theotherphil

I've been running great for over a year with my current setup:

MY95 UK Turbo Saloon
Apexi PFC and boost control kit, 1.35bar (Andy F mapped)
Hybrid FMIC
Apexi Induction
Revolution 3" DP and system
FSE FPR (slightly raised pressure)
NGK PFR7B's
Tesco 99 and Nitrous Formula Race OB (mapped for Tesco 99 only)

The knock levels are usually below 10 when just cruising and hit 18-20ish max on full throttle through the gears. Today though when overtaking a lorry (part throttle) on a dual carriageway, the CEL illuminated and flashed. I backed off and looked at the commander unit and it had registered a 68 max. On reapplying the throttle, the knock reading was very lively, taking next to nothing to illuminate the CEL. I drove very carefully home and managed to keep the knock level below 20. The engine sounds sweet still, nothing leaking, no smoke etc. Checked the boost pipes but they look OK, nothing obviously disconnected under bonnet. I disconnected the dump valve to eliminate that as leaking. If I let it idle, the knock reading remains about 3 but if I rev it at a standstill the reading will hit 25ish.

I am still on the same tank of fuel that I've been running for over a week with and am about 90 miles into it. Here's a s/s of my sensor page (at idle) on my commander if anybody can decipher it (I know my O2 sensor is dead - closed loop running has been disabled since it was mapped):



Any ideas as to why the sudden increase in noise? Obviously, I am reluctant to drive it until I can get this sorted.

jaytc2003

iTrader: (1)

maybe remove the filter and check the condition of the elements on the maf. I have an induction kit, and if my levels of knock increase its the first place I look. I tend to find it dusts up and with a gentle clean knock levels seem to drop down again.

I had a 35 today, but mine may have been down to a low fuel level (ie level on min - had to do an emergency stop of for some of morrisons finest)

rmtypeR

Someone told me that you couldn't get knock unless the engine was under load - i.e. revving it in neutral won't do it. Could it just be a problem with the knock sensor?

theotherphil

I get what I'd call light knock (20-25) when revving at idle. This has increased from the usual <8. I tried going down the road yesterday. Pulled off my drive and got about 20 feet before I hit a 78 on the knock sensor . I promptly turned round and left it on the drive again! The engine sounds fine to my non mechanical ears....exactly as before. No smoke or obvious fluid loss but something just isn't right.

WHEELSHOP0_0

Could it be the start of the dreaded piston slap? I know this is not what you want to hear but if you have plenty oil and the car is not under load (reving in neutral) and you are getting the noise I would be suspicious of the noise.
Can you turn the boost way down (0.9 or so) and try short drive, if it still does it might be worth getting it looked at by someone who knows classics of that age. hth and good luck.

theotherphil

I did that yesterday when pulling off the drive. I didn't even get the turbo to spin up before it hit that 78 on the knock reading

WHEELSHOP0_0

Hmmm sound like an expert ear is needed here, sorry but I think its time for a check even if it just lets you get better peace of mind.