2001 codes

[uss11]

I have a 01 bravada that died when I came to a stop. Igot it started and it runs rough and will not idle. Ipulled the codes and got four codes[ actron code reader ] first a po101 second a po306 third apo306 and last a po101 can anyone help!

[MT-2500]

Originally Posted by uss11

I have a 01 bravada that died when I came to a stop. Igot it started and it runs rough and will not idle. Ipulled the codes and got four codes[ actron code reader ] first a po101 second a po306 third apo306 and last a po101 can anyone help!

Code 101 is Mass air flow sensor is not within specs of the VCM/PCM performance check.
And can be caused by a bad map (BARO) sensor reading.
Or low vacuum.

Code 306 is engine miss on no 6 cylinder.
Check that end out.

Make sure MAF sensor has no air intake leaks and is not dirty and good wiring and plug in.
Check and fix engine miss and.
Confirm good AC Delco plugs and wires and cap and rotor.
Clear codes and see what comes back.

Also check fuel pressure.
Post back your pressure readings.
Low fuel pressure will cause engine miss and other problems.

[MT-2500]

Another dye and rough idle problem can be caused by EGR valve stuck open.

Check engine vacuum reading and post back.

[uss11]

Ok I cleared the codes, then I changed all six plugs and replaced the MAF. The wires check good with a owm meter. I start the vec, and it runs rough and comes up with a code po 300 multiple misfires. also all six spark plugs are black as if the engine is flooding. at this point i'm lost! If it had a carb I would know what to do but now I do not HELP !

[MT-2500]

Originally Posted by uss11

Ok I cleared the codes, then I changed all six plugs and replaced the MAF. The wires check good with a owm meter. I start the vec, and it runs rough and comes up with a code po 300 multiple misfires. also all six spark plugs are black as if the engine is flooding. at this point i'm lost! If it had a carb I would know what to do but now I do not HELP !

Well it is time for more testing and checking.

Black plugs point to enfine running rich.

Got good hot blue spark to all plugs?
How is fuel pressure ?
Engine vacuum?
Have you checked EGR valve?
Are you tempt sensors good?

[uss11]

No compression on number 6 cyl. pulled the head and found the ex valve bent and it hit the piston. Ijust can't figure this one out.

[MT-2500]

Originally Posted by uss11

No compression on number 6 cyl. pulled the head and found the ex valve bent and it hit the piston. Ijust can't figure this one out.

Well you have figured out the problem.
What are you going to do about it?

What is the mileage?
Is the rest of engine good?
What is the repair and service history on it?
Is the timing chain worn?
Has it been operated at high RPM?
Are valve springs weak?
Are the rest of the valve guides good or tight or gaulding?

[uss11]

The heads are in the shop for a valve job. The rest of the motor seems to be in good shape. Mileage is in the 90,000 range and the motor has never been apart. All that I can is that a chunck of carbon broke free and jammed the valve then shot out the exhaust. There was nothing in the cyl.

[MT-2500]

Originally Posted by uss11

The heads are in the shop for a valve job. The rest of the motor seems to be in good shape. Mileage is in the 90,000 range and the motor has never been apart. All that I can is that a chunck of carbon broke free and jammed the valve then shot out the exhaust. There was nothing in the cyl.

Be sure to check the timing chain and that the machine does a good job on the heads.
Good Luck

[viggy58]

if you have the time and money, i would go ahead and change the coolant over to green, flush the system, and replace the water pump, since you'll be replacing the lower intake manifold gasket anyways...

[MT-2500]

Originally Posted by viggy58

if you have the time and money, i would go ahead and change the coolant over to green, flush the system, and replace the water pump, since you'll be replacing the lower intake manifold gasket anyways...

Not a good idea on a system that calls for GM dexcool.

[uss11]

Got the Bravada back from the shop today. At the shop the starter went out. Changed the starter and it started right up. We drove it home[ mich to chi] and it ran OK. At the shop I took a look at number 6 ex valve. It seems to have been stuck in the valve guide, so that would explain how it got bent. I also had them replace the injector pod just to be safe. It was refilled with DEX-COOL and 10x30 oil. Ido not like the 5x30 that it calls for. So we will see what happins now. Thanks for the help.