- Location
- MilkyWay Galaxy
OK, my question is this, I have an aftermarket Catalytic converter that was installed to replace my plugged, broken cat 2 years ago. It was installed days after I bought this jeep. It was about $100 installed, and seems to be the aftermarket typical replacement (meets somebody's minimum specs) size. Ratherbecamping looked at it yesterday at tells me it is about half the size of the OEM Cat. The Muffler shop today looked at it and checked thier cat catalog and said it is the standard after market size looking at the outside of it, but said there are larger, high flow cats available, but they are like $200, versus the $100 one I have. Now I know the material on the inside could have larger or smaller diameter passages in the cat support material, so outside size is not the whole story.
So my question is:
1) should I replace the Cat?:dunno:
2) What size and brand should get?:dunno:
3) How much should I pay for it?:dunno:
4) Is it likely to significantly improve my my high rpm power, and overall MPG's based on my history in this thread?:dunno:
Here is a detailed 2 year background on my Jeep :read:, 87 Wagoneer Ltd., ed., 4X4, 4.0 Liter, automatic trans., Renix, all stock except thermostat and radiator.
On the general topic of possible causes of poor fuel economy, as many of you know from reading some of my other preiodic posts I have been working on that issue with my 87 Renix system for nearly 2 years now.
Yesterday, I went to a second muffler shop for a second oppinion on my exhaust system which I have thought for some time might be part of my low power, low MPG problem, and the second muffler shop oppinion was that my system was OK. He shot the cat converter with a IR gun and it read 235 F on the inlet and 285 F on the exit which he said was OK, but I was not impressed. He said it was on the F range, but that makes no sense to me, I am thinking those numbers had to be degrees C for the exhaust, Right? As I recall I check my exhaust manifold last week and read something 485 F on it.
Long story short I had him replace everthing after the Cat (the Cat was only 2 years old) including the muffler. Before this I could barely feel exhaust gas flow (pressure) at 3" from the tail pipe at idle (which two muffler shops said was OK). Now I can feel the exhaust pressure at at least 12" to 14" from the end of the tail pipe. I will post MPG results later after this and the next tank of fuel to see if it affected MPG's, but it has already improved the power and performance some (maybe 15%).
Ratherbecamping looked at my Cat yesterday and said it is about 1/2 the size of the OEM cat, so I will be looking at replacing the Cat next. But I need experience based feedback and oppinions on which Cat I should get????:dunno:
Also, additonal background for my question below, I run a 165 F thermostat, and I checked the O2 sensor performance on mine yesterday with an analog multi meter and at 165 F water coolant temperature it oscilated at a about 2 second frequency (360 degrees, 0.8...0.2....0.8), from 0.2 to 0.8 volts and on occasion closed into a 0.33 to 0.67 V range indicating that my O2 sensor is working, and indicating that my Renix is in the closed loop mode at idle even at 165 F (I verified the 165 F with two different IR gauges). Also it stayed in the 0.2 to 0.8 range during accelaration and fell to a steady 0.2 volts for about 5 seconds during hard decceleration.
I need to check, but if anyone knows for sure I am thinking the drop to 0.2 volts on the O2 sensor for 5 seconds during deceleration is normal???? :dunno:
Lastly my 2.2 L diesel has twice the exhaust gas flow rate (but a smaller diameter pipe) as my 4.0 gas jeep with the new muffler, so I am thinking my cat is also part of the problem, specifically that it is too small.
Lastly, I have run repeated tests on and replaced ALL questionable Renix sensors except the Block Temperature sensor which tested OK. Fuel injectors are fairly new, Fiveomotorsports, premium, new, multi pin/needle (4) injectors. Distributor, rotor, cap, plugs, wires, ignition coil and electronic ignition controller are all new. Good grounds, less than 1 ohm, new alternator....etc......New fuel pressure regulator a year ago, new CPS 2 years ago, fuel filter (old fuel filter one was OK), replaced yesterday, new air filter 8 weeks ago.....Fuel pump and new fuel presure regulator passed the fuel pressure and flow tests 6 months ago. Engine vacuum in park (idle, accell, decell) are normal. Tires are new, lots of front end parts are new too.
I am basically down to the Engine and the exhuast system or one hell of drive train loss for the last 2 years (brakes are new 6 months ago). Transmission is not the problem, it is not slipping, if it was wheel bearings or the like I would have heard it getting worse the last 20,000 miles and 2 years of driving it, right?
So my question is:
1) should I replace the Cat?:dunno:
2) What size and brand should get?:dunno:
3) How much should I pay for it?:dunno:
4) Is it likely to significantly improve my my high rpm power, and overall MPG's based on my history in this thread?:dunno:
Here is a detailed 2 year background on my Jeep :read:, 87 Wagoneer Ltd., ed., 4X4, 4.0 Liter, automatic trans., Renix, all stock except thermostat and radiator.
On the general topic of possible causes of poor fuel economy, as many of you know from reading some of my other preiodic posts I have been working on that issue with my 87 Renix system for nearly 2 years now.
Yesterday, I went to a second muffler shop for a second oppinion on my exhaust system which I have thought for some time might be part of my low power, low MPG problem, and the second muffler shop oppinion was that my system was OK. He shot the cat converter with a IR gun and it read 235 F on the inlet and 285 F on the exit which he said was OK, but I was not impressed. He said it was on the F range, but that makes no sense to me, I am thinking those numbers had to be degrees C for the exhaust, Right? As I recall I check my exhaust manifold last week and read something 485 F on it.
Long story short I had him replace everthing after the Cat (the Cat was only 2 years old) including the muffler. Before this I could barely feel exhaust gas flow (pressure) at 3" from the tail pipe at idle (which two muffler shops said was OK). Now I can feel the exhaust pressure at at least 12" to 14" from the end of the tail pipe. I will post MPG results later after this and the next tank of fuel to see if it affected MPG's, but it has already improved the power and performance some (maybe 15%).
Ratherbecamping looked at my Cat yesterday and said it is about 1/2 the size of the OEM cat, so I will be looking at replacing the Cat next. But I need experience based feedback and oppinions on which Cat I should get????:dunno:
Also, additonal background for my question below, I run a 165 F thermostat, and I checked the O2 sensor performance on mine yesterday with an analog multi meter and at 165 F water coolant temperature it oscilated at a about 2 second frequency (360 degrees, 0.8...0.2....0.8), from 0.2 to 0.8 volts and on occasion closed into a 0.33 to 0.67 V range indicating that my O2 sensor is working, and indicating that my Renix is in the closed loop mode at idle even at 165 F (I verified the 165 F with two different IR gauges). Also it stayed in the 0.2 to 0.8 range during accelaration and fell to a steady 0.2 volts for about 5 seconds during hard decceleration.
I need to check, but if anyone knows for sure I am thinking the drop to 0.2 volts on the O2 sensor for 5 seconds during deceleration is normal???? :dunno:
Lastly my 2.2 L diesel has twice the exhaust gas flow rate (but a smaller diameter pipe) as my 4.0 gas jeep with the new muffler, so I am thinking my cat is also part of the problem, specifically that it is too small.
Lastly, I have run repeated tests on and replaced ALL questionable Renix sensors except the Block Temperature sensor which tested OK. Fuel injectors are fairly new, Fiveomotorsports, premium, new, multi pin/needle (4) injectors. Distributor, rotor, cap, plugs, wires, ignition coil and electronic ignition controller are all new. Good grounds, less than 1 ohm, new alternator....etc......New fuel pressure regulator a year ago, new CPS 2 years ago, fuel filter (old fuel filter one was OK), replaced yesterday, new air filter 8 weeks ago.....Fuel pump and new fuel presure regulator passed the fuel pressure and flow tests 6 months ago. Engine vacuum in park (idle, accell, decell) are normal. Tires are new, lots of front end parts are new too.
I am basically down to the Engine and the exhuast system or one hell of drive train loss for the last 2 years (brakes are new 6 months ago). Transmission is not the problem, it is not slipping, if it was wheel bearings or the like I would have heard it getting worse the last 20,000 miles and 2 years of driving it, right?