2007 Tahoe sudden P0300 P0154 P0352 P0354 P0356 P0358

[OR VietVet]

OK, I can’t help but wonder if the problem is a connector that’s not passing along enough power to run the coils under load. Did you hit all of the connectors with electrical contact cleaner? Did you remove, clean, and reconnect the primary ignition ground?

Did you check each connection and make sure a pin is not being pushed out of the connector when plugging it in?

 

[Roger08LTZ]

Did you check each connection and make sure a pin is not being pushed out of the connector when plugging it in?

The connectors look perfect, contacts are clean, but yet it does feel like the issue is in the connector issue. I'll test under load tomorrow night.

Thanks!

 

[OR VietVet]

The connectors look perfect, contacts are clean, but yet it does feel like the issue is in the connector issue. I'll test under load tomorrow night.

Thanks!

They can look perfect and be clean but still can push a spade pin backwards out of the connector when you push them together.

 

[Roger08LTZ]

99% sure the issue is the wire at ground point G102. Under load the voltage at the coil was 1-2 volts lower than the battery. When I inject ground to the wire I get spark. I cleaned and reinstalled the wire at ground point G102 and the problem got worse. The eyelet connection to the wire seemed weak and pulled off with not too much effort. I need to crimp a new eyelet on and I bet the problem will go away. It's difficult to access it though, nothing is ever easy!

 

[OR VietVet]

99% sure the issue is the wire at ground point G102. Under load the voltage at the coil was 1-2 volts lower than the battery. When I inject ground to the wire I get spark. I cleaned and reinstalled the wire at ground point G102 and the problem got worse. The eyelet connection to the wire seemed weak and pulled off with not too much effort. I need to crimp a new eyelet on and I bet the problem will go away. It's difficult to access it though, nothing is ever easy!

View attachment 381032View attachment 381033

That is why, especially on these ground(s) problems, when you locate and disassemble them and repair them, make sure you do it once and do it right. I was hoping that a connection problem, like I described above, would be a connector that controlled the entire side of the engine. That ground is a good find. Make sure, if you fix it with this ground repair, that you pat yourself on your back and have an ice cold beer. Lots of people would have just given up. Think of the diagnostic time $ you saved if this works.

 

[Roger08LTZ]

The ground wire fixed it. I haven't road tested it yet, but it's idling on all 8 with no misfire codes

 

[OR VietVet]

Happy days are here again!

 

[Roger08LTZ]

It's not quite fixed. It's running fine, but as I was afraid, the money light came on with the dreaded P0420 Catalyst system low efficiency bank 1. I assume the raw fuel hitting the Cat killed it. Any chance this thing will burn itself clean? A new GM cat is over $1,000. Rock auto has some for about $400. Any experience with aftermarket cats?

 

[OR VietVet]

I have had luck with Walker exhaust systems. I would use OE though if it was me but it is your money. How old are the sensors?

 

[Geotrash]

It's not quite fixed. It's running fine, but as I was afraid, the money light came on with the dreaded P0420 Catalyst system low efficiency bank 1. I assume the raw fuel hitting the Cat killed it. Any chance this thing will burn itself clean? A new GM cat is over $1,000. Rock auto has some for about $400. Any experience with aftermarket cats?

It depends on whether the honeycomb media melted or if the coating just got saturated. You might try a bottle of Cataclean before dropping the money on a new cat.

I haven't used an aftermarket cat for one of these trucks, but I did install one from Rock Auto (AP/Eastern) in my LR2 about 20K ago and it's been fine.