Re: New idea on engine backfiring/popping/burbling

From: BlackDak93 (sbarnett56@adelphia.net)
Date: Mon Feb 14 2005 - 00:06:01 EST


Thanks,
No, I don't have a PCM for an automatic. Mine was a 3.9 with a 5-speed
originally. I am using a '93 RAM 5.2L-5-speed PCM. I wonder, did your
friend's truck have cruise control? If it did, does it work now the
automatic's PCM?

I have used a 93 MP PCM that is really intended for an automatic, and it
backfires too, but I had to disconnect the Park/Neutral switch line before
my cruise control would work, but even then it won't disengage when I press
in the clutch. I didn't like that, so I went back to the factory PCM.
thanks for the info.

<baddak@excite.com> wrote in message
news:cup54q$epi$1@bent.twistedbits.net...
>
> In article <cuobfb$d9p$1@bent.twistedbits.net>, sbarnett56@adelphia.net
> ("BlackDak93") writes:
>
> My friend had the same problem with his 93 after we swapped in a
> 5-speed.
> We thought the truck had to use a 5 speed pcm. We used the pcms (factory
> and
> Mopar Performance) from my 95 318 5-sp, and the truck did just that,
> backfired
> heavily out the exhaust on the 1-2 shift, and then dropped off through the
> upper gears. The truck seemed to have a lot less power as well. Just for
> the
> heck of it we put the factory pcm (automatic) back in and it ran fine. I
> am not
> sure if you tried that, but thats what worked for us. I dont think it
> would be
> an exhaust issue. My friends truck has MP headers (Doug Thorley), stock
> cat and
> a Borla cat-back exhaust. My 95 has some popping/burbling through the
> exhaust,
> but I think that was normal with 95-96 5-speed trucks, but it is
> definitely not
> backfiring. Just my .02, hope it helps.
>
> Mike
>
>
>
>
>
>>
>>
>> It does backfire, mostly between 1st and 2nd gears but the popping and
>> burbling which happen anytime I decelerate are, at least in my opinion,
>> much
>> more than what could be considered normal. My exhaust is not extremely
>> loud.
>> It is actually pretty mellow compared to a lot of trucks around here. I
>> have
>> shorty headers, a high flow cat, a Magnaflow XL with 2.5" dual tailpipes.
>> The 2.5" tailpipes are probably too much, but I have had 2" and 2-1/4"
>> and
>> it did the same thing. It did the same with a stock muffler, a turbo
>> muffler, a Flowmaster 50 an IMCO chamber muffler and with resonated tips
>> and
>> a glass pack between the cat and the muffler. I even took the advice of
>> the
>> mechanic and dropped the factory 3" pipe bwtween the cat to the muffler
>> down
>> to a 2.5" pipe. I wish I had not done that. It made no difference and it
>> messed up a pretty sweet looking exhasust system.
>> "steve preston" <steves287dak@yahoo.com> wrote in message
>> news:20050213193645.63951.qmail@web41828.mail.yahoo.com...
>> >
>> > I`m not really sure of the noise you describe.
>> > Backfiring is one thing,but popping or burbling a
>> > little bit when going down a hill,or when the engine
>> > has no load on it seems normal to me. Mine does
>> > that,and I`ve seen it on many vehicles with a "loud"
>> > exhaust. (My Dak has a conventional exhaust into a
>> > race muffler,then split out to the rear.) It seems
>> > like once the engine has gotten the vehicle up to
>> > speed and you decelerate,there`s no load on it anymore
>> > and it will sound different because your transmission
>> > and driveline are pulling up the RPM`s that would
>> > normally have a tendency to drop. But please keep in
>> > mind that I have no official training as a mechanic.
>> > However,I did stay at a Holiday Inn Express last
>> > night. :) Steve P.
>> >
>> > P.S. I start my new job tomorrow,in heating and
>> > cooling. After twenty years of electronics repair,I am
>> > conceding to the Chinese,and Walmart. So if your $169
>> > 27" TV breaks,do what everybody else is doing,and go
>> > buy a new one that will last 1/10 as long! :)
>> >
>> >
>> >
>> > --- BlackDak93 <sbarnett56@adelphia.net> wrote:
>> >
>> >>
>> >> I brought this topic up a few months ago, and I am
>> >> still trying to find a
>> >> solution to it. The problem is my '93 Dakota 5.2L
>> >> with 5-speed manual,
>> >> backfires through the exhaust on deceleration. I
>> >> have been through hundreds
>> >> of hours and many more dollars trying to resolve it.
>> >> I have been through
>> >> everything I can and been to several shops,
>> >> including my friendly Dodge
>> >> dealer to have it checked out. The Dodge technician,
>> >> charged me $180.00 to
>> >> tell me that there is abosutely nothing wrong with
>> >> the engine. He believed
>> >> the problem to be my exhaust. To make a long story
>> >> short, it is not my
>> >> exhaust, although it does make it more noticeable.
>> >> Stock exhaust did the
>> >> same thing. The second leading theory is that this
>> >> is normal for Dodge
>> >> Magnum engines, and the problem is worse with a
>> >> manual transmission (it pops
>> >> back when I let off the gas to shift). I am not
>> >> willing to concede that this
>> >> is normal, although I have come to the decision that
>> >> the problem is the
>> >> manner in which the PCM controls the fuel. My
>> >> primary basis for this theroy
>> >> is that when I install a different PCM ( I have
>> >> three) the
>> >> backfiring/popping/burbling disappears for about
>> >> three days until, I assume,
>> >> the PCM gets itself reprogrammed. Then the popping
>> >> comes back. Every
>> >> technician I have been to is unwilling to accept any
>> >> other theory except the
>> >> exhaust system and will not objectively pursue any
>> >> other ideas. I am not
>> >> going to put the exhaust back to stock just to prove
>> >> them wrong. I have been
>> >> studying my manuals, and have decided to try a 94 or
>> >> 95 PCM, to see if they
>> >> would work any better. I believe that a later model
>> >> (pre-'96) PCM will still
>> >> work. All the connections are the same with the
>> >> exception of pin 5 which is
>> >> a signal ground that goes to the DataLink connector.
>> >> On the later model,
>> >> this line is still grounded, but not connected to
>> >> the PCM.
>> >>
>> >> I have a few questions: First, I would like to hear
>> >> what you guys all think.
>> >> Any new ideas about this? Has anyone tried running a
>> >> 94 or 95 PCM on a 93?
>> >> Also does anyone have a 94 or 95 PCM for a
>> >> 5.2L-5speed with Federal
>> >> emissions that they would part with? I would rent,
>> >> buy or borrow just to try
>> >> my theory. I have searched the internet and I
>> >> believe that part number
>> >> 56028262 is the correct part. There may be a
>> >> 56028341 also, but I can't
>> >> verify if that number is correct. Or does anyone
>> >> have a Mopar Performance
>> >> PCM number 5249542 they would sell? There is a
>> >> remanufactured PCM out there
>> >> made by a company called A-1 Cardone. Has anyone
>> >> ever used one of these? I
>> >> am desperate to get this fixed. I have had this
>> >> truck for over 10 years and
>> >> I love the truck. I spent a lot of money swapping in
>> >> this engine but it
>> >> makes me want to park the truck and not even drive
>> >> it anymore.
>> >>
>> >> Any new ideas or help would be appreciated. BTW, I
>> >> have gone through the
>> >> entire intake/exhaust systems checking for leaks.
>> >> Replaced the leaking belly
>> >> pan gasket. All the sensors have been replaced and
>> >> checked. Compression is
>> >> good. Timing is good according to the Dodge tech.
>> >> Distributor cam sync has
>> >> been set. Vacuum has been checked. All the normal
>> >> stuff.
>> >>
>> >>
>> >>
>> >
>> >
>> > =====
>> > Steve P.
>> > Two-thousand one (2001) Flame Red Dodge Dakota Sport RC 4X4,4.7L
>> > eight-piston w/3.92 limited-slip,air,cruise,tilt,knob(not
>> > shifter)induced
>> > four by,with optional hand crank windows and finger locks that added
>> > substantially to the overall cost. Steigerperformance air intake
>> > providing
>> > twenty additional RWHP (ten at the flywheel). PLUS,a custom
>> > dual-exhaust
>> > than is real loud,with gigantic 2 1/4" pipes sticking out the
>> > back,reminiscent of warship cannons primed and ready for the heat of
>> > battle. The other mods (headlight and taillight covers and black step
>> > bars) do not add significantly to the speed of this vehicle,but are
>> > there
>> > purely for intimidation purposes,as the markings of a cobra signify
>> > it`s
>> > deadly potency. Put simply,this truck cannot be stopped.
>> >
>> >
>> >
>> > __________________________________
>> > Do you Yahoo!?
>> > Yahoo! Mail - now with 250MB free storage. Learn more.
>> > http://info.mail.yahoo.com/mail_250
>>
>>



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