Bad Alt. Codes 61 & 63. - ZR-1 Net Registry Forums

RICHARD TILL · 07-09-2013

Pulled the plenum on 1990 #2161 today. On the last several outings at night i`ve noticed that every light on the car pulsated as if there was a voltage swing. Last week it completely quit charging and today i pulled the alt.. Bearings are surely too noisy. Its 120k bone stock except for the nice new 25 hp mercruiser tag on the map sensor. Also several times lately i`ve had the service light come on while running 65-70 mph for maybe 2-3 miles then go off. Sometimes it`ll sound as if it had a dead miss at idle and a little above then come to life. I have two codes, 61 & 63. My ST-364-90PSID manual says that the code 61 is secondary port throttle valve system and code 63 is right oxygen sensor circuit. Injectors are factory. I checked them today and every one of them checked 12.2-13.0 ohms. I don`t know but i hope that they can check good and still be bad. Could bad injectors cause the code 63? My plans are to get the alt. rebuilt at a shop that i trust and order a set of rebuilt fic injectors. Check the coils and wires. I unpluged the vacuum pump about 5 years ago because it ran too often while still leaving satisfactory performance. I`ll dig into that too. Any advise on those codes? I`m in unknown territory and this manual i have has all the info but sometimes its like looking for a needle in a haystack. Any words of advise from the experienced? Many Thanks in advance.

07-09-2013	#1
RICHARD TILL Join Date: Aug 2005 Location: Iuka, Mississippi 38852 Posts: 756	Bad Alt. Codes 61 & 63. Pulled the plenum on 1990 #2161 today. On the last several outings at night i`ve noticed that every light on the car pulsated as if there was a voltage swing. Last week it completely quit charging and today i pulled the alt.. Bearings are surely too noisy. Its 120k bone stock except for the nice new 25 hp mercruiser tag on the map sensor. Also several times lately i`ve had the service light come on while running 65-70 mph for maybe 2-3 miles then go off. Sometimes it`ll sound as if it had a dead miss at idle and a little above then come to life. I have two codes, 61 & 63. My ST-364-90PSID manual says that the code 61 is secondary port throttle valve system and code 63 is right oxygen sensor circuit. Injectors are factory. I checked them today and every one of them checked 12.2-13.0 ohms. I don`t know but i hope that they can check good and still be bad. Could bad injectors cause the code 63? My plans are to get the alt. rebuilt at a shop that i trust and order a set of rebuilt fic injectors. Check the coils and wires. I unpluged the vacuum pump about 5 years ago because it ran too often while still leaving satisfactory performance. I`ll dig into that too. Any advise on those codes? I`m in unknown territory and this manual i have has all the info but sometimes its like looking for a needle in a haystack. Any words of advise from the experienced? Many Thanks in advance.