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280z slow to return to idle, any thoughts?

Hi,

I thought I knew a fair amount about EFI in the 1975 on Zs but this one has me stumped. 1977 280z, runs well, in time, valves set right, head replaced recently with a 1975 rebuilt head.

Car idles fine but the idle screw has little effect, gently tightened the car idles at 800RPM, half a turn open gives 1000 RPM.

On the road the engine does not return to idle quickly enough, this means that for had acceleration you can’t go up to the next gear for a few seconds. The engine dawdles back to 1000RPM and sometimes stays at

2500RPM for ten seconds or so before beginning its slow decent to idle speed.

Any thoughts?

Best,

Phil Sharkey

Reply to
Phil Sharkey
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Are the return springs in good condition? Or there is a devise to raise the idle when the engine is cold that could be bad. My 87 will change idle speed when I turn on the blower for heat or turn on the lights. It somehow senses the added load and jumps up about 100 rpm

Randy

Reply to
Randy

Phil Sharkey ( snipped-for-privacy@netscape.net) wrote on Friday 18 July 2003 04:14 pm:

Phil,

This may be an obvious one, but have you checked the dash pot? It's the thing that keeps the idle from dropping off too quickly. I had mine seize up once while under heavy acceleration (went well past redline). Of course, that was on a '75. I don't know if they're on the '77s.

Reply to
Michael White

Yes, I checked it and it's shot, need a replacement to find out if that's the problem<G>

Thanks,

Phil

Reply to
Phil Sharkey

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