Question

Sharaz508 · 06-06-2006, 10:28 PM

Would a clogged cat make my car backfire while driving and at idle?

jfunez · 06-07-2006, 03:14 AM

actually a clogged cat would actually make your car run like crap, even at idle ,specially under acceleration....If you could borrow a back pressure tester gauge from somebody you could get that possibility out of the way....Its easy to test..if you need any help let me know...

mrnickleye · 06-07-2006, 03:21 AM

Timing off can do it. An exhaust leak can do it. A sticking open injector can do it (raw gas down the exhaust).

Sharaz508 · 06-07-2006, 03:05 PM

it idles fine just back fires a little. But it does run like crap its a 5 speed and when i start to move the car starts bucking (and i no how 2 drive standerd). its does that till like 2000 rpm then it runs a little better but then after that it runs like shit agian. It back fires when im driveing to. But it does have an exhaust leak it needs an exaust pipe gasket but i dont think it would make it run this bad. Ill be going down the street then floor it and it will speed up but harrably. it cant be spark plug (irridium) or the plug wires becasue there where just changed recently.

Im ganna try and test the back pressure. what should it be?

mrnickleye · 06-07-2006, 08:31 PM

Well now you have given us more info. runs poorly, not just backfiring.

If its N/A, Cap & Rotor = replace !

Misfiring is your problem. Why is the question. Could be a lean fuel condition.

Sharaz508 · 06-08-2006, 01:47 AM

Quote:

Originally Posted by mrnickleye

Well now you have given us more info. runs poorly, not just backfiring.

If its N/A, Cap & Rotor = replace !

Misfiring is your problem. Why is the question. Could be a lean fuel condition.

How could i tell if its a lean fuel condion? and what should i do?

jfunez · 06-08-2006, 02:25 AM

if u get your hands on a backpressure tester ,hook it up on the o2 sensor orifice before the cat. I cant remember but it should be in the low 0 to maybe 3, cant remember but it pretty much should be steady on the verry low also during acceleration, there should not be much fluctuation on the gauge under accel..

rnoswal · 06-08-2006, 12:41 PM

First do a tune up! Plugs, wires, cap and rotor. Most of the time that is all it is. If you have a cylinder or two that aren't firing, it will have no power and buck and backfire. Try that simple stuff first then see how it runs. Air filter too.

Russ

theWeezL · 06-08-2006, 01:46 PM

is your car throwing any codes (engine light is on)?

if not then I agree, do cap and rotor, check your timing, check all your vacuum hoses for cracks or missing connection, replace your fuel filter, and perhaps test your fuel pressure.

if you still cant solve the issue, sometimes its nice to take it to a mechanic for a scope check. Its usually a reasonable fee and a good mechanic can usually figure out whats wrong for you. Then you can do the work yourself to save money.

Anyway, just a suggestion

Sharaz508 · 06-08-2006, 07:25 PM

no codes but i think i narowed it to a boost leak and it must be giving my car to much gas and not enough air because the air goes in the MAF then most of the air must come out some where on the way from the turbo to the intake manifold. But would it make my car flutter or wanna stall when i get on it or start moving? i got it up 2 around 5-6 rpm and the boost only goes to 4-5 psi

06-06-2006, 10:28 PM	#1
Sharaz508 Stock Join Date: Jun 2006 Location: Fall River MA Posts: 17	Question about clogged cat Would a clogged cat make my car backfire while driving and at idle? Last edited by Sharaz508; 06-07-2006 at 02:48 AM.

06-07-2006, 03:21 AM	#3
mrnickleye 1000whp postwhore Join Date: Jun 2005 Location: Mojave Desert, Calif. Posts: 1,705	Timing off can do it. An exhaust leak can do it. A sticking open injector can do it (raw gas down the exhaust). __________________ Had a Red 1989 N/A. Automatic. Sports Pkg. w/wing. TEMS, and some nice MODS. Sold to a friend 10/08/08.

06-07-2006, 03:05 PM	#4
Sharaz508 Stock Join Date: Jun 2006 Location: Fall River MA Posts: 17	it idles fine just back fires a little. But it does run like crap its a 5 speed and when i start to move the car starts bucking (and i no how 2 drive standerd). its does that till like 2000 rpm then it runs a little better but then after that it runs like shit agian. It back fires when im driveing to. But it does have an exhaust leak it needs an exaust pipe gasket but i dont think it would make it run this bad. Ill be going down the street then floor it and it will speed up but harrably. it cant be spark plug (irridium) or the plug wires becasue there where just changed recently. Im ganna try and test the back pressure. what should it be? Last edited by Sharaz508; 06-07-2006 at 03:08 PM.

06-07-2006, 08:31 PM	#5
mrnickleye 1000whp postwhore Join Date: Jun 2005 Location: Mojave Desert, Calif. Posts: 1,705	Well now you have given us more info. runs poorly, not just backfiring. If its N/A, Cap & Rotor = replace ! Misfiring is your problem. Why is the question. Could be a lean fuel condition. __________________ Had a Red 1989 N/A. Automatic. Sports Pkg. w/wing. TEMS, and some nice MODS. Sold to a friend 10/08/08.

06-08-2006, 01:46 PM	#9
theWeezL 12psi boost Join Date: May 2006 Location: Oregon Posts: 376	is your car throwing any codes (engine light is on)? if not then I agree, do cap and rotor, check your timing, check all your vacuum hoses for cracks or missing connection, replace your fuel filter, and perhaps test your fuel pressure. if you still cant solve the issue, sometimes its nice to take it to a mechanic for a scope check. Its usually a reasonable fee and a good mechanic can usually figure out whats wrong for you. Then you can do the work yourself to save money. Anyway, just a suggestion __________________ *____________* *Eagles may soar, but weezl's never get sucked into jet engines!*

06-07-2006, 03:14 AM	#2
jfunez 12psi boost Join Date: Oct 2005 Location: georgia,usa Posts: 338	actually a clogged cat would actually make your car run like crap, even at idle ,specially under acceleration....If you could borrow a back pressure tester gauge from somebody you could get that possibility out of the way....Its easy to test..if you need any help let me know...

06-08-2006, 02:25 AM	#7
jfunez 12psi boost Join Date: Oct 2005 Location: georgia,usa Posts: 338	if u get your hands on a backpressure tester ,hook it up on the o2 sensor orifice before the cat. I cant remember but it should be in the low 0 to maybe 3, cant remember but it pretty much should be steady on the verry low also during acceleration, there should not be much fluctuation on the gauge under accel..

06-08-2006, 12:41 PM	#8
rnoswal Lexus & 550's Join Date: Apr 2005 Location: Bossier City LA Posts: 556	First do a tune up! Plugs, wires, cap and rotor. Most of the time that is all it is. If you have a cylinder or two that aren't firing, it will have no power and buck and backfire. Try that simple stuff first then see how it runs. Air filter too. Russ

06-08-2006, 07:25 PM	#10
Sharaz508 Stock Join Date: Jun 2006 Location: Fall River MA Posts: 17	no codes but i think i narowed it to a boost leak and it must be giving my car to much gas and not enough air because the air goes in the MAF then most of the air must come out some where on the way from the turbo to the intake manifold. But would it make my car flutter or wanna stall when i get on it or start moving? i got it up 2 around 5-6 rpm and the boost only goes to 4-5 psi

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Question about 7m-gte.	AzNbOi2626	MKIII Supra	3	03-29-2011 06:55 PM
Starter Removal question	OkieRA29	MKIII Supra	13	05-11-2010 12:08 AM
Pre89 versus 89+ nose and support.	lifesnotfair	MKIII Supra	2	01-08-2010 09:06 PM
Help! Question on front NOSE and bumper supports.	lifesnotfair	MKIII Supra	1	12-26-2005 03:54 PM
Quick question	AutoXMan	MKIII Supra	12	09-30-2005 06:40 AM