Threw a code today...

[mendozer]

Driving back from the coast today it threw a code when i stopped for coffee. P0306 engine misfire. My initial thoughts were spark plugs and it wires since I'm likely due for it.

But also, "vsc off" and "vsc trac" lights were on. That's not related to a misfire is it? The scangUge only reported one code. My other thoughts were if the rear traction sensor got wonky from driving on the sandy beach. But this was a solid 1.5 hours later. Thoughts?

 

[Ed_C]

VSC and TRAC lights will turn on when the check engine light does.

 

[mendozer]

ah ok. So I'll get around to the sparks and see if that does it.

 

[mendozer]

Today I fixed it. Wasn't sure exactly what it was but didn't want to waste time testing everything. I have no idea how old the plugs, coils, or wires were so I replaced all three. Aside from having spark plug socket issues (rubber gasket falling out, disconnecting from extension and getting stuck in the tube, etc) it was a maybe 2 hour process. I was trying to not remove certain things, but after struggling a bit ended up removing more things for access. NGK plugs and wires, and some coils I found on Amazon all for maybe 100 bucks maybe less.

 

[JohnMc]

That's the best P0306 you can get - plugs.n-wires.

Mine was a bad injector, which involves a bit more work.

 

[mendozer]

I'm not in the clear! Today it threw the p0306 again while in traffic. I reset the scanguage, then about 3 hours later it came on again, this time p0300. So I know it's not plugs, wires, and coils, yet somehow changing those three bought me about 2 weeks of code free driving.

What's next? I've been reading about fuel pressure testing, fuel injector testing, etc. I'm looking for least invasive first. I have a fuel filter I've been meaning to install, maybe I'll start there.

 

[jgue467]

Yeah probably fuel system next to check based on FSM's suggested list/order of debugging a P0306:

Open or short in engine wire Connector connection
Vacuum hose connector
Ignition system
Injector
Fuel pressure
Mass air flow meter
Engine coolant temp sensor
Compression pressure
Valve clearance
Valve timing
PCV valve and hose
ECM

Luck and enjoy the runner. :cowboy:

 

[mendozer]

did the fuel filter Sunday. Then today P0306 came back on. Guess it really is cyl 6. I looked up how to test the injector, but what about the other things? Are these quick voltmeter tests or replacing parts and "wait and see" approach?

 

[DaMonkey]

I’m thinking you have a clue in that new plugs bought you 2 weeks and then it’s cycling quick again.

2 weeks seems fast to burn a new plug I’d guess fouled, but you got 2 weeks from new ignition and now it’s gone.

Start by pulling plug and inspecting. Swap w a plug other head and see if it buys you time again. Maybe leak down test is in order.

Driving in sand that day can load the motor pretty heavy. That by itself shouldn’t damage a motor but if ignition components were overdue or dirty MAF or improper fuel pressure, could cause something like piston ring damage.

Just a thought but I’d check the plug.

 

[FunBobby]

Just went through this, it's probably an injector, you can read through my build thread and see the process of elimination I went thru

 

[mendozer]

I guess it's not that bad of an idea to just pull them and have them serviced. My valve cover gasket doesn't leak, but again, it's one of those "might as well since the top's off!"

 

[19963.4lsr5]

Ohm out the injector cold not hot to test it


Sent from my iPhone using Tapatalk

 

[mendozer]

Disassembled the intake assembly and TB last night. being an idiot, I accidentally removed two more bolts unnecessarily. What are those? The shiny holes in the picture, just above the valve covers. I couldn't find names of those or torque values. they're 12mm bolts, fairly long, and have thick shoulder washers.

 

[gamefreakgc]

Disassembled the intake assembly and TB last night. being an idiot, I accidentally removed two more bolts unnecessarily. What are those? The shiny holes in the picture, just above the valve covers. I couldn't find names of those or torque values. they're 12mm bolts, fairly long, and have thick shoulder washers.

Picture didn't load. Going from memory, it might have been intake manifold bolts.

 

[mendozer]

You intake manifold bolts. Just found the picture in Haynes manual and put them back on

Turns out the ohms were all spot on 14.0. But I ordered reman injectors anyways and I'll send these in for core charges. after all this is what's left to hope for. There was some nasty red junk mixed in with debris on the driver front corner (near injector 1?) the valve cover didn t seem like it was leaking. I guess it wouldn't hurt to do those too, but buggy i don't want to

 

[mendozer]

Did all injectors last week and it was clear for about a week and a half. Then it threw #6 again. Got a compression kit from Autozone and My numbers were 190 all around except 135 on #4 and 90 on #6. That explains the code for 6 and the one time random code after clearing the original #6.

So now I'm nervous thinking about head gaskets, piston rings, etc that are beyond my skillset.

 

[mendozer]

the guy I use for harder jobs is booked 3 weeks out. Am I safe driving this thing with the low compression? I'd rather not have to take my 1 ton truck everywhere. It's a yard truck and it's not very nice on gas, and who knows how reliable it is driving for a month straight.

 

[mtbtim]

the guy I use for harder jobs is booked 3 weeks out. Am I safe driving this thing with the low compression? I'd rather not have to take my 1 ton truck everywhere. It's a yard truck and it's not very nice on gas, and who knows how reliable it is driving for a month straight.

You're fine driving it. You should find out where you are losing the compression by doing a leak down test before you pay a shop to fix the issue. It wouldn't be wise to pay for a rebuild of the upper or lower end of the engine if it's just a head gasket issue.

Here's a video that will help you out.

<iframe width="560" height="315" src="https://www.youtube.com/embed/8yuCHzqH7MY" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

 

[mendozer]

Leakdown eh? I'm at work and can't view videos. is that where you see if it holds the pressure?

If 6 was about half compression and 4 was also noticeably low, I'm wondering if it is the head gasket, worn between the two cylinders. Does that make sense? I'm trying to visualize the anatomy of the engine and that's something that links those two together in terms of proximity. Anything else I can do besides the leakdown to rule in or out other things? I'm glad I got a response from you Tim I use your videos all the time!

 

[gamefreakgc]

the guy I use for harder jobs is booked 3 weeks out. Am I safe driving this thing with the low compression? I'd rather not have to take my 1 ton truck everywhere. It's a yard truck and it's not very nice on gas, and who knows how reliable it is driving for a month straight.

Pefectly safe. I had 60 PSI in cylinder 6, so I decided to up the boost and run my supercharger at 11 PSI, then add water/meth injection and crank up the HP. No issues, well other than bad compression in that cylinder! Drove it that way for several years.