My neon
2003 Dodge Neon SE 2L 4 Cyl engine.

I was getting a p0301 code intermittently, like twice a month then today all hell broke loose. The car started running rough and throwing p0301 like crazy and got this sound, not sure what's wrong. It's got 150k miles, compression test shows 150psi on cyl 1 & 4 and 170psi on cyl 2 & 3, sparkplug was black on cyl one, but clean on 2-4. Replaced spark plugs, and got strong sparks from wires although 2 and 4 seem to be sparking twice as fast than 1 & 3.
I cleared the engine code and it has not thrown another engine code but I got this bull**** sound and the engine runs more rough than it did before.

When you rev high, it backfires a bit.
It sounds like blowback through the intake.

Not sure what's wrong.

Any ideas?

 

Well since this forum sucks and I got my answers elsewhere, I figure I'll update this so that anyone else has a similar situation may have some confidence in confirming their problem by my post.

It's a rod bearing, specifically the rod bearing on cylinder 3, although I may have caught it in time before it ate the babbit. It has too much play from side to side and up and down, other bearings have minor play and it's time to change them.

Also cylinder 1 has a bad piston ring, new sparkplug was fouled after 3 hours of troubleshooting, even though it has compression, it's a dead cylinder since removing plug wire saw no change in engine performance while the other three saw a degradation in performance.


I'm going to rebuild the engine, parts are cheap, and the car is not too difficult to work on.

 

lol. People aren't getting paid to sit here on this site and give answers; it's 110% volunteer. Most of us (like yourself I'd imagine) have jobs that we have to go to in order to have money to pay the internet bill and answer questions like yours

Regardless, glad you figured it out. Sucks about the engine, but at least you know.

 

Yeah I know, just in a bad mood. I'm sorry.

But I did find the source of the shavings, which cause the rod knock, and my dead cylinder, which would be #1.

The roller bearing for the exhaust rocker arm on cylinder one seized up and started grinding down the cam lobe, and now it's the grand canyon.

Photo below!

 

Mad,
Good job that you followed up and posted your findings even though your irritated. IMO this can potentially help others with similar engine noise in the future.

 

pretty clean in there too hard first rocker bearing I've ever seen do that, thanks for your findings

 

Yeah no problem, I figured if I had this problem, someone else will.

I think this problem could have been avoided if I didn't use FRAM Oil Filters. I found out at the beginning of year from one of my buddies How ****ty they were and switch to purolator. The crappy anti-drain back valve found in most FRAM oil filters could cause this kind of damage during a cold start leaving the bearings high and dry in the top end.

From what I've gather, the rocker bearing had been seized for awhile up til Sunday it was fine. Then Sunday rolled around and the pressed-in pin snapped in the rocker/bearing which in turn caused the engine knock.

Because the firing order is 1-3-4-2 and it sounded like a rod bearing knock every time cylinder 3 fired, but in reality, it was the exhaust rocker arm on cyl 1 snapping back to it's resting place when the cam lobe rolled over, and the valves slapping shut echoing out through the block.

I thought the rod bearings were bad at first, I went back and inspect them again then compared it to the other rods for play and it seemed to be comparable to normal wear and tear. But the weather has sucked here and I haven't had time to break the engine down further. I will have to check the crank journals and rod big ends for damage then plastigauge it. I'm hoping I was lucky and they didn't take any damage and I can just put new bearings in.

A new rod with piston from Factorychryslerparts.com is $234 and no one makes the stock rod as an aftermarket item that can be purchased by consumers. Although there is a lot of aftermarket racing rods, but I feel those might be too light (weight wise) for the crank and throwing it's balance off.

http://www.factorychryslerparts.com/...8067340AA.html

 

If your getting in deep $$ wise might think of just doing a re-manufactured short block or used motor swap at the junk yard thats got one under 70k, if you wanna keep the car just my 0.02 when I was about to add a re-engine kit.

those fram filters are something else though, I stopped using them 20 years ago when stories were popping up about them being junk, surprised they are still made the same but maybe because alot of older farm engines the filter is run parallel