Check engine light code 174...
Bamathy
10-03-2008, 12:52 AM
I own a 96' Caprice 4l with 60,000 miles and my check engine light turned on recently. I already have the code and what it means just wondering if anyone knows which issue/part needing maintenance is more common with this car. My car is running kinda funny and a high pitched weasing noise comes from the car when I 1st start it for a few minutes and then it goes away. Not sure if it's the oxygen sensor or MAF sensor or either 1 because I've heard the code can men dif things. I'm assuming since mine is making that noise someone might know which part needs replacing. I also got the 300 code which means a misfire in multiple cylinders but I dnt thnk that is as serious as this problem just spark plug replacing. I'm going to get both problems fixed soon and any help would be greatly appreciated...
j cAT
10-03-2008, 03:49 PM
I own a 96' Caprice 4l with 60,000 miles and my check engine light turned on recently. I already have the code and what it means just wondering if anyone knows which issue/part needing maintenance is more common with this car. My car is running kinda funny and a high pitched weasing noise comes from the car when I 1st start it for a few minutes and then it goes away. Not sure if it's the oxygen sensor or MAF sensor or either 1 because I've heard the code can men dif things. I'm assuming since mine is making that noise someone might know which part needs replacing. I also got the 300 code which means a misfire in multiple cylinders but I dnt thnk that is as serious as this problem just spark plug replacing. I'm going to get both problems fixed soon and any help would be greatly appreciated...
when you first start your engine the noise you hear for about 5 minutes is the air pump [secondary air injection]...this is a dc motor that along with a check valve injects air into the exhaust manifold by way of the 2 check valves mounted on each side of the engine... these 2 check valves must be replaced every 5 years as the diaphram fails causing the air pump to get damaged....this then causes the air input to this pump ,,, to work backwards ,, this then shoots exhaust into the input side of the maf....take off the air box cover and look at the maf if it is wet and also black it is the air pump and all the check valves that are causing your problems...
then to ensure that you have no other issues causing your,,,,,,,DTC 174/300 make sure ALL the vacuum/PCV rubber lines have no leaks ,collapsed, split,cracked, loose fitting and hardened...as this also will cause you problems....obviuosly you will not pass the emissions test...and if you have been operating this way for a while it could get expensive...
The MAF will need cleaning or replacement....
lastly your engine has platinum plugs...these plugs in this engine usually last 60,ooomi with no problems....the plugs at this mileage will be most likely not your problem...the dtc 174 must be fixed first....
other problems that could cause this on driver side of engine .....exhaust manifold leak,injector O rings,and intake vacuum leaks ...
when you first start your engine the noise you hear for about 5 minutes is the air pump [secondary air injection]...this is a dc motor that along with a check valve injects air into the exhaust manifold by way of the 2 check valves mounted on each side of the engine... these 2 check valves must be replaced every 5 years as the diaphram fails causing the air pump to get damaged....this then causes the air input to this pump ,,, to work backwards ,, this then shoots exhaust into the input side of the maf....take off the air box cover and look at the maf if it is wet and also black it is the air pump and all the check valves that are causing your problems...
then to ensure that you have no other issues causing your,,,,,,,DTC 174/300 make sure ALL the vacuum/PCV rubber lines have no leaks ,collapsed, split,cracked, loose fitting and hardened...as this also will cause you problems....obviuosly you will not pass the emissions test...and if you have been operating this way for a while it could get expensive...
The MAF will need cleaning or replacement....
lastly your engine has platinum plugs...these plugs in this engine usually last 60,ooomi with no problems....the plugs at this mileage will be most likely not your problem...the dtc 174 must be fixed first....
other problems that could cause this on driver side of engine .....exhaust manifold leak,injector O rings,and intake vacuum leaks ...
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