86 4kq idling at 2500RPM

[Brady Moffatt]

Hi All,

I recently replaced 2 fuel hoses that had been leaking on my 4kq. The good
news is that it doesn't leak anymore, and that my fuel economy increased by
20%, back to where it used to be.

The bad news is that it now idles at 2500RPM. If I blip it, it comes back
down to 1300 or so, hovers unevenly + or - 300RPM, then shoots back up to
2500 ish.

There is an exhaust leak at the flange just before the cat that could be
wreaking havoc with the O2 readings, but it was there before I repaired the
fuel leaks. Exhaust leak gets fixed today at noon.

The fuel lines are not kinked, at least at the repair area. The rest I
haven't touched.

The area in question is at the front of the floor, just after the hard lines
come down from the firewall. There had been a splice by a PO, and the hoses
started leaking. I replaced them (with 175PSI FI hose).

If I unplug the ISV, nothing changes.

Same with CSV.

The idle air bypass screw on the side of the intake is screwed in all the
way.

The throttle linkage is not stuck.

If I unplug the DPR, then the car drops to an unsteady, unhappy idle of
around 800RPM.

What is causing this high idle?

Thanks!

Cheers,
Brady Moffatt
Montreal, Quebec, Canada
83 UrQuattro with 54,000 miles
86 4ksq with 311,000km
86 4ksq parts car
72 Datsun 240Z with 180,000 miles
in middle stages of quattrosis accumulatus




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