Bad plug or coil / 250XS

[Eagle670]

i was out friday and motor feels rough on idle, on plane it feel a litte sluggish ...

but i dont think so much of it , cruising at 4000 rpm and POW !!! rpm get up to 5300 and speed 60 mph.... and i dont have moved the trottle ??? i couldn't stop it was rough sea ... when i check later a plug wire have comes off , and i see some corrision in plug wire.... after i cleaned it upp an remount the wire , it still feels sluggish w/ some vibration so i wonder if the coil broke when i run it w/ spark-cap off ??

[EuropeanAM]

Peter:

That is possible- or the plug is now fouled. Use an inductive timing light to check for spark on each plug wire with the engine running.

Coil failure modes are usually "open" (this is only found by the PCM/ECM if the coil is failed open when the key is turned on, and engine NOT running), or "shorted"- this is usually found propmtly by the ECM/PCM, but can also result in damage to the ECM/PCM).

The catch with the "timing light" is that it has to be "open or shorted" at the time you are checking for spark- we see a few of these coils that are intermittent, and are difficult to "catch in the act".

[Eagle670]

Don !

plug looks ok , light brown in color maby the gap was bigger ? or maby just an illousion... I understand it is no good for wire or plug when it comes loose, the spark have to get somewear

My engine nr is 1E003730

[EuropeanAM]

Any difference in the plug for the "coil that the wire came off of" and the others?

I would go ahead and check for spark with an inductive timing light (or spark tester).

[Eagle670]

Coil side of wire was ok , but inside spark cap it looks litte worn .... ohm resistans 0.782 is't ok ?

i must find somewear to buy sprkplugs at resonble prices..... price in Sweden is INSANE !!!! ( 43 usd one plug )

[EuropeanAM]

There is no "technical spec" for the plug wires.... compare all wires, any one that is "substantially different or suspect" should be replaced.

Being in Sweden, perhaps you should look at E-bay as a plug purchasing option- provided the shipping does not increase the price substantially, you may be able to purchase them there. Just do a search for "IZFR6J"

[Eagle670]

Looks like 3: coil gone bad , plug is wet , i change plug 1 w plug 3 , after change plug 1 was dry and 3 wet , so that show plug is OK ! spark light show no spark on no:3 plug wire ALL plug wire 0.728-0.734 ohm exept no: 2 0.724 ohm

[EuropeanAM]

Did you check for Spark on the #3 wire?

That will be the only way to know for certain- there are other possible causes for a "wet plug".

[JAZII]

Don,
You missed it, he said no spark on #3.
JAZII

[Eagle670]

No spark at nr :3 plugwire i have the light flashing a litte , but stop when i check again ..... i speak w/ my dealer and he belived he have one in stock ...

he said the 150 opti & 250Xs use same coil ?? true ?? if thats correct do they use same plugwire ???

[EuropeanAM]

Same coil. From the readings you provided, you should not need the plug wire...

As far as the same plug wire, that would depend on what "production year" 150 we are talking about. If the plug wire is the same length, it's the same wire.

Here's the part# for the coil without the wire: 339-879984T00

Sound's like you're ready to "slap a coil on it" and be happy!

[Eagle670]

by the way ! shouldn't Smart craft give a warning when a coil goes down ??

[EuropeanAM]

It will, in certain cases:

Shorted coil (primary or driver side)
Open Coil (driver side- it must be "open" when the key is turned on, and engine
is not running). Hence, it does not see a fault for most "intermittent
open coil failures" that occur with the engine running.

Remember, Smartcraft is only reporting what the PCM "sees or knows".

[Bullet20dc]

Put that motor on a DDT and do a spark test. Im betting he has a bad coil driver
Try switching it to a working plug/coil and see if the problem follows the driver.

[EuropeanAM]

Better yet- do an "Auto Self Test" with "plugs out of head".

That way you can see all six cyl's on a spark board at one time....

[Eagle670]

" Murphy " keep kicking my A** i collect a coil yes ! but not for a 250XS so now i have to be an " Angry customer on monday "

[Eagle670]

the " angry " customer gona collect a coil from DHL tomorrow

[EuropeanAM]

You're really having a hard time there, aren't you Peter?

[Eagle670]

The hardest is to be angry , im a nice guy and if my merc man get me a coil from Belgium to sweden in ONE day, it's WEARY hard to be angry He is one of 4 merc high perfomance dealer in Europa , so i rather have a good relation with him

[esdbass]

Peter: Now when are you going to buy a Stroker to put that 250 XS of yours on