Engine misfire

Hi,

If that is running, it is too high. Max is 62 engine off. It sounds like the fuel pressure regulator is bad. Do me a favor. Connect the pressure gauge and start the engine. Note the fuel pressure. Then, remove the fuel pressure vacuum hose. Pressure should increase. If it doesn't, replace the regulator. Also, confirm there is no fuel getting into the vacuum hose.

Here are the directions for replacing the regulator. The attached pictures correlate with the directions.

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2005 Buick Allure (CANADA) V6-3.8L
Procedures
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Pressure Regulator Service and Repair Procedures
PROCEDURES
FUEL PRESSURE REGULATOR REPLACEMENT

REMOVAL PROCEDURE

IMPORTANT: Always maintain cleanliness when servicing fuel system components.

pic 1

1. Relieve the fuel pressure. Refer to Fuel Pressure Relief Procedure.
2. Clean any dirt from the fuel pressure regulator retaining ring.
3. Remove the vacuum line from the pressure regulator.


pic 2

4. Remove the snap ring (7).
5. Using a shop towel to catch any spilled fuel, lift and twist the fuel pressure regulator in order to remove the fuel pressure regulator (6) from the fuel pressure regulator housing (1).
6. Remove the regulator O-ring small (2).
7. Remove the regulator O-ring large (4).
8. Remove the regulator O-ring back up (5).
9. Cover the fuel pressure regulator housing (1) to prevent contamination from entering the fuel system.

INSTALLATION PROCEDURE

NOTE:
- Do not use compressed air in order to test or clean a fuel pressure regulator as damage to the fuel pressure regulator may result.
- Clean the fuel pressure regulator filter screen with gasoline if necessary.
- Do not immerse the fuel pressure regulator in a solvent bath in order to prevent damage to the fuel pressure regulator.


pic 3

1. Install the new O-rings on the fuel pressure regulator (6), if a new fuel pressure regulator is not being installed. Lubricate the O-rings lightly with clean engine oil.
2. Install the regulator back up O-ring (5).
3. Install the regulator O-ring large (4).
4. Install the regulator O-ring small (2).
5. Install the fuel pressure regulator (6) in the fuel pressure regulator housing (1).
6. Install the snap ring (7).


pic 4

7. Connect the vacuum line to the fuel pressure regulator.
8. Tighten the fuel fill cap.
9. Connect the negative battery cable.
10. Inspect for leaks.
1. Turn ON the ignition for 2 seconds.
2. Turn OFF the ignition for 10 seconds.
3. Turn ON the ignition.
4. Inspect for fuel leaks.
11. Install the fuel injector sight shield.


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Let me know if that helps.

Joe

I'll work on it. Thanks

I don't have a fuel pressure regulator on my fuel rail or anywhere on the engine. I think it's in the fuel tank? The pressure of 70 was when the engine was running. (My car listed above has a series 3 engine) if that makes a difference.

I'm having good luck! I removed injectors and cleaned with mass air flow sensor cleaner (so I don't destroy any plastic or rubber like carburetor cleaner can). Ran multiple scans had random misfire pending, check engine light went out on its own!!!!! Yeah!! Running a little better but has a minimal rough idle. I have a new fuel pressure sensor that goes on top of fuel pump, I'm waiting to see if I'm going to need it or not. Going to put injector cleaner in full gas tank and go from there. Thanks a million for helping me with solutions to fix the issues on this Buick nightmare. Please thank Ken and Renee for the shirt and correspondence. 2carpros.com "Rocks". Saved me hundreds of dollars. Anyone out there looking for solutions to help to fix your vehicle, without having to pay money for answers, this is the only site to go to! All the mechanics are seasoned professionals and work together to find a solution to your specific vehicle needs.

You are more than welcome. I would replace the MAF if the problem returns. Use 2CarPros anytime, we are here to help. Please tell a friend.

Can this report tell you anything about my car ? Still have rough idle in drive? See attachment of report.or do you have a email I can send report? Can't post it on here file not allowed.

Hi,

What type of report are you referring to? Also, can you change the file type to attach it for us?

Let us know.
Joe

Vehicle VIN: 2G4WJ532051333257
Vehicle Manufacturer: Buick
Vehicle Calibration ID: 12598322
12607894

Freeze frame information:
------------------
Fuel Status = 0 byte
Engine Load = 32.549 %
Engine Coolant Temperature = 192.2 °F
Fuel Trim Bank 1 Short Term = -1.562 %
Fuel Trim Bank 1 Long Term = -7.812 %
Intake Manifold Pressure = 6.962 psi
Engine RPM = 1,410.75 rpm
Speed (OBD) = 29.826 mph
Timing Advance = 38 °
Intake Air Temperature = 41 °F
Mass Air Flow Rate = 12.53 g/s
Throttle Position(Manifold) = 12.549 %
Run time since engine start = 75 s
EGR Commanded = 21.569 %
EGR Error = 2.344 %
Fuel Level (From Engine ECU) = 50.98 %
Distance travelled since codes cleared = 11.806 miles
Evap System Vapour Pressure = -8,173 Pa
Barometric pressure (from vehicle) = 12.763 psi
Catalyst Temperature (Bank 1,Sensor 1) = 1,042.7 °F
Voltage (Control Module) = 14.265 V
Engine Load(Absolute) = 23.137 %
Commanded Equivalence Ratio(lambda) = 1.005
Relative Throttle Position = 9.412 %
Ambient air temp = 41 °F
Absolute Throttle Position B = 5.098 %
Accelerator PedalPosition D = 8.235 %
Accelerator PedalPosition E = 10.98 %


End of report.

Things look mostly normal. Was this test done at an idle? I ask because the MAF seems a bit high. Normally at an idle, it should be near 5 grams per second (G/S). I have a feeling Ken was correct with his last recommendation.

Joe.

Have new MAF. still idles rough when in drive. Maybe I could run a scan and put in drive and let idle? Thanks again for your help! Maybe charcoal vapor canister is bad? Has cap light came on last 2 times when fueling up. Had to use pliers to get gas cap off. Have a nice weekend! I'll keep checking for possible vacuum leak in fuel tank/fuel tube/pump etc.

Interesting the fuel cap light is coming on. Are you sure there isn't an issue with the filler tube? They can develop pin holes from rust. Just a thought.

Also, are there presently any codes?

Joe

Code P0300 came back on. I'll have to check the filler tube. Thanks

A random misfire is wide open to possibilities. Let me know if you find any leaks in the filler tube. If you don't, I'm going to suggest having the EVAP system smoke tested. Basically, smoke is forced into the system at a very low pressure. If there is a leak, the smoke will come out at that point. It could all be related.

Let me know
Joe

Sounds good, thanks. I did a review of different car parts I purchased and in it I said, "with the help of (2car pros dot com) figured out which parts needed to be replaced" they check reviews so I had to spell your site like that so it wouldn't get deleted. It's on a few reviews!

Thanks!!! And you are very welcome. Hopefully, we an get to the bottom of the P0300 now. LOL

You take care and have a good weekend.

Joe

Had to reprogram idle. Simple fix, turn on (not running) for30s then off 30sec then on 60sec found manual said to do when replacing maf or throttle body. Runs fantastic, park, idle, drive. 98% perfect. Still have P0303 but can't tell the way it runs. Maybe old injectors need replacing? Reading up on injectors and bad coil in injectors can go bad especially after warming up engine. Check gas cap light went off. Hope I'm not jumping the gun but this runs like a Buick should! Thanks a million!

You are very welcome. I'm glad it's running good for you. Take care and feel free to come back any time.

Joe

Me again. Lol. Would a a bad or slow firing injector cause all injectors to get out of sync? Are they wired in a series type circuit? One injector read 13 ohms and the electrical connector had 11 volts.

No one won't cause the others. I do have a question. Ohms is used to test resistance. What was the voltage reading on that injector?

13 volts on injector. In the meantime I'm putting sealer on the gas filler tube. It's pretty rusty so I'll clean it up then put "Seal All" all over the rusty spots and more.

The idea that the voltage is different is odd. Are you sure there isn't a corrosion issue with all but one?

Joe

The electrical connector read 11 volts with the key on. The injector was unplugged and I tested the 2 post on the injector itself in ohms. Because no voltage connected. Tested with multi-meter. I went ahead and changed the connector plug. Now I'm sealing the tank filler tube (takes forever to dry in the cold here in Michigan) it the sealing doesn't work I'm going to order 6 rebuilt injectors. Then if they doesn't work I'm taking it to a mechanic in town. I can't keep bothering you for free advice. But I do appreciate the help!

(2nd of 2 messages) fuel fill tube was severely pitted from rust on the bottom half of the pipe. I cleaned it up really good with brass brush and got down to bare metal the used. Truck bed liner spray to seal and cover the whole thing. Bed liner works great under vehicles and it doesn't flake or peel off. Rust is a big problem here in Michigan because of all the salt they put on the roads. I'm pretty sure this is going to fix the P0300.

Let me know if it helps. Also, I'm in PA. Isn't rust a great thing? LOL Ugh, everything falls apart.

Joe

Well I found the problem! I did my own smoke test and found I had a leak where the evap line connects to purge valve. It was a little loose so I used permatex to seal it up!! I also sealed the gas filler tube and replaced the evap canister and I probably didn't need to? I'm so glad I fixed the problem. Thanks for suggesting the smoke test, I never would have found that leak. Thanks a million! Stay safe with this virus going around.

Glad to hear you got it fixed. And, you are very welcome. Feel free to come back anytime you need something.

Take care and you, too stay safe.

Joe

Hello again. Found out I have a bad cylinder or burnt valve on #3 cylinder. Only had about 50psi shop said other cylinders were 150psi. Would it be easier to replace valve's on #3 or I can get a new head for $230.00 what would you suggest? I've never done valve's. Thanks again.

Hi,

If you can get a complete new head for that price, I would replace it. Doing a valve job isn't a five minute job and there is always a chance a valve will need replaced or there is damage to the head.

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Here are directions for replacement of a cylinder head. The attached pics correlate with the directions.

_______________________________________

2005 Buick Allure (CANADA) V6-3.8L
Cylinder Head Replacement - Left
Vehicle Engine, Cooling and Exhaust Engine Cylinder Head Assembly Service and Repair Procedures Cylinder Head Replacement - Left
CYLINDER HEAD REPLACEMENT - LEFT
Cylinder Head Replacement - Left

Tools Required
^ J45059 Electronic Torque Angle Meter

Removal Procedure
1. Disconnect the negative battery cable.
2. Raise and support the vehicle. Refer to Vehicle Lifting.
3. Drain the engine oil.
4. Drain the cooling system.
5. Lower the vehicle.
6. Remove the air cleaner intake duct.
7. Remove the ignition control module and the bracket from the left cylinder head.
8. Remove the right engine mount strut bracket.
9. Remove the left engine mount strut bracket.
10. Remove the lower intake manifold.
11. Remove the left spark plugs from the left cylinder head.
12. Remove the left exhaust manifold.
13. Remove the left valve rocker arm cover.
14. Remove the left rocker arms and the push rods.


pic 1


15. Remove the left cylinder head bolts. Discard the cylinder head bolts.
16. Remove the left cylinder head.


pic 2


17. Remove the cylinder head gasket.
18. Remove the caps, the springs, the valves and the seals from the cylinder head.
19. Clean the gasket mating surfaces on the cylinder head, the cylinder block and the intake manifold.
20. Clean the cylinder block bolt hole threads.
21. Inspect the engine block.
22. Inspect the cylinder head.

Installation Procedure
1. Install the valves, the seals, the springs and the caps to the cylinder head.


pic 3


2. Position the head gasket with the arrow pointing to the front of the engine.

Notice: Head gaskets are not interchangeable. The head gasket must be installed with the arrow pointing to the front of the engine. Installing the head gasket in any other direction will cause gasket failure and possible engine failure.



pic 4


3. Install the cylinder head.


pic 5


4. Install the new cylinder head bolts (1-8).
1. Tighten the cylinder head bolts (1-8) in the following sequence to 50 Nm (37 ft. lbs.).
2. Use the J45059 to rotate the cylinder head bolts in the following sequence (1-8) an additional 120 degrees.

Notice: This bolt is designed to permanently stretch when tightened. The correct part number fastener must be used to replace this type of fastener. Do not use a bolt that is stronger in this application. If the correct bolt is not used, the parts will not be tightened correctly. The system or the components may be damaged.

Notice: This engine uses special torque to yield head bolts. This design bolt requires a special tightening procedure. Failure to follow the given procedure will cause head gasket failure and possible engine damage.

Notice: Refer to Fastener Notice in Service Precautions.


5. Install the left push rods and rocker arms.
6. Install the left valve rocker arm cover.
7. Install the left exhaust manifold.
8. Install the left spark plugs to the left cylinder head.
9. Install the lower intake manifold.
10. Install the left engine mount strut bracket.
11. Install the right engine mount strut bracket.
12. Install the ignition control module bracket and the ignition control module to the left cylinder head.
13. Install the air cleaner intake duct.
14. Fill the cooling system.
15. Fill the crankcase with engine oil.
16. Connect the negative battery cable.
17. Inspect for leaks.

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At least on this engine, you don't have to worry about the timing when removing the head. Let me know if this helps or if you have other questions. Don't be worried about doing it. I'll do my best to help, so you are not alone doing it.

Take care,
Joe

Thanks. I replaced both head gaskets so I should be okay. I have to get another head gasket and bolts. It's a bummer because I have new gaskets and bolts on it but I want to do it correctly so I don't have to do it again. I'll keep you posted.

You are very welcome. Let me know how things work out when you finish.

Take care, stay healthy, and Happy Easter.

Joe

I changed the head and it was running like a charm for 2 weeks. I followed the step by step instructions you posted and saved me a lot of work.after I put the head on exactly like you said, new gasket,bolts and used a torque angle meter. A few weeks later a code popped up saying bank one running to lean and then evap system code gross leak detected. The only thing I question in my work is, I used the fairly new lower intake gaskets. I ordered the lower intake gaskets and I'll try it again. I sent an earlier message with Obd2 report but I think I hit reply and erased it? Hope your staying safe in Pennsylvania.