back pressure damage from clogged catalytic converter?
From : hrl
Q: i posted this to alt.autos.dodge this morning and got no response so thought id try it here.... 1989 dodge b250 van 318 cu.in. auto. 188000 miles..... i have noticed a big drop in power in the past few months but it all came to a head this past week. heres the scenerio driving down the interstate cruise on about 65 mph when the engine suddenly gave a whoosh sound lost power started missing and black smoke pouring out the exhaust. i managed to limp off at the next exit at about 30 miles per hour found a garage and get it looked at. the engine analyser showed bad o2 sensor so had it replaced. the mechanic at the time mentioned if this didnt fix it then maybe the cat. converter was bad as small dust and particles fell out when he removed the o2 sensor. i continued down the road everything fine. next trip out the same thing the whoosh sound missing smoke etc. this time i limped into a garage and explained the history of the problem and asked if there was any way the cat. converter could be cut out and a straight pipe put in its place. this was done to temp. get me home as they had no cat. converters or ability to get one. the smog line from the engine was also cut and tack wleded to the side of the new straight pipe. anyway the cat. converter was in bad shape once removed. the pack has been worn away at the inlet end rounded down lots of dust and small particles in the shell of the thing plus the pack had come loose and was floating around in there. started the engine lots of black smoke and particles came out then cleared up after about 5 miles driving. the change in the power and engine feel was amazing. much more peppy etc. also the last tank of gas that i burned filled up just after the cat. removal got me 9.2 mpg instead of the normal 15.3 that i had been getting. all in all the engine runs like a new one again. after i got home i replaced the muffler it was mushroomed and full of the same dust and particles. i recovered even more smooth running and power. now my concerns and questions this engine was obviously to me suffering from several months of restricted exhaust flow back pressure and the resulting buildup of deposits inside the engine. the only difference i can find now is the valve chatter is somewhat louder when the engine is under a good load climbing a hill etc. from the drivers seat i cant hear any normal idling chatter but with the doghouse off it is really noisy at idle with some valve chatter. i plan to change the plugs check the timing and distributor. i dont plan to put the cat. converter back unless it requires it for the engine working properly. my questions what is the likely long term result of running this engine for say 500 miles in this condition of restricted exhaust outlet what is the chances that there is a lot of deposit buildup inside it what is the best way to clean these deposits out if they are there what about the chatter under heavy load can not having the cat. converter in the exhaust system have changed the engine to the extent that i need a gas booster or to go to a higher octane level gas any help or thoughts will be appreciated. james -- hrl never underestimate the power of stupid people in large groups e-mail munged--remove the obvious .
Replies:
From : sqdancerlynn
im suprised a mechanic removed the cat it is very illegal to remove it. not haveing it can screw up the o2 sensor readings .
From : snoman
on sat 01 jul 2006 205422 gmt hrl hiletroynotthis@orthismyrealbox.com wrote unless you overheated the motor doing this the chance of any real damage to it is light. you did stop it and take action when it got bad which may have saved your engine. i would change oil and put in some fresh oil and as far as lifter tick given the miles on engine i would not worry much about it unless it starts getting worse. ----------------- the snoman www.thesnoman.com .
From : hrl
on sat 01 jul 2006 210224 gmt snoman admin@snoman.com wrote on sat 01 jul 2006 205422 gmt hrl hiletroynotthis@orthismyrealbox.com wrote unless you overheated the motor doing this the chance of any real damage to it is light. you did stop it and take action when it got bad which may have saved your engine. i would change oil and put in some fresh oil and as far as lifter tick given the miles on engine i would not worry much about it unless it starts getting worse. ----------------- the snoman www.thesnoman.com thanks i appreciate your thoughts.... -- hrl never underestimate the power of stupid people in large groups e-mail munged--remove the obvious .
From : big al
on sat 01 jul 2006 205422 gmt hrl hiletroynotthis@orthismyrealbox.com wrote unless you overheated the motor doing this the chance of any real damage to it is light. you did stop it and take action when it got bad which may have saved your engine. i would change oil and put in some fresh oil and as far as lifter tick given the miles on engine i would not worry much about it unless it starts getting worse. ----------------- the snoman www.thesnoman.com some of the crap may now be clogging the muffler. take it off and see what falls out when you hold the inlet down and shake it. on my car it looked like all the stuff out of the converter was in the muffler. al .
From : hrl
on sat 1 jul 2006 165218 -0700 big al sal1@qwest.net wrote on sat 01 jul 2006 205422 gmt hrl hiletroynotthis@orthismyrealbox.com wrote unless you overheated the motor doing this the chance of any real damage to it is light. you did stop it and take action when it got bad which may have saved your engine. i would change oil and put in some fresh oil and as far as lifter tick given the miles on engine i would not worry much about it unless it starts getting worse. ----------------- the snoman www.thesnoman.com some of the crap may now be clogging the muffler. take it off and see what falls out when you hold the inlet down and shake it. on my car it looked like all the stuff out of the converter was in the muffler. al yes it did. i replaced the muffler last week and the old one was mushroomed out had lots of dust and pellets/particles in it.. its amazing the amount of junk that came from one screwed up converter... -- hrl never underestimate the power of stupid people in large groups e-mail munged--remove the obvious .
From : bob
hrl wrote i posted this to alt.autos.dodge this morning and got no response so thought id try it here.... 1989 dodge b250 van 318 cu.in. auto. 188000 miles..... i have noticed a big drop in power in the past few months but it all came to a head this past week. heres the scenerio driving down the interstate cruise on about 65 mph when the engine suddenly gave a whoosh sound lost power started missing and black smoke pouring out the exhaust. i managed to limp off at the next exit at about 30 miles per hour found a garage and get it looked at. the engine analyser showed bad o2 sensor so had it replaced. the mechanic at the time mentioned if this didnt fix it then maybe the cat. converter was bad as small dust and particles fell out when he removed the o2 sensor. i continued down the road everything fine. next trip out the same thing the whoosh sound missing smoke etc. this time i limped into a garage and explained the history of the problem and asked if there was any way the cat. converter could be cut out and a straight pipe put in its place. this was done to temp. get me home as they had no cat. converters or ability to get one. the smog line from the engine was also cut and tack wleded to the side of the new straight pipe. anyway the cat. converter was in bad shape once removed. the pack has been worn away at the inlet end rounded down lots of dust and small particles in the shell of the thing plus the pack had come loose and was floating around in there. started the engine lots of black smoke and particles came out then cleared up after about 5 miles driving. the change in the power and engine feel was amazing. much more peppy etc. also the last tank of gas that i burned filled up just after the cat. removal got me 9.2 mpg instead of the normal 15.3 that i had been getting. all in all the engine runs like a new one again. after i got home i replaced the muffler it was mushroomed and full of the same dust and particles. i recovered even more smooth running and power. now my concerns and questions this engine was obviously to me suffering from several months of restricted exhaust flow back pressure and the resulting buildup of deposits inside the engine. the only difference i can find now is the valve chatter is somewhat louder when the engine is under a good load climbing a hill etc. from the drivers seat i cant hear any normal idling chatter but with the doghouse off it is really noisy at idle with some valve chatter. i plan to change the plugs check the timing and distributor. i dont plan to put the cat. converter back unless it requires it for the engine working properly. my questions what is the likely long term result of running this engine for say 500 miles in this condition of restricted exhaust outlet what is the chances that there is a lot of deposit buildup inside it what is the best way to clean these deposits out if they are there what about the chatter under heavy load can not having the cat. converter in the exhaust system have changed the engine to the extent that i need a gas booster or to go to a higher octane level gas any help or thoughts will be appreciated. james in theory a clogged cat will put so much pressure back into the heads that the exhasut valves can carbon up burn or even melt. in theory. if the engine seems to run good ignore it. you could try putting some sea foam or marvel mystery oil in the gas tank but i dont think it will change much. that engine will take an incredible amount of abuse and still keep running. -- ..bob arrived 2006 fxdi red. 1997 hd fxdwg - turbocharged stolen 11/26/05 in denver 1hd1gel10vy3200010 co license j5822z 2001 dodge dakota qc 5.9/4x4/3.92 1966 mustang coupe - daily driver 1965 ffr cobra - 427w efi damn fast. .
From : hrl
on sun 02 jul 2006 001058 -0600 .bob bobcowan@access4less.nospam.net wrote hrl wrote 1989 dodge b250 van 318 cu.in. auto. 188000 miles..... i have noticed a big drop in power in the past few months but it all came to a head this past week. heres the scenerio driving down the interstate cruise on about 65 mph when the engine suddenly gave a whoosh sound lost power started missing and black smoke pouring and distributor. i dont plan to put the cat. converter back unless it requires it for the engine working properly. my questions what is the likely long term result of running this engine for say 500 miles in this condition of restricted exhaust outlet what is the chances that there is a lot of deposit buildup inside it what is the best way to clean these deposits out if they are there what about the chatter under heavy load can not having the cat. converter in the exhaust system have changed the engine to the extent that i need a gas booster or to go to a higher octane level gas any help or thoughts will be appreciated. james in theory a clogged cat will put so much pressure back into the heads that the exhasut valves can carbon up burn or even melt. in theory. if the engine seems to run good ignore it. you could try putting some sea foam or marvel mystery oil in the gas tank but i dont think it will change much. that engine will take an incredible amount of abuse and still keep running. thanks for the reply. that is reassuring.....have you ever poured marvel mystery oil or similar down the carb on a vehicle to clean things out any experience with the various brands of engine restorer -- hrl never underestimate the power of stupid people in large groups e-mail munged--remove the obvious .
From : bob
hrl wrote thanks for the reply. that is reassuring.....have you ever poured marvel mystery oil or similar down the carb on a vehicle to clean things out any experience with the various brands of engine restorer ive put mmo in the fuel tank as a carb cleaner. that seemed to work ok. i also use b-12 chemtool as a carb and injector cleaner. i do that every so often usually when im in the parts store and i happen to think about. i put a fair amount of miles on my vehicles use cheap gas and i never seem to have any trouble with clogged jets or injectors. ive used restore on a number of vehicles over the years. it does seem to help. cuts down on oil burning anyway. years back i tried a product called matrix. very expensive and there was more to it than just dumping it into the crank case. didnt do a thing; huge waste of time and money. about 15 years ago i had a 69 mustang with a 351w engine. on cold startup esp in the winter the valves would really clatter for about 30 sec and then fade away. i put in a can of slick 50 and the valve clatter went away. didnt do anything else though. no change in performance still burned the same amount of oil no change in fuel mileage. 5 years later i rebuilt the engine and it was pretty clean inside. thats my story and im sticking to it ; -- ..bob arrived 2006 fxdi red. 1997 hd fxdwg - turbocharged stolen 11/26/05 in denver 1hd1gel10vy3200010 co license j5822z 2001 dodge dakota qc 5.9/4x4/3.92 1966 mustang coupe - daily driver 1965 ffr cobra - 427w efi damn fast. .
From : snoman
on sun 02 jul 2006 001058 -0600 .bob bobcowan@access4less.nospam.net wrote in theory a clogged cat will put so much pressure back into the heads that the exhasut valves can carbon up burn or even melt i question your theory. the biggest danger here is engine over heating and damamgeing headgasket and other engine parts not burning exhaust valves. ----------------- the snoman www.thesnoman.com .
From : hrl
on mon 03 jul 2006 031653 -0400 sqdancerlynn sqdancerlynn1@verizon.net wrote im suprised a mechanic removed the cat it is very illegal to remove it. not haveing it can screw up the o2 sensor readings thats why i didnt use location details being under the table emergency gotta get home work with a wink a nudge and cash money... how does not having it screw up the o2 sensor- specifically---fule mixture idle speed timing advance i wondered what if any effect that would have. although now is so much better than then.... -- hrl never underestimate the power of stupid people in large groups e-mail munged--remove the obvious .
From : tom lawrence
how does not having it screw up the o2 sensor- specifically---fule mixture idle speed timing advance i wondered what if any effect that would have. although now is so much better than then.... it doesnt.... it will only affect an obd-ii-equipped vehicle with a post-cat o2 sensor. and even at that all it will do is light up the check engine light due to the post-o2 sensor being out of whack. however the post-cat o2 sensor has nothing to do with fuel injection control - its just an emissions cop. youre pre-obd-ii vehicle will have no issue running without a cat - except maybe for a decrease in peak torque because of lower-than-designed backpressure in the exhaust system. stick a half of a potato in the exhaust pipe to compensate ^ .
From : clare at snyder on ca
on sat 01 jul 2006 205422 gmt hrl hiletroynotthis@orthismyrealbox.com wrote my questions what is the likely long term result of running this engine for say 500 miles in this condition of restricted exhaust outlet what is the chances that there is a lot of deposit buildup inside it what is the best way to clean these deposits out if they are there what about the chatter under heavy load can not having the cat. converter in the exhaust system have changed the engine to the extent that i need a gas booster or to go to a higher octane level gas any help or thoughts will be appreciated. first things first - about the valve chatter under load. if it is under load more likely than not you have spark knock or ping. try a tank of premium fuel and see if it is better. if so you need to find out why/ if your egr is not working that could be part of it. or you could have a good dose of carbon in the cyls. if the premium does not solve it it may be valve lifters. change the oil. put in10w30 or 10w40 with one quart of marvel mystery oil and see if it gets better in about half an hour of driving. if the premium makes it better put a can of fuel injector cleaner in the tank and/or get a can of combustion chamber cleaner your gm dealer will have it your chrysler dealer should.follow the instructions on the can. the lack of the converter will not cause an engine to require higher octane fuel but a 318 with 188000 on it may very well like mid premium. james -- posted via a free usenet account from http//www.tera.com .
From : big al
on sun 02 jul 2006 001058 -0600 .bob bobcowan@access4less.nospam.net wrote in theory a clogged cat will put so much pressure back into the heads that the exhasut valves can carbon up burn or even melt i question your theory. the biggest danger here is engine over heating and damamgeing headgasket and other engine parts not burning exhaust valves. ----------------- the snoman and ruining the egr valve. they get very hot when the converter plugs. on my vehicle i was lucky the converter plugged so tight the engine just quit. al al .
From : hrl
it is true that with enough rtv you can basically seal anything but you trouble may lay in how your are assembling it. prep it as you have in the past but when you assemble it install bolt littlemore than finger tight and then let is sit overnight at very least because it you take it to full torque instantly you can squeeze the sealant out 24 hours would be great and then snug bolts up to about 15 to 20 in lbs and drive it and after it heat and cools the first time recheck bolts torque and take it to maybe 25 to 30 in lbs max. this is important to do frequently people apply to much torque to these bolts and warp the seal area. you might check them again after several more cycles. as far as rtv i have found the black stuff or kind to work about the best overall. ----------------- the snoman www.thesnoman.com .