C5 Trouble shooting question
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Joined: Nov 2005
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From: Wisconsin
C5 Trouble shooting question
Hi all,
Was wondering if anyone out there knows what a H P0307, P P0307, H P0300, DTC codes are?
I just bought a C5, and it is running rough at idle and smells really rich.
I'm assuming that it has some bad O2 sensor, but do not know for sure. Does anyone have any suggestions?
Was wondering if anyone out there knows what a H P0307, P P0307, H P0300, DTC codes are?
I just bought a C5, and it is running rough at idle and smells really rich.
I'm assuming that it has some bad O2 sensor, but do not know for sure. Does anyone have any suggestions?
Le Mans Master
Joined: Nov 2002
Posts: 7,179
Likes: 2
From: Charlotte, NC
Yep it's a Cycl #7 missfire, and random missfire code. I'd check the easy stuff, inspect the plug wire & the plug first.
Smells rich most likely due to the miss fire. Does it missfire under load / acceleration? Or only at idle.
-=Rick
Smells rich most likely due to the miss fire. Does it missfire under load / acceleration? Or only at idle.
-=Rick
Thread Starter
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Joined: Nov 2005
Posts: 59
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From: Wisconsin
Originally Posted by VetteTech81
Yep it's a Cycl #7 missfire, and random missfire code. I'd check the easy stuff, inspect the plug wire & the plug first.
Smells rich most likely due to the miss fire. Does it missfire under load / acceleration? Or only at idle.
-=Rick
Smells rich most likely due to the miss fire. Does it missfire under load / acceleration? Or only at idle.
-=Rick
It miss fires at idle, but when I lean on it a little it seems to go away??
I thought at first it was in a limp mode, but I reset all dtcs and it still runs the same.
Le Mans Master
Joined: Nov 2002
Posts: 7,179
Likes: 2
From: Charlotte, NC
Hmm.. I'd still check the ignition components but you could have an injector that is leaking, in other words your demand for fuel is minimal at idle if more fuel is entering the cyclender that could cause a miss and the fuel smell....
Off idle / accel your demand for fuel increases so if an injector was leaking it might not show it's effects...
Just some ideas..
How does it start after sitting a long time, does it fire right up? When you first start it are you getting a nice puff of fuel vapor out the pipes?
-=Rick
Off idle / accel your demand for fuel increases so if an injector was leaking it might not show it's effects...
Just some ideas..
How does it start after sitting a long time, does it fire right up? When you first start it are you getting a nice puff of fuel vapor out the pipes?
-=Rick
Thread Starter
Advanced
Joined: Nov 2005
Posts: 59
Likes: 0
From: Wisconsin
Originally Posted by VetteTech81
Hmm.. I'd still check the ignition components but you could have an injector that is leaking, in other words your demand for fuel is minimal at idle if more fuel is entering the cyclender that could cause a miss and the fuel smell....
Off idle / accel your demand for fuel increases so if an injector was leaking it might not show it's effects...
Just some ideas..
How does it start after sitting a long time, does it fire right up? When you first start it are you getting a nice puff of fuel vapor out the pipes?
-=Rick
Off idle / accel your demand for fuel increases so if an injector was leaking it might not show it's effects...
Just some ideas..
How does it start after sitting a long time, does it fire right up? When you first start it are you getting a nice puff of fuel vapor out the pipes?
-=Rick
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Thread Starter
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Joined: Nov 2005
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From: Wisconsin
Originally Posted by runman
vac leak around #7 intake? spray alittle carb cleaner there see if miss goes away.It's not hard to swap injectors and see if misfire follows. What color smoke? if blue,pull the plug and look for oil
Black smoke.
I will check for the vac leak thanks
Intermediate
Joined: Dec 2005
Posts: 37
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must be excessive fuel to be black,fuel leaking into cylinder,injectors that spray to much is extremely rare(stock,factory anyway).I've replaced O2 sensors that told PCM its lean when actually its too rich, but it should affect other cylinders. You can unplug the sensors(or swap side to side) and see if you condition changes(only will work after about 2-3 minutes of run time, sensors need to warm up and go to closed loop)Is the car stock?You can disconnect #7 injector and find out if rich exhaust goes away
