Dakota Durango Forum banner
Cancel
Create thread New Garage Forums

Hot Cat

Jump to Latest
1 - 20 of 20 Posts
F

Four20

· Registered
Joined
·
11 Posts
Discussion starter · #1 ·
Ok I have a 02 dak with 3.9, It has recently had the head, intake, exhuast gaskets replaced. At first start it ran great setting at idle for 1.5 hr. everything looked good so it was road test time. within 3 miles of normal driving it started to loose power noticable when accelerating in low rpm.

Upon return of its 3 mile journey I noticed the left cat was glowing red. so ive got alot of unburnt fuel getting into the exhaust.Checked codes and pulled p-0132 o2 sensor short, and nothing else. It puzzles me because i should be getting a misfire code with the amount of fuel getting into the exhaust.
Next day i go to begin my troubleshooting. crank the engine a she is not running smooth. Even tho the cap and rotor are well worn it did appear that i have good fire to the plugs, but upon removal i found cyl 5 plug to be very wet. Both 1 and 3 seemed intermitant as well, but the plugs looked allright.

Now im not into parts slinging I know a great auto tech shop that can handle this problem. Id like to try to work thru it myself. So i will keep yall posted on what i find. Any help is greatly appreciated. Who knows i may just have alot of moisture accumulation in the fuel from setting for 6 months.
 
#2 ·
bad 02 sensor.
 
Save
Reply Quote Like Like
#3 ·
More like a dead injector. And you also now have a plugged cat and the O2 sensor's are burned out from the plugged cat. Had this happen to me last summer due to getting the wrong plug wires from Summit for my 2.0L Neon. Didn't think about at the time when I had to get he work done at the dealer but since it less than 80K miles, I was covered under the Federal emissions warranty. :fawkdance: :funny:
 
Save
Reply Quote Like Like
Discussion starter · #4 ·
Dead injector? as in stuck open or closed? ill recheck the electrical connection to the injector. hope no trash got in the fuel rail. So yall think there is no hope for that cat? replace it? i know the sensor wont hold up to the temps they just went thru.
what is they best testing method for the injectors?
Can a straight pipe be used to replace the cat? I can weld in places for the 02 sensors on the straight pipe doubt they will read right but where do i get this little cat from cause normal auto stores are not showing them like this design just the aftermarket. I dont have to worry about emissions testing but dont want poor fuel milage.
 
#5 ·
I don't remember how to test if an injector is working, so I'll leave that for the others to answer.(Never had an injector go bad on me, not even my dads 94 Dak 5.2 with 327K+ miles.)
As for the cat, they not supposed to get that hot and that is sign they are plugged. Once plugged, they are trashed. :sorry: As for replacement, SummitRacing.com has universal or custom fits cats on there, but IDK if you have precats as well. If it is one of those, you may have to go to a dealer for that one unless you can get a Magnaflow Y-pipe with the pre-cats on it. Or just straight pipe it, several have here but I think they have tuners that compensates for the missing cat or the O2 sensor at the rear reads what the A/F mixture is and is the only one that will give a CEL if running too rich or lean.
Now that I think about a dead injector, it would be dry instead of wet, so that injector is stuck open and probably junk now.
 
Save
Reply Quote Like Like
Discussion starter · #6 ·
ok from what i can tell i have left and right precats each containing 2 o2 sensors each. After the y pipeis another exhuast device id say its the main cat. after that is the muffler. The left precat is wat was glowing. those are the only o2 sensors in the exhuast
Ive found that cyl 2,4,6 have burnt white plugs
cyl 5 is black and wet after running, but while running if i pull the plug wire for cyl 5 i get backfiring; same as 2,4,6 exhibit the same backfiring.
cyl 1,3 plugs are wet not as 5 but when i pull the plug wire while running there is no change its like they arent even there
 
#7 ·
id put my money on the injectors are fine, one of the front 02's are bad. caused by back up from a clogged cat. my solution would b, JBA y pipe (gets rid of the front cats) junk the main cat and see if that fixes it. if not, replace the 02's
 
Save
Reply Quote Like Like
Discussion starter · #8 ·
well i swapped injectors 1,3,5 for 2,4,6 guess what no change .injectors are fine. i can bet the plugs and wires are fine also. If i get rid of the 2 front cats what do i do with the connectons for the o2 sensors
 
Discussion starter · #10 · (Edited)
yes but what of the electrical connections do they not run back to the pcm. how do i get the pcm to work without the o2 sensors. maybe this would be easier to understand if i knew what an o2 sensor was and hoiw it reacts and how the pcm reacts to it. compresion test on cyl 1.3showing right at 140.
 
#11 ·
Why make an easy problem difficult? Change the cat and O2 sensor.

It has cats on both banks, right?
The cat on the L side is bad, right?
You have 1, 3 and 5 bad, right?
The O2 sensor is bad on that side so it's telling those cylinders to dump more fuel.
 
Save
Reply Quote Like Like
#12 ·
MoPar Maniac said:
Why make an easy problem difficult? Change the cat and O2 sensor.

It has cats on both banks, right?
The cat on the L side is bad, right?
You have 1, 3 and 5 bad, right?
The O2 sensor is bad on that side so it's telling those cylinders to dump more fuel.
Click to expand...
The new y pipe would get rid of the cats (cant go bad if they are not there) , free up more power ( no cats and smooth bends), takes 2 seconds to weld in new o2 bungs( put both y pipes right next to each other match up where the 02's go drill and weld), and cost less money.
I don't see what's so difficult about doing that?
 
Save
Reply Quote Like Like
Discussion starter · #14 · (Edited)
i think its a comnbination of both o2 sensors and the exhaust.

Ok guys i unplugged both upstream o2 sensors.
then after a pcm reset the engine ran smoothly so road test time again. didnt take long with all cyl firing right that i started to smell the cats.
began cutting looking for exhaust obstructions.
removed muffler and the loss of power went away quickly.
cats are still on. the slight skip seems to be gone and it dont cut off when decelerating engine.
i have good flo thru the cat but that just means i took some backpressure off the engine? right?
Jeez i hope no-one stuffed my tailpipe!!!!!!!!
i am on a tight budget so buying new y pipes are not an option so i need to know if there is any catylist in the precats ill knock out if so. will the o2 sensors be effective if i do knock out the catalyst in them
thanks for the help
 
Discussion starter · #15 ·
the main cat is no longer an issue had that taken care of today.
O2 sensors are still unplugged
engine is running smoother but only at idle
loss of power still present after 1 mile of road test.now the right pre-cat is glowing red
got some new codes tho
p-0123 TP Sensor Circuit High Input
p-0108 MAP Sensor Circuit High Input
 
#16 ·
moore_716 said:
You act like you know something about making a 3.9 run.

HAHA how the fuck you been? Where have you been hiding out at?
Click to expand...
Im good man how about yourself? I have been lurking in the shadows, my buddies truck is done and i think were guna hit the track this weekend (high 50's all weekend!!). If all goes well his numbers are going to destroy mine. the truck weighed 2995 with him in it. thats around 350 lbs lighter then mine. On the dyno the truck made 205/250. tonight and tomorrow night hes going back for nitrous tuning, 150/175 shot..

Four, there is catalyst in the precats so you can hollow em out. I would do that then reset the pcm again and see if the other codes go away.
 
Save
Reply Quote Like Like
Discussion starter · #18 ·
ok i re-connected the front o2 sensors. wow the truck will not even get up to 5 mph it just backfires badly. in an earlier post is said that i swapped injectors 1,3,5 for 2,4,6 and the problem didnt follow. i think it did follow cause now my right cat is glowing not the left.this test was done before i re-connected the o2 sensors.
also i feel dis-connecting the 2 front 02 sensors was not an effective test as i read last night the pcm can readjust fuel air mix by testing the rear o2 sensors.
 
#19 ·
Did you REPLACE the sensors?

ANY time you change the cat, change the sensors as it's a good bet the sensor is what caused the cat to go bad.
 
Save
Reply Quote Like Like
#20 ·
The front 02 sensors are the only ones that control A/F. The rear 02 don't do anything in terms of performance. Def do not drive the truck around with out the fronts attached, thats why you got the map and tps codes.
Gut the cats, and replace the front 2 sensors.
 
Save
Reply Quote Like Like
1 - 20 of 20 Posts
About this Discussion
19 Replies
7 Participants
Last post:
Slow97dakota
Dakota Durango Forum
posts
1.4M
members
58K
Since
2003
A forum community dedicated to all Dodge Dakota and Durango owners and enthusiasts. Come join the discussion about modifications, troubleshooting, towing capacity, maintenance, and more!
Full Forum Listing
Explore Our Forums
Photos & Videos General Automotive Discussion Troubleshooter's Forum 4.7L/4.7L HO/4.7L Gen II Engines Suspensions - Lifted & Lowered