Codes after head swap 2.4

594 Views 16 Replies 5 Participants Last post by Ultrascott, 4 d ago

Venomous Duck

Discussion Starter · 16 d ago

Hi all. We just finished putting on a new head and timing chain from Jeggs on a friend's 2013 Equinox with the 2.4L. After assembly we fired it up, ran rough with P00C6 and P228C. Did some digging and realized the new head did not come with the fuel pressure regulator cam follower. Swapped it over, making sure we were on a flat lobe when we installed it. Fired back up and ran great for about 10 seconds. Now we are getting both of the same codes and now P0300 misfire on all cylinders.

New head came with new cams. reused the sprockets/phasers. Reasonably certain both are on the correct cams. Reused the cam solenoids, both OHMed out good and looked clean. Injectors looked really dirty so we cleaned them with carb/injector cleaner. I am 100% certain the new chain is on correctly, 3 of us fought that thing for 2 hours. Fuel pressure is 62 with key on, 60 running.

Going to start chasing down the harness looking for loose connections. And considering buying new injectors since they looked pretty dirty in the first place. Anything else to check? Hate to just start throwing parts at it. Would injectors being bad or seated incorrectly cause misfire codes? I had it with my Trailblazer and it ran rough but i dont recall getting the P0300 code for it. Any guidance on testing the fuel regulator sensor and maybe the cam position sensor?

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repairman54

· #2 · 16 d ago

Just the generic P300 misfire code or are you getting specific each cylinder codes like P301, P302, etc.
Could be a fuel pressure sensor issue or the harness to it. Bent pins in connectors since you had it apart are a possibility.
Any codes in the B,U and C code families?

Reactions: 1

Venomous Duck

Discussion Starter · #3 · 15 d ago

Just the 00c6 and 228c plus the misfire. My helper was in the vehicle with the scanner watching the misfires rack up on all cylinders, so he may have gotten multiple misfires and just said it was misfiring and p0300

Colt Hero

· #4 · 15 d ago (Edited)

@Venomous Duck : What was the full extent of the damage that precipitated the Head replacement?

And I'm not a Mechanic, but yeah .. bad or malfunctioning Fuel Injectors could certainly contribute to misfires ... but I'd doubt they'd result in a (random misfire) P0300 Code. I would think a P0300 Code would point to something more "common" to all Cylinders ... like ... the Timing not being quite right ... or some component involved in the VVT not working quite right (affecting the overall Timing). Oil flow and pressure is so critical to the VVT working properly ... and if you've had Plastic Guards disintegrate in there ... you could have tiny fragments of plastic obstructing Oil flow through the tiny Oil ports of the system.

Reactions: 1

Venomous Duck

Discussion Starter · #5 · 15 d ago

The timing guide broke, but did not disintegrate. Most of the intake valves bent, about half of the exhaust valves. I understand fuel issues cause misfire, I just wasn't sure if it would throw the P0300. Basically I was asking if p0300 is thrown because the ECM doesn't detect detonation in the cylinder some how, or if it is strictly attributed to the coil. I am starting to think it is detecting donation since i have seen 300 with bad plugs but good coils before. Granted that was on my sisters hyundi, and the coil went right after changing all 4 plugs. If it was due to the VVT and oil issues wouldnt i be getting P0010 and/or P0011 instead of or in conjunction with 300 (or 301,301,303,304)?

Colt Hero

· #6 · 15 d ago

@Venomous Duck : if the Plastic Guide didn't disintegrate and only "broke", then maybe not a lot of risk there for obstruction in the Oil paths ... but some debris likely still ended up in the system. And you did say you reused the Oil Control Solenoids ... so ... probably would be a good idea to at least re-check the Solenoids as the Oil continues circulating to make sure no latent debris shows up.

I guess if I were you I'd be concentrating on Fuel delivery... which would be something "common" that could factor into the 'random' Misfires.

How does the ECM detect Misfires? Ya got me! AFAIK, just some mysterious algorithm correlating inputs from the Camshaft Position Sensors, Crankshaft Position Sensor, and maybe a few other Sensors ... like the MAP?

@Ultrascott , (our resident ASE Master Tech) ... can you shed more light on this?

Reactions: 1

repairman54

· #7 · 15 d ago

P300 code is generated by the crank position sensor not seeing smooth rotation.
Crank sensor lets PCM know where the crank is and PCM knows which cylinder it's firing at the time. If it sees a variation in rotation but not at a cylinder firing moment it will set the P300 code. Variation at a firing moment identifies the cylinder setting the P301, P302, etc.
That's how I understand it.

Reactions: 1

Venomous Duck

Discussion Starter · #8 · 15 d ago

That makes perfect sense repairman54.

So the question seems to be would bad injectors contribute to the C6 and 228C codes, or does that seem more like a wiring or sensor issue. I am going to order new injectors today or tomorrow.

Ultrascott

· #9 · 14 d ago

@Venomous Duck the codes you are getting are related to the high pressure pump.check your connector to make sure no terminals have backed out on you.we have seen wiring issues setting these codes especially at the ecm terminals. it's not seeing the correct fuel pressure in the fuel rail is why it's setting those codes and running rough.also it might not hurt to pull the valve cover back off and make sure those lobes that the follower rides on are all there and not damaged/worn since it's happened after repairs.let me know what you find out.

Reactions: 2

Venomous Duck

Discussion Starter · #10 · 13 d ago

Pulled the fuel rail, made sure seals were all intact. Cleaned every connector we had apart and reassembled. Was hard starting, finally started and ran rough/wouldnt idle. I bumped the throttle up to about 2500-3000 and ran like a top. Eventually went to Reduced power mode, and oddly idled mostly fine. I ran live testing while running and was getting High Pressure Fuel Malfunction or something like that. Random misfires were way down but still there. I checked more live data and saw the fuel injector control circuit status was showing NOT RUN randomly, seemingly in time with the misfire, but cant be 100% sure. I didnt get any injectors showing shut down for misfire though. I let it idle for over 10 minutes, it bumped between 800-1000 RPM, running rough. CEL did not come on, but i did get P0171 and generic P0300 misfire. Have new injectors, pressure sensor, and plugs coming today. Will see what that does.

Colt Hero

· #11 · 13 d ago

Venomous Duck said:
Have new injectors, pressure sensor, and plugs coming today. Will see what that does.

Are you going to introduce them one at a time, re-testing each time ... to see which one (if any) corrected the problem?

Reactions: 1

Ultrascott

· #12 · 12 d ago

did you install new injector seals when you replaced the head? the lean code p0171 could be from leaking o-rings and could cause a rough running concern.let us know how it turns out and what codes return. did you remove valve cover and check the cam lobe for the high pressure pump? did you look at data while running to see what the fuel rail pressure was at?

Reactions: 1

Venomous Duck

Discussion Starter · #13 · 12 d ago

We replaced everything. Plugs had 110k in them so were due anyway. Injectors looked pretty gunked up to start with and we tried to just clean them so we figured regardless, it would help all around with performance and fuel consumption to replace them. The sensor was because of the code and we were on a time table to finish, so not a lot of time to test and swap, so it went in. Good news is after a rough start and idle for a minute or so it is running great and no codes. I am thinking Ultrascott hit it on the head and the seals were the main issue. The gasket set we got had o-rings, the 2 rubber seals at the stem, and one of the plastic disks at the o-ring. It did not have the cup stem seal and missing one plastic seal so maybe we didnt have it sealed good enough. The new injectors had all new seals already installed. Thanks for all the help, I am not sure if it saved us much in the "just throwing parts at it" philosophy, but definitely gave us some place to focus on. We still managed to get it done for a quarter of what the local shops wanted for a motor and in less time. Not sure if the like button is the same as the "rep points" of the old forum days, but you all will definitely get them. Thanks again.

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Reactions: 1

Ultrascott

· #14 · 12 d ago

glad to hear that you got it up and running good again. i try to help when i can to help save everyone money.

Reactions: 1

Colt Hero

· #15 · 12 d ago

@Venomous Duck : I'm confused. @Ultrascott was suggesting you needed new Injector Seals for a P0171 (Lean) Code ... and you think that was what fixed it?

Which Gasket Set did you use?

uluz2a6

· #16 · 4 d ago

If the replacement cylinder head was from a 2010 Chevrolet Equinox or GMC Terrain, the intake camshaft will be different than what you need for the 2013. The lobes on the cam that run the HP fuel pump are in a different position and as a result the regulator ub the pump will not have control.

If you did get the proper year replacement cylinder head, you also need to verify that the camshaft snout/keyway hasn't shifted. This is an issue I am seeing more often. The engine will run (very well sometimes) but timing is off enough that the ECM will not be happy and set codes. Sometimes the codes will refer to timing or may be "useless" P0300.

The other possible cause is the cam follower that operates the HP fuel pump can become damaged and result fuel pressure control codes.

If you were near Las Vegas, I would be happy to help you diagnose. Actually I am still happy to help where ever you are. Feel free to message me for my number.

Ultrascott

· #17 · 4 d ago

@uluz2a6 it was the fuel injector seals that was causing the issue.

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