I have an 88 dx with DPFI, and the thing idles very high (around 3k) when first started and for 2-5 minutes afterward. Once engine and coolant are warmed idle speed is fine. My factory manual explains that the MPFI has a separate cold temp idle circuit, but there is no mention of one on the DPFI. I replaced the EACV (with a used one), but that didn't help. I'm not getting any codes from the ecu. I'm desperate, and thinking of replacing the EACV again, just because when looking at the manual I can't figure out any other component that might cause this- cept maybe the ecu itself. Anyone got any ideas for me?

 

Does this help at all?

 

Thanks, but no, that doesn't help. My issue is cold idle. Your posting shows how to adjust idle speed at normal operating temp. My idle speed is fine at normal operating temp. Thanks for giving it some concern.

 

You might want to look for an intake air leak from the throttle body and intake manifold, and also check the EACV mounting O-ring for leaks.

You could also try to bleed the cooling system of possible trapped air.

 

Do you have a tach? Is it really 3000 rpm? Normally it will idle 1500 rpm, much faster than the normal 750, immediately after a cold start.

I have a DPFI one and though I haven't looked at it closely there is some device on the throttle shaft that may be holding the throttle plate open when cold. Also make sure that your throttle cable isn't sticky or adjusted too tight.

I really doubt it's the ECU. If you unplug the wires from the EACV and the idle drops then the ECU was indeed commanding it to idle that fast. But I think when you do that test nothing will change, indicating that the ECU has correctly turned off all the drive to the EACV but it still idles too fast for some reason.

Anything that lets excessive air into the manifold will cause it to idle too fast.