misfire at 3500rpm

[el colon]

Hi there,

I was hoping someone could maybe take a look at the data log file I've attached and let me know if there is anything "wrong" with it.

My car (K20 supercharged Ariel Atom) has started "misfiring" at approx 3500rpm in pretty much every gear, most noticeably in 3rd and 4th. It doesn't do it every time, probably seven out of every ten times that I rev through 3500rpm.

I pulled the spark plugs and this is what they look like:



It feels almost like the fuel momentarily stops flowing, the engine jerks and sometimes there is a loud backfire. I've changed the fuel filter which made no difference, and I also changed the battery as it wasn't holding a very good charge (the Atom uses a very small battery). The injectors are ID1050X and only recently fitted.

If it was an injector issue, I would have thought that the "misfire" would be random, but it's always at approx 3500rpm.

The datalog was made whilst I drove in a manner trying to repeatedly get the car to exhibit the issue, so I'm hoping something has been captured that will mean something to someone who fully understands these logs.

I would really appreciate any help.

Thank you

datalog0003.fpdl

(1000.1 KiB) Downloaded 33 times

[Spunkster]

What injectors are you using?

[el colon]

What injectors are you using?

Hi Spunkster,

As above, they are Injector Dynamics 1050X

Many thanks

[Spunkster]

Post the calibration as well.

[el colon]

Post the calibration as well.

Unfortunately I can't as the tuner (CPL) refuses to provide it to me, despite leaving me with the rev hang issue as posted about here:

viewtopic.php?f=28&t=22190

They have refused to offer any help with the rev hang issue and now this "misfire" has developed, the only thing I can provide using my Flashpro is datalogs. I am going to have to get my car mapped again (obviously not by CPL) but am reluctant due to the poor experience I've had so far. The Injector Dynamics 1050X were supplied/fitted by CPL when they mapped my car as they told me I needed bigger injectors. I'm concerned in case this misfire will cause engine damage, especially if its some sort of fuelling issue causing the engine to run lean.

Would really appreciate any help you can offer!

[Hondata]

You don't have a working o2 sensor. Looking at the lambda would be a good start.

Without the calibration we can't do anything.

[el colon]

You don't have a working o2 sensor. Looking at the lambda would be a good start.

Without the calibration we can't do anything.

Thank you very much indeed, really appreciate that. I'll investigate the lambda sensor.

Can I ask how you can tell that from the datalog, is that something I can do myself? If I know how to read the data log to check the lambda, I can fit a new one and recheck a fresh data log myself. I would like to learn more about interpreting the data from FlashPro.

Once again, many thanks!

[Spunkster]

Is your ECU a PRA?

[el colon]

Is your ECU a PRA?

This is my ECU:



Many thanks

[Spunkster]

sorry, I mistook this for a K-Pro, ignore that question.

[typer86]

I think I am be able to create a tune for you.
I have tuned some K20 SC via etune over the internet.