Any new ECU options?

[AmaRose19]

Hey everyone, i'm new here so i apologize if this has been asked before.
I have an 02 RT that I've modified with an SRT exhaust and K&N cold air intake. Of course the AFR is now lean so I need to balance that out. After hours of scouring the internet and forums (if i'm understanding this correctly) our stock ECU's "can't" be tuned unless we get an MS chip, or AEM aftermarket ECU. Am i missing anything with MPx? do they offer something i'm missing? if so can anyone provide me some direction or links on where to begin?

[occasional demons]

If your AFR is actually lean from that, you have other issues. An exhaust change, and a CAI are well within the stock PCM's capabilities.

What are you using to monitor AFR?


The biggest thing that would affect it from just that very minor, not really adding much power change, would be a tired o2 sensor.

I had a 60mm throttle body, shorty header, SRT exhaust, Magnum cam, Magnum head, larger intake manifold (Home made) and short ram inlet on the 60mm TB, all on the stock SE PCM, and never had an issue. I know have an '02 R/T PCM, all the above and still have zero issues.

So there is no way you are "going lean" from those two very minor mods.

If it is an actual lean condition, it is from something else, like injectors, TPS sensor, MAP sensor, o2 sensor, etc, not from that.

The stock PCM and injectors can easily handle a 20 hp increase from real bolt on power adders, like camshaft, TB, long tube header, etc.

The stock SRT exhaust is actually smaller at the rear axle, if you went from the cat back, than the R/T exhaust. If that's the case, you downgraded.

Thr R/T is a true 2.25" system. The SRT and SE, neck down to 2.00" at the rear section connector.

[AmaRose19]

as far as scanners, I had a mechanic friend of mine hook up his computer scan tool to the OBD2 port. (one of those 1800-2000 computer scanners) the live graph showed that while driving through town, the AFR was 50/50 split between rich/lean, but once i got into power it went straight lean with an occasional spike going rich. My car is throwing a check engine light (P1193) for inlet Air Temp Sensor Circuit High Condition after installing the CAI.
Regarding the Exhaust, the RT may be bigger but it has a large muffler in the rear that added too much back pressure where the SRT exhaust does not. it was a full mani-back replacement.

[occasional demons]

Unless the muffler is clogged, it probably flows adequately enough. The stock SE neon muffler outlet is only 1 and 7/8" OD. I have never had an issue hitting the rev limiter using the stock SE neon muffler.

The body size has nothing to do with back pressure. it is mostly sound absorbing packing, that the perforated pipes pass through. The actual flow does not pass through the packing, it flows through the pipes/chambers, and the sound passes through the holes in the perforated pipe to the packing.

My Subaru Impreza has a muffler the size of a 55 gallon drum and makes 170 hp N/A on a 2.4 liter engine. That's 10 to 15 more than the 2.4 in a PT Cruiser or Stratus.


If you removed the AIT sensor, and did not at least plug it back in, then yes, you will get a code for that. Not sure it would run that lean from it missing. Mine was not reinstalled after a body shop did some work, and it didn't make a huge impact on performance. It did have a CEL and a battery light.

If it is plugged in, there is an issue with the connector or wiring. "Circuit High Condition" means there is an open circuit, and has nothing to do with sensor output, unless the sensor itself has an open.

I would check fuel pressure first to verify it is at least 58 psi, and put a fresh o2 sensor in it.

Your stock R/T pcm has more than enough wiggle room to compensate for what you've done. I have run more than 50% E85 on mine ('02 R/T pcm) and the PCM was able to handle it on stock injectors. E85 in itself needs a heavier fuel curve than most bolt on mods. To run 100% E85, you need to run bigger injectors. Stock neon injectors are 19lb/hr. IIRC you need 24lb/hr for E85.

So to claim that just installing a CAI, and an exhaust is making it run lean is a stretch. You have other issues.

[AmaRose19]

I do have a CEL and a battery light. Same as what you are describing. Nothing wrong with the battery tho. I will check the air temp sensor and make sure the hole for it in the CAI isn't leaking and that it's properly plugged in. I'm not sure which O2 sensor I should replace on it. I can check the voltage on both to make sure they are in proper ranges. Otherwise May hap i'll have to replace them both.

[AmaRose19]

after a few tests. i was able to clear the battery light and CEL. both are off. sensor was not plugged in all the way. i scanned the O2 sensors and fuel trim banks while idling and while driving. All seems to be operating within normal ranges. just have to find someone with a computer that can properly test the AFR and fuel pressure.

[occasional demons]

Yo have to physically check the fuel pressure at the port in the fuel rail. Your 2002 should still have the port. The schrader valve may need to be removed, depending on what type of pressure gauge you buy to screw onto the port. It is an AN or JIC type connection. There is no sensor that tells any electronic device what the pressure is.

Only the o2 sensor telling the PCM that it is too rich or too lean. If you are not getting a CEL/code for an overly lean correction factor, then the o2 sensor may not be in good enough condition to tell the PCM that it is leaning out. A tired upstream sensor will be slow to react, but on continued hard acceleration, it should still set a code.

When I replaced my 02 sensor, the throttle response improved better than any other mod I did.

Ideally, they should be replaced in pairs. Otherwise you can get a false catalytic converter code.


But the one before the catalytic converter (upstream, or 1/1) is the one that immediately impacts fuel trims.

[AmaRose19]

the fact that i'm not getting a CEL for a bad 02 sensor or lean AFR leads me to believe its within acceptable parameters and i'm just over reacting?
i'll check the fuel pressure though and go from there.

[occasional demons]

If it was lean or rich enough to really hurt something, you would get a CEL and code for it. But it doesn't mean it is optimal if you don't.

It never hurts to verify everything is within acceptable limits.

[AmaRose19]

Thank you. That helps a lot.

[INVUJerry]

There are tuning options available. Syked ECU tuning offers a programmer for our cars now.

[occasional demons]

From what I have read on the dot org, Kevin is mired in some kind of legal battle, and there have been some complaints about his stuff working as advertised. So the hand held might not be the best option.