jdroth50

I just installed a C&L CAI and an SCT 93-octane tune from Brenspeed. I'm hearing a "rattling" or "knocking" sound when the engine is under a load past 3k RPM. Is this because there was still some 87-octane left in my tank when I filled up with 93-octane? Or did I screw something else up when I installed the CAI?

22kart22

no. Engine knocking is actually in most cases a form of mis-firing. When an engine knocks, about 95% of the time the engine is wayyyyy to LEAN, and in order for this to occur, the engine must be under a load.

The first thing that I would do is check that the engine is recieving an appropriate amount of fuel, if that is possibe to do in your case.

NyFordTech

+1 what he said, also there is a tsb for a stuck lash adjuster it would make a ratteling or clickng noise.
but that is prollly not ur problem havent seen many in for that tsb.
i thinkmaybe running lean

Daniel60

Go to the tune load on your SCT2 tuner and when it ask the question adjustments outside the parameters then take out spark on the 2000-8000 selection. Take out 3 to 4 on the spark then go back and load your tune. If this isn't explain good enough then call brenspeed tomorrow and he will talk you through it better.

wmtheflash

Also, double check your install. You should make sure all seals are properly tightened and no air is leaking in past your MAF sensor. That can cause it to knock.

At least a few people on other Mustang boards had their engines knock after a CAI and tune. It turned out it was improperly installed. Check your hose clamps and make sure you properly tightened them (but don't over tighten!) make sure all seals are properly lined up, etc.

2cokeman

on the 06 auto, there is int. pinging on load using 87 or 89 with the factory tune!! anyone else get that too?

Getaway

I had a rattle/click totally stock when running any gas brand or octane at full throttle in upper rpms. After an intake and tune...still has the same noise.The sound does not changewith rpms (frequency/pitch/etc.). I can't find it though since it only happens under load and not in neutral.

I think the stuck adjuster can be heard in neutral...at least that's what my Ford tech said.

I'm currently driving a 2006 GT, but I had a 2005 GT with the exactsame noise I have now. I wish I could find its source.

2cokeman

I agree, 100percent, I spoken to lots of people with the same condition!

jdroth50

Talked to Brent from Brenspeed.com this morning. I still had probably 1-2 gallons of 87 octane in my tank when I filled up with 93-octane. Brent said the sound is from the timing not being correct, which is accurate since I had a 93-octane tune with less than 93-octane fuel. He called the sound "pinging", which is commonly confused with "knocking". He said my engine isn't running lean, but that the timing is just off because of the fuel mixture. I put a 91-octane tune on for that tank, and it fixed the problem. Now I have a full tank of 93-octane, and retuned for 93-octane. No more pinging. I've never experienced such high-quality customer service as I received from Brent. Very friendly, and he kindly explained everything w/o making me feel like an *** (which I am for mixing the octanes).

scrmngt

I saw in one of the other posts about the "tick tick tick" noise from the fuel injectors...could this be it? My engine isn't amking any "pinging" sounds just what I believe to be the injector noise...low/subtle/but there.