I just installed a MSA 3-2 header and exhaust system on my 1972 240z and now my idle is too high. It used to idle around 800 rpms, now it idle around 1200-1300 rpms. Overall it seem to run great. Just idles high. Is there a quick idle adjustment on these SUs ? Any help would be greatly appreciated.

I know there is tons of info. already in this forum, but it is very hard to find any specifics... Thanks again in advance

Do you perchance have the linkage not connected to both carbs the same, possibly holding one open?

I would expect that after installing headers a full carb adjustment would be in order.

Do you perchance have the linkage not connected to both carbs the same, possibly holding one open?

It ran like a champ prior to header and exhaust installation. It still runs very well, just the idle is 400-500 rpms higher. I have checked the linkage and all seems to be fine.

You can't expect to change one thing like the header and not impact something else. Not to mention you had to move the intake to put the headers on and you can't expect it all went exactly like it came off. You need to fully tune the carbs.

"Z-Therapy";)

I understand they offer a visual set up guide for SU's.

I agree that with the removal and installation of the headers you need to set up and balance your SU's.

JLP

Just try backing off the idle adjustment on the carbs (evenly). Hopefully you have a flow meter to sync them. If not you should get one.

Sounds like a vacuum leak to me. Start by spraying starting fluid (or something similar) around the parts that were removed or tampered with when you installed the header. I'd suspect a hose that is cracked or not quite sealing, or the intake/exhaust gasket especially if you didn't install a new one.