[BoyPinoy]

Hello everyone, someone poured either sugar or salt on my gas tank. I already changed the fuel pump, fuel filter, add Chevron fuel injector cleaner twice, and changed oil, but the engine is still running rough, and finally it gave me the error code of P0301. I'm thinking that fuel injector 1 might have been ruined as well. 6 months ago, I succesfully change the spark plugs, spark plugs wire, pcv valve, valve cover gaskets (inner and outer valves) and intake plenum gasket using the method in the following link:

http://www.paulsrichards.com/2008/06/13/changing-the-spark-plugs-on-a-chrysler-voyager-v6/

So I'm somewhat familiar with removing the intake plenum. Questions:

1) I'm suspecting that fuel injector #1 is the bad injector because of error code P0301 (engine cylinder misfire cylinder #1). Please confirm.

2) Do I need to change all injectors, or just the faulty injector?

3) I need detailed instructions on how to remove the fuel rail and fuel injector because this is first attempt in doing this work. As mentioned above, I'm familiar up to the part of removing the intake plenum.

Thanks in advance to everyone.

 

[mgbmike]

3) I need detailed instructions on how to remove the fuel rail and fuel injector because this is first attempt in doing this work. As mentioned above, I'm familiar up to the part of removing the intake plenum.

Thanks in advance to everyone.

Check out the videos from 905speedgta. Here are a couple links but he has more.

Only allowed two videos per post so here is a third one:

 

[BoyPinoy]

Thanks for the link. I was able to change all 6 fuel injectors. But the idle is still rough, and today it gave me code P0301 again. I'm sure I changed the fuel injectors properly. I forgot to mention that around the time I changed the fuel pump and fuel filter, I also Seafoamed my van using one of the vacuum lines. I emptied an entire can of Seafoam by vacuum lines exclusively. I realized after the fact that I should have only used half a can of Seafoam on the vacuum lines.

According to this website, http://www.obd-codes.com/p0301, possible causes of the P0301 are:

• Faulty spark plug or wire
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector
• Burned exhaust valve
• Faulty catalytic converter(s)
• Running out of fuel
• Poor compression
• Defective computer

I'm ruling out faulty spark plugs and plug wires 'coz those were changed in November 2011. I'm ruling out fuel injectors too 'coz I just changed it. I'm suspecting either faulty oxygen sensors or dirty TPS and IAC sensors.

Any ideas please?

 

[ImperialCrown]

O2 sensors, IAC and TPS would likely affect all cylinders, not just the #1 cylinder. You need to do more diagnosis.
Does the #1 spark plug show any difference in color or appearance from the others? You may want to swap it with an adjacent spark plug just to see if the misfire follows the plug.
Did you flush or replace the fuel tank? I have seen fuel contamination cause thousands of dollars of damage from the fuel tank to the engine combustion chamber.
Many internal fuel rail problems will appear at the end of the rail and affect that particular cylinder. Air bubbles or deposits will collect at the ends.
Measure fuel pressure at the rail (~49 psi/338 kPa). Have the pump partially fill a fuel sample in a clear soda bottle. It should come out of the fuel hose as pure gasoline color and no foam or bubbles. Use safe fuel handling procedures.
A cylinder leakdown test will check valve leakage issues. A compression test may not show the problem. Leaky valves will be more pronounced at idle/low engine speeds. Does the misfire/roughness go away at higher engine speeds?
Sugar is carbon, it's one of the meanest things you could do to someone's car.

 

[Ray Green]

I recently had a bad coil pack effecting #1 cylinder, and maybe #4 as well. Like you, I changed plugs, wires, and then the #1 injector. The way I finally pinpointed the coil pack was while pulling plug wires. I was second-guessing my hearing so I started pulling wires again to see which one didn't effect the engine. I noticed that when I went to re-attach wires 3 and 5 I could see and hear the spark fly off the coil pack connection. On #1 I couldn't. Got the coil pack at AAP, about $55 tax in.

 

[BoyPinoy]

Does the #1 spark plug show any difference in color or appearance from the others? You may want to swap it with an adjacent spark plug just to see if the misfire follows the plug.

Thanks, I'll try this and will report back.

Did you flush or replace the fuel tank? I have seen fuel contamination cause thousands of dollars of damage from the fuel tank to the engine combustion chamber.

Yes, I replaced the fuel tank with a used one because I damaged the breather hoses in the process of removing it. It turned out to be a blessing because after cleaning the damaged tank, and drying it out overnight, there are still some sugar so I decided to just replace it.

Many internal fuel rail problems will appear at the end of the rail and affect that particular cylinder. Air bubbles or deposits will collect at the ends.
Measure fuel pressure at the rail (~49 psi/338 kPa). Have the pump partially fill a fuel sample in a clear soda bottle. It should come out of the fuel hose as pure gasoline color and no foam or bubbles. Use safe fuel handling procedures.

I'm a newbie at DIY, so I don't know how to measure the fuel pressure. Any good DIY guide on how to measure fuel pressure, particularly on a 96 Grand Voyager SE?

I vaguely recall, not 100% though, that when I emptied the gas from the fuel rail by just pouring it during the injector change, the color is clear but slightly yellowish. Is this normal?

Leaky valves will be more pronounced at idle/low engine speeds. Does the misfire/roughness go away at higher engine speeds?

Yes the roughness goes away even at lower speed, less than 20 mph. The rough idle is noticeable while parked, and particularly while stopped with my foot on the the break.

I recently had a bad coil pack effecting #1 cylinder, and maybe #4 as well. Like you, I changed plugs, wires, and then the #1 injector. The way I finally pinpointed the coil pack was while pulling plug wires. I was second-guessing my hearing so I started pulling wires again to see which one didn't effect the engine. I noticed that when I went to re-attach wires 3 and 5 I could see and hear the spark fly off the coil pack connection. On #1 I couldn't. Got the coil pack at AAP, about $55 tax in.

Good idea, I'll try this procedure. Thanks.

Will a bad coil pack create rough idling during idle?

 

[Ray Green]

Good idea, I'll try this procedure. Thanks.

Will a bad coil pack create rough idling during idle?

Indeed it will and it's worse when idling in gear while holding the brake. Another symptom mine had was under acceleration, the engine light would flash but at steady throttle or coasting, it would be off. Only a couple times did it illuminate and stay and I got the P0301.

 

[BoyPinoy]

Got an inline spark tester, and tested the spark plugs wires and ignition coil pack, and those were fine. There's no smell of gas in the engine compartment or inside the cabin. But when the intake plenum was removed, the plenum gasket was wet with gas. In addtion, 4 minor drops of gas came out of the plenum. So the plenum is damp inside. I think this is what's causing the P0301 code. I removed the fuel rail, removed all injectors, cleaned the injectors and changed the O'rings. I'll give it several weeks to see if this solves the problem. If this procedure doesn't solve the problem, my next step is to do a cylinder leakdown test.

What could cause gas to seep inside the intake plenum? How does one know if the fuel injectors was installed incorrectly? Thanks again for all your help.

 

[Bob Lincoln]

Did you pre-oil the injector o-rings with engine oil before installation? If not, the o-rings can tear during installation and leak.

 

[BoyPinoy]

Yes, I did lightly coat the O'rings with clean engine oil.

Talked to my mechanic, and he seems to think that the rough idling while stopped is due to a failing idle air control valve. I removed the throttle body and IAC valve, cleaned both and the well where the IAC connects to the TB with some TB cleaner. Put it back on, the rough idling has improved, but not completely to so I replaced the IAC.

I will report back after several weeks if this solves the problem or not. So far, I have the van idling for an hour on two occasions, and it seems to idle smoothly. Thanks for all your help. Until next time