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So, what are the best type of plugs for a Chrysler 5.2L V8 Magnum engine? (It was used in Ram trucks like mine as well as Grand Cherokees, Vans, Dakotas and Durangos) It has either Autolites or Champion copper plugs stock and I’ve been recommended NGK Irridium for the best performance, others have told me to get Bosch, but are either of these worth the price? Others still have told me that the stock coil isn’t powerful enough for the irridium plugs to really make a difference. If a cheap set will do just as well, I’d like to save the money of course. As far as I can tell, these engines don’t respond poorly to non-OEM plugs like a Honda would, so does it even matter?
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motor mounts usually cause an engine shift when dropped into drive or reverse. open the hood and see if it moves excessively when switching between drive and reverse. or if its a stick it will do it when letting out the clutch in 1st or reverse
I’ll try it and report back.
Aside from that, I meant to include this in my last post but at idle, outside it sounds OK next to the engine but at the exhaust, it sounds like there’s a miss.
At 260k you could have low compression in one or more cylinders. I would do a compression test to rule out internal problems.
I’ll still check compression when I get a tester, but for the moment, a new air filter and some carb cleaner sprayed into the TB have cured my issues. The throttle plates were black and the filter was getting there too. (both from when the intake was full of oil) It idles smooth now and it’s significantly quieter than before. I guess it happened so slowly I didn’t notice, but this engine was running very loudly (considering it’s stock exhaust).
I dabble in both performance (11 second GSX) and I am a Subaru technician. I know from experience, OEM plugs work best, whatever your car used from factory, use. You may have to step up to a colder plug, but stick with the brand and type. My car came factory with NGK copper plugs, I run NGK copper plugs, just 1 step colder (considering 2 steps colder).
There have been cases where we have pulled out some ritzy expensive plugs from cars with drivability issues and replaced with factory and fixed the issue just like that.
The only reason I didn’t use the factory plugs is because I’ve heard plenty of people say you can do better, especially for a super high mileage engine like this one. But, I’m almost to the point of putting OEM Champions in it because:
It runs perfectly when it’s cold, hence my previous post. When it gets hot, it all comes back. In park, you can hear a knocking sound and feel it in the steering wheel. In drive, it doesn’t make a sound but it shakes intermittently. And, when idling in reverse, it doesn’t shake or make noises but the idle falls from 600 to 4-500 and you can hear that it’s missing when that happens. It doesn’t stall, but it acts like it’s going to. Under acceleration of any amount and when cruising, its all much better than before.
I’m so confused.
It seems reasonable to reach for OEM plugs, though I find a lot of that debate is biased by advertising, witchcraft, and instinct rather than anything more scientific. Note that many plug manufacturers don’t advise antiseize any more, over concern about the risk of over-torquing.
On a more concerning note, what I’m hearing sounds like an unrelated problem. You describe it as running perfect when cold, then worse after it warms up. That sounds like a problem when the engine goes into closed loop. Black plugs suggest rich combustion, and you nicely describe what may be a misfire, improved with acceleration. Your attempt to fix this with an electrical tuneup has failed, so I would go further with diagnostics. I would put a scanner on the vehicle and look for clues in fuel trim balance, and look for codes. For example a vacuum leak could be detected by the computer, which might respond by increasing fuel, leading to fouling plugs. It may be that your engine is just wearing out, but I would look for things that might lead to an easy fix.
I was going to get a live scanner with my next check anyway. This is just even more reason to. I wish the knocking was loud enough for a video to pick up or I’d post one so you can hear exactly what it does.
My old plugs were either all black and carboned up or encrusted with white and on some of them, the electrode was beginning to burn through. Remember that not only were the plugs likely almost 80,000 miles overdue for replacement, they were subjected to at least 20,000 miles of large amounts of oil burning.
I do not get a CEL except under extremely hard acceleration, and even then it only flashes for a few seconds when I hit 4.5k on the tach. There are no codes. Strangely after every “fix”, it ran perfectly for a few days before something else happened. When the plenum was repaired, it was fine for a week or so and then it began to misfire which led to me changing the wires, cap and rotor. Since then it’s been running great, until a week ago when it started misfiring again. This time, the fix just didn’t work. At least it didn’t work completely. I was getting flashing CELs going up most large hills and that’s gone. (for now)
Today, when COLD it decided to almost stall out at a red light. Idle dropped to about 400 every few seconds. I cycled it into park and back to drive and it stopped.
So just for grins I decided to check the transmission fluid. It’s fine, but what’s weird is when I put it in neutral (Chrysler recommends you check it in neutral w/ brake on as opposed to park), I hear a strange humming sound. (doesn’t do it in park, it makes a knocking sound then) And more interestingly, when I leaned on the vehicle it creaks very loudly. I turned off the engine, and… it didn’t do it anymore. Didn’t do it at all in any other gear other than neutral and only with the engine running. The engine itself appears solid, it doesn’t move or shake visibly by itself in any gear at any RPM. But now I suspect the transmission may be loose. Is this a reasonable conclusion?
Personally, I’m in the camp of using what came in there from the factory. You really can’t go wrong with that.
you need to find a set of pliers that will fit into the area, then pry against the engine or stick a piece of wood in there to pry against. dont pull on the wire, pull on the boot.
I just picked up 8 Bosch Platinum Plus 4002 plugs for my Neons today. Ordered them off of eBay for $3.61 each. There’s a $3.00 / plug rebate so end cost will be 0.61 / plug plus 0.40 for postage Copy of rebate form below.
[quote=”LJ11194″ post=45885]Today, when COLD it decided to almost stall out at a red light. Idle dropped to about 400 every few seconds. I cycled it into park and back to drive and it stopped.
So just for grins I decided to check the transmission fluid. It’s fine, but what’s weird is when I put it in neutral (Chrysler recommends you check it in neutral w/ brake on as opposed to park), I hear a strange humming sound. (doesn’t do it in park, it makes a knocking sound then) And more interestingly, when I leaned on the vehicle it creaks very loudly. I turned off the engine, and… it didn’t do it anymore. Didn’t do it at all in any other gear other than neutral and only with the engine running. The engine itself appears solid, it doesn’t move or shake visibly by itself in any gear at any RPM. But now I suspect the transmission may be loose. Is this a reasonable conclusion?[/quote]
Hi. Glad to hear you’re making progress.
OK for the loud creak I’d check suspension bushings and shocks.
For the trans sounds, is there anyway you can record and post them? That would help a bunch.
It sounds as if you’ve done the common items for ignition misses. Let’s do a compression check and vacuum test next. Also if you can get short and long term fuel trims that will give more evidence to look at.Really sounds as if we’re looking at multiple problems, so lets take them ‘one bite at a time’.
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