So here is the story, the truck will barely (missing and chugging) start. Then after it starts it will idle ruff vibrate and I can hear it missing in the exhaust note along with black smoke for a few seconds. It will also miss after its warm at idle. I also this week just got a p0175 code rich in bank 2 I believe (ds or ps?)? I am wondering what you guys think it could be? It also does not sputter of miss when I am on the gas. My thoughts are a stuck injector or a bad COP? Not sure but any help you guys could give me will be great as I have been dealing with this for months now.

Thanks for all the help in the past also!

Dave

ps. Sorry posted this in the v8 section but didnt get anything...

 

Pull the cops while running one at a time and see if its one of them . Then you could start checking injectors. Well it could be running running rich from the tune which caused your plugs to foul up. You might want to check your plugs to see if they are in fact fouled.

 

Ah good call... I ordered a new set of COP's from uneek today so I will be pulling them this weekend. What would cause the tune to be rich at idle? Under power it's 11.5ish of the wideband.

 

If it just started it probably isn't the tune. Hopefully if you're lucky it'll be all cleared up with the new COP. You might also want to check/clean the MAF.


EDIT: Here is the firing order. Bank 2 is driver side.

 

So the plugs in the DS bank are clean and look good and tan. The ones in the PS bank look like below and I believe are fouled. They have about 2000 miles on them max.

Any ideas what might cause this and should I put new plugs and COP's in first or try and fix whatever it is first?

 

You have to do some detective work first to get a direction to go in.
Here is what you need to keep in mind.
To much fuel for some reason will foul plugs.
1. Leaking injectors. Test fot fuel pressure leak-down.
2. Fuel regulator diaphram allowing fuel thru the vacuum hose into the intake manifold. Look at the vacuum hose for sighn of fuel inside it.
3, Exccess fuel will be sensed by the OX sensors as to much air possibly causeing them to signal the computer to apply even more fuel. The sensors don't react directly to excess fuel
4. Thermostat stuck open. Ingine very slow to heat up.

Next, ignition.
1. Absent ignition will allow the unburnt fuel to pass thru the motor. The Ox sensors see the condition as to much air and also richens up the fuel even more.
There should be a code to give you a hint.
If you were to use a good scanner, not a reader, to view the live operating data, the signs would be evident.
But then you must know what you are looking at to recognoze the issue like log term fuel trim values, missfire counts etc..
None of this is a big mistery if looked at properly.
Like a doctor, find the cause, then the cure is easy.
Good luck.

 

So I checked the fuel pressure on startup and it goes to 48lbs (not sure if the gauge is correct) right away with no drop. It sounds to me like the injectors are failing and bleeding off pressure when the truck is off into the cylinders. Anyone agree? I am going to test the injectors tonight also.

Thanks Dave

 

To test inital bleed-down just look at the gage after engine shutdown to see how quick the pressure drops.
It should stay at least a minute to a slow bleeddown.
If it drops low within 30 seconds either an injector or the check valve in the pump is not holding.
Then you can go from this point inspecting injectors if there is an indication that's needed.
The system normally will not just keep pressure in the rails for very long.
It's the reason the pump is run just before cranking so the rails have fuel for starting and don't have to wait for pressue to build.
48 psi, if accurate, is on the high side..
One reason pressure can go high, is a line collapse or pinch on the return line.
If that happens the pump will build it's max possible pressure in the rails that could go well up toward 100 psi. That would be enough to drown an elephant.
Good luck.

 

When I start the truck fuel pressure goes to 48lbs right away(not sure about the gauge) and is stable after running. After shutting the truck off it stays at 42lbs for about 15min then goes to 35 after about 30 min off. Doesn't sound bad to me but the more I think about it makes me think that the injectors on the PS bank are leaking somehow after the truck is off and flooding it so it smokes and misses for the first 20 sec on startup. I am going to do an injector test tomorrow.

Would a slight exhaust leak about 3 inches above the upper o2 sensor make it kick full rich? Its a pin hole leak in my cap for the wideband sensor...

Thanks Dave

 

With a leakdown rate that good, I would doubt you will find an injector leaking.
A pin hole could allow outside air to enter the exhaust.
The hole being that close to the sensor will detect it to some drgree and richen the fuel delivery.
I also doubt that it is the 'major' cause of the problem because even with the OX sensors disconnected, the PCM resorts to fixed fuel tables to run the motor, even though it will be somewhat rich.
A pin hole in that position is under exhaust pressure 'outward'. The only time air could enter is between exhaust pulses of which there are 4 for that bank, so it should have only a minor effect.
If you still feel it's a fuel leak, try bleeding the rails down after the last time you use the truck to take pressure of.
Then the next cold start, see if it had any effect.
I would still get the use of a good scanner and take a look at live data for any indications of something out of line, for somthing the look into.

 

So I tried another set of injectors on the pass side of the motor and it did nothing. Still the same issue with a really ruff start and black smoke for the first 20 sec. Fuel pressure is good, new COP's and not the injectors. Anyone have any other idea's?

Thanks Dave....

 

Check the fuel regulator for a leaking vacuum diaphram allowing gas to flow directly into the intake manifold through the rubber hose.

 

I did the datalog but I think Justin is really busy or something because I haven't received an email back yet. I was wondering if I could send someone here my datalog to see if you guys can spot something wrong. PM me please with your email if you would like to take a shot at it! Thanks for the help in advance...Dave

 

dont forget to TQ your plugs

 

I just looked back on your photo and noticed you have an xcal.
Do you also have a blower on?
The plug threads have black coloring 'up' way to many threads.
Go back to the stock tune to see if the issue goes away.
We are trying to look at this as if the truck were stock when you may have some other issue going on due to your mods.
Good luck.