Hey guys, finally we got around to fixing the old rango. We got plugs, wires, and cap and rotor. For the plugs we got NGK G-Power plats. The other parts are all Durablast lol, yeah cheap stuff but hey it works. The old cap and rotor looked bad, all the points inside the cap were pretty much toasted. Now all the new parts on, it feels like a different vehicle.
My dad also advanced the timing by quite a bit, because it was running retarded. it sounds, runs, and feels completely different. No pings. And under WOT, it pulls smoother, stronger, and sounds a lot stronger.
But a problem still remains. On cold starts it begins to idle rough about a minute of running. And down the road if i dont let it warm up, it hesitates. Like it used to. Warmed up, it is completely fine. Could it be an O2 sensor?

 

If i give it a little rev in park when it idles rough, it will idle fine after that. And if it hesitates down the road, it will correct itself after a few seconds

 

First those plats are way to hot of a plug, these engines love a little cooler plug like the oem champions, this could be your problem. That hot of a plug will after a while start to burn the piston and start digging a hole through it. If not then the IAC could be the culprit, have you cleaned the TB correctly lately? Glad to hear that you got it mostly figured out.

 

Yes the throttle body is clean as a whistle. Never knew the platinums wernt good for these engines. I guess because they're low comp engines..well my dad got platinums because he's lazy and doesnt feel like replacing copper plugs every 10,000 miles. ah well.
The durango could really benefit from a 5.9 mod lol

 

yea plats are not good for these trucks

btw copper plugs are 30k mile parts, NOT 10k miles, if you change them every 10k you probably have more $$ than brains.

 

or replace the copper with Iridium champion plugs. 5.9 runs great on Iridium. More expensive, but good for 100k miles.

 

haha funny guy.
make a better joke, it didnt impress me

 

"you change them every 10k you probably have more $$ than brains."

NOT very helpful.

 

Well I see a few issues,

Pull those POS platnum plugs and go get some regular Champion Copper plugs, gap at .040 and install. The wires aren't my favorite but what ever.

Your dad did NOT advance the timing as it is controled by the PCM, it's impossible unless modified somehow through the PCM. The only way to do an adjustment is called "indexing" the distributor and that is only done on the 5.2L and 5.9L motor. You index the distributor to run square at around 6 degrees before TDC on #1, and that is the only thing you can do, however if you set it right you will get the best response and fuel econ. The only way to truly set the distributor is with a DRB-II or DRB-III and hook it up and index it, that is the correct way to do it. But as for advancing the distributor and timing by moving the distributor, well that's a thing of the past. Second, if you do advance in old engines you only advance enough to take the worn slack out of the bearings, and this is only about 1-3 degrees. For that matter, how do you know if it was running retarded, because of a timing light when you trun the distributor the PCM will only compensate.

Take your TB off and clean it out real good including the IAC and IAC port and put a new gasket down. Then reset the PCM, and index the distributor.

 

My dad replaced the cap and rotor 40,000 miles ago and he said he turned it and thought he advanced it but turned it the wrong way and claims he retarded it. So your saying that turning the distributor does absolutly nothing on these engines?
Also, it came with champion platinum plugs from the factory so isn't that what should go in?
And, we did the parts over 2 days. The first day i put in the spark plugs and my dad turned the distributor to advance the timing..or so we thought. Spark plugs that came out were fine, i just said replace them since we're doing all the other parts. We fired it up and he turned the distributor to advance it. He turned it until the motor shut off. He turned it back a hair and i started it up. It cranked over quick, and ran good so he tightened the srew back up and we took it for a ride. It sounded different, the tone of the engine changed and its ALOT quieter and smoother. And like i said it felt and sounded different under WOT. So, if turning the distributor doesnt do anything, than how did it run so different? It must do something..
Next day we put the wires, cap and rotor on and they really made a difference. The gas guage doesnt seem to move as much, and i notice that its more responsive and under load the motor feels and sounds better.
But does the PCM learn that the distributor was turned and then compensate for that?