Ok guys fuel, electrics or something else.....Last couple of times I've taken the 7 out for a drive I've been plagued by a random misfire! I'll try and explain it as best I can and see if anyone knows what the problem is....
- Its been cold! Car starts fine and idles perfectly when warm but obviously needs some help when its cold! Go for a blast and everything is fine....suddenly hit a 30 limit or get stuck behind a car and a funny misfire starts. Basically it will cruise along at 1/8 throttle but when you put your foot down it starts missing. Sounds like electric something as its a very deffinate miss and the car loosses all power. If you plant your foot it misses for a second or two as the revs build and then all hell breaks loose as full power comes on. They're doesn't seem to be anything else wrong and it only does it once warmed up. My plan is to undo all the plugs and wd40 them all to see if that helps but I've got a suspicion that its fuel related (running bike carbs - ZX7r which up to now have been great!) as its not at any particular revs, speed etc etc....Is there anything else I should think about doing?? Megajolt'd so could I alter the map for it being cold or something?? Oli.

I had very similar in the summer, it was a bit warmer then mind. Turned out it was all down to a slack alternator belt, missfire down to low voltage fixed itself as battery recharged.

[Edited on 30/11/06 by Pants On Fire]

sounds like carb icing/running weak

zx9 carbs have coolant piped through them as standard - don't know about the zx7 ones?

If yours do normally and aren't plumbed in then it could well be icing as already suggested.

Ice! Madness! I don't run an air filter at the moment - too much horse power wastage! lol.....think I'll investigate this weekend....anything else I should be looking for?? I don't think its running too lean as it stinks of petrol every now and again....will check the plugs. The real answer is to have it rolling roaded properly but a Zetec is going in, in the Spring so there's little point.....Oli.

Why run without an air filter? A proper one (K&N) won't lose you a single HP, but will protect the engine. If you do it really properly with a force fed thingy, you could actually gain a bhp or two.

Cheersw guys....I was joking about the air filter. The reason I don't run one is that I live in Scotland and so am inherently tight! I can't afford the nice ones and don't want to cut a hole in the bonnet as the zetec is going in soon to fit an airbox or alike. So for the moment it will have to stay how it is. The engine has only done 450 miles since being recon'd so not much damage done and it will be out and in a new home soon enough where it will get the love and attention it so deserves! Oli.

PS.
Thanks for the tips, I'll get my spark plug wrench out at the weekend along with my wd-40 and see if I can get it sorted....

Oli
I had a similiar problem a few months back .I tried everything to sort it including , plugs, leads coil, edis, crank sensor and megajolt but eventually found it to be a fault in the diode ciruit I was using for the tacho drive from the coils.I used 2 diodes and a zener diode to provide a signal the zener diode was a glass cased version and the casing had cracked causing an intermittent contact which was spiking the edis unit.It was worse when hot due to being wrapped in heatshrink and insulating tape that softened when hot and allowed to move.
Not sure if you fitted this mod to yours for the tacho but if so it is a possibility or something similiar.
Paul.

Replace the ening for one more reliable, lighter faster and all together an improvement on the old boat anchor.

Steve