Misfire and turbo issues: yet another thread
07-19-2016, 06:46 PM
#41
Member
Thread Starter
Join Date: 08-07-2015
Location: NC
Posts: 62
No, I don't. Haynes recommends 4 special tools: injector bore cleaning tool, seal installer and sizer, slide hammer, and injector remover.
Now that I think some more, you should check fuel pressure before you go to all this trouble. If your pressure is lower than it should be, it may be just barely enough for injectors 1, 2, and 3, but not quite enough for 4. I would think that if it were low, you would have gotten a code for low fuel rail pressure, but I don't know what the threshold is. I've gotten that code twice, but had no driveability issues, and it's gone away, so I didn't have to deal with it. Still, worth checking out.
Looks like you regularly drive dirt roads? That's a lot of dirt sitting in there, might want to look at your air filter again.
It sounds like you ran the seafoam before you replaced the spark plugs. If you ran the seafoam after, over your new plugs, though, you may want to think about replacing them again(at least #4). About 2 months after I seafoamed, I started getting misfire codes, and what fixed it was new plugs(again).
Now that I think some more, you should check fuel pressure before you go to all this trouble. If your pressure is lower than it should be, it may be just barely enough for injectors 1, 2, and 3, but not quite enough for 4. I would think that if it were low, you would have gotten a code for low fuel rail pressure, but I don't know what the threshold is. I've gotten that code twice, but had no driveability issues, and it's gone away, so I didn't have to deal with it. Still, worth checking out.
Looks like you regularly drive dirt roads? That's a lot of dirt sitting in there, might want to look at your air filter again.
It sounds like you ran the seafoam before you replaced the spark plugs. If you ran the seafoam after, over your new plugs, though, you may want to think about replacing them again(at least #4). About 2 months after I seafoamed, I started getting misfire codes, and what fixed it was new plugs(again).
No, no dirt roads... I live in the city
Last week was kinda rainy :S
Air filter is clean.. I've removed the airbox so many times and every time I check it, no issues there
I run seafoam and the GM product before replacing the plugs.... but this set has gone through 3 re-gapping and 1 top end cleaning (CRC) so I'll change them. Just as a reminder, they are 1 step colder for the hotter coils. I still have some used ACDELCO oem plugs around.
About the fuel pressure... here's one of the latest freeze frames:
Fuel Status = 0 byte
Engine Load = 100 %
Engine Coolant Temperature = 87 °C
Fuel Trim Bank 1 Short Term = 0 %
Fuel Trim Bank 1 Long Term = 0 %
Intake Manifold Pressure = 30.458 psi
Engine RPM = 3,548.5 rpm
Speed (OBD) = 55.923 mph
Timing Advance = 6.5 °
Intake Air Temperature = 42 °C
Mass Air Flow Rate = 1,147.941 cfm
Throttle Position(Manifold) = 83.137 %
Run time since engine start = 952 s
Fuel Rail Pressure = 2,145.108 psi
Fuel Level (From Engine ECU) = 21.176 %
Barometric pressure (from vehicle) = 14.214 psi
Voltage (Control Module) = 13.805 V
Engine Load(Absolute) = 199.216 %
Commanded Equivalence Ratio(lambda) = 0.956
Relative Throttle Position = 69.02 %
Ambient air temp = 34 °C
Absolute Throttle Position B = 83.922 %
Accelerator PedalPosition D = 76.471 %
Accelerator PedalPosition E = 76.078 %
07-21-2016, 05:10 AM
#43
Platinum Member
Join Date: 12-06-2009
Location: Alabama
Posts: 11,099
Looks like you may have an oil leak around the high pressure fuel pump shaft/gasket.
I had small leak there before. The foam cover over the pump soaked up several ounces of oil before in became oversaturated. It them started "oozing" out the excess leaking oil in the same places your pictures show.
Wouldn't hurt to check that foam cover to see if it's soaked in oil.
I had small leak there before. The foam cover over the pump soaked up several ounces of oil before in became oversaturated. It them started "oozing" out the excess leaking oil in the same places your pictures show.
Wouldn't hurt to check that foam cover to see if it's soaked in oil.
07-21-2016, 08:30 AM
#44
Member
Thread Starter
Join Date: 08-07-2015
Location: NC
Posts: 62
Looks like you may have an oil leak around the high pressure fuel pump shaft/gasket.
I had small leak there before. The foam cover over the pump soaked up several ounces of oil before in became oversaturated. It them started "oozing" out the excess leaking oil in the same places your pictures show.
Wouldn't hurt to check that foam cover to see if it's soaked in oil.
I had small leak there before. The foam cover over the pump soaked up several ounces of oil before in became oversaturated. It them started "oozing" out the excess leaking oil in the same places your pictures show.
Wouldn't hurt to check that foam cover to see if it's soaked in oil.
I'm not familiar with the part but will look into it
Did the leak create any other issues to you? Did you fix it?
07-21-2016, 10:40 AM
#45
Platinum Member
Join Date: 12-06-2009
Location: Alabama
Posts: 11,099
That's your HP pump circled in red. Look under it and see if there is oil leaking. You can push in on the bottom of the foam cover to check. If it's been leaking, then that foam may be saturated like mine was.
I never did any repairs to mine. I just removed the foam(GM put it there to deaden the noise of the pump )
In fact, over time, my leak appears to have just about stopped. I get a slight wet area under the pump but never enough to accumulate or drip.
07-26-2016, 07:58 PM
#47
Member
Thread Starter
Join Date: 08-07-2015
Location: NC
Posts: 62
This the fuel pressure at idle... I am used to carburetors and motorcycles... no clue is such "erratic" fuel pressure is normal.
https://www.youtube.com/watch?v=0uix...ature=youtu.be
https://www.youtube.com/watch?v=0uix...ature=youtu.be
08-10-2016, 01:00 AM
#50
Member
Thread Starter
Join Date: 08-07-2015
Location: NC
Posts: 62
Got brand new plugs NGK LTR6IX-11 Iridium (remember I have hotter ZZP coils), no changed gap (0.040") and added TORCO octane booster, 104 octanes about total... still same issue, same backfiring.
At this point I have to take the intake off and look at the valves and replace the injectors seals (already got the kit)
What would I need? Intake gasket kit (GM 12589366 right?) for sure. What else?
Is it worth removing the valve cover too (and new gasket as well)
I will be installing also top and bottom IC pipes (performance auto werks)
I'll do this next month, so I have time to collect parts
At this point I have to take the intake off and look at the valves and replace the injectors seals (already got the kit)
What would I need? Intake gasket kit (GM 12589366 right?) for sure. What else?
Is it worth removing the valve cover too (and new gasket as well)
I will be installing also top and bottom IC pipes (performance auto werks)
I'll do this next month, so I have time to collect parts