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P0304 and 305

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo's stylish, distinctive "P2" platform cars.

2001 - 2007 V70
2004 - 2007 V70 R
2001 - 2007 XC-70
2001 - 2009 S60
2003 - 2007 S60 R

h20ham
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P0304 and 305

Post by h20ham » Sat Jan 11, 2020 1:39 pm

I purchased a rough idling 2004 xc90. Not getting a lot of help on the xc90 section.
I did a compression test, and #4 seemed to be leaking. So as one would suspect, cam followers.
I first added some seafoam to the oil, and fuel. New plugs gapped to 27. Had a 2nd set of coils from a car with 80k miles
Changed oil
Still no change. Tested all hoses. Turbo control hoses etc.
Replaced PCV, vacuum hoses, flex boost hoses.
Another oil change. Seems to me, if all cylinders had issues, one might consider air leak. Maybe i missed something
Fuel pressure 55 at idle, and 6000

Still at the p0304 & 5
The plugs look the same, and after resetting computer (not just erasing codes) full 30 minute battery disconnect (usuallly left overnight) it has boost. Not the limp mode. Does idle better too.

I initially thought it was a ECM issue.

I will borrow a friends VIDA soon.
68 125 b18 4 speed
72 164e b30 5 speed
79 242 16v 5 speed
84 744 T 5 speed
86 745 T 5 speed
88 765 T aw71
91 745 T 5 speed
95 965 T shift controller in progress
05 xc90 rough idle

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RickHaleParker
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Re: P0304 and 305

Post by RickHaleParker » Sat Jan 11, 2020 1:47 pm

Do a compression test on all five cylinders and post the measurements.
Platform: P80 1998 C70, B5234T3, 16T, AW50-42, Bosch Motronic 4.4, Special Edition package, Plant: Uddevalla Sweden.

Platform: X40 (Nedcar) 2003 S40, B4204T3, 14T twin scroll AW55-50/51SN, Siemens EMS 2000. Plant: Born Netherlands.

Platform P2 2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0,
Plant Torslanda Sweden.
----------------------------------------------------------------
1997 S90, B6304S, AW30-42, Bosch Motronic 4.4 - Sold

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Re: P0304 and 305

Post by abscate » Sat Jan 11, 2020 1:53 pm

Move coils, move plugs. Mark everything so you can keep track. Separate plugs from coils on each test

See if you can get codes to move.

Remember , a rough running car doesn’t indicate faulting cylinders reliably
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h20ham
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Re: P0304 and 305

Post by h20ham » Sat Jan 11, 2020 1:56 pm

Compression is 80. On #4. It takes a while for it to build up

The others are fine. Though 5 also takes some time to come up
68 125 b18 4 speed
72 164e b30 5 speed
79 242 16v 5 speed
84 744 T 5 speed
86 745 T 5 speed
88 765 T aw71
91 745 T 5 speed
95 965 T shift controller in progress
05 xc90 rough idle

h20ham
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Re: P0304 and 305

Post by h20ham » Sat Jan 11, 2020 2:19 pm

No clatter, so I dont think its a valve spring
68 125 b18 4 speed
72 164e b30 5 speed
79 242 16v 5 speed
84 744 T 5 speed
86 745 T 5 speed
88 765 T aw71
91 745 T 5 speed
95 965 T shift controller in progress
05 xc90 rough idle

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volvolugnut
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Re: P0304 and 305

Post by volvolugnut » Sat Jan 11, 2020 3:38 pm

When you do the compression test, count the revolutions, pressure pulses, or cranking seconds. Use the same number or time for each cylinder to get a good comparison. Typically, 4 or 5 revolutions or cranking seconds are used. Remove all spark plugs before testing any cylinders.
Write down the results and report them back to MVS for evaluation of all cylinders.
If you already knew this, my apologies.
volvolugnut
2001 V70 T5, 1986 244DL, 1983 245DL, 1975 245DL, 1959 PV544, multiple parts cars.

h20ham
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Re: P0304 and 305

Post by h20ham » Sat Jan 11, 2020 5:44 pm

1, 2, and 3 fine. 5 comes up after a couple turns of the crank
#4 takes 5 or 6
I have done the test twice. And same reading both times

Kind Regards
Jim
68 125 b18 4 speed
72 164e b30 5 speed
79 242 16v 5 speed
84 744 T 5 speed
86 745 T 5 speed
88 765 T aw71
91 745 T 5 speed
95 965 T shift controller in progress
05 xc90 rough idle

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volvolugnut
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Re: P0304 and 305

Post by volvolugnut » Sat Jan 11, 2020 5:58 pm

Several things can cause low cylinder pressure.
  • 1 Bad cylinder rings. Test the cylinder again with a teaspoon of oil in the cylinder.
    2 Bad valve seating, Generally will not improve with oil in cylinder. A vacuum gauge on the running engine MAY have a bouncing low to high needle.
    3 Head gasket leak. If adjacent cylinders are low this points to gasket leak between the cylinders.
volvolugnut
2001 V70 T5, 1986 244DL, 1983 245DL, 1975 245DL, 1959 PV544, multiple parts cars.

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SuperHerman
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Re: P0304 and 305

Post by SuperHerman » Sat Jan 11, 2020 9:39 pm

How many miles on the car? How has the service history been?

I had a 2001 XC70 with the 5 cylinder - the head gasket blew and I opened it up and replaced it. Note the lifters were solid - not hydraulic.

I was the second or third owner at 140k, but changed oil often and with quality oil. I thought it was serviced well.

When I pulled up the cam cover I noticed the cam lobes were clean on 1-3, 4 had some crud and 5 had more crud. One explanation, consistent with this, is your cam lobes are "crudded" up and the valve is not closing all the way. Usually even on dirty cams the wear area is clean metal - on mine - mainly #5 it was not clean metal, but build up.

I would try a leak down test - looking for valve leakage - focusing on 4 and 5. Then if you have access to a boroscope with a mirror you can get it angled to look up at the valves (valve seats). The leak down test will also tell you if you have ring issues - which is another explanation. You can get some viewing by taking off the intake or exhaust manifold, but I doubt this will be too probative.

Along this line - either your cam is "crudded" up and not allowing proper function or your valve seats on 4 and 5 may have issues.

If you have sticking piston rings - like you were told before - it takes time to clear. GM does make a cleaner that is very effective. If you have crudded up cams - you can pull the cam cover and clean it up. If you have valve issues you will have to pull the head. The leak down test is going to be very useful in figuring out your issues. If it is in the valve train - I would pull the head and rebuild it.

h20ham
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Re: P0304 and 305

Post by h20ham » Tue Jan 14, 2020 4:21 pm

It has 300,000km or about 200,000 miles
I wont have time for a month to do more
Seems to me, as it does build 80psi, after some cranking. Cam followers. But, i understand someone could have run it dry on oil or something. I just wish there would be an easyish fix. As i dont really want to get into valves or pistons etc
Maybe I should just look for a new engine.
Our family likes the car, we are not made of money. But I do have some time. Engine hoist, stands...also a vehicle hoist.
Question is, it its easy cam followers...
Doing a smoke or compressed air test to see where the leak it will be done in a month...thanks
68 125 b18 4 speed
72 164e b30 5 speed
79 242 16v 5 speed
84 744 T 5 speed
86 745 T 5 speed
88 765 T aw71
91 745 T 5 speed
95 965 T shift controller in progress
05 xc90 rough idle

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