Will a clogged cat prevent a car from starting?
TECH Resident
Joined: Oct 2005
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Originally Posted by Hamster Dance
How hard to replace just the coil?
I think I can get one at Autozone for like $15...
alot cheaper alternative compared to the new opti...
Can I do it in a day or so?
Where the hell do I find a new coil wire anyway?
I dont think it comes with one...
I think I can get one at Autozone for like $15...
alot cheaper alternative compared to the new opti...
Can I do it in a day or so?
Where the hell do I find a new coil wire anyway?
I dont think it comes with one...
Thread Starter
Teching In
Joined: Jan 2006
Posts: 21
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From: Chicago, IL
Originally Posted by skatinjay27
so did you find out if it was getting spark or not.and did youi put a gauge up to the shrader valve before you changed the pump.
now its coming out like a champ...
Cant really tell if theres fire from the coil though...
first its opti, opti then sends signal to ignition module on top of coil
ignition module tells coil to fire
then coil fires back to opti
then opti in turn fires to each cylinder
right?
correct.... heres what you do... place the coil wire by a bolt on the head so u can see the spark jump while cranking.. if u see it then do the same with a spark plug wire.. If you saw it with coil wire and not with spark plug wire opti is prettty much guaranteed toast... if u couldnt see it with the coil then it can be either the ignition control module or the coil itself... a new coil from summit is 35 bucks a ICM from chevy or napa is close to 100 so u know which to try first or if you have a friend with a lt1 just borrow stuff thats what I do so I dont waste money.. Hope that helps.. Reports back
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hey hampster how did your car die what were you doing? I was racing some car and my car was running great then after I won and slowed down i gassed it to drive normal and the gas pedel was dead and got no reaction at all but the car was still running and i started down shifting cause I thought it might be the trans and it would down shift but not drive then when i pulled off the road and stoped the car died and wouldnt start it would crank very strong but thats it.I got out and it had a weird burnt smell and the cat was GLOWWING RED.I called my dad and had him tow me and he said it was prolly the cat and it prolly had a meltdown and cloged up.I got a new cat and when i was installing it I tryed to start it with the cat out but still it cranked stronk but no turn over
TECH Resident
Joined: Jun 2005
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From: Finland
Talking about cats... I had a Blazer as a toy in the yard, (seriously it was bought as a toy...), anyways it ran great and then one day it seemed like it wasnt running on all cylinders, checked everything (cap, wires, fuel... etc)... then it went so bad it wouldnt start unless you had the peddle to the floor, and it barely ran then (had to move it to make space), wouldnt take rpms, as soon as you let off the gas a little it would die... anyways it ended up being a really clogged cat.
There are 3 things essential to the engine working... Fuel, Spark and air. if any one of thoes are fautly then the car will not run.
first i wuld check if the airflow is ok. just checking the air filter and allt that stuff.
second i wuld check the electric as it is the next easyest thing. just check the plugs cap and rotor and all that stuff.
if none of the above are faulty i wuld go to the fuel system but you seem to have it decked ok.
if none of the above work i have one idea. the hole in the gas tank may be cloged so you shuld try to start the car with the gas tank lid open and perhaps even hold thestuff that closes the hole, open.
you can also just unbolt the exhaust from the cat and check if it is clogged. its not hard. and you can just use a rod to smash the stuff that is clogging the system if it is cloged
first i wuld check if the airflow is ok. just checking the air filter and allt that stuff.
second i wuld check the electric as it is the next easyest thing. just check the plugs cap and rotor and all that stuff.
if none of the above are faulty i wuld go to the fuel system but you seem to have it decked ok.
if none of the above work i have one idea. the hole in the gas tank may be cloged so you shuld try to start the car with the gas tank lid open and perhaps even hold thestuff that closes the hole, open.
you can also just unbolt the exhaust from the cat and check if it is clogged. its not hard. and you can just use a rod to smash the stuff that is clogging the system if it is cloged
If your exhaust is clogged, then the car most likely won't start. The most obvious way to tell is to put your hand in front of the exit on the tailpipe to feel if anything is coming out. I once had a car that sat all winter, and I went out to start it in the middle of winter to keep the battery charged. It ran for a brief second, and then all of a sudden, it quit and it wouldn't start for the life of me. It would crank and nothing would happen. Well, it turns out that ice had frozen in the tailpipe and clogged it up. After removing the ice, it worked great. 
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Staging Lane
Joined: Nov 2005
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Originally Posted by Hamster Dance
I also cleaned the MAF by soaking it in Dawn...didnt scrub, just soak
.......and speculating 
Teching In
Joined: Nov 2005
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I had a very similar problem that started happening after it first snowed.
The car would not start, in fact heres the sound it made:
http://media.putfile.com/carstart69
Anyways, I tried to figure out what the problem was and at first thought it was the fuel pump. I had someone else turn the key while I was near the gas tank and I could hear the pump working, so I knew it wasn't that.
I ended up getting the car to start by turning and holding the key all the way, then pumping the gas pedal over and over. It finally started.
The next day I replaced the Fuel Filter and got the fuel system cleaned. The car seemed to run better for a while.
I didn't drive the car for a few days and when I went back out to drive it, it was having the SAME problem AGAIN (which I thought I fixed with the FF and clean).
I did the same thing again, turned the key pumped the gas and it started again. As long as I drive the car every day it seems like it will start fine, but if I let it sit for more then one day it will have trouble starting.
I was suggested that it might be the wires/plugs having trouble starting the car in the cold weather (although its just raining now, not cold enough for snow).
After reading this thread im thinking that my problem sounds similar to this, and a clogged cat could make sense.
I'm getting Longtube headers installed soon with an ORY and will probably leave the cat off until emissions time, I will also replace the wires and plugs at the same time. I'm hoping this gets rid of the problem for good.
The car would not start, in fact heres the sound it made:
http://media.putfile.com/carstart69
Anyways, I tried to figure out what the problem was and at first thought it was the fuel pump. I had someone else turn the key while I was near the gas tank and I could hear the pump working, so I knew it wasn't that.
I ended up getting the car to start by turning and holding the key all the way, then pumping the gas pedal over and over. It finally started.
The next day I replaced the Fuel Filter and got the fuel system cleaned. The car seemed to run better for a while.
I didn't drive the car for a few days and when I went back out to drive it, it was having the SAME problem AGAIN (which I thought I fixed with the FF and clean).
I did the same thing again, turned the key pumped the gas and it started again. As long as I drive the car every day it seems like it will start fine, but if I let it sit for more then one day it will have trouble starting.
I was suggested that it might be the wires/plugs having trouble starting the car in the cold weather (although its just raining now, not cold enough for snow).
After reading this thread im thinking that my problem sounds similar to this, and a clogged cat could make sense.
I'm getting Longtube headers installed soon with an ORY and will probably leave the cat off until emissions time, I will also replace the wires and plugs at the same time. I'm hoping this gets rid of the problem for good.
