How do you get past the check engine light?

[Ryan]

I’d like to hop up my 05 Dakota, 4.7 non-HO engine, and I cant seem to get a straight answer for modding an OBD2 engine and keeping the computer happy. I live in NY so an OBD test is part of state inspection, if the check engine light is on for any reason it’ll fail and not be legal until it passes. I’ve read about guys who install a turbo (6lbs of boost or so) and REALLY waking up the engine with it, but they never mention the check engine light.

Once I lined up to a red light with a Honda CRV and got beat, I was disappointed in my truck lol.

Topic

[college man]

You may be able to install a turbo but may need bigger injectors.

[Mike]

It’s really complicated, but if the vehicle is modified ‘properly’ it will not set a code. It’s really a check EMISSIONS (not engine) light. It technically is only for things that affect emissions. Good modifications will keep the emissions data within spec and codes won’t be set. If the modifications are serious enough to make codes (like major camshafts and engine work or forced induction), you’ll need to have aftermarket engine management of some kind, which commonly has provisions for working around an OBD 2 inspection. For instance I’ve seen a couple supermodified cars that come in having codes for several understandable things, and a basic code reader can be used to clear the codes and immediately all monitors are ready for inspection without ever having actually run on a proper drive cycle. I don’t personally know the specific software that allows that kind of thing, but I can assure you it exists. There’s only so much that can be put in writing without the 5th amendment being ignored, but I work in NY and can assure you that things can be made to work entirely on your end with the inspection station none the wiser.

I don’t know anything about what do with your Dodge situation specifically, but you would need someone making respectable aftermarket engine management solutions for your truck. Whether it can be done in your case depends on available tuning options for your specific truck. I don’t know if a any full aftermarket engine management system exists that can pass a OBD 2 inspection, but you rarely find them on street cars. Usually, you would have a tuner flash your existing PCM to run the aftermarket forced induction properly (dyno tuned) which would have the aforementioned feature of clearing codes immediately before inspection.

[Ryan]

Thanks for the info sir. I’ll keep snooping around and see what I can come up with. Although, after taking a look recently at my truck and realizing it’s starting to rot (thanks NY salt), I may just wait for a good deal and trade her in for an 09 or later full size dodge. Something I CAN do stuff with.

[zero]

I guess it would depend on how much money you are willing to spend and how much you want to “wake” it up. Anything like a turbo would definitely require a custom PCM tune, which may require a different PCM or a custom one and then you need someone to tune it. You should be able to do all the usual suspect bolt on stuff then add a plug in programmer and make more noise and some more power. Most of the plug ins will allow you to flashback to the OE program if needed.

Basically at the end of the day, the most efficient way of getting the power I’m guessing you’re after is to just buy a vehicle with it. That that a Dakota is a bad truck, but the phrase throwing good money after bad comes to mind.

But turbos are fun. Nothing quite like the turbo kicking in at highway speeds and spinning the tires a bit.

[Lorrin Barth]

[quote=”Fopeano” post=130648]For instance I’ve seen a couple supermodified cars that come in having codes for several understandable things, and a basic code reader can be used to clear the codes and immediately all monitors are ready for inspection without ever having actually run on a proper drive cycle. I don’t personally know the specific software that allows that kind of thing, but I can assure you it exists. [/quote]

This has me grinning. I’ve alluded to this in a couple of posts here. Not all Mitsubishi cars can be trusted, some of them lie. :woohoo:

Actually the explanation is simple. Add a few lines of code to the ROM and a new section pops up, a section where Mitsubishi selects in the computer what equipment the vehicle has. This makes sense since Mitsubishi sells cars all over the world and by having this section they can use the same code for all. If I select from the list that the vehicle has X doodad the computer will run the check. If no then the computer will report to the testing station that that item is okay.

Now, when I write “list of equipment” you don’t see a list you can read, it is in code. Which items the code refers to were discovered by experimentation. The way you indicate yes or no is also some goofy alphanumeric. If you are a tuner you know all of this stuff and that is why they make money doing what they do.

Edit: Back when this section was discovered one guy with a heavily modified car announced he was going to turn everything off and then head for the testing station. Next day he wrote the car passed with flying colors, the ECU reporting parts the car didn’t even have were working perfectly.

[Lorrin Barth]

I hope people aren’t getting bored with this but I was just now reading how a patch for the Evo ECU has been written to work with an ethanol sensor installed in a fuel line. This makes the car flex fuel. Run the car on pure ethanol, pure gasoline or anything in between and the ECU makes adjustments accordingly.

[wafrederick]

The Chrysler 4.7 is not a reliable engine to me.I cringe when one of these come in with problems.One is timing chains and the other is dropped valve seats.Chrysler installed the valve seats loose from the factory and drops out of the head.If the valve seat comes apart in pieces,I throw the intake manifold away.One piece plastic and can’t take it apart.

[Frank Gonzalez]

When you go from N/A to forced induction an ECM recalibration will be needed. That’s because the ECM is programed for a stock engine. When a mod like like a turbo is added, those program perametets are way off on the ECM may not be able adjust to those readings and give you that C/E light.

[Author]

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