2004 Mercury efi idle issue

R

Ranger330

Cadet
Joined
May 21, 2014
Messages
29
Last trip out fouled a plug/plugs. Back at home did compression test all good, ohm all coils and they were within specs, replaced plugs, replaced spin on fuel filter. Took it out today and ran great but won’t idle when you start it up after sitting for 30 minutes or so. When you run it down the lake and stop it will idle fine 700 rpms. But when she cools off it won’t idle. This is the second set of plugs. Previous owner just replaced them before I bought it.
 
J

jiffyboat

Petty Officer 2nd Class
Joined
Oct 4, 2009
Messages
114
you need to locate a hose at the bottom of the intake right behind the filter , it comes from the injector rails , disconnect that hose , and try starting the motor , if you see a lot of fuel coming out of that hose , is the fuel pressure regulator , the diaphragm or the spring went bad , that is the return line , if the regulator goes bad is pouring fuel all the time and fouling the plugs , burning more fuel .. another way is early in the morning spin the motor several time and them look into the intake , if you see fuel at the bottom , is the same problem since the hose is connected to the intake , I just had similar problem and had to end it up replacing all the rails, since the fuel pressure regulator is no available for sale along
 
You must log in or register to reply here.
Top