Im on my iphone at work trying to figure this one out. Have 2000 dodge Dakota with v6. Keeps melting cat converts. Runs fine then all of a sudden it runs like crap. Sputtering, no power then it will come out of it. And do it again. Some times it will not start, let it sit and it will usually fire up.
Truck had tune up and no change. Scanned and all systems are normal.
Why is it getting so hot that it is melting the internals of converter.
Timing, bad ECM, ??
Sorry for bad typing and short desc of problem. Hate typing a novel on iPhone.

 

it would be hard to guess but it has something to do with over-fueling, misfires etc... its the convertors job to clean emissions ie unburnt fuel but too much fuel=excessive heat generated. i see alot of simple misfire cars ran long enough they toast the convertors. do you have a ck eng light on, misfires codes, lean/rich o2 codes, black smoke from tailpipe??? could be a ignition/spark concern, fuel pressure/injector concern. pcm/wiring issue.

 

X2 on the over fueling. Could be a lot of things...

Not to start going off on a long list of things, but I would check for the cheap, simple stuff first... blown fuses, vacuum hoses disconnected from the Throttle body, bad coil (if it has coils, bad distributor if it has one of them), but I'd try to get it to autozone and see if it throws any codes...

 

Is the MIL on? Reason I ask is that any condition that would melt a cat would more than likely also set the ck eng light (i.e., fuel trim too high, missfire etc).

 

Either it is overfueling or the engine is missing. (check your o2 sensor)
BTW. . . .A miss would cause it to overfuel due to 02 sensor reaction to extra oxygen in the exaust.

 

It did have codes. Dont have numbers right, now, but I belive they were:
Alternator overcharging
Misfire in cyl 1, 2,5
Random Multiple Misfires
Emissions Catalyst ?? Something Something.

It is strange, because it is sporadic/random.

The misfire codes have gone away. Others are still there.

We've done full service(fluids/filters), Checked fuel pressure/output,
New Distributor pickup, cap, rotor, plugs, wires, coil.
2 cat converters, both melted.
Scanned several times, all parameters are within spec.
Plus it has heater core leak and getting to it is probably harder to get to than on our fullsize rams.
Shop manager says it is time for this truck to go. has 130,XXX miles.
Needs tires, drivers seat repair, etc.

What about Idle air control? EGR?

I'll maybe check the 02 sensors, but we dont want to sink any more $$$ in to this thing, unless its guaranteed to fix it.
Thanks

 

iac or egr wont cause it, dont know how much monet you wnt to spend but whatever its takes to fix truck, looks like you will probably need another cat conv. if intermittant that can be harder to find. i could still be ignition misfires, or injector/circuits problems. injectors ecm etc...

 

Wow, I'd be looking at the over charging issue, or a bad ground. Could cause an ecm to go nuts, causing misfire. If you had over fueling or a bad o2 sensor, you would get a code for it.
Ted

 

Pull the distributor and look for a worn drive gear.

 

For work i drive a Chev. Express van and when i go up any good grade of a hill on the freeway the CEL comes on and flashes. So i asked our service tech (former GM service tech.) and he told me that the flashing CEL means a CATalist harming misfire.

I would say, if you can get away with it put in a "delete pipe" and put it back in for safety and emissions testing.

As for you heater core, if it's anything like the full size trucks heres a link for a quick way to change it. https://www.dieseltruckresource.com/...st+heater+core

just my .02