Cold Start Cylinder Misfires

[Ecomike]

Yes it's a 2001 with the cats built into the exhaust.

No plug wires. The coil sits on the plugs on the 2001.

I replaced the O2 sensors. That seems to have cleared that fault, but it is still misfiring cylinder 2. And it gave me a "System Too Rich" fault on Bank 1 and 2 (codes P0172 and P0175).

The exhaust sounds louder than normal as well.

I'm ready to nuke this thing.

Did you get OEM style 4 wire O2 sensors? O2 wire cheap universals?

Running too rich may mean the O2 sensor system is not working yet (fuse? voltage at the pre cat O2 sensors, should be about 13 DC volts on one and about 0-5 volts, AC on the other) and 2 ground wires back to the PCM/battery ground network? Check all four wires with a volt meter, there should be no voltage (Less than about .01 V) on the ground wires to the engine/battery ground.

Could be a stuck or sticking open injectors.

Could also be the notorious 2001 bad head casting leaking.... That is why the old spark plug color and contamination would have been important to save, photograph.

Is the air filter OK? OBD-II sights say a dirty Mass air flow sensor might do this, but the Jeep version is MAP sensor not an MAF and other than a bad vacuum line under it to the throttle body they are pretty much bomb proof.

02 sensor wiring damage is very common jeeps!!!!

 

[Ecomike]

"And it gave me a "System Too Rich" fault on Bank 1 and 2 (codes P0172 and P0175)." that sounds like possible O2 sensor wiring damage. Is the O2 heater fuse good? I forget which fuse the O2 heater is on, it is ganged up with other stuff. Any damage to any of the four wires could be causing the rich codes. So could a leaking injector(s).

 

[GamblySmurf]

Fuses were all good.

Didn't see any damage to the O2 sensor wires when I replaced them. I replaced them with 4 wire OEM style NKT sensors.

I will double check the O2 wires and the air filter.

Leaking injector makes sense. There is a lot of fuel in the exhaust.

 

[GamblySmurf]

Holy shit! Could a ground fault be causing all of this???

I just looked at the wiring to the battery, and the ground connection to the frame that branches of the negative of the battery clamp is broken off! Could that be causing all of this?

 

[Ecomike]

YEEEEEEEEESSSS

 

[Ecomike]

That corrosion on the post clamp and bolt looks iffy too. When I start diagnosing any problem on Jeeps or any rig I start with a multi meter at the battery....wires and grounds. No code scanner days pre OBD-II taught me that, especially Renix jeeps. HO's are getting old enough to have battery cable issues too.

 

[Ou2mame]

Holy shit! Could a ground fault be causing all of this???

I just looked at the wiring to the battery, and the ground connection to the frame that branches of the negative of the battery clamp is broken off! Could that be causing all of this?

I wouldn't get my hopes up. It would be convenient, but unlikely

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[Ecomike]

I'll put my money on the bad/ busted ground in the photo as one of the problems for sure. Maybe not the only one.

 

[GamblySmurf]

I'll put my money on the bad/ busted ground in the photo as one of the problems for sure. Maybe not the only one.

How do I fix that?

 

[Ou2mame]

I installed new terminals and wires. My terminals were so corroded and the wires were half disconnected from being stressed and corroded that it wouldn't start sometimes.

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[GamblySmurf]

I installed new terminals and wires. My terminals were so corroded and the wires were half disconnected from being stressed and corroded that it wouldn't start sometimes.

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Where/how do you tie the old wires into the where you cut the old ones out?

 

[Ou2mame]

The terminals I got have set screws to connect your wires to them. I got them on ebay for like 10 bucks shipped. They're actually pretty nice. I was installing an amp and wanted to make sure all my grounds were good so I replaced all the ground wires and strap and whatnot.

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[GamblySmurf]

The terminals I got have set screws to connect your wires to them. I got them on ebay for like 10 bucks shipped. They're actually pretty nice. I was installing an amp and wanted to make sure all my grounds were good so I replaced all the ground wires and strap and whatnot.

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Do you have a link to them?

 

[Ou2mame]

http://www.ebay.com/itm/231897698183

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[GamblySmurf]

http://www.ebay.com/itm/231897698183

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Do those come with any wires?

 

[Ou2mame]

No just the terminals. I used some of the wires that were on the jeep already and just cut the corroded parts off, and I replaced some with the wire I bought to power my amp.

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[Ecomike]

I use a steel or stainless wire brush to brush the corrosion off the ends of wires I reuse. It does wonders. Also a little "sudsy household ammonia" (old stuff been around sine parents days) from the detergent isle at the grocery stores on the ends for 2 minutes eats corrosion off the copper wire like crasy, then Distilled or DI water rinse (bottled water isle at the grocery store) to remove the ammonia then a final wire brush get them back to new condition. I like the brass connectors myself from the local auto parts stores, they usually have wire and a selection of connector options, That set on ebay looks nice, not too expensive.

 

[Ecomike]

That one end of the ground at the frame that is busted just needs a common electrician/electrical connector that is crimped on with pliers, or a ground fitting that looks like the ebay fitting on the wire connection end and is designed to bolt to frame, a version of ground terminal strip.

That wire to the body may have been too short (It is not OEM from the looks of it) and with worn engine mounts it got wiggled to death till it snapped.

You might try something like the one on the left and top middle in the photo below from home depot electrical section. Or get a crimp fitting from the battery sections of auto parts stores. You may need a crimp tool of sorts if you use the crimp style fitting, or a drill to get the hole the right size for the bolt on the jeep ground wire (take the bolt with you to get one large enough?)

There are many options. The aftermarket auto radio shops should have a nice selection too.

http://i.ebayimg.com/images/g/ouYAAOSwX6VTyy-H/s-l300.jpg

 

[GamblySmurf]

I use a steel or stainless wire brush to brush the corrosion off the ends of wires I reuse. It does wonders. Also a little "sudsy household ammonia" (old stuff been around sine parents days) from the detergent isle at the grocery stores on the ends for 2 minutes eats corrosion off the copper wire like crasy, then Distilled or DI water rinse (bottled water isle at the grocery store) to remove the ammonia then a final wire brush get them back to new condition. I like the brass connectors myself from the local auto parts stores, they usually have wire and a selection of connector options, That set on ebay looks nice, not too expensive.

I used plumbers abrasive tape to shine them up. I think the terminals are fine. Just need to fix that ground.

 

[GamblySmurf]

That one end of the ground at the frame that is busted just needs a common electrician/electrical connector that is crimped on with pliers, or a ground fitting that looks like the ebay fitting on the wire connection end and is designed to bolt to frame, a version of ground terminal strip.

That wire to the body may have been too short (It is not OEM from the looks of it) and with worn engine mounts it got wiggled to death till it snapped.

You might try something like the one on the left and top middle in the photo below from home depot electrical section. Or get a crimp fitting from the battery sections of auto parts stores. You may need a crimp tool of sorts if you use the crimp style fitting, or a drill to get the hole the right size for the bolt on the jeep ground wire (take the bolt with you to get one large enough?)

There are many options. The aftermarket auto radio shops should have a nice selection too.

http://i.ebayimg.com/images/g/ouYAAOSwX6VTyy-H/s-l300.jpg

Hmmmm, wonder if Home Depot has something that will work??