Weird missfire won't go away - DodgeIntrepid.Net Forums - Dodge Intrepid, Concorde, 300m and Eagle Vision chat

BustedinBellevue · 07-06-2012, 07:37 PM

Last week I drove to work and all was good...after work, put in the key and just got a hard CLICK and all the instruments went down. Key off. Key on. dash is back up so hit the starter and again, just a hard click then nothing. Got a jump and she started right up so I figured just a bad battery. When I went to drive home it started missing and shaking - especially above 2700rpm then everything started "flickering"... warning lights... everything. I pulled over (on the freeway) and had a rough idle but oil and temp were ok. Did the key-on, off, on, off, on trick to get my codes and there were a bunch!
Drove her on home but it was BAD! Some of the codes were 0303, 0353 and some others but the very last one was low voltage.

Replaced the battery at home and discovered that the brass neg cable end had coroded through and it had been intermittantly making and breaking connection while I was driving home! That explained the flickering. So I repaired the cable and replaced the battery and took it on the road to the parts store to turn in my battery core and clear the codes. It ran better, but still had a solid miss and the 0353 code for coil #3. I have always been so happy with this car and now it runs like crap.

I swapped coil 3 with 6 and the code still says 0353. I replaced the plugs.. no joy. This weekend I am going to check for voltage supply and trigger at the coil plug and probably buy a Haynes or Chilton.

Any ideas?

**Ronbo** · 07-06-2012, 07:40 PM

Check your connections and clean them. Particularly the battery posts directly and the Positive and Negative jump posts.

BustedinBellevue · 07-06-2012, 08:14 PM

Thanks man, thats good advice. The first thing I checked. I replaced the end of the negative cable when I did the battery. I'll probably replace the whole cable with OEM if nothing else pans out in the mean-time. I am worried that it could be a wire thats chafed somewhere from when it was doing the herky-jerky on my way home. I'm confident that it's electrical or PCM but I'll probably check the compression in that hole anyway.

**peva** · 07-06-2012, 09:03 PM

Most experienced people will agree when I say "Do not buy any aftermarket manual!". FSM *only* is the way to go.

**Adpros** · 07-06-2012, 09:15 PM

Quote:

Originally Posted by peva

Most experienced people will agree when I say "Do not buy any aftermarket manual!". FSM *only* is the way to go.

I agree with you Bill!

He's got about 50% of this P0353 done already though. Since swapping the coil to another hole and the fault still shows active for cylinder #3, I'd be looking at a failed driver circuit in the PCM. Possibly brought on due to abnormal spikes from the crap battery.

To me, it looks like the trip home killed that driver circuit.

Here's hoping he finds a chafed wire.

BustedinBellevue · 07-06-2012, 09:54 PM

Dang! I have been afraid to admit I was even thinking of that! I'll test the coil circuits at the harness plug tomorrow. If that shows good on the 12V and no trigger would that sort of nail it down? Can the dealer test the PCM definitively?

**Adpros** · 07-07-2012, 12:38 PM

Quote:

Originally Posted by BustedinBellevue

Dang! I have been afraid to admit I was even thinking of that! I'll test the coil circuits at the harness plug tomorrow. If that shows good on the 12V and no trigger would that sort of nail it down? Can the dealer test the PCM definitively?

They can. But so can you. Do you have a noid light? I was recently at a local Harbor Freight store and saw they have a small kit. In fact, I can't seem to ever get out of that place without spending $50 or a hundred bucks.

BustedinBellevue · 07-07-2012, 12:54 PM

I hadn't thought of them. I have a gift card for HF that my wife got me when I turned 54 that's been burning a hole in my wallet. My wife said that I always come away with at least 3 things that I wasn't actually looking for.

There is an outfit that sells on Amazon called PCM Experts and they have one for $245 is this the sort of thing you can get online? It looks like they program the VIN and Mileage and then you have to do some other programming after you install. I might go work on my 59 Apache for a techno-break.

**Adpros** · 07-07-2012, 01:32 PM

I haven't had a chance to deal with an aftermarket PCM yet. Some of the other members might chime in here and give suggestions.

I did see one or two on ebay that will repair the one you have. If it does turn out to be a PCM that might be an option. I've seen replacement PCM's fix one issue but start a whole new problem.

BustedinBellevue · 07-08-2012, 07:46 PM

OK. Got my noid light. Not what its called but it connects to both pos and neg and the led shows green with the probe point on ground and red when it gets pos.

Anyway, this afternoon the P0303 code is back along with P0353. I read green for ground at all wires for all coils with the key on but not running. When started and running I get a solid red on the top green wire at each coil connector and the yellow bottom wire gave me a flickering red on all cylinders except 3 (it's solid red). I haven't exposed all of the harness but I have followed the wire and traced them back to the PCM and didn't see any evidence of damage or distress. It's looking more like PCM.

There's an outfit on ebay called autocomputerexchange-ace with one for $99.99 (flashed and free shipping). Every other place seems to be $275 and up for reman. They've got 99.9% positive with 11,000+ sales. For that price I think I'll chance it.

My '59 and my Caravan don't have A/C...

**Adpros** · 07-08-2012, 08:16 PM

Looks like you might be right...

If you have traced the Tan/Orange wire back to the PCM plug with no evidence of a break or open then I'd agree the PCM is not driving that circuit.

Any chance you can track it back to the PCM? and be 100% sure about a possible open?

BustedinBellevue · 07-08-2012, 10:17 PM

It seems like I see continuity to ground through the PCM at the power-on/not running test I did at first. I cant garanty that there are no Flaws in the circuit without pulling the harness... but there is no appearance of a break. Just can't be 100% so there is a little risk...

**Adpros** · 07-08-2012, 10:26 PM

I also found a picture of a C2 plug at the PCM for you:

You should be able to use this as a guide to find the direct end of the wire at C2, (Which is the second plug from the left at the PCM)

If you have good continuity from end to end, (Connector C2 pin #7) and Coil #3, and, the wire does not show continuity to chassis ground, then I'd go ahead and order the PCM.

BustedinBellevue · 07-09-2012, 01:24 AM

Good call. Thanks for the graphic. I do have good continuity and no ground. My brother has my volt/ohmmeter so I can't read resistance, but I am going to order the unit tomorrow.

**Adpros** · 07-09-2012, 09:50 AM

Something I just thought about while checking back this morning...

You mentioned the Tan/ Orange side had 12+ steady. I assumed this was due to the voltage passing through the coil and being picked up while plugged in.

If you happen to think about it, check to see if there is still 12+ with the coil unplugged and check a few others as well. I just had a nagging feeling the Tan/ Orange might just be shorted to voltage instead of a ground.