******10 MPG caused by what? Update******** - Page 5 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

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Old 04-30-2007, 07:39 AM   #41
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An O2 sensor, as new as it is, won't kill the cat that quick...even if the sensor was bad from the start. I think you may have something else wrong. For you to kill a new cat that quickly, you are either running pig rich, or you are burning something that ain't supposed to be burned. And if your new O2 is bad now, along with the cat, then I suggest looking at these items:

LIM gaskets. Once these go bad, you can start ingesting coolant into the combustion process. Burning coolant WILL take out plugs, O2 sensors, and converters with no problem.

Stuck injector. Yup, it can happen. Not only will that cylinder NOT burn fuel right, it will foul the O2 and eventually take out the cat.

Also keep in mind ALL new converters carry I think a 70,000 mile warranty, which is government mandated. So if your cat IS bad, you can easily get a new one swapped.
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Old 04-30-2007, 01:15 PM   #42
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ok thanks. I have to find my warranty info for my cat. Lower intake manifold? Should I change both? How much are they? And I can test the injectors by taking them off while the car is running one by one right? Just the make sure a cat that is burnt, shows it doesn't? Mines is a burnt color at the bottom. It looks scorched.
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Old 04-30-2007, 01:20 PM   #43
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Quote:
Originally Posted by trigga_b
ok thanks. I have to find my warranty info for my cat. What is a LIM gasket? How much are they? And I can test the injectors by taking them off while the car is running one by one right? Just the make sure a cat that is burnt, shows it doesn't? Mines is a burnt color at the bottom. It looks scorched.
LIM=lower intake manifold, this a LIM gasket, the ones with the green lines on them.. i got mine for $44 at the dealer
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no, you cant test injectors by pulling them out, they would be spraying fuel everywhere

your cat it burnt? can we get a pic? when cats go bad, they either get clogged or fall apart internally... give yours a kick and see if it rattles
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Old 04-30-2007, 01:26 PM   #44
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I dont have access to a camera, unless I get a disposable one, take it to walmart, then scan the pics whcih is a lot to do. When I get my i930 I will start posting pics. But the bottom of my converter is a brown burnt color.

So, this is where my coolant is disappearing. I haven't really thought about my coolant and where it was going, a lot isn't missing though.

YESSSSSSSSSSSS, I got the GXP title.
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Old 04-30-2007, 06:19 PM   #45
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Ahh...now it seems we are getting somewhere.

First, the pic Haro showed ya...yes, that is where the lower gaskets go. BUT series 1 engines ONLY have plastic gaskets. Now then, how much coolant has gone AWOL since you have owned this car? Take a look at your intake manifold where it mates up to the heads. Is it oily or slightly wet looking? With the age and miles on the motor, I would highly suspect the gaskets need replacing regardless if it helps the current situation or not. But if they did fail, your engine will need new plugs (don't waste your time cleaning what you have) and a new O2 sensor. Your cat, being as new as it is, may not need to be replaced. In fact, make this your last item on the list.
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Old 05-01-2007, 01:46 AM   #46
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I had the car for a year now. I can't really say how much coolant drained out from the cousre of the whole year, but from what I noticed it was like a inch and a half above the full line (top line) and that was like in august of 06. In december of 06 it was just at the low line and now it was like 3 inches below the lower line. I forgot how it looked, but I dont remeber it being dry, prolly a greasey look. I'll check tomorrow with a confirmation. So my gaskets need changing regardless, but my power and fuel lost could be a damaged injector.
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Old 05-01-2007, 03:13 AM   #47
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Quote:
Originally Posted by trigga_b
I had the car for a year now. I can't really say how much coolant drained out from the cousre of the whole year, but from what I noticed it was like a inch and a half above the full line (top line) and that was like in august of 06. In december of 06 it was just at the low line and now it was like 3 inches below the lower line. I forgot how it looked, but I dont remeber it being dry, prolly a greasey look. I'll check tomorrow with a confirmation. So my gaskets need changing regardless, but my power and fuel lost could be a damaged injector.
save youself a run around and take it to a shop and let them figure out what to do with your car

i have a feeling your going to waste alot of cash and TIME misdiagnosising your problems
and the lack of knowledge on the fundamentals of what makes a engine tick
use the search feature search Poor MPG i bet numerous causes come up right?
start there
by the way th L27 rarely i mean Rarely has intake gasket leaks
so go to autozone rent a coolant system pressure checker and see where you coolant is coming or going
just my .02
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Old 05-01-2007, 11:49 AM   #48
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thats the thing, I never saw any coolant on the ground or on the engine from what I lost. The only coolant i see on my engine is from when I changed my 95 stat to 180, didn't use rtv water pump gasket and it squirted out. Other than that I haven't seen any sight of coolant. Every thing I checked from searching isn't my problem I checked everything. I need to just find someone with a scan tool. But personaly I think its one of my injectors
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Old 05-03-2007, 08:17 PM   #49
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I got access to a scan tool, so what am I suppose to be looking for? so far at idle my A/F ratio is 15.3. It runs lean when I first start the car and at idle, after 10 minutes it runs rich, then when I drive it switches back and forth. What is VATS status, because thats bad. TPS sensor is .55V. The o2S crosscnts avg is 30 since it jumps around that number. My MAT degree was 152 F. The MAF (Gr/Sec ) is around 1700. And I have no codes. Why aren't there any codes? I used the actron scan tool.
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Old 05-05-2007, 02:28 PM   #50
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My PVC Rattles-
Coil packs readings are 5.5 to 5.7-
Beldin wires are like a month old, readings are fine-
Engine responded to each connector that was pulled from the injectors and they're NOT leaking-
I DO have an exhaust leak in my rear left tail pipe-
Spark plugs look fine-

???????????????????????????????????????
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