I've been having a pinging sound under load for a very long time. I've also been burning quite a bit of oil. I changed the spark plugs about a year ago, and it ran like new, up until recently. I decided I would do the fix by getting the Hughes Engines plenum plate and intake manifold rebuilt kit. When I took the manifold off, there was lots of black crusty build up. I assume that is carbon build up? I clean what I could, and put everything back together, with the new parts ... and it runs the exact same! I'm thinking of checking the spark plugs again, maybe they are fouled? It has 350,000 miles so it's had a good life. I intend to just keep driving it as-is, but I was hoping to restore some of it's life. Maybe I should stick with 93 octane, because it does run better.

 

Normal build up. More frequent oil changes may reduce the build up.... but, with that many miles on it, I think it looks pretty good.

A compression, or leakdown test would give you a better idea of the condition of the motor...... With that many miles on it, I would also expect that the timing chain is pretty stretched out. On my 96, with just under 200K miles on it, a new timing chain made a MAJOR difference in how the engine run.... Smoother, more power, and gas mileage actually went up a point or two.....

 

I change the oil every 3,000 miles with 10w30, and at this point, I have to add 2 quarts before I reach 3,000 miles, and when I drain it, I take out about 2 quarts, so by my estimation I am burning 5 quarts on 3,000 miles. I am starting to just think the engine is old, and it's a fact of life. I don't think the timing chain has ever been done, and with the value of the vehicle being pretty low, I'm not sure how much more money I want to dump into it. Maybe if it's something I can do I will take a chance, but it's definitely not worth paying anyone.

 

Yeah, likely rings, and valve seals are shot...... Timing chain can be done for 150 bucks or so. Question becomes, how much longer do you plan on driving it? No point in putting money into it, if you aren't going to hang on to it for a while. That, and my luck would be, spend the money, then something else that is too expensive to fix breaks.... and it's just done.

 

Just following up, my alternator died this weekend, and I had to replace it. Thought it was weird, considering I had just torn the motor apart. I tested it myself with a multimeter, and also tested it at O'Reilly, and both failed the test. I also put premium gas in it, and it seems to be running really good now. The gentlemen at O'Reilly said it looked to be OEM. I thought I had gone through a few alternators, but maybe I was wrong. It had the little Chrysler emblem on the old alternator, and the new one was slightly different. The ground post was slightly larger, and I had to widen the hole on the ground connector to make it fit. Maybe I had a weak spark from the alternator? or maybe it's the premium gas? Not sure, but I wanted to follow up.

 

If you replaced the alternator you would have to look at or know what what amp the stock one was. Unless you got a larger one but then you would have to change the amp rating of the fuse in the pdc. Denso made the alternators for Chrysler and it will have a part # on it.