[Mk2] [Turbo] Strange Det problem

[832ARK]

All of a sudden I've been getting a random det warning (CEL flashing). It doesn't do it all the time but when it does, its just above 4K rpm, doesn't seem to matter whether its set at 1bar or 1.2. Most of the time it'll pull quite happily to the redline. I wondered if it could be a bad tank of V-Power but I've filled up again (from 1/2 tank) and added an octane booster. Could it be the knock sensor? What about plugs/dizzy cap/rotor arm? Its due a set of plugs anyway. Back in the winter it would have a slight missfire occasionaly in the cold/damp before fully warmed up. Other thing to mention is a slightly slipping alternator belt which is being replaced this week - surely that couldn't affect it?

Rev 3
Apexi PowerFC
HKS Exhaust
Berk Downpipe
ST205 CC

Other than that the car runs beautifully and pulls well.

Thanks in advance

Al

[832ARK]

Anyone?

[jimGTS]

is it a flashing cel light?

if your running a powerFC, this is used to warn of high knock readings....
seems to me you may require a slight remap.

i asume you dont have the commander?

[832ARK]

Yeah, it'll be the knock warning, I don't have the commander. Why would it start all of a sudden?

[jimGTS]

hard to say, more warn rings/to much advance.....(now thw weather getting warmer)

could even be some ghost knock, it maybe picking a sound up from somewhere and confusing that as knock.

one for the tuners really.

[832ARK]

I wondered about warmer weather but have tried running at night in cool air. Could ghost knock come from a slipping alternator belt? How much vibration would be required? Do knock sensors get more sensitive before they fail? I'd have thought that turning the boost down would improve if it was genuine knock but it makes no difference.

[jimGTS]

im not entirely sure...
would speak to your tuner tbh....

[832ARK]

He suggested I ask here first, I'll have another chat with him tomorrow, the problem is he's not exactly local.

[greeny]

A slipping alternator belt could well be the problem.

Can you check/log the voltages with the ECU?

If the alternator is not providing enough voltage at full load, the fuel pump could be struggling to keep up and not provinding enough flow/fuel pressure and may be running lean.

I had this on my car, where the alternator was fine to 7k, but after that till 8.7k it would drop the voltage and i visibally watched the fuel pressure drop at higher rpm and then running lean.

Does the commander show/log voltage?

[832ARK]

I don't have a commander unfortunately but i'm changing the belt at the weekend anyway so we'll see what happens.
Many thanks!

Al

[832ARK]

New plugs and alternator belt seems to have done the trick! fixed a slight boost leak as well so less lag!