I run the X4 street tune and the Atlas 40 FICM tune in my ‘04 X. When I start it for the first time, it starts fine and then I get about 5 minor chugs (don’t feel like misses). If I drop it in gear right after the chugs, I get maybe 1 or more “cylinder imbalance” codes and they are always from cylinders 1,3,5 or7 and a P006A code.

Now if I start it and let it run for a couple of minutes, I get no codes and it starts fine the rest of the day with no other chugs.

If I’m running on the road and I approach or exceed 20 psi boost, I get a P006A code and maybe a CI code. But I don’t ever feel any misses.

I have 168k on it with the original injectors.

Any ideas/suggestions would be appreciated.

Ed

 

Very logical - sensor (EBP inference value) and the PCM is saying sensor imbalances - caused largely by the EGR Delete and those tunes (I'm no fan). You're probably also close to the last leg on those injectors and should plan on either rebuilding (I've done many sets myself and once you get past the top "C" clip it's all downhill) or replacing with Moto parts.

 

P006A is a MAF sensor code. Try cleaning the MAF sensor with either alcohol or an electronics spray cleaner.

Is the MAP sensor hose on securely with no cracks or leaks in the hose? Also, make sure the nipple on the intake manifold that the MAP sensor hose connects to, is not plugged up.

At KOEO, post the MAP, Baro, and EBP sensor values (even though the 03 engine, and your 04 has the 03 engine, doesn't use the EBP sensor, it can help as a check on the other pressure sensors) ... all should read the same (within apprx 0.5 psi) at KOEO.

Could also be an intake leak (especially between MAF sensor and intake manifold), possibly an exhaust leak (or restriction), or maybe even a turbo issue.

Do you monitor fuel pressure Ed? If not, you should.

I agree you could have injector issues, but there could be a root cause for having them.

 

Mark, you're right about MAF, but the newer software in 04 (his truck) uses MAF in the EBP inferred calculations to control VGT, EGR flows --- that's why I included the technician aid.

 

That is a good reference document. Been a while since I have seen it.

 

Mark, I loaded the stock ECU/TCU program with all the updates in yesterday morning and no codes. I still have the FICM Atlas 40 tune and the chugs but not as noticeable as with the X4 street tune. I drove about 40 miles not pushing it past 20psi of boost and no codes. Did the same today pushing it to 25psi of boost 4 times and still no codes. I think I’m going to can the X4.

A couple of things.

It appears the X4 Street tune is causing my “cylinder imbalance” (injector) issues. Time will tell.

I monitor boost, fuel pressure and EGT with door post gauge cluster. I have an AD2 and my fuel pressure is nominally 50psi. If I replace filters, it will go to 60psi but I just replaced the filters and its back to 50psi. The AD2 adjustable pressure regulator sucks. I have had it apart twice to replace the O ring and it still sucks. Also I treated the fuel system with Killem biocide.

My ECT is normally 192*F but will go to 200*F if I go to 25psi boost. However, my EOT, with the stock program, has declined from 235*F to 213*F. That is a head scratcher.

On advice of my mechanic, I’m getting the original fan clutch replaced tomorrow. He replaced the AC condenser and noticed the Freon high side temp was higher then it should be at idle. The fan clutch high speed does work.

Thanks for the reply and the help.

Ed

 

I wouldn't be surprised if you aren't addressing your issues with what you have already done, and with those other items that you are planning on doing.