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Starting problem


nelmo
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I recently changed coil pack, HT leads and plugs (to try cure what turned out to be an injector problem). Ever since, I'm getting intermittent starting problems - the engine turns, I'm getting fuel through (I can smell it eventually and I've taken the fuel system apart to confirm all the pumps work and filters are not blocked) but it just won't fire.

It fortunately only seems to be a problem when trying to start up first thing in the morning (so I've not been left stranded anywhere yet). When it does start, it drives fine (no misfires, stuttering, pops or bangs etc) and when I come to start up to come home from work, it's no problem either, although a bit more hesitant than it used to be before the new bits.

Battery is fine (12.4v before starting) and I've just tried another set of plugs as the first set were put in by the AA and were all he had in his van at the time. The new set (from Halfords, one of the 4-prong jobs) don't seem to have made any difference one way or the other.

I bought these HT leads - could they be the problem? Are they known to be rubbish?

I also got this coil pack - again, ok?

This is for a 2004/5 2L Blacktop Zetec, FI.

 

Any help appreciated - I'm supposed to be going to Goodwood tomorrow - don't want to have to go in the tin top... 😞

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I have found that my engine/ecu works best with basic spark plugs in my case NGK BCR8ES and when I have tried to use the expensive options it misfires and carbons up - my tuner has said that he has found that some times this is the case and depends greatly on the mapping criterias.

The other problem I had was that the spark plug was passing current along the outside of the ceramic casing - try fully cleaning outside of plugs, clean connections to leads and lubricate with GT85/WD40 or similar insulating compound to make sure no jumping of spark can occur. Some sheath the spark plugs with thin silicone tubing to assist with this. It may not be the answer but it is a simple cheap try to cure the problem.

 

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An obvious suggestion, can you put the old stuff back in one by one to see if the problem goes away :) ?

I'm also not a fan of these "fancy" mutli-prong spark plugs. It would seem to me you're maybe not getting as strong a spark at the plug - which could be any of the aspects you've changed, so it sort of makes sense.

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Yeah, I put the original coil pack and HT leads back - no difference. I haven't got the original plugs but they were 10 years old (from the crated engine) so doubt they were ever at their best.

It seems to be temperature related - first thing in the morning is worst. This evening, it finally started after much cranking and, once the engine was warmer, started immediately after switching off (did it a few times). What the heck does that mean? (FI so no carb icing to worry about 😊).

Edit: ah hold on, maybe some sort of air leak into the plenum which closes up when the engine warms up and expands? Is that plausible or utter rubbish?

Edited by nelmo
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Hmmm. No-one's dicked around with the map, I take it?

If it started immediately after you changed those bits, then "ergo" it has to be in some way related to them (or incredibly unlucky that another problem started at exactly the same time!)...? So... doesn't make much sense really, maybe ignore the HT/coil/plug aspect and just treat it as a separate problem. In which case I'd be looking at the cold start map and fueling first. If you had an air leak the idle would most likely be off...

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I did have NGK and I've put them back but no difference.

I haven't changed the map on purpose BUT I did start up the Emerald software to use the datalogger - wonder if I changed something by mistake? But I would have had to consciously save it, so I doubt it...

I didn't touch the injectors Bob - but I had a misfire which seemed to resolve itself by just leaving the engine to idle for 10 minutes.

The only other thing I have noticed is that the engine is running 5 -7 degrees hotter than before I changed all the leads etc. (and not just because of the warmer weather), if that means anything?

 

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Leaner mixture or advanced ignition timing would do that. Amongst other Things but that’s where I’d look if you’ve had furling issues. Where to you get your trigger from for spark? Has that been knocked/adjusted. Your fuel pressure hasn’t been changed has it? 

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