Exhaust Rattle on start up only

11Thumper · 09-27-2011, 05:18 PM

Mine does it as well (always has since new). It takes about 15 seconds to go away unless I put the transmission in D (and it goes away right away). Perhaps it's just at a particular RPM since the 6MT guys get it also? A cold start has a high RPM and it slows down after 10-15 seconds, putting the 7AT in gear also slows down the RPMs.

wstar · 09-27-2011, 05:30 PM

My car has always been rough initially as well, and it's been that way through a long series of exhaust changes (all factory, stillen headers + berk HFCs + factory CBE, stillen headers + berk HFCs + stillen CBE, stillen headers + berk HFCs + FI CBE, and now FI LTH + FI CBE).

With the very aggressive exhaust setup I have now, the initial "rattle" period actually rattles the loose hardware on my garage door, which makes it sound like a loose bolt on the car, but it's not on that car at all

. It's pretty insanely loud and vibrational.

But anyways, it used to make me nervous, and I'd go back and triple-check bolts all over the place. Never found anything loose. The engine's just really rough and rattle-y for the first few seconds when started dead cold, and it passes as the revs begin to drop from the ECU's cold-start process.

SS66 · 09-29-2011, 03:18 PM

Finally got around to dropping off the car for the rattle noise. They checked the exhaust and said everything was tight. It might just be the intial start up and quites after 30 seconds. Normal I guess.

09-27-2011, 05:30 PM	#2 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3595	My car has always been rough initially as well, and it's been that way through a long series of exhaust changes (all factory, stillen headers + berk HFCs + factory CBE, stillen headers + berk HFCs + stillen CBE, stillen headers + berk HFCs + FI CBE, and now FI LTH + FI CBE). With the very aggressive exhaust setup I have now, the initial "rattle" period actually rattles the loose hardware on my garage door, which makes it sound like a loose bolt on the car, but it's not on that car at all . It's pretty insanely loud and vibrational. But anyways, it used to make me nervous, and I'd go back and triple-check bolts all over the place. Never found anything loose. The engine's just really rough and rattle-y for the first few seconds when started dead cold, and it passes as the revs begin to drop from the ECU's cold-start process. __________________ 7AT Track Car! Journal thread / Car setup details

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09-27-2011, 05:18 PM	#1 (permalink)
11Thumper Track Member Join Date: Mar 2011 Location: Bay Area, CA Posts: 754 Drives: '11 370Z, '01 S2k Rep Power: 18	Mine does it as well (always has since new). It takes about 15 seconds to go away unless I put the transmission in D (and it goes away right away). Perhaps it's just at a particular RPM since the 6MT guys get it also? A cold start has a high RPM and it slows down after 10-15 seconds, putting the 7AT in gear also slows down the RPMs.

09-29-2011, 03:18 PM	#3 (permalink)
SS66 Base Member Join Date: Apr 2011 Location: Overland Park, Kansas Posts: 165 Drives: 2011 370Z SP m6 Rep Power: 15	Finally got around to dropping off the car for the rattle noise. They checked the exhaust and said everything was tight. It might just be the intial start up and quites after 30 seconds. Normal I guess.