wade

iTrader: (1)

Have a new engine for a FI application. Engine fresh from machine shop (GSR). Fully sleeved, built head, supertech valve springs, etc....


The issue: Engine idles and runs fine, but when it idles back down from a rev, sometimes you hear a little metallic sounding "pop/clank" kind of noise. It is not rod knock, engine oil is fine. It only happens ONE time during a de-cel.

Sorry I can not be any more specific. But it is pretty consistent. Straight off of a rev, as the engine starts to idle back down to resting, it makes the little metallic pop sound. Almost like what a valve would sound like when being pulled back into the bowl from being stuck open or an injector closing fully for a split second as I let off the gas.

I am now thinking, since the car has NO tune on it and just a fuel map of random numbers calculated in to JUST make it run, then just mayyybeeeee... it is the injectors... Can 1600cc injectors be THAT loud when they close possibly?

again: The issue ONLY happens right after I left off of gas pedal. It can hold a constant rev, idle ALL day and no problem.... but AS SOON as I left off the accelerator... it gives me ONE click/pop sound. Which, leads to the injector briefly shutting off as Autronic is pretty severe on that i hear.

I will get a wideband on it this week to get it to idle in the correct A/F range and pray it goes away, or I will also swap in some different injectors and try again.

redboost10

hey wade, my 1600 cc injectors are pretty clicky. i talked to tony about it and he recommended i fire them off individually with the car off through i believe it was the diagnostics in motec. mine are only loud at idle, about 900 rpm. if autronic does not let you do this, you can always use a wooden broomstick method to see if it is the injectors.

may i ask what brand injectors these are? mine are precision, just wondering

wade

iTrader: (1)

Fic

wade

iTrader: (1)

its more than a click i should say, it mean, it sounds like metal on metal contact. Like something is 'binding' up, then 'releasing' ,metal on metal sound. i will try and get a video if I can

redboost10

yeah i think im talking about something different then, mine are just the regular 1600cc clicking you get from those big injectors. take a stab at the wooden broomstick method, sounds dumb but it works for us on cars that are louder than normal when its hard to find a noise. you may be able to narrow it down to which injector or if it is the injector.