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View Full Version : Arrhh! Another problem! Engine check light on!

BLUETHUNDER
09-19-2010, 08:25 PM
After the problems ive had with the windshield washers,and my crappy iginition switch,i thought nothing else could go wrong but it has.

I went and put some gas in it yesterday morning and after 30 mins the engine check light came on. Its on constant. Not flashing. Thought i may not have put the gas cap on properly. But it was. Then suspected that maybe ive used some ****ty gas. I then went and put some premium stuff in. But still no joy.

I went to see a mate this morning who is also a mechanic. For some time now i have suspected that the cats are on there way out. My friend comfirmed this by tapping the cat gently with a rubber mallet. He said its all broken up inside and thats why i'm getting the light on.

I said ive had cats go before on vehicles and never had a light come on. But he said on the Hummer you have two 02 sensors per cat. Its the sensors that are after the cat thats getting a incorrect reading due to the cat being broken up inside. Could this be true....??.

Looks like i will be ordering some universal cats from Rock Autos. Anyone else used them??.
Easy Ed
09-19-2010, 08:29 PM
Gas cap on good and tight ? Will set the SEL if not

Ed
BLUETHUNDER
09-19-2010, 09:32 PM
Gas cap on good and tight ? Will set the SEL if not

EdIve taken the cap off and re-tightened it. The light is still on.
Olfart
09-19-2010, 09:39 PM
I believe the Cats are warranty by GM for 80,000 miles. You might check before you buy any
Xotik H3
09-19-2010, 09:43 PM
Before you spend any cash on CAT's. Read the codes or have the codes read, seems rather odd it would come on right after a fill up and not have to do with the gas cap. Also, the light may go on easy, but they rarely turn off on their own with resetting. :beerchug:
BLUETHUNDER
09-19-2010, 10:10 PM
Before you spend any cash on CAT's. Read the codes or have the codes read, seems rather odd it would come on right after a fill up and not have to do with the gas cap. Also, the light may go on easy, but they rarely turn off on their own with resetting. :beerchug:
Ive had the light come on before when ive had a loose gas cap. But it has gone out after a few hours. This has been over a day now and the light is still on. Does it make any sense about what my friend said??. The cats will have to be changed anyway as they are rattling quite bad.
Xotik H3
09-19-2010, 10:17 PM
It does, but in my experience a Cat will clog, and choke exhaust flow through it. Not sure what would rattle... not saying it would not, just don't know what would case it to rattle. If you do a search for a cross view of the inside, there are no part to come loose on later cats, after the late 90's.
BLUETHUNDER
09-19-2010, 10:38 PM
Isn't some of the cat ceramic??.I'm guessing this is whats broken up inside.
Xotik H3
09-19-2010, 11:49 PM
I did a quick search and came up with the below.

http://wiki.answers.com/Q/Why_does_a_catalytic_converter_rattle

Really, best thing to do would be to read the codes.
twr
09-20-2010, 01:02 AM
Hi thats 2 of us read the codes first because if you need more than cats it will be one order because where you live.
Scarsman
09-20-2010, 01:51 AM
Not sure about there, but over here almost any decent parts store will read the codes for you for free. Pretty easy way to find out exactly why the light came on.
BLUETHUNDER
09-20-2010, 09:40 AM
Over here its different. I will have to pay one of the specialists here about $80-$90 to read the codes.
BLUETHUNDER
09-20-2010, 05:07 PM
Well. I thought my luck had changed. I went out this afternoon. And within 10 minutes the light went out.But one hour later it came back on.
Easy Ed
09-20-2010, 11:26 PM
Besides the programmer I got that reads the codes I also bought a Actron Model #CP9175 for $106.00 US for other OBD II vehicles. It won't read body module codes but will read the ones for engine problems. Just a idea..

Ed
H200
09-21-2010, 10:02 PM
The codes are your friend, believe it or not. I'd go by that, even if you have to pay the $80-$90 to have it read for you.
IRA51
09-23-2010, 12:04 AM
The codes are your friend, believe it or not. I'd go by that, even if you have to pay the $80-$90 to have it read for you.
Reading the codes are the way to go ,but if your cats are rattleing when you smack them your going to have to change them any way .
BLUETHUNDER
09-23-2010, 06:51 PM
Yep! Ordered them on monday with along with a new ignition switch from Rock Auto,s. I have put a probe in to the exhaust and the reading would would give a fail if i had to do the m.o.t. I am sure this is what causing the light to come on. I will let you know how i get on next week when ive fitted the new parts.
Luv2Camp
09-23-2010, 09:21 PM
It does, but in my experience a Cat will clog, and choke exhaust flow through it. Not sure what would rattle... not saying it would not, just don't know what would case it to rattle. If you do a search for a cross view of the inside, there are no part to come loose on later cats, after the late 90's.


MY right side CAT went out about a month ago. Before the light came on, I heard the rattle. Went under the truck and heard it coming from the right CAT. I knew it was shot! Within 15 min of hearing the rattle the check engine lamp came on. They can rattle when they go bad