misfire on V10... - Diesel Forum

joestruck · 04-12-2007, 10:55 AM

Tech says intermittent ground from ECM preventing the injector from fueling the cylinders (3 and 5) causing the skip. Only recent repair had a blown plug repaired and needed a new coil pack. That cylinder is firing fine.The Tech says I need a new/used ECM.

Does anyone have a similar experience and what did you do about it?

thanks.

jade97 · 04-12-2007, 11:17 AM

The misfire I experienced was due to a bad COP. Initially it did not throw a code (for about 1.5 months), but finally the COP died completely & thew a code indicating the misfire on cyl 4. I replaced the COP & everything is good.

If there is an intermittent ground, then make sure it's properly grounded...don't just replace the PCM.

joestruck · 04-12-2007, 06:26 PM

Thank you for your reply.

What is a COP? I think I know,but want to be sure I understand you.

Also, I really don't know enough about it but doesn't the PCM provide the ground internally (assuming wires to and from are ok), and in turn this "cycling" fires the injectors ?

It was tested with a "node" ? I think that the device has an LED that blinks when the cylinder is to normally fire the injector. I was told #3 and #4 fire intermittently based on the test.

In turn they are telling me it needs a new 'puter.

We are in no rush , I have another vehicle and we haven't found a used one yet.

Any more thoughts? [img]/ubbthreads/images/graemlins/confused.gif[/img]

Thanks.

jade97 · 04-13-2007, 08:35 AM

COP=Coil On Plug, or as you called it a coil pack.

In my case I used a OBDII code reader that I picked up from EBay for $28. Your local Autozone will read the codes for free. When my misfire was intermittent, no code was stored in the PCM. When the COP finally died, the Check Engine light did not come on, but a code was stored in the PCM and read by my code reader.

Not sure if this helps?

Finding a bad ground in electronics can be difficult (I'm an Electrical Engineer...whoopdie-doo [img]/ubbthreads/images/graemlins/phoney.gif[/img]). By the description you gave of their troubleshooting, well I have my own opinion.....I doubt it is "a bad ground in the PCM".

joestruck · 04-15-2007, 06:32 PM

Someone probably knows for sure, but I believe I was told the ECM grounds internally , and this cannot be repaired,only replaced with a unit that is compatible with the VIN. Assuming all prior diagnostics were correct to this point.

I really don't know enough about it, that's why someone else is fixing it for me naturally. I spent $450 on the plug repair, and then another $250 on 2 more COP's and more diagnostics to find the skip, so I am trying to find out as much as I can .

I'm at the point where I want the "final" repair done .

Thanks again for the info..

jade97 · 04-17-2007, 08:43 AM

I hope it works out for you.

In my opinion, I think that they do not know what the problem is, so they just want to start throwing new parts on your truck until the issues is solved.

joestruck · 04-17-2007, 11:01 PM

Yes, I was skeptical myself, and it's pretty much the reason I originally posted.

Not to belabor this problem, but I have checked with my FORD service advisor, the one who I have used for the past 15 years (when I had new trucks under warranty!), and he agrees with the method used to diagnose the problem. He verified the ECM provides the ground, and that it can't be simply re-flashed and he gave me some more background so that I am comfortable with the other guys diag..

It still SUCKS though!

Thanks.

jade97 · 04-25-2007, 04:00 PM

Please let us know the outcome.

dockrocker · 04-28-2007, 10:41 PM

What does a misfire sound like? I've got a wierd sound/vibration on my 2005 V-10. Almost sounds like a heat shield or other metal component underneath is vibrating. Very intermittent, and only when the truck is rolling (i.e. it is under some degree of load). No codes, and the monkeys at the stealership are content to keep replacing exhaust components. Wondering if this is what I'm seeing.

budman451 · 04-28-2007, 11:08 PM

[ QUOTE ]
What does a misfire sound like? I've got a wierd sound/vibration on my 2005 V-10. Almost sounds like a heat shield or other metal component underneath is vibrating. Very intermittent, and only when the truck is rolling (i.e. it is under some degree of load). No codes, and the monkeys at the stealership are content to keep replacing exhaust components. Wondering if this is what I'm seeing.

[/ QUOTE ]

I recall seeing a TSB that pertained to the issue you are having. IIRC, it directed us to replace the front exhaust pipe with a revised part. I no longer have OASIS access, so I can't look up TSB's to look up specifics, but there may be another tech here who can look it up, or may have a little better memory than what mine is tonight.

Buddy

dockrocker · 04-30-2007, 11:39 PM

Thanks - the dealer has replaced the muffler with no effect. It does sound like it's coming from about where the exhaust pipe would start - almost around the tranny hump. I'll get it in this week and see if they can (not) find the problem, again....

todlake · 05-01-2007, 11:32 AM

On my 99, the sound you are describing was made by the heat shield at the base of the down pipe. One of the welds broke. I used a pipe clamp to put it back on and the sound went away.

Robb

dockrocker · 05-01-2007, 11:46 PM

That's what I believe it is as well, a heat shield. Unfortunately, my local dealer is more of the "replace and pray" school of diagnosis, so I have to help him along....

jade97 · 06-05-2007, 01:23 PM

joestruck,

Did you get your truck straightened out?