Cold Start Issue - Possible Injector Replacement

[midwestdenaliguy]

All parts were ordered and arrive starting today through Friday. Assuming no shipping delays, I'll be replacing all 8 injectors and 3 fuel lines on Saturday. Below are the OEM part numbers and prices I paid in case anyone else wants to do this job. You want all brand new OEM parts for this that have never been installed, no takeoffs or non-oem because they can leak or go bad quickly. Be sure to double check your VIN against these part numbers with a dealership, you don't want to be installing the wrong parts for your set-up. I confirmed all of these part #'s against my VIN with my dealer - NOTE that I have the 6.2L L86 engine. Dealer pricing was naturally much higher for most parts, so I searched online for better pricing. Obviously this pricing can vary depending when and where you look, so don't expect these exact numbers.

 

I'll be doing a How-To write up on this assuming all goes well. Dealers want $1500-$2000 to do this job, I'll be spending $422.43 for the parts and a couple hours of my time to do it myself. Budget for the right tools if you don't have them: socket/wrench set and a torque wrench are required. You don't need the injector teflon seal sizing tool if you buy the injectors brand new (the tool is extremely expensive because it's a specialty tool - $200+). The only other tool to consider is an injector puller, but that's only needed if the injectors are really stuck. You should be able to pull them off by hand, but be careful not to yank like crazy. The fuel pipe/line fittings have to be torqued to spec (21 ft/lbs) due to this being a high pressure system. Too little torque and it'll spray fuel - too tight and you risk damaging the stainless steel and causing a leak. The rest of the torque specs will be included in my How-To write up.

 

Injectors 

Part # 12668393

-          $319 on eBay from seller 'fuel-injectors' (national wholesaler of injectors who flow match and test all new injectors in the set for perfect pairing - come with 1 year ACDelco warranty)

 

Fuel Lines

Part # 12677002 (Intermediate #1 Fuel Pipe – Crossrail Line/Connects Between Rails)

-          $41.02 on eBay

 

Part # 12677004 (Intermediate #2 Fuel Pipe – From High Pressure Pump to Crossrail Line)

-          $23.42 on eBay

 

Part # 12618338 (Fuel Feed Pipe w/check valve - Connects to High Pressure Pump from Low Pressure Fuel Line)

-          $38.99 on eBay

[6_2LTZ]

This is great! Hope it goes well. My dealer charged $300 an injector. Luckily I only needed two. This may come in handy down the road. 

[midwestdenaliguy]

All went well this weekend. Took a little longer than I wanted, but that's to be expected with any first time job like this (for me anyway). Learned a few things and know how to tackle this much faster next time, hoping there isn't a next time though. Injector 3 and the intake valve for 3 were NASTY (pics below). All other injectors and intake valves had build up, but nothing compared to 3.

 

Crazy as it sounds, I had 2 issues happening at the same time (hence why I got P0303 and P0106 codes). Fuel injector 3 was failing on me and same for my purge valve solenoid. I got all the injectors and fuel lines swapped out on Saturday and the truck started and drove beautifully that night and on Sunday. Come Monday, I started it to go to work and holy sh*t, it had a rough cold start. Threw the P0106 code again so I figured my next step was the purge valve solenoid since I had replaced both the MAF/MAP sensors and couldn't find a leak in any hoses/lines. Swapped out the purge valve solenoid and now I haven't had a rough start since. 

 

I'll write a How-To when I get a chance. Hopefully in the next week or so.

 

So here's the injector on 3, and the intake valve on 3 compared to 1. There was definite blow back as well as MAJOR build up partially blocking 3 from pulsing properly. I'm guessing the build up would harden enough over night or after sitting all day that it would cause misfires in 3 on start up, but soften as it warmed up and then be good. I'm also guessing seals were going bad. Anyway, all intakes looked like 1, except the dark cavernous hell that awaited me in 3. Keep in mind my truck had 77k miles on it when I took the pics of the intakes.

 

INJECTOR 3

 

INTAKE VALVE 3

 

INTAKE VALVE 1

Edited January 16, 2019 by midwestdenaliguy

[SS502]

2 hours ago, midwestdenaliguy said:

All went well this weekend. Took a little longer than I wanted, but that's to be expected with any first time job like this (for me anyway). Learned a few things and know how to tackle this much faster next time, hoping there isn't a next time though. Injector 3 and the intake valve for 3 were NASTY (pics below). All other injectors and intake valves had build up, but nothing compared to 3.

 

Crazy as it sounds, I had 2 issues happening at the same time (hence why I got P0303 and P0106 codes). Fuel injector 3 was failing on me and same for my purge valve solenoid. I got all the injectors and fuel lines swapped out on Saturday and the truck started and drove beautifully that night and on Sunday. Come Monday, I started it to go to work and holy sh*t, it had a rough cold start. Threw the P0106 code again so I figured my next step was the purge valve solenoid since I had replaced both the MAF/MAP sensors and couldn't find a leak in any hoses/lines. Swapped out the purge valve solenoid and now I haven't had a rough start since. 

 

I'll write a How-To when I get a chance. Hopefully in the next week or so.

 

So here's the injector on 3, and the intake valve on 3 compared to 1. There was definite blow back as well as MAJOR build up partially blocking 3 from pulsing properly. I'm guessing the build up would harden enough over night or after sitting all day that it would cause misfires in 3 on start up, but soften as it warmed up and then be good. I'm also guessing seals were going bad. Anyway, all intakes looked like 1, except the dark cavernous hell that awaited me in 3. Keep in mind my truck had 77k miles on it when I took the pics of the intakes.

 

INJECTOR 3

 

INTAKE VALVE 3

 

INTAKE VALVE 1

Nice write up...Do you by chance run an Oil Catch can? I am not advocating either way, just curious if you have this build up with or without.

[midwestdenaliguy]

3 minutes ago, SS502 said:

Nice write up...Do you by chance run an Oil Catch can? I am not advocating either way, just curious if you have this build up with or without.

No catch can. The intake valve 1 picture is the best representation of my 77k mile engine build up (3 is not accurate due to the injector failure). I did the BG air fuel induction cleaning service right before I pulled the intake off, but I have no idea what they looked like before the BG service. I can tell you that I do not use oil though. I do my own changes and there's always a hair under 8 quarts that drains out (obviously some oil will still be on parts in the crankcase and some sticks to the oil pan I drain into), so I'm not getting any blow by. Not arguing against a catch can, but if I'm not using oil I'm not sure why I would invest in one. I get why others would do it for preventative measures or if they're using oil though.

[snowboundrmk]

Did you clean the valves before putting the intake back on, or what’s a good way to clean them?

[midwestdenaliguy]

21 hours ago, snowboundrmk said:

Did you clean the valves before putting the intake back on, or what’s a good way to clean them?

No I didn't touch them while the intake was off. If you get any of that gunk or hard carbon build up in your cylinders you can really mess up your engine. My opinion, it's best left to a professional that's covered by warranty if they screw it up. A professional will either media blast each valve (Walnuts believe it or not), perform a BG air fuel induction cleaning, or pull the intake and clean them with brushes. There are plenty of videos in YouTube of guys cleaning their intake valves. You need to make sure they are completely closed by turning the cam, doing it one valve at a time. Even then debris that you knock off from cleaning it can fall in once you turn the cam or start your car.

 

Something you can do yourself that doesn't hurt anything is buy a can of CRC GDI Intake Valve cleaner (has a long plastic hose on it). Follow the instructions and it can help clean some of the build up.

 

An update to this whole thing for me was that a dealer ended up having to replace both heads due to a coolant leak. The entire top end of my engine is now brand new (clean intakes, valves, pistons, etc.) and GM covered the bill.

Edited February 1, 2019 by midwestdenaliguy

[SS502]

1 hour ago, midwestdenaliguy said:

No I didn't touch them while the intake was off. If you get any of that gunk or hard carbon build up in your cylinders you can really mess up your engine. My opinion, it's best left to a professional that's covered by warranty if they screw it up. A professional will either media blast each valve (Walnuts believe it or not), perform a BG air fuel induction cleaning, or pull the intake and clean them with brushes. There are plenty of videos in YouTube of guys cleaning their intake valves. You need to make sure they are completely closed by turning the cam, doing it over valve at a time. Even then debris that you knock off from cleaning it can fall in once you turn the cam or start your car.

 

Something you can do yourself that doesn't hurt anything is buy a can of CRC GDI Intake Valve cleaner (had a long plastic house on it). Follow the instructions and it can help clean some of the build up.

 

An update to this whole thing for me was that a dealer ended up having to replace both heads due to a coolant leak. The entire top end of my engine is now brand new (clean intakes, valves, pistons, etc.) and GM covered the bill.

That’s a very good update! Did they say what caused the coolant leak? Glad they took care of it for you. Basically have a nice new engine, the bottom end rarely fails.

[midwestdenaliguy]

10 hours ago, SS502 said:

That’s a very good update! Did they say what caused the coolant leak? Glad they took care of it for you. Basically have a nice new engine, the bottom end rarely fails.

Apparently there was a batch of heads that weren't casted up to quality specs and can allow coolant to leak through very tiny holes into the intake/cylinder. The bad casts have thin areas and excessive pitting that allow coolant to wear it down eventually leaking through a pin-sized hole. The coolant collects in the cylinder over night or after the truck sits for a few hours. When you start it up it has to burn the coolant off resulting in misfires and a really rough cold start. The severity of it varies depending on how quickly the leak(s) form.

 

In my case it took over 70k miles for them to form. The worst leak was in cylinder 3 so that's where I had the most misfires, but there were smaller leaks found by the dealer in other cylinders. They put a dye in the coolant and ran the engine for a bit then let it sit. Then they pulled the intake off and used a black light to see if there was any glowing in the intake/cylinders. Sure enough there was, on both sides of my engine. They sent the diagnosis to GM and they said pull it all off and replace with new heads that were made at a different factory with stricter quality standards. Google PIP5498 and it covers the symptoms and repair of this issue.

 

Technically I'm over my power train warranty mileage but my service director got them to agree to cover it all. Pretty awesome.

[SS502]

4 minutes ago, midwestdenaliguy said:

Apparently there was a batch of heads that weren't casted up to quality specs and can allow coolant to leak through very tiny holes into the intake/cylinder. The bad casts have thin areas and excessive pitting that allow coolant to wear it down eventually leaking through a pin-sized hole. The coolant collects in the cylinder over night or after the truck sits for a few hours. When you start it up it has to burn the coolant off resulting in misfires and a really rough cold start. The severity of it varies depending on how quickly the leak(s) form.

 

In my case it took over 70k miles for them to form. The worst leak was in cylinder 3 so that's where I had the most misfires, but there were smaller leaks found by the dealer in other cylinders. They put a dye in the coolant and ran the engine for a bit then let it sit. Then they pulled the intake off and used a black light to see if there was any glowing in the intake/cylinders. Sure enough there was, on both sides of my engine. They sent the diagnosis to GM and they said pull it all off and replace with new heads that were made at a different factory with stricter quality standards. Google PIP5498 and it covers the symptoms and repair of this issue.

 

Technically I'm over my power train warranty mileage but my service director got them to agree to cover it all. Pretty awesome.

That’s REALLY awesome! Thanks for the detailed response ?