believe we may have found the gremlin but looks like we uncovered another problem. It might be unrelated to my first issue. Let me do some more troubleshooting and I’ll report back. Thanks for your help thus far.

[abuxs]

Did you end up finding the issues I am getting this issue with my car as well and running out of ideas on what to do.

[hooda66]

Check for boost leaks! I double clamped the PRL charge pipe off the cold side turbo as the shit would easily blow off at high boost. Also worth checking other charge pipes as well, the elbow off the throttle body is the other most common problem child.

[abuxs]

I double-check for boost leaks and see nothing, I have the same issue with the maf unplugged it idles fine as soon as I plug in maf it idles but then dies after a while. Fixing your boost leaked fixed that issue?

[hooda66]

Yeah, fixing the leak solved my issue. What changed when you started having the issue?

[abuxs]

Im on big turbo, g30 900, ctr 500, xdi fuel pump, 1420 injectors, intank fuel pump 5 inch exhaust, custom inlet pipe. I have tried everything and can't find it. I did a smoke test and can't find leak.