pulling a trailer last weekend i got within 20 mi. of our campsite and found that there was major surging when i gave it more gas to go up a hill...also the check engine light came on and stayed on, pulled over and looked under the hood...nothing seemed out of the ordinary. now could only get 40mph on highway. pulled into a town after i dropped the trailer off..and went to a repair shop..they told me it sounds like a plugged cat. i then took it to a muffler shop.. and they reved the engine and could hear a rattling sound...says the cat is dead. they will cut the cat off, install a Y pipe and put an o2 simulator in to fool the computer and not give me the check engine light. i asked why they couldn't just put a new cat on? they said it can't be done..i have to do the Y pipe thing! ??? anyway..i just wanted to get it fixed so that i could pull my trailer home. the repair went fine and they showed me the o2 simulator. on the way back to the campsite i was going 60mph on the highway..everything seemed fine until i thought i would floor it and see if i have the power back...needless to say...major surging again! and check engine light on!!...slowed down again..and all was fine... this just happens when i floor it. i reset the light back at my campsite by unhooking the battery...then limped my trailer home the next day at 50 mph...no check engine light..i took it easy and didn't want to give it extra gas going up a hill.
anyway thats how i sit still.
my questions are.
do you think that there are 2 -o2 sensors on my truck?
if there are.. would these symptoms suggest that they put the 02 simulator in the front of the cat...hence giving the main control module fits and resulting in bad F/A ratio?
any other suggestions what the prob may be?

please give me your feedback on this, as i would be forever grateful.... this is my first post here and i feel you guys are pros at this. i just need something to go by before i take it into a dealer to put it on a scope.

thanks all!

 

Do not put an o2 simulator on the front of the cat! this o2 helps to control the AFR like you though. O2 sims are for the rear o2's only.

The best way to test the cat is to have someone in the cab rev the motor to about 2000 or 2500 rpm's and put a temp gun on the input and output of the cat. the output should be around 50 deg hotter than the input for proper cat operation. if the temps are the same, the cat is not working, if the input temp is high and the output temp is low, you have a plugged cat and you should have it swapped out immediately.

If the cat checks out ok, then check your airflow and fuel pressure.

Welcome to DF!

 

2nd gen rams have a huge problem with cats cloggin up after 75k miles. when mine did that i took off the cat and sawed the primary tubes off with a sawzall. then i welded them to a Y pipe i bought from jegs and a 3 inch cat i got from summit. put an o2 sensor bushing in the Y pipe and a o2 sim AFTER the cat. im in PA so i still need to run a cat. actually if it came with a cat no matter where you are its against a federal regulation to not run with one, no matter what state you are in inspection or not. but sadly to say PA has inspection every year for my county. the fine for not running a cat is about 10000 dollars if they decide to prosecute and 15k for each emission station you go to (two in pa). next time your engine light comes on take it to an auto zone or advaced and they will read it for free, or just buy your own scanner. but it also sounds like either you got that sim on the wrong sensor or your 02 sensor is bad.

 

steve00ram360...the cat has been removed and a Y pipe installed with an o2 simulator...now wether the simulator was installed to the jack before the cat or after the removed cat is another question..
cfmiller58... i live in alberta canada...there are no regulations here stating you must have a cat...i know in bc and ont. there are. today i am taking it into a dealership to put it on a scope... thanks for your advice...at least now i know a couple things as to what the fault may be.

thanks for your help guys!

 

I would check ASAP to see if the Sim is in the front position or rear position assuming you have 2 o2's. if you don't have 2 o2's, then the sim needs to be removed and put in a real o2 sensor.

Reason being... the sim is going to tell the PCM that all is good, it'll never report back that it's running too rich or too lean. If your motor is running too lean you can do internal damage over time and performance will suffer same thing for too rich. carbon buildup can occur on the pistons causing detonation.

Check out where the sim is ASAP, also you could be loosing HP/TQ with it installed incorrectly.


edit: seeing you have a '96, you should have 2 o2's... make sure the sim is in the rear or downstream o2 position...