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1997 chevy 1500 4.3l misfire codes, running rich
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revolute
New User
Jun 3, 2012, 8:08 PM
Post #1 of 11
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1997 chevy 1500 4.3l misfire codes, running rich
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I have a 97 chevy 1500 with 4.3l. 350000 miles on it. It runs like poop. It idles rough, and is very sluggish when accelerated unless i put alot of gas into it. Pretty much typical running rich symptoms. Ive changed plugs, wires, rotor, cap, and air filter, and fuel filter. Ive cleaned the maf sensor-no difference. Ive tested the hz load on the maf and it fluctuates a good bit even in just idol. The numbers are jumpy...possibly bad? Ive sprayed carb cleaner looking for vacuum leaks but came up with no leaks.
I bit the bullet and got a scan tool with live data stream. It comes up with 0300, 0102, 0172, and 0175.
Ive looked at the live data but im not really sure what this engine should read normally like timing, and o2 sensor specs. This info or where to find this info is what i need the most right now. Ive searched google but came up with nothing as far as how to interpret the info coming from the scan.
Some other things i need to check is my cat converter and fuel pressure. I really dont wanna spend a ton of money fixing parts that have nothing wrong with them which is why i bought the scan tool.
I need to get this thing fixed because ill be using it for my new job and ill need the best mpg's i can get.
Any help would be great. Thanks.
More info...I pulled my cat off to see if it was clogged up. It wasn't.
In fact i could see right through it and see that it was in fact hollow. So my thinking is that the downwind o2 sensor is picking up the unburnt
exhaust and changing the way the engine is running. Does this make sense?
Im pretty desperate to figure this out. Please help.
(This post was edited by Double J on Jun 3, 2012, 9:11 PM)
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Hammer Time
Ultimate Carjunky
/ Moderator
Jun 4, 2012, 3:08 AM
Post #2 of 11
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Re: 1997 chevy 1500 4.3l misfire codes, running rich
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No, the cat and downstream sensor have nothing to do with the way it's running. You have a rich condition and a MAF code so that's where I would be starting. There is something wrong with the MAF circuit.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Tom Greenleaf
Ultimate Carjunky
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Jun 4, 2012, 3:45 AM
Post #3 of 11
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Re: 1997 chevy 1500 4.3l misfire codes, running rich
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revolute: 350,000 miles! Do you have a good history on what has been done with hard mechanical/wearing drivetrain everything on this? If original engine if known and so on.
A truly hollow cat converter!? Wouldn't be surprised if some place sells them to appear real.
What did old plugs look like compared to each other? For the moment I'm not so concerned with codes but the miles unless a typo I would be concerned about general mechanical condition of this engine. Compression ok? Does or did it burn oil? Oil pressure quick to come up to spec and so on.
Would hate to hear of anyone losing new employment over being late or a no show because of a vehicle and can happen to any at any mileage but this is pushing it IMO,
T
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revolute
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Jun 4, 2012, 6:43 PM
Post #6 of 11
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Re: 1997 chevy 1500 4.3l misfire codes, running rich
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Ive unplugged the maf but it didnt change anything. short fuel trim readings are -30% and long term is -18% and goes up when i hit the gas.
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Discretesignals
Ultimate Carjunky
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Jun 4, 2012, 6:53 PM
Post #7 of 11
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Re: 1997 chevy 1500 4.3l misfire codes, running rich
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With fuel trims like that you definitely have a rich condition.
Got a feeling you have a problem under the intake. Leaking fuel pressure regulator or injector itself. Your going to have to remove the plastic upper intake and then pressurize the fuel system by turning the key on to see what is leaking under there after putting the fuel pipe back on the top of the injector. Should be pretty obvious.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Jun 4, 2012, 6:57 PM)
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Discretesignals
Ultimate Carjunky
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Jun 4, 2012, 6:59 PM
Post #9 of 11
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Re: 1997 chevy 1500 4.3l misfire codes, running rich
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You can also remove the throttle body and then use a flashlight and small mirror to see under there.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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nickwarner
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Jun 5, 2012, 3:19 PM
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Re: 1997 chevy 1500 4.3l misfire codes, running rich
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If you want an idea how to interpret your data streams go on YouTube and look for ScannerDanner. the guy is a tech instructor and has some great videos. He gets very technical and can be hard to follow as a novice but well worth watching to pick up some knowledge.
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Discretesignals
Ultimate Carjunky
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Jun 5, 2012, 3:26 PM
Post #11 of 11
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Re: 1997 chevy 1500 4.3l misfire codes, running rich
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He's my hero....
Nick, you bought his E book yet?
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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