Stumped in Colorado

[steve47co1]

I have a '12 Civic Si with Hondata Flashpro installed and several bolt-on mods. The car was last tuned on a dyno by a pro in October 13 and has been running great until 2 weeks ago. I inadvertently left off the gas cap and the fuel door open and went through a hi pressure car wash. Predictably, the car began running poorly shortly thereafter. I took the car to a Honda dealer where they drained the tank, purged the fuel lines and the fuel rail, and swapped out the fuel pump. The car ran slightly better, but would sputter at VTEC in 3rd gear (it would accelerate to redline in 1st and 2nd
gear) and would run on only a few cylinders until I would turn off the key and then turn it back on again. Same thing would happen again and again until I decided to just overwrite the tune (with FP), with the last known good tune. In the process of updating the tune, I did the firmware and the FP Manager update to the latest versions. Last known good tune uploaded successfully.

Still no change in the way the car ran; good in 1st and 2nd gear; at VTEC in 3rd, the car would stumble and sputter until I turned the key off and on again. Honda dealer put the HDS on the OBDII port and the only errors reported were misire codes and immobilizer ban warnings.

Since then, we have checked the gas - no water present - replaced the fuel pump (again), replaced the injectors, checked all the grounds, changed out the MAP sensor and the O2 sensor, inspected the catalytic converter, and checked the fuel pressure. When the car does stumble in 3rd gear at VTEC, the fuel pressure falls from 55psi to 30psi precipitously, but returns to 55 again when the key is turned off and on.

Long winded explanation, but do ECU's that have been flashed ever work occasionally or are they like most electrical devices and they either work or don't work?

Thank you.

Steve

[pepperdanky]

You replaced the fuel pump but not the filter?

[steve47co1]

I replaced the entire fuel pump assembly which includes a filter (the dealer was able to warranty it). There is no fuel filter inline besides that one on this car.

[pepperdanky]

There is a mechanical issue causing your fuel pressure to drop under high load. It doesn't happen in 1st or 2nd gear because the fuel demand is lower. What misfire codes? Random? Always in the same cylinder(s)? Did you check the plugs in those cylinders? If you post your calibration and a datalog of what is happening, you will be much more likely to get an informative response.

[steve47co1]

Thank you. I can post a datalog, but what do you mean by the "calibration?"

In the meantime.......update...........

1. Put in new injectors (same RDX's); no change.
2. Leak down test; within spec (5%).
3. Ran a wire through the RV6 cat (RV6's recommendation); no obstructions.
4. Pulled valve cover; all parts in place, so it is not the rocker arm issue.
5. Pulled all 4 plugs - good color.
6. Cleaned K&N filter on PRL CAI - wasn't really dirty.

Just as puzzled as I was before, and it is still running the same - dies at VTEC, but it seems to be narrowing down to the ECU/programming. I have eliminated everything else?

[steve47co1]

I think I have the answer to my problem...........typed in Flashpro and misfire codes in Google; came up with a lot of information. When you put in a different weight flywheel (aftermarket), you have to disable misfire codes in FlashPro in the calibration screen. Going to check it now and will get back to you all.

[steve47co1]

SOLVED. If you install an aftermarket lightweight clutch, be sure to (1) have FlashPro, and (2) disable misfire codes under the calibration tab on the main screen.

Postmortem; I had two problems; the first was water in the fuel tank and then I compounded it by installing the new clutch and flywheel, which created a new problem I didn't know about. Then I made it more complicated by keeping my focus on water as the problem, even though I had eliminated the water in my system. Lesson learned; solve one problem first, before changing/adding anything else.

Thank you to all that have contributed ideas to my challenges. Much appreciated.

[ajpturbopittsburgh]

It's unlikely the clutch had anything to do with it at all. You really need to post the calibration and the datalog. Really sounds like you had a water problem. It may have taken a long time to fully expel the water in the system even after purging it. How will you detect any misfires now? You won't want to face this but you really didn't post anything that is helpful....You should be able to keep the misfire settings and fix the problem. I've never heard of a lightweight clutch and fly causing this...You really don't have any crazy parts that would cause that. I have a 6 puck clutch and never had this type of issue.

What did you disable exactly. I don't even see any setting to disable misfire codes in my Fpro manager

[pepperdanky]

Glad you figured it out. If you had posted your calibraiton and datalog I'm sure someone would have noticed that right away.

He has a 9th gen with a lightweight flywheel, which will cause the ECU to think it is misfiring.

[steve47co1]

Thank you, pepperdanky; this issue is well documented once you know what you are looking for!

ajpturbopittsburgh - to disable misfire codes, connect FP Manager; go to calibration tab, miscellaneous, and you will see "disable misfire codes." As I understand it, though, this does not apply to 8th Gen civic Si's, only 9th Gen.

[ajpturbopittsburgh]

Ah ok. Yeah my software doesn't have the disable misfire codes. I didn't know the 9th gens needed that. You are talking about a crank relearn I think. In new mustangs you need to do that or you will get misfires when you change a clutch/flywheel.

I wouldn't want to disable misfire detection totally though. Maybe you need a Honda scan tool to do a crank relearn or a misfire monitor neutral profile correction

[steve47co1]

I had access to the Honda Data System scanner for the OBDII port, but, even though we tried several times, it would never relearn. I did find out that Clutch Masters has a clutch for 9thGen that doesn't trip the crank position sensor.