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Hawaii Dak
Dodge Dakota
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5/31/2003
18:05:00
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 Subject: New pipes come with check engine light?
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I have a 2003 quad cab 4.7L Dak with 1400 miles on it. So far all I have done is a K&N drop in filter and add a Flowmaster cat back to a dual exhaust. The exhaust was the latest change. About 250 miles after the exhaust change out I got a check engine light on the dash. Is there something I should have adjusted/changed after putting on the new system? If it had been an old car I would have adjusted the jetting but I thought on these newfangled cars the computer did all that air fuel mix control? Is there something I missed or a common problem others have seen? BTW I did make sure the gas cap was all the way on. :) thanx for the help and if anyone is planning to visit Hawaii drop me a line and I will show you the town!
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assclown
Dodge Dakota
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5/31/2003
18:28:31
|  RE: New pipes come with check engine light?
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Seeeee...... you should have just left it alone
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pat
Dodge Dakota
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6/01/2003
17:08:47
|  RE: New pipes come with check engine light?
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Your are correct about the air/fuel mixture. You've got a magnum engine so its sequential port fuel injection and the ECU (engine control unit) controls the injectors adjusting how much fuel to put in. My guess since it happened after an exaust mod is oxygen sensors. A cat. converter (most anyway) need oxygen for one of the stages in its emissions reduction (its a oxidation reaction). So they put an oxygen sensor (Can't think off had if its before of after the cat. but I'd assume before) in the exaust. The ECU reads how much O2 is getting to the cat, and if it needs more it will lean the air/fuel mixture. When you changed the exaust you might have damaged, or removed the o2 sensor all together.
Your best bet would be to plug a computer thing (I figure what they are called) into your port for it (my father's 99 durango has one just under the steering wheel) and pull up the error code.
Pat
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02Sport+
Dodge Dakota
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6/01/2003
19:07:17
| RE: New pipes come with check engine light?
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If there are Autozone stores in Hawaii, they'll usually check error codes for free. Or, you can probably check them yourself by turning the ignition key to ON...NOT START!...3 times, then leaving it in the ON position on the 3rd time. You'll get a P code in your odometer, read what it is, then go to OBDII.com and find it, or post it here, and maybe someone can help tell you what it is.
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TECH
Dodge Dakota
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6/01/2003
19:28:10
| RE: New pipes come with check engine light?
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You'd have to find the code first, it may be something totally unrelated to your mods.
Pat, about the cats and oxygen sensors, you are a little miss-informed. The cat needs to be at a high temperature to operate properly, which is often speeded up on cold start by an air pump. The oxygen put into the exhaust will heat the cat up quicker. I don't know if this truck has one or not, some do not.
The purpose of oxygen sensors is to monitor the exhaust gases. The 4.7 has an o2 sensor in front of the cat and one behind the cat. The one in the front is for the fuel trim adjustments for the engine. If it senses too much oxygen, it is interpreted as being a lean mixture, and will richen it accordingly. If the oxygen content is too low, it indicates a rich mixture, and the ECU will lean it out. This is all done constantly to achieve an optimum air/fuel ratio.
The o2 sensor behind the cat are there strictly to monitor the effectiveness of the catalytic converter. The signals from the precat o2 sensors are compared to the ones post cat. Any fault with either sensor, or the cat, can set a code.
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Hawaii Dak
Dodge Dakota
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6/02/2003
01:08:57
|  RE: New pipes come with check engine light?
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The OBDII page came up with "EATX or Aisin transmission controller has an active fault and has requested MIL" for the fault code P 0700. Looks like it is not due to my new exhaust. The good news is now I don't have to worry about the dealer trying to charge me for a warrinty repair. Thanx
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