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I watch all paul's videos but can't retain information that way.
I've been messing with my truck 2002 gmc Sierra 2500hd 6.0 that has been running rough and bogs and would die if I don't stop and give engine time to settle back while I turn around in driveway. Bogs slowing down at street light and turning.
Engine codes are knock sensors p0332 p0327 and EGR p0405 (EGR unplugged, removed and blocked off)
Fuel pressure is 55psi instantly with key on, 55psi bouncing needle around 4psi +or- idle, 61psi when snap throttle, no drain over 30 min. Pressure Reg has no fuel coming out of vacuum port.
200° ECT
STFT b1 0
LTFT b1 14.8
STFT b2 2.3
LTFT b2 14.8 I'v had both LTFT up to 20-25% at idle warmed.
map inHG 11.5
RPM 587
IAT 55
MAF lb/min 0.8
Note: I cant determine if LTFT gets better from cold to warm. Sometimes it does and others not so much.
My initial thought is vacuum leak. I tried water test around intake but engine already runs little rough and I couldn't tell difference.
I cleaned MAF sensor, witch was dirty. I noticed the air filter indicator thing was missing from air housing, leaving hole for dust to bypass filter and cake intake. I cleaned throttle body, probably not very well but where the butterfly valve seats the housing.
HERE IS SUBJECT TITLE, I took off pcv valve, driver side rear of valve cover. Really dirty, didn't hear rattle. Cleaned it up and I can see all the way through, Nothing inside...
I unplugged maf and ran engine. The Fuel trims looked way better. Is that a sign? I'm guessing A. vaccum leak and now the maf is in default and not correcting vacuum leak? B. MAF is not reading correctly.
What do you think it is or next step.
I would love to throw smoke machine on but the only way that will happen if I modify Halloween gimmick machine to work if that is possible.
If it's the good ol' PCV valves that GM used in most engines around that time, then there should definitely be something in there. :lol: Looks like this?
If that valve is wide open, then you end up getting a vacuum leak through the crankcase of the engine. You can also get stuff like excessive oil consumption and squealing noises at idle (air getting sucked past seals).
If you plug the PCV vacuum hose, what do the trims do?
I put a new pcv on and trims where 14 17 test drive around driveway was good, no bog. I believe idle rpm is still low.
it's rather warm out today (55) compared to when symptoms started happening. I don't drive truck that often but last 3 times it was under 40 deg. And had the symptoms. Truck came from Michigan road department.
I did notice that the old pcv orifice is size of pen head ball, very small. New 1 is slightly smaller then ehh a pen but has a valve lol.
I can only imagine what the intake looks like with a double combo. Oil bypassing pcv, hole in air housing for a dust express way.
begs the question... what happened to the pintle from the PVC? did it get sucked into the intake or drop into the valve train.
the p0332 and p0327 codes should be gone unless you still have a lean condition. A lean condition will set off the knock sensors. The p0405 will remain as you have disabled the EGR.
Clear codes and re-scan. What are your new STFT & LTFT"s
"an open mind let's knowledge flow in and wisdom flow out for a man who has neither never listens to those who have both".
Being wrong doesn't bother me, it's being right and not understanding why that does
Turns out it has a fixed orifice pcv. I don't think that is oem for this truck. It is a GMC thing, new ish. And also gm bulletin to switch to this if oil consumption. Google Search 1614660 gm to read bulletin.
P/n 12572717
Now I'm debating on re-installing it.
I'll clear codes and grab live data next.
Updates. It starts with longer crank then dies, starts second time right away. Will bog and sometimes die while backing out of driveway or drive while turning slow.
LTFT1&2 25 cold 15% 220°
New code: P0300 Misfire
I went and pulled coil plug off each 1, 1 at a time. All of them made tiny difference running worse.
Coils, Plugs, Injectors?? Coils do look like crap/rusty.
Injectors, wouldn't that also cause lean at higher rpms?
the only change was to install a new PVC and now a long crank time...
which PVC do you have installed at this time?
if the injectors are not allowing a sufficient amount of fuel, yes, that can cause a constant lean condition and the P0300. Open too long is a rich condition. Sticking shut would be lean. Do a injector balance test. All injectors should be the same.
You do not drive the truck that much... if the injectors are partially clogged, that can make it worse. Gently tap on the injectors and see if the idle smooth out. Not full proof but can be an indicator.
"an open mind let's knowledge flow in and wisdom flow out for a man who has neither never listens to those who have both".
Being wrong doesn't bother me, it's being right and not understanding why that does
I have the fixed orifice pcv in now.
The long crank was already present at times.
Long as is in 6sec. I think only on cold days.
Dies right away. Second crank is instantly running.
Warm days will be 3 sec.
I'll try and come up with a way to do injector balance.
I have pictures of coil packs and Map.
Will be changing both because used parts are very available for next to nothing for me.
New plugs too. anybody have recommendation for what plugs in the 6.0
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