V-10 Excursion missing; no code or pending code

[jspringator]

My 2001 X V-10 is missing (stuttering) at 1,500 RPM (or below) under load. Not setting a code or pending code. I have replaced 2 coilpacks and plugs in the last month, so I know about coils. It always sets pending codes. I do have a 5 star tuner set in 87 economy.

I'm thinking a heavy dose of Seafoam.

Any other ideas?

[jspringator]

Mine was originally sold in the Tampa area, but I don't know what it has on it. It does set pending codes that will indicate what cylinder is misfiring. It may take a bunch of misfires to set the pending code. I've been intentionally getting it to misfire to see if it will set a pending code.

[carringb]

Yeah, many or most V10s did not have the typical OBD2 emissions package (they are all OBD2 reader compatible though) since they are all over 8500 pounds.

Mine came with the Low Emissions Vehicle package, so it came with everything including EGR and does monitor cylinder contribution.

[BurbMan]

You guys know the V10 way better than I do, just seems logical to me that if a condition is noticeable to the driver, i.e. is creating a driveability issue, then it should be noticeable to the PCM, i.e. as evidenced by a code of some sort. I know, logic doesn't win the day in trying to figure out how vehicles are engineered....

Dodge Guy that is unusual to have OBD I software in an 02...much less no O2 sensors or EGR...any idea what market your truck was intended for? Had to be outside the US somewhere...

[dodge_guy]

And like I said earlier, some excursions do not monitor misfires. It all depends on the way the PCM is programmed which is dependent on what market the Excursion is destined for. My X doesn't have downstream O2's, monitor misfires or have an EGR system. It has a GVWR of 8900lbs, which is why in IL it doesn't have these things. Other states have there own requirements for emissions. Mine runs OBD1 software in the PCM.

[carringb]

BurbMan wrote:

carringb wrote:
A weak coil won't set codes until it completely fails.

That makes sense that the coil won't set a code as long as the PCM detects that it is firing, but if it's weak enough to cause a noticeable driveability issue you would think that the PCM would use its other resources like the O2 sensors to detect incomplete combustion or call it a misfire even if it doesn't know which cylinder..

O2 sensors only measure the air/fuel ratio, and not how complete combustion is, at least not directly. The closest it can get is a "slow response" or "slow switching" code, but that can be triggered by other problems unrelated to the ignition system. In reality, a single misfire will just result in more oxygen present in the exhaust (since it isn't combining with fuel), so it simply adds more fuel to the entire bank.

What the PCM is really looking for is a change in crankshaft velocity. The reason the V10 can't pick up misfires as easy is because there's more cylinders firing per revolution, so the change in crankshaft speed isn't as apparent as smaller V-motors. Its basically less sensitive to a misfire.

[BurbMan]

carringb wrote:
A weak coil won't set codes until it completely fails.

That makes sense that the coil won't set a code as long as the PCM detects that it is firing, but if it's weak enough to cause a noticeable driveability issue you would think that the PCM would use its other resources like the O2 sensors to detect incomplete combustion or call it a misfire even if it doesn't know which cylinder..

[roverdover]

Others have mentioned a fuel problem. I don't know how the V10 compares to the old straight 6, but had one that was doing the same thing. After several visits to different shops, finally had one suggest carbon build up. The owner suggested putting in on a machine to burn a cleaner through the engine. He did not think it would work and would probably have to pull the head. But half way through the treatment we were standing by the truck when the engine sound noticeably changed. No more low rpm miss.
I don't know what the machine is called or what is uses. But the problem was definitely fuel related.

[jspringator]

carringb wrote:
A weak coil won't set codes until it completely fails.

That is where I am.

I only live a mile from work, so That would probably do more harm than good. I will figure out a way to drive it every weekend. I like to use it to pick up my daughter from school because she has so much stuff, but looks like I should stop that. I have been using it to tailgate football games. It is a very useful vehicle to have around, but the maintenance has been brutal.

[jspringator]

From my house to my boat storage unit in Jamestown, KY I got 17 MPG. I was so excited I took a picture of the display (it is spot on accurate) and posted it on Facebook! I didn't go over 50 and didn't stop. The tuner set on economy helps the mileage on the highway.

[BurbMan]

Interesting....maybe having 10 cylinders instead of 8 makes a misfire less noticeable on one.

carringb wrote:
And here's what I noticed.... It doesn't matter if a drive like a grandma, or I drive like I just robbed a bank. Gas mileage is just as bad either way

You got that right....new plugs, wires, cleaned/rebuilt fuel injectors, new filters, new fuel pumps, and to top it off a new transmission....and still 10 MPG :E

[carringb]

jspringator wrote:
I'm a member over there. I'll post up a query. I drive it short distances 2 times a week and on towing vacations twice a year. I may drive to the lake 100 miles away 4 times a year.

That'll do it! The V10 is a BIG motor that needs to work to fully warm up. Try getting on it a couple times a month. The extra fuel for a couple extra (hard) Sunday drives will reduce headaches like your coil problems, and will clear the carbon out of the intake, and cook the moisture out of the engine and transmission oils.

Without getting the engine HOT, condensation builds up in the spark plug wells causing a short which damages the coils.


And here's what I noticed.... It doesn't matter if a drive like a grandma, or I drive like I just robbed a bank. Gas mileage is just as bad either way;)

[carringb]

BurbMan wrote:
jspringator, you mention the shudder is at 1500 rpm and below, so assume it smooths out at higher RPM? If so that wouldn't indicate an ignition problem....as supported by lack of codes...if one or more plugs wasn't firing the miss would be more noticeable at higher RPM.

My experience matches his. The V10 is a smooth running engine, and a miss is most noticeable at low RPMs. When my coil failed it really was only noticeable in OD below 50 MPH. But mine did set a code. A weak coil won't set codes until it completely fails. Had that problem on a 2000 Jaguar S-type (same 3.0 V6 used in other Fords). One or more were weak. Codes said "Multiple Random Misfires" so I changed the plugs. That cleared the codes, but it still had a slight miss at lower RPMs, mainly under load such as climbing a freeway grade (6.5% in Portland). Ended up just changing all of them because half the motor is buried under the intake.

[jspringator]

I'm a member over there. I'll post up a query. I drive it short distances 2 times a week and on towing vacations twice a year. I may drive to the lake 100 miles away 4 times a year.

[BurbMan]

jspringator, you mention the shudder is at 1500 rpm and below, so assume it smooths out at higher RPM? If so that wouldn't indicate an ignition problem....as supported by lack of codes...if one or more plugs wasn't firing the miss would be more noticeable at higher RPM.

Sounds like you are inclined to assume spark issues given your COP problems...but I would be more inclined to look at fuel/air for a roughness at low rpms.

Have you ever taken out the MAF and cleaned it? Air filter? Fuel filter? Fuel injectors? I did a MAF and throttle body cleaning and also pulled the injectors and sent them out to be cleaned, made a huge difference in idle smoothness.

[artguys]

jspringator...as 2 previous posters gave you links to Ford Truck Enthusiasts, go to the site...they have sub-forums, one for your engine(V10). Not that well visited these days but you can get responses from on of the others...so join and ask the question. You'll find qualified help.