Engine issue

[olliej]

Hey all,

As i have a bit of time off i thought now would be as good a time as any to sort out a few nagging problems with my car. This time last year the car developed something similar to a misfire, where the car would not rev above 4k rpm in any gear for prolonged periods, but then would progressively allow more revs, then go back to 4k rpm. I thought i had traced the problem to fouled plugs so they were changed and after a while the problem went away and i didn't think anything of it.

That was until around two weeks ago when the issue resurfaced, same problem, same characteristics. The only saving grace i can find is that both times it has been on a long (six hours) journey, with extended periods of time spent at consistent revs, since then the car has progressively improved, until it now seems the power is nearly as linear as before. My question is this, has anyone experienced similar issues? or can anyone offer insights into what could be causing this. Oh, and being in New Zealand there is no official Caterham service centre to speak of. For reference the car is a 1.6 superlight sv.

Any help is much appreciated.

[sjmmarsh]

It is worth checking the coil packs as these can produce odd symptoms as they start to fail.

Is it a K Series?

Steve

[olliej]

sigma 150hp, cheers, will look into that

[mickrick]

Are you sure it's a misfire? As in ignition.
I'm thinking sticking valve.

[Incorrigible]

If it is a sticky valve and you've driven it for long periods it would almost definitely have low compression on the affected piston. Have you measured anything like that yet ?

I'm suspecting air mass meter or lambda sensor, but you need to get it plugged into some diagnostic kit. Plugs shouldn't foul on such a modern engine

[olliej]

Cheers for the replies,

Hadn't thought of those and will look into it. I have the diagnostic connector but not the software, looking to try and locate this from caterham. In terms of missfire, it was literally the first word that popped into my head. The car revs normally through to 4k, then stops, sometimes quite violently. When you change down to a lower gear at speed it lurches and refuses to rev.

[Tango7]

Hi,

I have got a Sigma Academy car with the 125 bhp engine and an MBE ECU. Assuming you are running an MBE, you can download the Easimap software free of charge from the SBD Motorsport website. I have the Easimap 6 version : http://www.sbdev.co.uk/Engine_Management_Systems/E...

The 16 pin OBD11 connector is just above the steering column and tucked well out of sight. When you connect the system, start the software and turn on the ignition and the software determines the correct version.

Good luck!

[olliej]

Fantastic, that's exactly what i was after, yes my car does run an MBE ECU, but to a 150hp output, is this program compatible with both 125 and 150 models?

Cheers.

[Tango7]

Excellent I don't think the software will matter whether its a 125 or 150 variant. It will simply give you a full review as to what's happening to the engine. There is a couple of relevant Blatchat threads which may be useful and give you a steer on what to look for :

http://www.blatchat.com/t.asp?id=192999
http://www.blatchat.com/t.asp?id=192629

Don't worry about the PIN bit, the software should read the ECU straightaway but be careful not to try and write any edits back to the system as I think this will cause problems!

[Incorrigible]

Tango7 said:

Excellent I don't think the software will matter whether its a 125 or 150 variant. It will simply give you a full review as to what's happening to the engine. There is a couple of relevant Blatchat threads which may be useful and give you a steer on what to look for :!

Not wishing to teach my Grandmother to suck eggs or anything, but the important thing with most diagnostic kit is that it will give you a full review as to what THE ECU THINKS is happening to the engine

But yes, what he said, basically

[olliej]

Cheers, good to know, thanks for all the help.