Running really rich after FMIC install

[turboAWDfanatic]

I'm using TunerPro with the Ostrich emulator to tune. I have the Zeitronix wideband setup to monitor. All mods are in my profile.

After installing my FMIC I'm running very rich at WOT, and my fuel trims are off, compensating for a rich condition. At first I suspected a boost leak (I eliminated all but one small leak), but it wants to run rich on and off boost.

My question is, what route I should take to correct the problem? Should I adjust the MAF compensation in TunerPro, or should I just go ahead adjust the fuel maps? If I adjust the MAF compensation, it will throw off the timing. FYI, the MAF adjuster screw is already backed out.

Basically, I know a few different ways to change the mixture, I just want to make sure I'm correcting the issue rather than sweeping it under the rug.

 

[jrohner]

If you are running richer everywhere, just adjust your injector size compensation up to lean it out. The fuel map is totally ignored in closed loop mode, so messing with that won't work right for your situation. If you can tell that your airflow on your logger seems off from where you think it should be, mess with the MAS compensation.

My tune didn't change at all when I recently moved from a SMIC to a huge FMIC; there must be something you are overlooking. A hose or gasket somewhere. You are recirculating the BOV right? Fuel pressure?

 

[turboAWDfanatic]

If you are running richer everywhere, just adjust your injector size compensation up to lean it out. The fuel map is totally ignored in closed loop mode, so messing with that won't work right for your situation. If you can tell that your airflow on your logger seems off from where you think it should be, mess with the MAS compensation.

Your thoughts are mine exactly, though I didn't think about adjusting the injector compensation rather than the MAF compensation.

My tune didn't change at all when I recently moved from a SMIC to a huge FMIC; there must be something you are overlooking. A hose or gasket somewhere. You are recirculating the BOV right? Fuel pressure?

I didn't think the tune should change at all. I've double checked everything, but I'll take another look. I haven't looked at fuel pressure, but I haven't done anything that would change it. I'm starting to wonder if I had overlooked something during the time I was running a SMIC that I inadvertently "fixed" while installing the FMIC.

About your comments on airflow...is there any bar to measure by? Is there a certain airflow number I should be aiming for at idle to help me tell whether or not I'm off on the MAF compensation? One thing to remember when considering all of this is that I have a 2.3L stroker, so I'm not sure whether or not I'd be aiming for an airflow similar to 2.0L guys.

Either way, I believe I can get around the issue by adjusting MAF compensation or injector compensation. It would be nice to track down the cause of the problem, though.

Thanks for the help! Oh, and yes, I am recirculating the BOV.

 

[tkelly27]

If you had a leak pre turbo, but post MAF, that would cause a rich condition if it were suddenly fixed. It would also be universal, boost or not, because that area will always see below ambient pressure under all conditions.

It's also why it's common to put the boost leak tester pre turbo and pressurize all off that too.

If you didn't remove that, then I'm stumped.

 

[No_Skillz]

If you had a leak pre turbo, but post MAF, that would cause a rich condition if it were suddenly fixed. It would also be universal, boost or not, because that area will always see below ambient pressure under all conditions.

It's also why it's common to put the boost leak tester pre turbo and pressurize all off that too.

If you didn't remove that, then I'm stumped.

That would cause a lean condition because there is always negative pressure, i.e. there is always a force sucking IN air that was unmetered. The rest of your theory (universal condition) is correct.

OP: can you please tell us what method you used for your BLT? What PSI did you build to and how long did it hold after the pressure source was taken away?