New to me...has a miss

[Brains646]

Hello,

This is only my second post, my first was my intro and I'm sure this won't be my last.

I just picked up an 02 Yukon 5.3 2wd with 185k. It's mainly going to be for my son when he's mature enough but until then it's a "gopher" vehicle. I have a few issues that i need help with and I'll list them here. I've searched but I seem to find lots of questions but no answers. If we keep this truck looking I promise to be the kind of member that shares solutions as well as issues !

First, I have a miss and it's got me confused. I did the pull the plug test and found the two rear plugs on the drivers side made no change when i pulled the wire, so i pulled the plugs and the one farthest back had a lot of oil on it. The one just in front of it was just old and covered in carbon. I swapped them out and the truck runs better but it's still missing and it seems that i can still pull those wires and see no change. Am i missing something? Are these engines like Dodge where every component has to be identical?

I also have no dash lights and the radio only lights up when the ignition is off . I'm planning on getting a switch but once again...am I missing something?

Lastly, my rear blower doesn't work at all. I'm sure there's a series of tests to run down the culprit but I ran out of time.

There are a few other things but i have them figured out, i just have to get the parts.

I apologize for the length of the message but I want to try and paint a clear picture. Thanks again for any and all help!

Jay

 

[Brains646]

Anybody?

 

[#1taho]

Have you tried switching the coils ?

 

[Brains646]

Not yet. I havent had time to get back to it. But I do have spark all the way to the plug. I havent measured its strength but there is fire. My plan is to see if I can get a scan tool that can read fuel trims to see where those numbers are. I'm thinking that I may have a bad injector or something along those lines. Both of the cylinders that arent firing are right next to each other so maybe the fuel isnt making it that far?? I'm just guessing though. This saturday I plan on cleaning the MAF but I'll see if I can check the injectors tonight.

 

[Kingx1]

I also have a very rough idle and I feel like it should have a lot more power than what it has at the moment too. I think i'll try puling wires to see if I notice anything as well. You must be low on power too with only 6 cylinders firing

 

[Brains646]

So i get home and take a closer look and find this! it was hissing and definitely not right. Isn't this the fuel pressure regulator?

 

[Brains646]

I also have a very rough idle and I feel like it should have a lot more power than what it has at the moment too. I think i'll try puling wires to see if I notice anything as well. You must be low on power too with only 6 cylinders firing

Yeah it's not right on acceleration but once you're going it's smooth.

 

[Kingx1]

Same here.....only thing is that it also feel like it doesn't have much power. I would think the 6.0L would have some really good power. Mine just feels weak.

 

[Brains646]

Can somebody tell me what this plug is? it's right in front of the first spark plug and the engine quits if you take it off . I'm pretty sure that this setup ain't right.

 

[lester319]

I think that's the coolant temp sensor.


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[Brains646]

The plug has a clip but it's just slid over two prongs. nothing is holding it in.

 

[mattbta]

Yes. Coolant temp sensor. I broke the clip on mine when replacing the plugs. Eventually I'll get a new connector, but it has held fine for several months just slid on there.

Edit: is yours unplugged in that pic?

 

[Brains646]

Yes. Coolant temp sensor. I broke the clip on mine when replacing the plugs. Eventually I'll get a new connector, but it has held fine for several months just slid on there.

Edit: is yours unplugged in that pic?

No it's plugged in. Why?

 

[lester319]

Looks like the sensor itself is broken. I would be checking compression in those 2 cylinders. Possibly head gasket issue.


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[Brains646]

Looks like the sensor itself is broken. I would be checking compression in those 2 cylinders. Possibly head gasket issue.


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It must be doing something because if i unplug it the truck stops. Everything works correctly with the cooling system. i checked the plugs and seems that one is getting good spark but the other had carbon on it

 

[Brains646]

Ok,

So I was able to get my mechanic to look at it and we have two bad injectors that are stuck open. I plan on replacing them but can they be cleaned?

 

[#1taho]

They are cheep enough I wouldn't bother

 

[Yukon2000xl]

Change the injectors cheaper than cleaning them and less risk that fracturing the injector tips.
The lights and radio could be as simple as the fuse/switch/dimmer switch.Mine was the dimmer switch (bypass it to check).
The rear blower can be one of three things,the control module box which has two wires coming out of it ,the power going to the control box,or the Motor itself .Check if power gets to the control module,if yes check to see if it gets to the motor,if yes it's the motor.If it gets to the control box but not on output from the box to motor it's the control box.If you have none getting to the rear it could be the control panels in the front or power harness behind kick plate driver side behind plastic trim.


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[Brains646]

Change the injectors cheaper than cleaning them and less risk that fracturing the injector tips.
The lights and radio could be as simple as the fuse/switch/dimmer switch.Mine was the dimmer switch (bypass it to check).
The rear blower can be one of three things,the control module box which has two wires coming out of it ,the power going to the control box,or the Motor itself .Check if power gets to the control module,if yes check to see if it gets to the motor,if yes it's the motor.If it gets to the control box but not on output from the box to motor it's the control box.If you have none getting to the rear it could be the control panels in the front or power harness behind kick plate driver side behind plastic trim.


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Thanks for that info, I plan on digging into the rear blower this weekend or next.

I've got the two injectors on the way and I'll have that done tonight. I also ordered a light switch and all three actuators/motors for the climate control as well as two upper ball joints and the fuel vapor release cannister. All these should be getting installed thise weekend. Hopefully by Saturday night I'll have control over the vents, lights on the dash and a smooth running truck!

 

[#1taho]

Your not messing around.