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Buzzbass said:
YES ! Cats go bad for a reason. Usually it's bad front O2 sensors. They make it run pig rich, which in turn fouls the cat(s). O2 sensors should be changed out every 60-70K miles as a wear item. At least the front 2 anyway, they're responsible for setting your A/F mixture.
I agree 100% but in my case I think that when the truck starts to run bad at start up and backfire through the intake wouldn't that indicate a lean condition?
 

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REDNECK SPACESTATION
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I agree 100% but in my case I think that when the truck starts to run bad at start up and backfire through the intake wouldn't that indicate a lean condition?
maybe i'm wrong, but backfiring usually points me in the direction of ignition timing.
 

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chizzle1 said:
maybe i'm wrong, but backfiring usually points me in the direction of ignition timing.

Agreed, but if the timing were out it would backfire all the time wouldn't it? I only experience it about 2 mins after cold start and then for a few minutes after that until the truck get up to operating temp. After that it idles and runs fine.
Another thing I noticed while the intake was off is that the truck does not begin to idle rough or backfire when I foot brake it (I did this to simulate the problem in my driveway) until the IAC opens and begins to draw air. My IAC is new so it may be coincidence but I have read in other threads while doing a search that others people have noticed a "whistling" coming from the intake whan the hesitation is present.
 

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REDNECK SPACESTATION
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You could try running your truck without the IAC, by that I mean wait until the truck is at operating temp (IAC closed) then unplug it. Tap the cover on the throttle body to expose the idle set screw. Set idle to whatever speed you desire.
It sounds like one of the sensors that is monitored during open loop isn't reporting correctly.
If someone can post up what sensors report during open and closed loop that can help narrow down which sensor(s) should be looked at.
I know for a fact that the 02 sensors don't come into play until you go into closed loop mode (engine at operating temp).
 

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Discussion Starter #46
heres the score...

Hottexhaust.com - A++
Fedex - F

ordered my cat and parts sunday night, shoulda been here today but fedex must have had an idiot workin the inventory or something. they got my address wrong so it wont be here till tomorrow /scream.
 

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REDNECK SPACESTATION
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you think FedEx is bad? Try DHL ! That is who the company I work for uses to ship and they suck!!
 

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XLRATION, i was re reading this post and noticed a reply of yours to my post ..........i guess it was a snap on scanner cause thats what the bay he drove it into said.......... or something to that effect.
quoting my text..............
discuss it with a loocal mechanic/friend with a scan tool. make arrangements to park your truck overnight at their shop/house. be ready for monitoring the first startup on a COLD motor.do not drive it inside/drive it to his house first. DEAD COLD MOTOR. takes ten minutes in all.

the test MUST be done on a dead cold motor. truck must sit at least four hours for the o2's too get good and cold. many tech's don't even know about voltages during warm up. i didn't until i ran into this problem on a 3.9 dakota(same engine management system). i've since seen it on a durango and two rams.

if your truck runs like shit one minute after start up. won't get out of it's own way, pops, etc for the first five minutes( till it's partially warm/ 140 degrees or so) then smooths right out and rund great till it sits for at least 4 hours again, you may be suffering from shorted o2 heaters or their wiring.

not trying to be a pain in the ass or anything. if that sounds like YOUR scenario, especially the running good warm, have the print off my test procedure and have him rerun the test. this time park it overnight. have him bring the scantool to the truck(NOT THE TRUCK TO THE SCAN TOOL) and be ready to watch the voltages on startup. enter the vehicle id with engine off and have data pids on the screen ready to watch THEN start the truck. make sure the tech and yourself, if he'll allow you to watch, know what you're looking for.

hope it helps ...........but feel free to ignore it..... just my thoughts.
 

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Well one last try on this thread- I have lost track of whos problem is what! But to the backfiring issue- nowadays that is nearly always spark plug wires crossfiring or crank and/or cam sensor. It happens because an intake valve is open when a plug fires out of sync. Used to be because carb was dumping too much gas into the intake. Since everything is fuel injected now the fuel dumping is not as much of an issue. When the spark plug fires is an issue especially with the high voltage systems of today. And if it fires when not supposed to, as in crossfiring between plug wires or bad signal to the PCM, big bang theory applies. It can also be caused by cracks or problems with the distributer cap which will create a crossfire like symptom. Do with this what you will-just don't yell at me. My hearing aid is turned off!!
 

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Discussion Starter #50
update update...! Direct fit from hottexhuast.com fit like a glove. the removal of the old y-pipes and cat was a bitch though... cutting torch required on 10year old bolts and nuts. overall, great setup for the price and most of all, FIXED THE PROBLEM. i never would have imagined the increase in sound from a high flow cat. sounds like a beast. anyways.. thanks for all the help in the area everyone, saved me a lot of time and money doing it myself (148.99 for the kit versus 450 for just the cat from a dealer) thanks again everyone!
 

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losinghope01 said:
update update...! Direct fit from hottexhuast.com fit like a glove. the removal of the old y-pipes and cat was a bitch though... cutting torch required on 10year old bolts and nuts. overall, great setup for the price and most of all, FIXED THE PROBLEM. i never would have imagined the increase in sound from a high flow cat. sounds like a beast. anyways.. thanks for all the help in the area everyone, saved me a lot of time and money doing it myself (148.99 for the kit versus 450 for just the cat from a dealer) thanks again everyone!

Great news. I only hope thats my problem also. Did you get the MagnaFlo catted y-pipe? If so can y confirm the PN is 23285. I'll have to order one this coming week.
 

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I wanted to add that I was debating just keeping the truck the way it is. What I do now is let the truck warm up for 5 mins. so I don't have the hesitation/stalling when I drive.
Well at work or when I am with friends they here the truck idle really rough and I have them convinced I put a 110 LSA cam in it. :D
 

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REDNECK SPACESTATION
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i never would have imagined the increase in sound from a high flow cat. sounds like a beast. anyways.. thanks for all the help in the area everyone, saved me a lot of time and money doing it myself (148.99 for the kit versus 450 for just the cat from a dealer) thanks again everyone!
glad you like it. I ran mine with just the cat for about a week, but was going deaf so installed the muffler.
 
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