Hey Bronco Folks, I am stumped. I have researched around here and got some information and tried it, but i still have a problem. I have a 93 Bronco, 302. The alternator, I assume is 3G, according to the pics and diagrams on Ford Fuel Injection. I have the Wht/Blk jumper (which is good), the Lt Grn/Red (which is good), and the Yellow, which is good all the way to the fusible link at the coil or solenoid, whatever is mounted on the passenger side of the engine compartment.

The problem, is the battery light is on and the car wants to die on me when I am at an idle. It idles really low, to the point where it cuts off sometime. I changed the serpentine belt (the batt light was NOT on before that) because I thought the truck was not charging. The batt light was not on, but the idle was low and it was charging at 12 when i was at idle. After i changed the serp belt, the batt light came on and the gauge in the truck still read 12 until i stepped on the gas.

I had the alternator checked at 4 different places in addition to my own checks. The alternator is good. The battery is good. I put a gauge on the battery with the alt on the truck, while running and it says it is charging good and at 14 volts.

I am getting ready to go buy some battery terminals now, but if anyone has any ideas, please post a reply. i will check when I get back. This morning my check engine light came on, but it didnt come on this evening.

All fuses are good also, from what i can tell. That fusible link, I know is good, because i put an ohm reader on the yellow wire on the alt plug to the solenoid on the passenger side of the vehicle and gotta short. So no breaks. Help!!

Sorry so long. i will be back in about 30 minutes.

 

I figure I would post in this one too. I changed the battery terminals and the batt light went off. The truck still idles really low and cuts off. This can be anything. The check engine light is not on so there's no code to read.

 

I bet the battery light is coming on because of the low idle and that there very well could be nothing wrong with the charging system.
-Johnboy

 

Thats what i had thought, but when the idle is up, the batt light was still on. it was a steady light. Its not on anymore, but the idle is still low and the light stays off. i have some things to check, like spark plugs, vacuum lines, and some kind of VECI thing. not sure what that is yet.

 

Just drove the truck today and the battery light came back on. YAY! this can't be related to the idle problem. the idle problem has to be related to this somehow.

 

You should pull the codes from the computer to see if the computer has stored a trouble code. Not all trouble codes trip the CEL.

Do you have a voltage gauge that you can watch while driving and see when the batt light comes on? Also was the new belt the right length, so as to not be too long and cause slipping of the belt?

Also, how low is your idle?

 

Okay on the codes. I did not know that not all trouoble codes trip the CEL. I will see what i can do on that one.

Yeah, I do have a voltage gauge in the truck. While driving it is at 14. The battery light is still on. The light stays on from when i start the truck all the way thru, low idle or normal driving.

My idle is running about 500 or maybe a little below. It seems to me that it is related to this battery light somehow. The guage reads 12 while at idle, but 14 when driving, and the batt light stays on regardless. I guess it is possible that the low idle is causing the low charge, which would cause the batt light to come on, but while driving? the engine is producing enough speed to charge normal and output the correct voltage, but the batt light is still on.

The belt? yeah i checked it to make sure it was the correct size. I have good tension on the belt and everything. I do have a chirping comeing from one of the pulleys. But I dont think that would cause this other issue. I dont know.

 

Clean your intake and AFM. or whatever that thing is called on the side of the intake. I can never remember the proper term for it. I was having the same problem with low Idle and veh trying to stall witch would set of the batt charge light. Grabed a can of intake cleaner pulled off the AFM soaked and cleaned it out and cleaned teh pasages. Bolteld everything back up and all the symptoms disapeared..

 

Thanks, Zrock, I will check it out after work today. Will my manual have what an AFM is and where it is exactly? It probably will. I'll check it out. Thanks.

 

It is called an IAC, Idle air control? Looks like a selinoid on the side driver's side of the throttle body. Has two bolts and one wired connection to it.

 

ya thats what i was trying to think of.... Took me about 20min to remove and clean reinstall.... Was taking my time...

 

I am working on this now. Thanks guys. I will let you know how it turns out. i just changed the spark plugs, now im on to the intake and IAC (thanks alxsnmr)

 

So, here's an update. I think it is fixed. The battery light did come on last night after i was done, but it was not on this morning. It still seems to be idling low, but not so low where the truck cuts off. This morning the truck started and did not cut off, but it did not start like it normally would, like where it idles higher and then comes down after it warms up a little bit. It still seems a little wierd, but for now, I am satisfied. Thanks guys for your help. I took some intake cleaner and cleaned the plates inside the intake, and i pulled the IAC off and cleaned that too. It was pretty black in there. I also put new plugs in, which were also pretty fouled up. The gap was way to big and they were pretty charred, but not wet, so thats cool.

I think i may need to check the timing. It seems there may be a slight miss. I have a timing light, but i am not quite sure how to check it. On my old F100 i could stick the light in thru the top and check, but on the bronco, the water pump and fan pulley are in the way. I looked underneath and saw the TDC markings, but my light wont reah under there. Any suggestions would be greatly appreciated.

Again, many thanks to the IAC idea. This seems to have worked.

 

You will have to disconnect the spout connector to set the timing. Sorry it has been a long time since I worked on a Bronco of this era but some one else should be able to tell you where it is. The computer uses this connector to adjust the timing and it need to be set with out the computer hooked up to get it right.
-Johnboy

 

Oh okay, i did read about this connector in the haynes manual. Thanks, Johnboy! The manual doesnt tell me where to put my light though. On my old F100 i could just do it up above with the hood open, but on the bronco, the waterpump is setting there with the fan. The marks showing TDC and so forth are underneath the truck.