Spark plug change

[kellen]

Hi all

I have just changed the plugs on my 98 EX. It had original Motorcrafts in it and whilst they were supposed to have been previously changed by the dealer (I have owned the Ex since near new and it now is at 123K) the condition was not that good and the gaps were (no exageration) over 3mm. I was changing them to help with MPG. I thought I would give the old girl a treat and fit Bosch Iridium plugs. Since the plug change there is a slight lumpiness (only slight) at idle and the idle speed seems to be slightly lower than before. Weirdly the engine seemed smoother before.

I have checked the forum now (normally check first but I though the iridiums would be a superior choice) and see that the boys accross the pond have mixed views on iridium plugs. Has anyone in the UK had a similar experience? Should I have stuck with the original Motocraft/ Autolites?

Cheers

Neil

 

[janolsson]

I like you took out old motorcraft plugs with a massive gap when I got mine. I replaced them with ngk iridium plugs and had no problem.
A couple of things I would suggest you look at;

1) Are the new plugs the correct gap as ford recommend, not bosch recommends. A slightly larger gap would help but you shouldn't really re-gap iridium plugs.

2) maybe during the change you may have damaged one of the HT leads or not connected it on the plug fully. May be worth closing the gap on the old ones and trying them to see if you still get the stumble (oh and the leads are all on the right plugs aren't they???)

If you are running LPG it tends to run better on copper plugs

HTH
Jan

 

[kellen]

Thanks for that. I may try increasing the gaps. However it is such a pig of a job getting them out that i thought about replacing them with original equipment plugs. If gaps are too small would that cause the fluffing or slight lumpiness? Leads are on correct plugs as did one at a time. May change leads anyway.
Cheers
Neil

 

[kellen]

Hi Jan

Thanks for your advice on this. I removed the plugs, increased the gaps, reinstalled them and it now runs perfectly. I guess the gaps were too small on the iridium plugs and not giving a fat enough spark for good combustion.

Cheers

Neil

 

[janolsson]

Hi Jan

Thanks for your advice on this. I removed the plugs, increased the gaps, reinstalled them and it now runs perfectly. I guess the gaps were too small on the iridium plugs and not giving a fat enough spark for good combustion.

Cheers

Neil

Glad to hear that Neil
Without searching I couldn't confirm what the gap should be. I do recall I think I may have had to alter my gap from the supplied 1.1 to 1.3 but that could have been a different car (I've played with a few over the past couple of years and I don't retain info as well as I used to )

 

[ihpj]

I decided to play it safe and went with Motorcraft originals when I replaced my plugs about 18 months ago because I felt I the Ex. was sensitive to non OE brands (and I didn't fancy dong the job again if I got something wrong!). But your post gives me confidence to go with something else if I fancy replacing the plugs again.

Would you have any recent feedback on how you feel the truck is performing?

 

[kellen]

Hi there.

Sorry I did not respond before but I have only just noticed your message.

The Ex is running OK on Iridium plugs but if anything I think it was a little smoother on the original Motorcrafts....not a lot in it mind you.

Cheers

Neil