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PCV valve


Shadowridr1

Well-Known Member
Joined
Jun 25, 2021
Messages
179
Age
50
City
Abilene tx
Vehicle Year
2003
Engine
3.0 V6
Transmission
Manual
I'm having issue with occasional rough idle and engine hesitation under acceleration. Both tend to improve the longer its driven. The CEL starts off blinking, then goes solid.... Pulling codes p0316, p0300, p0174.... I've changed the plugs, wires, coil pack, cleaned the IAC and the MAF. Did a smoke test today and got smoke coming from the grommet at the pcv valve and from the top side where the pcv tube is by the throttle body. Could this be causing my issues. I tried to do a compression test, but COULD NOT get the tester to thread into the plug holes. I triple checked to make sure the threads matched, but it was like the tested thread would not reach. Idk if I needed an extension of what....
 
Smoke should come out PCV valve at its end in valve cover, as its a planned vacuum leak
But not from the hose at the intake, it may be loose

P0300 Random/Multiple Cylinder Misfire Detected
P0316 Random Misfires are startup detected

These will cause the Lean Code, P0174 Lean on Bank 2(drivers side)

So I would suspect cylinders 4, 5 or 6 are misfiring and you will feel that when driving

Flashing CEL means BACK OFF THE THROTTLE RIGHT NOW!!!!
Computer is detecting misfires that can damage engine, so it Flashes CEL

Yes, you will need to do a compression test, should always do that first with Misfires so you don't waste time or money if it is a compression issue
Yes, get and extension or different hose for your gauge

Remove ALL spark plugs first, press gas pedal to the floor and hold it down when cranking the engine, that shut off fuel injectors and allows max. air flow
Get at least 5 "hits" of compression stoke
Then test each cylinder and write down results
 
Smoke should come out PCV valve at its end in valve cover, as its a planned vacuum leak
But not from the hose at the intake, it may be loose

P0300 Random/Multiple Cylinder Misfire Detected
P0316 Random Misfires are startup detected

These will cause the Lean Code, P0174 Lean on Bank 2(drivers side)

So I would suspect cylinders 4, 5 or 6 are misfiring and you will feel that when driving

Flashing CEL means BACK OFF THE THROTTLE RIGHT NOW!!!!
Computer is detecting misfires that can damage engine, so it Flashes CEL

Yes, you will need to do a compression test, should always do that first with Misfires so you don't waste time or money if it is a compression issue
Yes, get and extension or different hose for your gauge

Remove ALL spark plugs first, press gas pedal to the floor and hold it down when cranking the engine, that shut off fuel injectors and allows max. air flow
Get at least 5 "hits" of compression stoke
Then test each cylinder and write down results
Yes sir, thank you again for chiming in.... this thing is literally driving me crazy as other codes I have gotten are p0305 ,p0304, p0306, p0303. None of the old plugs looked bad. The coil pack was only giving me 9.2 ohms across every bank. I've got some not passed TID's but I can't figure out how to read them. I took a screen shot of my fuel trim and O2 volts at idle if that might help. The tester thing really pissed me off....I took it back, but haven't bought another yet
 
Ford coil pack should be 0.9 to 1.6ohms on each coil
Can't really test of a Coil is Good, you can only test if its bad, I know that seems very odd, but its true, any coil, single or in a 2 or 3 pack can show ohms tests within parameters but fail in actual use when they get HOT, and they all get HOT


O2s "see" oxygen, not fuel
High oxygen in exhaust shows as 0.1 volt, described as "lean" by computer
Low oxygen in exhaust shows as 0.9volt, described as "rich" by computer
0.3 to 0.4volt is where computer tries to keep O2 sensor feedback voltage

If a cylinder Misfires then NO OXYGEN is burned up and that oxygen gets dumped into exhaust manifold, so...........
O2 voltage on that bank drops to 0.1v, lean

So Misfires cause the lean code, Lean code does NOT cause misfires, so ignore Lean Code and try to diagnose Misfires

Because you have a 3.0l and because Ford was all over the map on the software for these
P0300 and P0316 can be cause by out of time or failing CAM sensor

Unplug the 2 wire connector on Cam Sensor, see if engine will start
It should
And it should set a new code, P0340 or P0341, this is a "sanity test" for the computer and cam sensor circuit
 
but COULD NOT get the tester to thread into the plug holes. I triple checked to make sure the threads matched, but it was like the tested thread would not reach.

Generic compression test kit has a shallow thread adapter for the 3.0 plug. It's upper part is too fat and hits the wall before it threads all the way in. I rented this one with a deeper thread head and a narrow upper part.
 
Ford coil pack should be 0.9 to 1.6ohms on each coil
Can't really test of a Coil is Good, you can only test if its bad, I know that seems very odd, but its true, any coil, single or in a 2 or 3 pack can show ohms tests within parameters but fail in actual use when they get HOT, and they all get HOT


O2s "see" oxygen, not fuel
High oxygen in exhaust shows as 0.1 volt, described as "lean" by computer
Low oxygen in exhaust shows as 0.9volt, described as "rich" by computer
0.3 to 0.4volt is where computer tries to keep O2 sensor feedback voltage

If a cylinder Misfires then NO OXYGEN is burned up and that oxygen gets dumped into exhaust manifold, so...........
O2 voltage on that bank drops to 0.1v, lean

So Misfires cause the lean code, Lean code does NOT cause misfires, so ignore Lean Code and try to diagnose Misfires

Because you have a 3.0l and because Ford was all over the map on the software for these
P0300 and P0316 can be cause by out of time or failing CAM sensor

Unplug the 2 wire connector on Cam Sensor, see if engine will start
It should
And it should set a new code, P0340 or P0341, this is a "sanity test" for the computer and cam sensor circuit
Ok so I unplugged the cam sensor the truck started and throw a code. I shut it off, reset the code started it back up and unplugged the iac. The idle slowed BARELY and throw a code. When I plugged it back in the trucks rpm increased tremendously then leveled back out. I shut it off, cleared the code, started it back up and unplugged the tps this throw a code as well but made no change in idle or anything so I plugged it back in, shut it off and cleared the code. I started it back up and unplugged tj maf. The truck died instantly and it throw a code. I plugged it back in, cleared the code and started the truck. Something NEW I noticed, and idk if it should be this way or not, but the pcv valve i assume, is rattling so much its vibrating the whole tube. I can hear it over the running engine and feel it in the housing of the intake where the tube runs. I freaking wish I could figure out how to post pictures and videos. I have takes so many...
 
PCV valve would only make a rattle noise if vacuum in intake is fluctuating rapidly
Which is a valve issue, need that compression test
 
Ok, I'll get another tester asap.... do you have an recommendations on one as the last one I got, from harbor freight, would not reach the threads.
 
Mines probably 30+ years old now, it came with 2 rubber hoses, each with the different spark plug thread size and uses compressor air fittings to connect to gauge so can be used for leak down tests

If yours has the one hose with the double stack thread I can see how that wouldn't fit in tight place
Not sure why they would do that
I expect they sell an extension that screws on the end so it can be used
Extension should be about the length of the spark plug and slightly smaller diameter
 
Mines probably 30+ years old now, it came with 2 rubber hoses, each with the different spark plug thread size and uses compressor air fittings to connect to gauge so can be used for leak down tests

If yours has the one hose with the double stack thread I can see how that wouldn't fit in tight place
Not sure why they would do that
I expect they sell an extension that screws on the end so it can be used
Extension should be about the length of the spark plug and slightly smaller diameter
1.155
2.155
3.150
4.140
5.90 - wet 92
6.150
Guess I'll be looking for a set of heads...
 
I guess you will, bummer

But at least, now you know
 
Yes sir, I just hope it's a FIX ALL...... bad thing is the truck is gonna sit for probably a couple months to I can get the funds together. I mean it does run, do you think it would be OK to just put around in every so often just to keep things turning....I live in a small town so....
 
Yes, its OK to drive, I might unplug injector 5 so unburned fuel doesn't wash off oil coating for rings and unburned fuel doesn't end up in exhaust(backfiring) or in the oil pan
 
Yes, its OK to drive, I might unplug injector 5 so unburned fuel doesn't wash off oil coating for rings and unburned fuel doesn't end up in exhaust(backfiring) or in the oil pan
Next question...I know they changed head designs at some point, but what heads are compatible and is is ok to maybe go the junkyard route and if so what yr heads should I avoid...also do i need new push rods, rockers and head bolts or will the rockers come with the heads.....sorry if I'm a bother just trying to get a list of expenses together.... I like to get my FREAKING OUT all done at once. Lol
 

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