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Tim
Dodge Dakota
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4/08/2002
12:59:39
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 Subject: Bernd
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Message:
I have a 98 5.2 ltr with a 5 speed. I have mp headers high flow 3 inch cat and mp 3 inch cat back exhaust. My problem is during deceleration the exhaust has a backfire to it. This is very annoying and would like to get rid of this. The muffler is round andyou could look straight through it. Did I cause this with the high flow cat? Could it be fixed with a different muffler such as a flowmaster 50 series? Any suggestions please. Do you possibly sell a muffler that would fix this, I would give up some sound to fix it.
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IntenseDak39
*GenIII*
 
4/08/2002
16:57:02
|  RE: Bernd
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Message:
a backfire wouldn't be caused by the muffler but more of ignition problem or fuel problem... have you had any performance problems?
intensedak3.9
http://www.geocities.com/intensedak39/index.html?1015106010330
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Duner
Dodge Dakota
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4/08/2002
17:17:23
|  RE: Bernd
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Message:
If you have even the slightest exhaust leak, when you back off the gas it will suck in air and ignite the unburned fuel in the exhaust......backfire.
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scat pack
GenIII
4/08/2002
17:17:49
| RE: Bernd
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Message:
Actually, I believe a lean fuel condition caused be the decrease in exhaust backpressure could cause just this type of backfiring. Sorry, I don't know the fix for your application (jetting up would work if carbed) but I'm sure Bernd or someone else will have a suggestion.
2K RC 4.7 4x4
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bernd
*GenIII*
4/08/2002
18:27:51
| RE: Bernd
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Message:
Reset the PCM and let it learn. Yes...even on a catalytic converter. (The lean condition - if any - will be compensated for by the relearn.)
1997 Dodge Dakota SLT - V6
Supercharged/Intercooled @ 10# w/Nitrous
14.55 @ 96.01mph
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Tim
Dodge Dakota
JOIN HERE
4/08/2002
18:42:44
| RE: Bernd
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Message:
The comp has been reset several times. This problem surfaced when I swapped to a 5 speed and occurs on deceleration. I know the collector gaskets were torn and have been replaced but this did not fix it. I cannot detect any exhaust leaks except a weld on the in side to muffler. I plan on welding this up. The headers may have lost there seal during trans install so I ordered a set of gaskets. I did replace them once with after market Mr gasket gaskets but these were actualy cut different so I may have a slight leak at the heads. I cannot detect any leak but do suspect one. Is there a way to detect a sure leak? I do hope the fix is this easy. Thanks for any help.
98 CC 5.2 ltr 5 speed 3:55 ls, MP headers, High flow cat 3 inch, MP 3 inch exhaust, Ported throttle body, KN FIPK, M1 intake, MSD ignition,
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Dakota/cali
Dodge Dakota
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4/08/2002
19:12:22
| RE: Bernd
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Message:
This happens to all of our trucks.Depending on muffler sound will increase or decrease.Try leaving your truck in a higher gear when slowing down.
automatics if you want the sound like that then downshift at high rpm to hear it.
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Anthony
Dodge Dakota
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4/08/2002
19:19:15
| RE: Bernd
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Message:
I'm running a Mopar 3" cat-back on my Dak and I get alot of back firing also when decelerating, but I like the way it sounds. My friend has the same setup and his is the same way too. Both Daks are stick.
Anthony
www.geocities.com/intense79/
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Tim
Dodge Dakota
JOIN HERE
4/08/2002
20:58:10
| RE: Bernd
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Message:
Anthony do you guys both have stock exhaust manifolds and stock pipes and stock cats? If you do then I know it is in fact the cat back system and I will learn to live with it. Thanks for your input.
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Duner
Dodge Dakota
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4/08/2002
21:10:35
| wrong kind of keyboard for sounds?
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Message:
I guess my next question is whether it's a series of pop-pop-pops? or is a ka-boom as in one big backfire when you back off the gas?
After experimenting with different pcms on my buddy's 4.7 - his would go pop-pop-pop type of noise with the stock pcm whenever he backed off the gas. With my pcm in his truck it just went brrrrrrr on decelleration.
Hahaha - it's tough discribing different sounds with a keyboard! LOL
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Tim
Dodge Dakota
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4/08/2002
21:16:26
| RE: Bernd
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Message:
I would say its more of a pop pop pop big pop. I like the brrrrrr or more of a rumble which it does sometimes or realy most of the time this is what it does. I do have the stock PCM. What PCM do you have in yours that cleared it up when you put it in your buddies?
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Duner
Dodge Dakota
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4/08/2002
21:25:53
| RE: Bernd
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Message:
OK, that big POP at the end helped me clear it up..... at least in my mind. Definately a leak somewhere in the system that's sucking in air to ignite the unburned fuel.
The pcm in my truck is basically the same as a Leach programmed one. The guy that did mine no longer does them for Dodge vehicles, but after comparing dyno curves with Matt Barret - they look like they are about the same.
The main difference between mine and a stocker is more advanced ignition timing and the fact that it's also leaner than stock.
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brad K
Dodge Dakota
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4/08/2002
21:26:32
| RE: Bernd
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Message:
This is just a guess, but can it be because of
the wrong PCM for the transmission? Is there a
different stock PCM for Manual trans like there
is for the performance PCM?
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Anthony
Dodge Dakota
JOIN HERE
4/08/2002
21:35:21
| RE: Bernd
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Message:
Like what Duner said "it's a series of pop-pop-pop" and the odd loud pop.
You can hear it at my site http://www.geocities.com/intense79/exhaust.html so everyone can hear what your talking about.
I'm running just the Mopar Cat-back & intake the rest is stock.
Even with the stock exhaust it still popped!!!
I hope this helps,
Anthony
www.geocities.com/intense79/
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Tim
Dodge Dakota
JOIN HERE
4/08/2002
21:40:02
| RE: Bernd
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Message:
Thanks Duner I do believe I have a small exhaust leak at the headers. I have gone over the entire exhaust with a stethoscope with the bell removed from the end. When you com across a leak its real clear its leaking. I found a leak at the muffler weld but I think this would be to far down stream, but I still will weld it up. The others were at the headers very small but still I will fix them.
Thanks Brad but I do have the stock pcm for the manual trans and yes they were different.
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