87 vett loses 3 cats at same time [Forums - C4 Technical]

C4 Technical > 87 vett loses 3 cats at same time
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istter1	87 vett loses 3 cats at same time	#1
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	Well lost 3 cats at same time. One theory rear cat clogged first making precats fry. Next. Vet slow start first time in morning. Excess fule in cats caused them to.melt down. Next they were old and all failed at same time. Tomorrow. Compression test Fule pressure test Injector test Make sure the 50000volt coil is working correctly. Already cleaned out mufflers. Exaust sounds great now. Anyother suggestions.
	Posted on: 2013/9/17 0:44
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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josephf31	Re: 87 vett loses 3 cats at same time	#2
Senior Guru New Jersey 375 Posts Member since: 2008/5/5 2:49	Quote: istter1 wrote: Well lost 3 cats at same time. One theory rear cat clogged first making precats fry. Next. Vet slow start first time in morning. Excess fule in cats caused them to.melt down. Next they were old and all failed at same time. Tomorrow. Compression test Fule pressure test Injector test Make sure the 50000volt coil is working correctly. Already cleaned out mufflers. Exaust sounds great now. Anyother suggestions. Main cat on my '91 was completely (and I mean completely, nothing but a metal shell) blown out. Still failing emissions I think the precats are likely shot too. How did you determine all 3 cats bad, did you pull and inspect them all? As for the slow start, I'd begin with checking the fuel pump that caused a of problems on my L98.
	Posted on: 2013/9/17 0:54
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Matatk	Re: 87 vett loses 3 cats at same time	#3
Webmaster SW Chicago Burbs 22807 Posts Member since: 2008/1/7 0:00	I would check your tune and figure out why so much excess fuel. Cats can go back after a long period, make sure everything is in good order and didn't contribute to it.
	Posted on: 2013/9/17 1:36
	_________________ 2002 EBM convertible, Magnusson supercharger, cam, headers, etc. 1989 Corvette...RIP
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bogus	Re: 87 vett loses 3 cats at same time	#4
Grand Imperial Pooh-Bah San Pedro, CA 20859 Posts Member since: 2005/9/7 0:00	yea, sounds like a tuning issue... too fat or too lean will kill a cat..
	Posted on: 2013/9/17 2:05
	_________________ The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me
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istter1	Re: 87 vett loses 3 cats at same time	#5
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	Quote: josephf31 wrote: Quote: istter1 wrote: Well lost 3 cats at same time. One theory rear cat clogged first making precats fry. Next. Vet slow start first time in morning. Excess fule in cats caused them to.melt down. Next they were old and all failed at same time. Tomorrow. Compression test Fule pressure test Injector test Make sure the 50000volt coil is working correctly. Already cleaned out mufflers. Exaust sounds great now. Anyother suggestions. Main cat on my '91 was completely (and I mean completely, nothing but a metal shell) blown out. Still failing emissions I think the precats are likely shot too. How did you determine all 3 cats bad, did you pull and inspect them all? As for the slow start, I'd begin with checking the fuel pump that caused a of problems on my L98. We took them apart. All shot. Mufflers full of crap. They shut the engine off.. Heated up everything. I have always thought I had a problem because I was losing so.many slave cylinders. Thst is why I went with the Mcloud hydrolic throw out bearing. The fule pump.is 6 months old. But recently the fullle gsge d 5 gallons off. Easy to pullout and check
	Posted on: 2013/9/17 2:10 Edited by istter1 on 2013/9/17 2:34:41
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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bogus	Re: 87 vett loses 3 cats at same time	#6
Grand Imperial Pooh-Bah San Pedro, CA 20859 Posts Member since: 2005/9/7 0:00	These cats have been dying for a while then. But I would still like to see some O2 sensor numbers before knowing if it was fat or lean.
	Posted on: 2013/9/17 2:37
	_________________ The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me
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istter1	Re: 87 vett loses 3 cats at same time	#7
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	Quote: bogus wrote: These cats have been dying for a while then. But I would still like to see some O2 sensor numbers before knowing if it was fat or lean. When I.get out of dr. Apoinment we have all the test equipment and smog equipment Finally have a little time at the shop Lol
	Posted on: 2013/9/17 3:11
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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istter1	Re: 87 vett loses 3 cats at same time	#8
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	Quote: bogus wrote: These cats have been dying for a while then. But I would still like to see some O2 sensor numbers before knowing if it was fat or lean. You know Andy you jared my memory of the problem of getting the Vet, with the new engine, to idle. My buddy John stepped up the TPS so it would idle smothly. I will check that out tomorrow. Thanks for the brain storming session!! http://www.oreillyauto.com/site/c/printablelist.oap
	Posted on: 2013/9/17 4:10 Edited by istter1 on 2013/9/17 4:26:16
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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bogus	Re: 87 vett loses 3 cats at same time	#9
Grand Imperial Pooh-Bah San Pedro, CA 20859 Posts Member since: 2005/9/7 0:00	TPS and IAC won't effect mixture.
	Posted on: 2013/9/17 15:51
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istter1	Re: 87 vett loses 3 cats at same time	#10
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	Replacing it any way. 11:00 am when I get out ofdr we will find out what the cause was I hope
	Posted on: 2013/9/17 16:14
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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bogus	Re: 87 vett loses 3 cats at same time	#11
Grand Imperial Pooh-Bah San Pedro, CA 20859 Posts Member since: 2005/9/7 0:00	dude... don't throw money at it... diagnose and fix the right way... If they are newer, they are fine. I am betting that whomever tuned it has it running a bit rich, and if anything, a weak or dead O2 sensor wasn't up to the job. I am also sure that 02 sensor is about gone. Do you have a friendly smog guy? If so, I would suggest you get an LT1 style cat back with a pair of Mangaflow cats... they will work on the 383 just fine, and will work better than the three that were there... one on each bank, and will flow better than anything else on earth, really! See if you can track down an LT1 dual exhaust. There is a used part vendor - I will find him - down here in the Ontario area. A used OEM LT1 cat back is CHEAP... get the good cats, hangers and such, and you have just liberated another 30hp from that engine. Seriously. And it will pass sniff any day of the week. I just wish the L98 engine controller could read 2 O2 sensors...
	Posted on: 2013/9/17 19:29
	_________________ The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me
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istter1	Re: 87 vett loses 3 cats at same time	#12
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	sounds cool Let me know Still working on a better tune right now.
	Posted on: 2013/9/18 16:28
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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istter1	Re: 87 vett loses 3 cats at same time	#13
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	Andy is this simular to what you were talking about? http://www.corvetteguruforum.com/modu ... ewtopic.php?topic_id=4207
	Posted on: 2013/9/18 16:34
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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Matatk	Re: 87 vett loses 3 cats at same time	#14
Webmaster SW Chicago Burbs 22807 Posts Member since: 2008/1/7 0:00	I seem to recall that the lt1 cats are not a direct swap to the L 98. The later cars had a clearance area in the frame rail where the lt1 cat sits. I know there is a thread out there outlining the differences.
	Posted on: 2013/9/18 21:51
	_________________ 2002 EBM convertible, Magnusson supercharger, cam, headers, etc. 1989 Corvette...RIP
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Matatk	Re: 87 vett loses 3 cats at same time	#15
Webmaster SW Chicago Burbs 22807 Posts Member since: 2008/1/7 0:00	http://forums.corvetteforum.com/c4-te ... 1-exhaust-on-l98-car.html What Joe said when he tried the swap: Quote: The offset oil adapter does not have provision for the cooler. The right side cat won't fit because the frame is not notched out like on the LT1 cars. In fact, the whole forward frame on the LT1 cars is a little different. If you are running aftermarket cats and the diameter is smaller than OEM, they will clear. I can give you the exact specs as I cut and rewelded an OEM cat to fit. You will need to run LT1 shorty headers as the stud spacing is wider on the LT1. Mine leaked like nothing else for some reason. I took it all apart. My headers are not "perfect", but I think the used cats I bought - I think the socket flanges on them are warped. If you made them together on the bench there is some gaps where it was leaking. I got pissed off and won't be putting it back together this way. The offset oil filter adapter is cool though. even if I go another route, it will keep the oil filter a bit farther away from the exhaust.
	Posted on: 2013/9/19 0:47
	_________________ 2002 EBM convertible, Magnusson supercharger, cam, headers, etc. 1989 Corvette...RIP
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istter1	Re: 87 vett loses 3 cats at same time	#16
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	Wow lot to do.
	Posted on: 2013/9/19 2:35
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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istter1	Re: 87 vett loses 3 cats at same time	#17
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	Quote: istter1 wrote: Well lost 3 cats at same time. One theory rear cat clogged first making precats fry. Next. Vet slow start first time in morning. Excess fule in cats caused them to.melt down. Next they were old and all failed at same time. Tomorrow. Compression test Fule pressure test Injector test Make sure the 50000volt coil is working correctly. Already cleaned out mufflers. Exaust sounds great now. Anyother suggestions. While checking lines we foung the vacume line going to the fuel pressure regulatered almost melted close.Fuel pressure varried from 40 -50 lb. Installed tpi and would have to reve engine to keep engine running. throwing code for mass flow sensor. Sensor ok. Might not be grounding correctly because prior fire damage to wires. Will pull computer and ground. Computer from autozone a year old. Problem of pre codes could be computer will check that out Life time warrenty Autozone. Any suggestions on Idle and mass air flow sensor.
	Posted on: 2013/9/19 5:25
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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bogus	Re: 87 vett loses 3 cats at same time	#18
Grand Imperial Pooh-Bah San Pedro, CA 20859 Posts Member since: 2005/9/7 0:00	if you think the wire are damaged, chase them. digital multi-meters are your friend here. make sure the wires are not damaged in some way. The magnaflow cats are much smaller than the LT1 cats, so you don't need to worry so much about the frame in the way.
	Posted on: 2013/9/19 14:01
	_________________ The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me
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istter1	Re: 87 vett loses 3 cats at same time	#19
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	Quote: bogus wrote: if you think the wire are damaged, chase them. digital multi-meters are your friend here. make sure the wires are not damaged in some way. The magnaflow cats are much smaller than the LT1 cats, so you don't need to worry so much about the frame in the way. When I get off work today will be third time this year for simular problems. Wish we never had the fire lol
	Posted on: 2013/9/19 18:03
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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bogus	Re: 87 vett loses 3 cats at same time	#20
Grand Imperial Pooh-Bah San Pedro, CA 20859 Posts Member since: 2005/9/7 0:00	fires suck.... I wish I was closer... but I will be around if you have qx, just post away!
	Posted on: 2013/9/19 23:44
	_________________ The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me
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istter1	Re: 87 vett loses 3 cats at same time	#21
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	Chased wires not a problrm. Had to drive to Lamont to get another ecm Autozone good warrent
	Posted on: 2013/9/20 1:18
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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bogus	Re: 87 vett loses 3 cats at same time	#22
Grand Imperial Pooh-Bah San Pedro, CA 20859 Posts Member since: 2005/9/7 0:00	that warranty has now been used up. I hope that's the problem!!!
	Posted on: 2013/9/20 3:04
	_________________ The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me
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istter1	Re: 87 vett loses 3 cats at same time	#23
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	Will know later today.. I think there may be more to the tune.
	Posted on: 2013/9/20 13:19
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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bogus	Re: 87 vett loses 3 cats at same time	#24
Grand Imperial Pooh-Bah San Pedro, CA 20859 Posts Member since: 2005/9/7 0:00	Not to be an ass, but "duh" comes to mind. cat's die for 2 reasons - too much fuel or not enough.
	Posted on: 2013/9/20 16:37
	_________________ The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me
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istter1	Re: 87 vett loses 3 cats at same time	#25
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	Quote: bogus wrote: Not to be an ass, but "duh" comes to mind. cat's die for 2 reasons - too much fuel or not enough. you know the nice thing about this site is after a while people treat you like family. Say something STUPID and lol Thanks for the help Andy lol
	Posted on: 2013/9/20 20:10
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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bogus	Re: 87 vett loses 3 cats at same time	#26
Grand Imperial Pooh-Bah San Pedro, CA 20859 Posts Member since: 2005/9/7 0:00	just being me. as I said above, I would really love to know what the O2 sensor is saying. you may even need a wide band to do the tune with... But that's the problem with tuning these older engines... is so manual... burn the chip try again burn again...
	Posted on: 2013/9/20 21:05
	_________________ The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me
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istter1	Re: 87 vett loses 3 cats at same time	#27
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	It's alive The money pit lives on
	Posted on: 2013/9/21 0:20
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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bogus	Re: 87 vett loses 3 cats at same time	#28
Grand Imperial Pooh-Bah San Pedro, CA 20859 Posts Member since: 2005/9/7 0:00	yay!! cause??
	Posted on: 2013/9/21 0:22
	_________________ The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me
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istter1	Re: 87 vett loses 3 cats at same time	#29
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	After replacing computer the tune took. Put it on smog machine will pass without a problem. No throttel hesitation Took a fine adjustment on tps so the maf sensor to work correctly Cleaned throttey body All I know is everything is working correctly Duh Lol
	Posted on: 2013/9/21 2:25
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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bogus	Re: 87 vett loses 3 cats at same time	#30
Grand Imperial Pooh-Bah San Pedro, CA 20859 Posts Member since: 2005/9/7 0:00	I am so glad! I wonder if the chips were properly installed in the old computer? just thinking...
	Posted on: 2013/9/21 14:08
	_________________ The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me
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Matatk	Re: 87 vett loses 3 cats at same time	#31
Webmaster SW Chicago Burbs 22807 Posts Member since: 2008/1/7 0:00	If the piggyback chip wasn't installed correctly it probably would run in limp mode or if the adapter wasn't installed correctly it probably wouldn't run at all. With the new computer in and everything running I would datalog it immediately and check the 02 function and fuel learn tables.
	Posted on: 2013/9/21 16:41
	_________________ 2002 EBM convertible, Magnusson supercharger, cam, headers, etc. 1989 Corvette...RIP
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istter1	Re: 87 vett loses 3 cats at same time	#32
Elite Guru Bakersfield Ca 2336 Posts Member since: 2011/7/4 21:23	Quote: Matatk wrote: If the piggyback chip wasn't installed correctly it probably would run in limp mode or if the adapter wasn't installed correctly it probably wouldn't run at all. With the new computer in and everything running I would datalog it immediately and check the 02 function and fuel learn tables. With the new computer in and everything running I would datalog it immediately and check the 02 function and fuel learn tables. We have all the information at the shop Good advice Since the day I bought this 87 Vet it has been so hot in the cabim. If you put a foam cup in the holder it would mealt a little the shifter metal was hot as hell. Themputer under the hood by either bank was scorching. Not now. I am wondering if the heat destroyed all the slave cylinders. They all showed signs of heat. Fluid boiled off readily. No problem since we installed the Hydrolic throw out bearing With the new cats you hardly notice it Thanks Guys for the help Steve
	Posted on: 2013/9/22 0:49
	_________________ Only I can change my life. No one can do it for me. Carol Burnett
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Matatk	Re: 87 vett loses 3 cats at same time	#33
Webmaster SW Chicago Burbs 22807 Posts Member since: 2008/1/7 0:00	Your cats were surely overheating for all this time and causing the heat issue in the floorboards. I'm glad they didn't damage anything else. I know we theorized heat could be causing the problems in the past with the clutch hydraulics but never figured it was from the cats being/going bad. Wow. Good info for the future and hopefully that solves a lot more problems!
	Posted on: 2013/9/22 13:00
	_________________ 2002 EBM convertible, Magnusson supercharger, cam, headers, etc. 1989 Corvette...RIP
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