Printable Version | Subscribe | Add to Favourites
New Topic New Poll New Reply
Author: Subject: Diagnose my duratec misfire
GreigM

posted on 31/8/14 at 03:50 PM Reply With Quote
Diagnose my duratec misfire

Just looking for clues as I'm under a bit of a deadline to get this fixed.

2L duratec

On a track day today, car starts and runs fine. Do the session on track, all seems ok, but on the cool down lap back to the pits the car is misfiring quite badly. Get back to the paddock, it idles fine and when under heavy throttle (above 4000 rpm) seems fine, its only under partial throttle that I get this misfire.

I let the car cool down over lunch, start it up, all seems fine - revving up fine under partial or full throttle so go out for another session, car running well, again on the cool-down lap under partial throttle the misfire returns.

So symptoms seem to be:
HOT car
partial throttle misfire
idle fine, WOT fine

Plugs are new (<300 miles), so I'm leaning towards HT leads or coil pack - any other suggestions? Are there any sensors I should be thinking about replacing also (I'd rather spend money and get it fixed quick)?

View User's Profile View All Posts By User U2U Member
owelly

posted on 31/8/14 at 03:59 PM Reply With Quote
Could it be fuel getting hot in the rail or fuel lines or has this set-up been OK in the past?





http://www.ppcmag.co.uk

View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
GreigM

posted on 31/8/14 at 04:13 PM Reply With Quote
quote:
Originally posted by owelly
Could it be fuel getting hot in the rail or fuel lines or has this set-up been OK in the past?

All been fine, no issues previously on other track days.

I'm kinda ruling out fuelling issues (maybe wrongly) as it runs fine at higher revs (meaning there is enough fuel getting through) - my simple mind thinks this must be electrical.

View User's Profile View All Posts By User U2U Member
scudderfish

posted on 31/8/14 at 05:09 PM Reply With Quote
At WOT the fuel will be flowing through the rail. I don't know the duratec, but if the rail is dead-ended (i.e. no return from it) then fuel will be lingering and potentially vapourising in a hot rail
View User's Profile View All Posts By User U2U Member
GreigM

posted on 31/8/14 at 05:56 PM Reply With Quote
quote:
Originally posted by scudderfish
At WOT the fuel will be flowing through the rail. I don't know the duratec, but if the rail is dead-ended (i.e. no return from it) then fuel will be lingering and potentially vapourising in a hot rail

Ok, understand and could be a possibility however I never had this problem before on hotter days with longer sessions. Previous owner never had it either and I'd bloody hope for the price of their cars Caterham would design the fuel rail better than this!

I'm going to nip out and examine the plugs shortly, just to make sure one of them hasn't had an issue..but as I said they are fairly new so wouldn't think so.

View User's Profile View All Posts By User U2U Member
jacko

posted on 31/8/14 at 06:04 PM Reply With Quote
Wot make of plug's are you using ?
View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
GreigM

posted on 31/8/14 at 06:44 PM Reply With Quote
quote:
Originally posted by jacko
Wot make of plug's are you using ?

Denso IT24 iridium

Think I may have found the issue, photo on the way

View User's Profile View All Posts By User U2U Member
GreigM

posted on 31/8/14 at 06:56 PM Reply With Quote
Would this cause the issues I have? #2 HT lead has been pinched by the screw holding on the cover - i has taken off some rubber outer and I can see the green rubber inner (although I can't see any metal). I'll replace it anyway as a matter of course, but just need to know if i can stop looking for other things to replace.




[Edited on 31/8/14 by GreigM]

View User's Profile View All Posts By User U2U Member
jacko

posted on 31/8/14 at 07:19 PM Reply With Quote
YES think you have found the problem
View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
GreigM

posted on 31/8/14 at 07:35 PM Reply With Quote
Next question - are fancy Magnecor HT leads worth their money?
View User's Profile View All Posts By User U2U Member
itsawindupuk

posted on 31/8/14 at 09:40 PM Reply With Quote
Id say so, I have them on my duratec, very thick insulation, look great and the quality of the plugs is spot on. They should last a very long time. Also you can have them made to any length you want.
View User's Profile View All Posts By User U2U Member

New Topic New Poll New Reply


go to top






Website design and SEO by Studio Montage

All content © 2001-16 LocostBuilders. Reproduction prohibited
Opinions expressed in public posts are those of the author and do not necessarily represent
the views of other users or any member of the LocostBuilders team.
Running XMB 1.8 Partagium [© 2002 XMB Group] on Apache under CentOS Linux
Founded, built and operated by ChrisW.