Marika Posted August 31, 2005 Report Share Posted August 31, 2005 Ever since I had the new cat. converter installed a few weeks back, my gas mileage has dropped A LOT. Roughly 4~5 miles per gallon less with the new cat. converter. Any ideas as to what's happening? If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans. Link to comment Share on other sites More sharing options...
Marika Posted August 31, 2005 Author Report Share Posted August 31, 2005 Any ideas? There are no codes being set, no "Service Engine Soon" light and the mileage of the car is 71,420 as of this morning. If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans. Link to comment Share on other sites More sharing options...
Scotty Posted August 31, 2005 Report Share Posted August 31, 2005 How sure are you that your mileage has dropped? Could it be the result of a different type of driving? What MPG are you getting? I can not imagine the CAT being so small that it would restrict exhaust. Didn't you make the statement that it felt much more powerful? Could your foot be heavier now as a result? Maybe the exhaust noise caused yoiu to baby it a bit? If you were getting codes like an O2 sensor code, I could see a drop, but this does not make sense. Link to comment Share on other sites More sharing options...
Marika Posted August 31, 2005 Author Report Share Posted August 31, 2005 How sure are you that your mileage has dropped? Could it be the result of a different type of driving? What MPG are you getting? I can not imagine the CAT being so small that it would restrict exhaust. Didn't you make the statement that it felt much more powerful? Could your foot be heavier now as a result? Maybe the exhaust noise caused yoiu to baby it a bit? If you were getting codes like an O2 sensor code, I could see a drop, but this does not make sense. I've been watching my driving and I've not noticed a difference but I'll pay closer attention. I'm now getting around 11 to 12 MPG when it used to be around 15~16 MPG which is what the computer shows as the "average" which is mostly local driving with a bit of highway. When the converter was first installed, it did feel more powerful. Now it could be the extreme hot, humid weather of these past days that's making the car feel weak and dead but it now seems that when I step on the gas, nothing happens. Bad tank of gas? Adverse weather? Pending failure of an O2 sensor? Also, no smoke of any type from the exhaust and only a very faint smell of exhaust. If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans. Link to comment Share on other sites More sharing options...
OynxSTS Posted August 31, 2005 Report Share Posted August 31, 2005 Depending on how they Re&re'd the Cat they could have "bumped" "bruised" or otherwise FooBar'ed your O2 sensor enough to cause it to act weird but not enough to trigger a code... If the cat was shot chances are that your O2 sensor is on its last legs anyway.. Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
Marika Posted August 31, 2005 Author Report Share Posted August 31, 2005 Depending on how they Re&re'd the Cat they could have "bumped" "bruised" or otherwise FooBar'ed your O2 sensor enough to cause it to act weird but not enough to trigger a code... If the cat was shot chances are that your O2 sensor is on its last legs anyway.. I've got the 4.9 litre engine. Any idea how many O2 sensors it has? Can I change them myself? I've not scraped my knuckles in a long time, I miss the blood shed... If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans. Link to comment Share on other sites More sharing options...
Scotty Posted August 31, 2005 Report Share Posted August 31, 2005 The O2 sensors are on the manifolds on the 4.9 not the CAT, so its not likely that they touched them or jarred them. Marika, I have a feeling that everything it OK... Reset your average miles per gallon and all the other parameters and try again.. Its possible that you have more local driving mixed in to that average. Its also possible that you were experiencing some exhaust backpressure before you changed your CAT. I recall you saying that she felt much more powerful... its possible that your foot is into it more now that the CAT is fixed which of course will have a negative impact on your gas mileage... Just a thought. I believe you would get codes if something was wrong, trust the system (force)....jedi Link to comment Share on other sites More sharing options...
Marika Posted August 31, 2005 Author Report Share Posted August 31, 2005 The O2 sensors are on the manifolds on the 4.9 not the CAT, so its not likely that they touched them or jarred them. Marika, I have a feeling that everything it OK... Reset your average miles per gallon and all the other parameters and try again.. Its possible that you have more local driving mixed in to that average. Its also possible that you were experiencing some exhaust backpressure before you changed your CAT. I recall you saying that she felt much more powerful... its possible that your foot is into it more now that the CAT is fixed which of course will have a negative impact on your gas mileage... Just a thought. I believe you would get codes if something was wrong, trust the system (force)....jedi I'll wait and see what happens. In the meanwhile, I'll have a little talk with my foot and see if I can get it to lighten up a bit. If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans. Link to comment Share on other sites More sharing options...
Bruce Nunnally Posted August 31, 2005 Report Share Posted August 31, 2005 I like the replace the O2 sensor suggestion. If you have not ever done that on the 92, it is not hard. You will want a O2 sensor socket, which allows for the electrical pony tail on the sensor. Otherwise easy replacement on the 4.9L, which I think has 2. The Northstars have 4. As I recall, they are around $50 each. Bosch suggests you change them every 50K, but if they are not setting a code it is inviting just to leave them be. Logan says they do get lazy though, so need to be treated as a maintenance item. As a powertrain guy would say, after 13 years on, those O2 sensors don't owe you a dime. Bruce 2023 Cadillac CT4-V Blackwing Follow me on: Twitter Instagram Youtube Link to comment Share on other sites More sharing options...
Marika Posted August 31, 2005 Author Report Share Posted August 31, 2005 I like the replace the O2 sensor suggestion. If you have not ever done that on the 92, it is not hard. You will want a O2 sensor socket, which allows for the electrical pony tail on the sensor. Otherwise easy replacement on the 4.9L, which I think has 2. The Northstars have 4. As I recall, they are around $50 each. Bosch suggests you change them every 50K, but if they are not setting a code it is inviting just to leave them be. Logan says they do get lazy though, so need to be treated as a maintenance item. As a powertrain guy would say, after 13 years on, those O2 sensors don't owe you a dime. Gotcha! If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans. Link to comment Share on other sites More sharing options...
Scotty Posted August 31, 2005 Report Share Posted August 31, 2005 That's interesting Bruce, in all my time of owning my 91 that was never suggested to me... At 120,000 miles I wonder how much better it would have run, if I had changed them... I didn't have O2 codes either. You learn something new every day.... Interesting that the gas consumption began when the cat what changed. The O2 sensors are located on the exhaust manifolds. Link to comment Share on other sites More sharing options...
Scotty Posted August 31, 2005 Report Share Posted August 31, 2005 O2 Sensor location 4.9 Link to comment Share on other sites More sharing options...
poopdeville Posted September 1, 2005 Report Share Posted September 1, 2005 I had my cat replaced earlier this summer and also had the muffler replaced. I had them put a Magnaflow high-bypass cat and a (slightly) less backpressure muffler on the old girl. My fuel economy average went from 10.5 or 11 litres per 100 km to 8.5 immediately. The US version of this improvement is as follows: 10.5 litres per 100km = 22 mpg 8.5 litres per 100km = 27.6 mpg I was very happy as 5 mpg = about 4% on my old girl. 4% represents about $3.00 (Can) per tankfull worth of more mileage. Based on the fact I spent $700 to fix the exhaust system, my fuel savings alone (based on paying $65.00 per tankfull) will pay for this repair in approximately 234 tankfulls... at about 600 (or so) km per tank; that represents about 139,000 km or approximately 86,000+ miles... ummm... I should have saved my money, scrapped the car and bought a CTS-V so I could lose my silly dog between the back seats... more fun. Mike P Link to comment Share on other sites More sharing options...
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