Just changed the plugs in my Mondeo (2000W), and want to check the HT leads are ok as the car has now covered 103k miles. Is it possible to do this by measuring their resistance with a common multi-meter? If so, what value should a lead not exceed if it is in good condition?
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Do you have any concerns as to their serviceabilty? Misfires/poor starting etc?
If nothing is evident, I'd leave them well alone. But if they are the original leads, they've done well - I'd suggest a change before the (damp) winter.
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The only way to check the leads it to put several thousand volts down them as the coil does. Garages have expensive kit to test them. The best way for a home check is
1/ look at the state of the plug noses when you take them out
2/ wait till dark, start the engine, lift the bonnet and give the leads a slight spray with a fine plant mister. Any fireworks or sparks visble then the leads are breaking down.
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The car is an ex lease car i bought at 100k miles from auction. I recently removed the plugs to check their condition and found they were knackered. The ground elctrode had eroded to an extent that it had become triangular in cross-section, and was almost completely worn through on one side. I have no idea how long they had been in their- could they be the original plugs!?. I suspect the leads are original. Yet the car starts easily first time every time. I investigated the plugs as i noticed the engine "missing" very slightly on cold damp mornings, and the engine was a bit "lurchy" when comming on and off the throttle at low engine speed in traffic.
When i fitted the new plugs i noticed a tiny gap between the "stick" part of the lead and the rocker cover. This was not there before. I have checked the plugs are screwed in properly. I have just checked which plugs i should have on sparkplugs.co.uk - the site suggets i should have PTR5A-13 NGK plugs, but that these are obsolete and have been replaced with the PTR5A-10 i have in my car. Are the plugs i have slightly different from the Ford ones as they are a "patterned" part, i never quite undestood what that term meant?
Even with the dead plugs the car managed 35+ mpg on the motorway so i dont think the leads can be that bad.
Is there any simple way to recover failt codes on this vehicles? On my mum's Vovlo 850 T5 it can be done with no tools or equipment at all.
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checking the resistance isnt always a tell tale of plug lead being weak ie the main lead could be perfectly ok wont say the outer sheath is.there may be cracks that are not visible to the eye but cause grief if they decide to short out.during damp weather.would be inclined to replace them as a matter of course especially at that mileage.just my 2 penneth.
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Thanks guys.
A few more questions!
Whats the gap on the Ford plugs? I was suprised to see NGK have changed the gap from 1.3mm to 1mm on the plugs they sell for the mondeo zetec engines.
And does anyone have any idea where i could get the leads dirt cheap?
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Well to be honest a cheap set may cost you later.ie if you get the originals they may outlast any you buy cheap.depends on the makeup and who makes them.others may dissagree?
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Ford reduced the reccomended gap on plugs for Zetec engines from 1.3mm to 1mm to reduce the stress on the HT leads. The original Ford leads breaking down and causing a slight misfire is a very common problem on these engines.
The NGK PTR5A-10's are the correct platinum tipped plug for the car. The OEM Ford plugs are marked Motorcraft, but they are in fact repackaged NGK plugs - the latest batches carry the NGK logo on the ceramic.
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As for leads, stick to the OEM Motorcraft ones - Motor Factors sell them cheaper than Ford dealers.
Other makes don't seem to last 5 minutes in these engines.
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Thanks very much for the info Quinny.
Does anyone know of a motorfactor selling OEM Ford parts in the South-east london area (Bromley)?
I'll go and ask at the Motor Factors i bought the plugs from- i imagine the £10 i paid for a set there, is less than Ford charge.
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you could try southern motor factors near the bus garage or sc motor factors both give reasonable discount.sc`s are in sidcup not too far from you phone no 02083027624 I have found them cheaper than smf but a phone call will tell
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So if the lpugs are identical, and my leads are not sitting plush with the rocker cover, do you think i have not screwed the plugs in far enough? I am worried about over-tightening them as i do not have a torque wrench.
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Ben, there are apparently some different lengths on the ceramic part of the plugs, something to do with ISO standards. There is a post on it, in the forums, on the Mondeo entheusiasts group (MEG) website at www.fordmondeo.org
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I read an article in Car Mechanics a while back stating there were 2 lengths of this plug, and that they'd heard of plugs hitting pistons if the wrong type were fitted!
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Thanks all.
Mech1: I often use Southen Motor Factors, but have not tried SC Motor factors. I'll give them a call as i am heading that way today.
I have had a look at the Mondeo forum, but not found anyhting on the different plug lengths. If i find out anything concrete i'll post it here. Better pull a plug out to make sue there is no contact in the mean time though!
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The only issue with spark plug length is that a short reach plug can be fitted which leaves the firing point way up inside the plug aperture. Make absolutely sure you use silicone grease inside the plug lead and inside the coil pack connections. Recommend you use the pukka Ford leads, I know they are a bit dearer but from experience they will last a lot longer. Oh by the way your cold misfire could be down to the oil in the engine, either too thick (5w/30 semi synth) or too old causing the hydraulic lifters to jack open when cold.
Andrew
Simplicate and add lightness!!
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I have had a close look at the old plugs and the new ones, and i am sure the reach is the same. The part of the plug that has different dimensions is the part that the lead attaches to, ie the part protruding from the head. It's longer, hence the HT lead does not sit snuggly against the rocker cover anymore.
Its only a slight hesitation i get when accelerating, when the car is cold. I hope the new leads tomo will remedy this. I am fairly sure the oil is not the problem. I have just changed it using 5w/30 oil, and the oil i drained out had *only* been in there 8.5k miles (motorway miles), so i doubt it was terribly degraded. I had quite a bit of trouble getting the damn filter off though- not in the best position for the DIYer!
Thanks for the tip regarding the silicone grease - i have never used it on leads before! Do i just spray it inside both ends of the leads when fitting the new ones tomo? When i fitted the plugs i just squirted a bit of VW "Spray Maintenance" over them, will i need to do anything to get that off the plugs first?
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Ben,
I've heard that your lucky to get 30k out of an original Ford set and less from OEM ones. Though to be fair I've just changed mine for the fourth time at 152k so they can't be that bad. I've also had to change back to the old set of Motorcraft plugs because the new Platinum Champions started to break down. I had trouble with NGK a long time ago in an escort so have avioided them in recent years, maybe it's time to give them another try!
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