Rolling Road printout info

[rodbloke]

Hi all, maybe one for the masters on here.

Griff has recently been for a rolling road tune, and has 1 or 2 problems (on another thread, going in Thurs), but i'm going through the printouts that I was supplied.
Now I understand some of the data on here (not just bhp and torque!), but there are figures for DYNAMIC FIRING KV for each cylinder. What exactly is this?

Only no. 7 has less than half of the value for all other cylinders for this. Spark and duration values are comparable for each cylinder.

Thanks in advance
Rod

[Equinox]

Sounds a bit technical for this time of night and after a few pints, but i'd like to know too. Lets see if there is any bright soles still awake....

[rodbloke]

Yes, thats what I would have thought too.

The operator didn't mention cyl 7 at all, but that I needed a new coil (arrived yesterday from Mr. Lamont) and is away this week (hence why I've asked here in the meantime.) They are brand new leads and plugs are less than 1000 miles old and appear to be ok too (checked after recent suggestions on another post).

As its only on the 1 cylinder it does look a bit suspicious (I wouldn't have thought a knackered coil would do this?). Whether its a dizzy problem if this is purely electrical, and not a blocked injector or something.

[trackcar]

A coil wouldn't produce those results, the coil doesn't know which cylinder is firing so wouldn't replicate the effect consistently. A small plug gap or a low resistance on that HT circuit would do it, but also things like a low compression pressure would do it too so did they do a cylinder pressure / leakage test or just assume it was an HT problem and changed the easiest item?

[dickymint]

Possibly distributor cap would do it, if rotor not making good spark on no.7 contact??

[rodbloke]

Thanks, Dist and rotor are on the check list for Thurs (its getting quite long now...).

Compression was tested recently and all was well then (thankfully)...the leads were replaced at the time anyway because the others were shot, so possibly something got disturbed. I'm not sure what diagnosis was done to be honest as I wasn't with the car during the testing, i'm not filled with confidence though.

[griffter]

Check that no.7 spark plug and the screw on terminal (which the HT lead clips on to) are tight.

- You never know, it could be something simple!

>> Edited by griffter on Wednesday 8th February 07:35