Bad Alt. Codes 61 & 63.

[RICHARD TILL]

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.

[We Gone]

Just a guess but the code 61 is secondary port throttle valve system may have something to do with the unpluged the vacuum pump. I'm sure someone who knows more than I do will offer up some good advice soon.

[SteelBlueZR1]

It is likely, based on personal experience, that your secondary solenoid is going bad and throwing a code 61. Does your car sometimes fall flat on its face when you get into the secondaries?

[XfireZ51]

Bone stock motor? How could you run full power w vacuum pump unplugged?

[Franke]

Richard, my 4 bad injectors read 12-13 ohms when cold but read anywhere from 6-8 ohms hot. The original injectors don't like ethanol fuel and started shorting out the coils somewhere around 50k miles or so. Replacing them will make a world of difference in performance and idle quality. Be sure to test the rebuilt injectors before you button everything up. You also need to find the vaccumn leak in your engine so that the pump doesn't run so often. It could be the cause of the 61 code. As Xfire says how can you run full power without secondaries vaccumn?

[Schrade]

What's the operating voltage on the right O2?

If over 1/2 volt cosistently, your burning rich, and cats will foul soon.

Isn't 13V inj impedance a borderline reading? Poor spray quality could be indicated...

[Paul Workman]

Originally Posted by Schrade

What's the operating voltage on the right O2?

If over 1/2 volt cosistently, your burning rich, and cats will foul soon.

Isn't 13V inj impedance a borderline reading? Poor spray quality could be indicated...

No. 12-13Ω across HOT injectors is normal (always test them HOT). At 11.0 Ω and less it indicates trouble with the solenoid windings w/in the injector coils, and as resistance decreases, so does the injector function until if fails completely.

AND, BTW, it is possible to burn a valve if one or more injectors become marginal. If an injector failure is severe enough, the cylinder won't fire. The worst case scenario is an injector that has not reached that level and simply leans that cylinder out waaay to lean, resulting in a burnt valve. (BTDT x2)

The spray pattern would be more a function of the tip being contaminated with carbon or dirt. But, I don't think that wouldn't foretold by the resistance, per se'

P.

[RICHARD TILL]

I thank all of you who have responded. Haven`t had a chance to work on the car the last couple of days but i do have the alt. rebuilt. It got new bearings, brushes, regulator and a rectifier. The charge was $80. After unhooking the vacuum pump it didn`t fall on its face in the full power mode. It did have a small dead spot. Hopefully tomorrow i`ll get the chance to identify and check the secondary system and reinstall the alt. Its a slow go for me in this unfamiliar territory. I do have a few mechanical skills as i have built and run a 10 second dragboat with a big block chevy with two 1050`s. Its all old school except for the msd ignition. Am definately getting new injectors but haven`t decided on new or rebuilt. I`ll post again when i have more news. Thanks again and i`m still all ears.

[RICHARD TILL]

A couple of questions just popped into my feeble mind. I`m exposing my ignorance. Evidently injectors are rated in pounds. Is that a rateing of pounds of fuel per hour delivered at a given pressure? Whats the stock rating? Should i specify a flow pattern? What are the questions i should ask to get the maximum benefit? Would i be better off by having my injectors rebuilt instead of buying different ones?

[Schrade]

Jon Banner FIC Injectors used to be the go-to guy for C4 injectors - as far as I know he still is.

Has logged lots of hours on other vette boards, including injector vid stickies which I suggested he start posting in '08.