Hey Rusty93RamVan, Ahab got his White Whale
 

So after battling the P0300, P0301, P0303, & P0305 along with a constantly illuminated CEL light for the past 5+ years the problem is solved. My CEL is now off! :icon_woot:

Very cool Alloro what was the issue and how did you resolve it?

Jason

When I bought the van I went through it before putting it on the road. Included in my 'going through it' was the installation of a new set of spark plug wires, which were Duralast from Autozone. Since they were new I never gave them a second thought. Recently I was reading a post with someone saying how they've had bad luck with Duralast wire sets right out of the box, so this got me thinking.

I did some research and decided to go top shelf and get the ACCEL 9039C Ceramic Spark Plug Wire Set which fits 92-01 3.9L V6 Dodge engines. They're a bit pricey from most places ($150.00 give or take) but I found a new set on eBay for $68.88 with the shipping. I installed them yesterday and decided not to clear the codes just to see what happens. Well when I went to make the 3rd trip today (3rd since changing the wire set) that ever omniscient CEL was off, all on it's own.

Ahoy there, Captain.

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No sh*t? Well, I know a ghost is still lurking within my engine management system somewhere but I will certainly replace my wire set since I too have the Duralast wires.

Congratulations!

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Sounds like it might be a good idea for anyone with Duralast wires to change them.

Jason

I hope changing the wire set solves your misfiring too. I'd be real interested to know if this has been everyone's problem, that have been getting the random misfire codes.

And change out the Duralast cap-n-rotor set for a Wells or other main brand name while you are at it. I'm not impressed with Duralast.

I will certainly report back here with my results. The timing on your discovery is quite good since I'm due for PA safety and emissions inspection by month's end.

I was planning to reset my CEL and then drive for 20 miles under 40 MPH in an attempt to get through inspection.

Maybe now I won't have to.

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That's funny, because that's exactly what I've been doing every year to get through the state inspection.

I'm wondering if you can give me a clarification on two finer points concerning our ignition wires. Most parts suppliers list two different wire sets, one with longer boots on the spark plug end and one with shorter boots.

First clarification - What determines which replacement set to buy for a particular 3.9L engine? Logical thought is that Dodge made different exhaust manifold shields for some reason and you should just "match" the set that came off when purchasing a replacement set of wires.

Second clarification - Which Duralast set did you have on your 3.9L, and were they in fact correct for your application?

BTW, today I reset the CEL and then drove my 20+ miles before emissions inspection. Worked like a charm.

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OK, not poking fun at you directly. Duralast would be my last choice for ignition wires for my van.

If you'll go back and read the entire post you'll see that we already came to that conclusion and that we are both using the ceramic Accel wires now.

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First clarification: I don't know for sure, but I suspect you would need the long ones if you have the metal shields around the spark plugs and the shorter ones if you do not.

Second clarification: It was 5 years ago, even though I've been carrying that part number around in my head, it just slipped out of my mind only yesterday. :p (and yes they were the correct ones.)

So are you saying that replacing the Duralast plug wires with new plug wires fixed your CEL issue too?

Well, yes and no. I still have the rough idle at warmup issue, so that causes the PCM to read cylinder misfires and turns the CEL on.

However, if I warm up the engine and then reset the CEL I can drive for the duration of an entire tank of fuel and the engine never misfires once.

So the Accel wires have the engine running smoothly but I have yet to find the source of my rough idle at warmup.

This happened to me a while back. I had to let the engine warm up before driving it, otherwise it ran like crap and there was a shudder and a misfire. It turned out to be a bad spark plug even though they weren't that old. I was able to find which cylinder it was by watching the misfire count when using my code scanner in the live data monitor mode.

In your case it could also be a bad injector.

Well, I'll have to rule out spark plugs for now. I bought the van with Champions installed, which I hate. I installed Denso 4503 (Platinum TT) plugs immediately and while overall performance improved my startup idle issue remained.

I have yet to replace my coolant temp sensor because it's buried behind the top hose neck, as you know, but I will get to that soon because my alternator bearing is beginning to get noisy and will soon need changing. I can't help thinking this sensor has something to do with my problem.

If I do in fact have a bad injector will it cause the PCM to throw misfire codes for multiple cylinders and not just the cylinder where it's located?

It might not throw a code at all. It takes two consecutive trips to set a misfire trouble code. So if the misfire exists on the first trip but not the second, the 2 trip counter resets to zero again.

Understood. But if the bad injector does cause the PCM to throw a code will it be only for the cylinder associated with that injector, or can different cylinders be affected?

My CEL indicated misfires for multiple cylinders when I read the codes.

Yes the injector code will be per cylinder, assuming you have one injector per cylinder and not throttle body injection.

If you're getting a pending P0300 code, then that could indicate a few things; most notably being a bad wire connection or worn distributor shaft bushings.

I do not think distributor shaft bushings are too expensive. I know its typical for them to cause a misfire problem on the 318 engine. If it was me I would replace them first.

Jason

I'm sure I'll sound stupid but I am new here...
After my CEL came on I replaced plugs(NGK V-Power), wires, cap, and rotor. I bought them all from Carquest. Is it likely to be a problem with another part considering I got the same code (P0305) before and after? Or just an unlucky conicidence and a bad wire set?

Thanks,
Bill

I would say yes.

So alloro you're thinking fuel injection? Cylinder 5 is the third one back on the driver's side right? What's the best way to test it?

Yes
Yes
Swap it with the one next to it to see if the problem follows the injector.

Sounds good. I'm not very experienced with mechanical work though. I'll probably just switch 5 and 7. What exactly would I have to do to swap out the injectors? Is it a good idea to try a bottle of injector cleaner first?

:confused: Ummm, remove them, swap their locations, and then reinstall them.

The benefits of injector cleaner are minimal at best.

I just meant what do I have to dissassemble in order to remove them?
Just unbolt the fuel rails on that particular side?

I would recommend unbolting the fuel rail on both sides, or at the least loosen them and try to lift the one side. If it lifts easily then switch and reinstall. If having trouble then pull the entire fuel rail.

Well, my factory fuel pump went completely belly-up this morning at 98K miles. I will know by Saturday morning whether my "White Whale" has been the fuel pump all along since I still have my CEL even after upgrading to the Accel ignition wires.

I'm trying something new this time -- changing only the fuel pump itself and keeping the OEM plastic carrier housing and sending unit in service. I'll be using The Racer's Edge Model 379 replacement pump.

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