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P0129 P0304 P0204


 
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Malarky
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Age: 42
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2005 Dodge Neon SXT

Post: #1   PostPosted: Fri Jul 29, 2016 10:28 am    Post subject: P0129 P0304 P0204 Reply with quote

05 automatic 175,000 miles.

For 2 weeks P0129 (doing the key dance) would come on sporadically immediately after starting. (I made sure not to quickly turn the key when starting).

When "in" P0129 im limited to 4k rpm. When driving, if I were to lift my foot off the accelerator there would be a slight shudder / clank. Like wise when pressing accelerator from "idle" position. Code would clear after a few drives and then reappear sporadically after starting.

When not "in" P0129, after 20 minutes of driving from first drive of the day (ie "cold") the car would shudder. There is no shudder if accelerating to pass when transmission would kickdown. There is no shudder when "in" P0129.

Replaced plugs and wires. Replaced MAP and cam sensors. No change.

The other day while driving the engine slowly lost power and would only go 15 mph. Sulphur smell. Turned off and had it towed to my brother's shop.

His code scanner showed there were pending codes P0304 and P0204 that are now active. Moved fuel injector for cyl #4 to cyl #1, problem did not follow the injector. Pulled plug from cyl #4 and noticed black oil on part of threads and inside plug.



Change oil, filter regularly. Trans fluid is about 4k miles new. No evidence of coolant and trans fluid mixed.

Going to do a compression and leak down test this weekend. What would be considered "normal" results for such tests?

These problems crept up about a week after seafoaming (aerosol).

EDIT- It was suggested that by seafoaming, any particulates released could clog the catalytic converter. I'm not knowledgeable enough to know if this could be true or not.

Any other help greatly appreciated.

Thank you!
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Malarky
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Age: 42
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2005 Dodge Neon SXT

Post: #2   PostPosted: Mon Aug 01, 2016 8:31 am    Post subject: Reply with quote

DRY

Compression;
1- 195
2- 190
3- 200
4- 155

26% leak down in cyl #4
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occasional demons
Mr One World
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Age: 51
Joined: 03 May 2007
Posts: 19781
Location: Ashland, Ohio

2001 Dodge Neon ES

Post: #3   PostPosted: Mon Aug 01, 2016 9:01 am    Post subject: Reply with quote

25% is the allowable spec per Chrysler. For what that's worth. The old rule of thumb is 10% per cylinder.

You might have a bad wire or bad connector for the MAP sensor. The PCM checks the sensor voltage when keyed on. If it is not where it should be in relation to atmospheric pressure, it sets a fault. The output should be less than 5 volts with the engine off/keyed on. If the ouput the PCM sees is 5 volts, or close to zero volts, it knows there is a problem.

Atmosphere is closer to the 5 volt end, and 30" of vacuum is closer to the zero end. It should have neither zero or 5 volts as an output.

If the PCM is feeding it significantly more or less than 5 volts, it might cause this too. (Or a broken 5 volt feed wire)



Was the oil on the plug due to leakage into the spark plug well? The tubes commonly loose their press fit, and oil seeps in from the bottom. With 175,000 miles, that would not be a shocker. It happens on heads with a lot less mileage.

Unless the oil was vacuumed out before removing the plug(s), it will give you wet compression numbers. If you happened not to notice, a teaspoon or so of oil will give you false readings. Not saying this is your situation, but just an example.


It might be a combination of oli and fuel on #4 plug. If the wiring has a short, it might be randomly flooding #4 and washing down the cylinder wall.

A wiring issue would be one reason why the issue did not follow the injector. It can also be an injector driver issue in the PCM. It is rare, but it does happen.
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2001 neon ES MTX with '02 R/T PCM
1999 neon 2.4 EDZ MTX
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Malarky
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Age: 42
Joined: 05 Feb 2013
Posts: 28


2005 Dodge Neon SXT

Post: #4   PostPosted: Mon Aug 01, 2016 1:37 pm    Post subject: Reply with quote

Thank you, Bill.

Does the sulphur smell and decrease in power to only sustain 15mph fit in with what's been observed thus far?
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Mr One World
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Location: Ashland, Ohio

2001 Dodge Neon ES

Post: #5   PostPosted: Mon Aug 01, 2016 5:52 pm    Post subject: Reply with quote

Sulfur smell could be excess fuel burning in the catalytic converter. That would kind of back up an injector ground not being switched off.

If the #4 cylinder is being randomly/constantly flooded with fuel, it won't fire too well which could also be why you are down on power. The converter may also be getting damaged from overheating due to the excess fuel.
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Malarky
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2005 Dodge Neon SXT

Post: #6   PostPosted: Tue Aug 02, 2016 12:33 pm    Post subject: Reply with quote

Thank you much again.

What would explain the "symptom free" driving for the first 20 minutes of the day?
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Malarky
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2005 Dodge Neon SXT

Post: #7   PostPosted: Thu Aug 11, 2016 5:47 am    Post subject: Reply with quote

cyl #4 intake valve

https://drive.google.com/open?id=0ByTuHJqlPZ_gSWFKckJFZkNsTHM

valve guide also tore up.
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Mr One World
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Age: 51
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Posts: 19781
Location: Ashland, Ohio

2001 Dodge Neon ES

Post: #8   PostPosted: Thu Aug 11, 2016 12:35 pm    Post subject: Reply with quote

Ouch.

I have no explanation how it could run symptom free for 20 minutes with a bent valve. Shocked

The valve guides can be replaced, just be sure to take it to a knowledgeable shop, because the head can be destroyed if they are incorrectly pressed in.

If the remaining valves/seats/guides are good, you can probably get the head fixed for $50 to $60.

But might want to spend to have all the valve seals replaced. I would think it shouldn't be too bad to just change the seals on the other valves.

But if it needs new guides, and a valve job, sadly a reman head is probably the cheaper route. I paid $275 back in 2007 to have a valve job done on my head. That included new exhaust guides.

I did a mild port job on it, while I had it apart, so that made it a little more worth the cost, but I could have gotten a reman head for less.

The irony is back then, Mancini Racing dealt in 2.0 and 2.4 parts. Shortly after I got it back together, they clearance'd all the 4 cylinder stuff. I got a brand new Magnum head - bare casting for $175.00.
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Malarky
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Age: 42
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2005 Dodge Neon SXT

Post: #9   PostPosted: Fri Aug 12, 2016 7:33 am    Post subject: Reply with quote

Was thinking about this last night....

This time last year, timing belt tensioner seized and belt shredded (while attempting to start). Towed to nearest service station, replaced water pump, seals, belt and new tensioner. Wondering if that was a contributing factor.

P0129 started several weeks after seafoaming (first time using aerosol type). Nearest cyl to intake - #4.

No evidence of damage to other valves.
No evidence of piston head to valve head impact.

Ah well. Rebuilt head on the way.
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Mr One World
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Age: 51
Joined: 03 May 2007
Posts: 19781
Location: Ashland, Ohio

2001 Dodge Neon ES

Post: #10   PostPosted: Fri Aug 12, 2016 8:46 am    Post subject: Reply with quote

If it was an exhaust valve, I can almost see there being enough carbon build up to seal it until the seafoam dissolved the build up.

But an intake always has fuel hitting it to keep it a lot cleaner. Being these don't have EGR to gunk up the intake, it makes it even more rare.

My exhaust valves had so much carbon build up that I couldn't get the cylinders to hold compressed air to remove the valve keepers. But it ran fine. Had i not tried to swap the springs to the Magnum ones with the head on the engine, I would have not had a clue they were that bad.

But either way, you found the problem.
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2001 neon ES MTX with '02 R/T PCM
1999 neon 2.4 EDZ MTX
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Malarky
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Age: 42
Joined: 05 Feb 2013
Posts: 28


2005 Dodge Neon SXT

Post: #11   PostPosted: Fri Aug 12, 2016 2:10 pm    Post subject: Reply with quote

Well, mechanic brother, who took ownership of it before it died (but not before P0129 issues first arose) Smile discovered it. We only get the chance to text rather briefly. Latest he said;

seafoam = snake oil.
reman head with bolts, gaskets and all new belts around $800.


anyway, his problem now. I'd really like to have a NTSB / NASA type investigation as to the cause of the bent valve and why the piston didn't impact it but experience earned and information learned so some good can be taken away.

thanks Bill for all the info (and time) !
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