I was driving home today and developed a bit of a miss at part nd mid throttle. At the same time i threw a SES light. I checked the codes and i am getting a code 42, 33, and 32. I unplugged the MAF sensor and it helped a little bit, but i still have a pop and acceleration stops dead and then goes again from idle. Its almost like im taking my foot of off the gas but...Im not. Could this be bad gas. I have heard about a lot of people getting bad gas now and i have run two bottles or gas dry with this tank but to no avail. What makes the battery light come on? I checked the normal things, cap, rotor, wires, timing, fuel pressure( doesnt stay solid but its there) Anyone have any ideas?

 

It sounds like you have a battery problem. I would address that before addressing codes. A weak battery will cause codes to fly.

 

The last time I had a battery light come on it was the charging system. The alternator was dieing. Check DC voltage of battery with car off. It should be 12.5 to 13 or so. Now start the car and check the DC output of alternator at the post that has the wire that goes to battery. With car running this should read 13.7 to 14+ if alternator is charging the battery. If it reads the same as the battery did with car off then your alternator is shot.

A well charged healthy battery will start the car and run systems for a while without the alternator but as soon as voltage dips below around 11.8 then many systems begin to fail. Sooner or later the car will quit all together.

As bogus suggested, check you battery out. But also make sure it's getting charged via the alternator.

 

the alternator is chrging the battery while driving it holdsat a steady 13 volts. I confirmed this by taping the VOM to the windshield while i drove and it was 13.1 but it drops at idle to 12.4. Would a battery going out cause this or maybe my hardwired fans are drawing too much for the alt to charge?

 

12.4 at idle is not acceptable. I have seen alternators that work, just not good enough under load or like in your case at low rpm's.

Hardwired fans you say?? In what way are they hardwired? If you wired them straight without use of the relays then yes, it could cause more troubles than just excessive current draw on your alternator.

I made this mistake with my last Vette, an 84. These fans draw alot. When I attempted to hardwire one on the 84 without a relay the wires got very hot and even a 30 amp fuse wouldn't hold.

About the only way to wire fans that is acceptable is to run a ground to a switch and tap into the relay at the same location where the ECM grounds the relay to activate fan. That way when you flip the switch it just fools the relay into thinking it is an ECM ground command.

Auto zone or Advanced will check your alternator and battery for free. You may want to run by there and see what they say. You may just have a bad battery but I still suspect the alternator. Good luck and let us know.

 

The battery symbol light comes on when the alternator is not charging the battery. You likely have a defective alternator. You can remove the alternator and have it tested free at most auto parts stores. Charge the battery up with a battery charger, do not rely on the alternator to charge your battery up!

 

My alternator went south today. There were pieces of plastic in it that were apparently grounded to bits and I guess one of the bits sliced the wires to the armature brushes. It was under warranty so I took it to Advance Discount Auto Parts and they replaced it for free. What I got back was a rebuilt 105 amp alternator and gave up my non-working core. Took me 20 minutes to put it back on my Vette. Isn't 105 amps kinda low for an 89 C4 or is that the stock rating from the factory??? When at idle, it is 13.0 volts and when above 1000 rpms, it is 13.4 volts instead of 14.4 like it has always been. Isn't 13.4 volts, steady cruising also a bit low too???

 

The alternators for early C4 were poorly built and reman units are junk.I replaced so many under warranty for all kinds of failure I stopped laughing.

So theres no way of knowing for you if your alternator is performing like you would expect it to.I believe the numbers should be higher than what you stated.I replaced an alternator on my 91 Lumina and its the same style alternator as the one used in the early C4's.It has 14.4 volts at start up and fast idle and will warm up and drop to the high 13's.Its working very well.13.0 wamred up is "acceptable" but is still low for a C4 that has alot of electronics running.

I think these crzppy alternators are the CS-130 style.I believe the newer style alternators that came in later cars are the CS-144,which is a mod you can do by upgrading to the better alternator for more juice and longevity.I think you have to modify the mounting points a bit to make it fit.A few people here have done it.Im sorry if I got the alternator numbers wrong.Im sure someone will chime in for the info if im off or tell you how to upgrade if you need it.

 

Anything over 12.6v is showing a charge.
CFI-EFI please correct me if I am wrong.