Allpar Forums banner

1 - 11 of 11 Posts

·
Super Moderator
Joined
·
13,926 Posts
Discussion Starter #1
I was just towed in this morning due to my 1994 Caravan 3.3L dying.

The 'Check Engine' light came on and a few minutes later the 'Check Gauges' light lit up along with the charging light. I drove about 10 miles till I could stop at a convenience store along the freeway in rural Arizona near the California line. Started up the van again and just the 'Check Engine' light came on; drove about 6 miles and the other two lights flashed back on. Note this was at 1 AM so I drove as far as I could till the battery was almost dead whereupon I pulled off and shut it down.

I let it sit for a few minutes then tried to restart the van; click. Waited about 30 minutes while waiting for the tow truck and the van started up, again with just the Check Engine light. But the idle was unsteady and the battery was draining down again. Tried starting it again and nada.

I'm thinking alternator but maybe a defective computer?
 

·
Super Moderator
Joined
·
31,983 Posts
I'd want to get fault codes. Based on whats' written, probably a shorted diode or two in the alternator.
 

·
KOG
Joined
·
6,994 Posts
Don't know if you've swapped an alternator on that one before, but the FSM procedure is difficult to impossible. Better to remove upper plenum to have room to work. I've done it both ways several times. If it's got over 150K on the original brushes they're probably toast. FSM says to replace at 100K or less if I remember correctly. They last longer than that, but not 200K.
 

·
Super Moderator
Joined
·
13,926 Posts
Discussion Starter #5
My job went away a couple of weeks ago (laid off) so I have no access to scan tools. I guess I'll try an alternator first.

[at]KOG: I don't believe the plenum is removable on my Caravan; it's a 1994 which is the same body as a 1991-95. I know what you mean on the 1996+ minis hence my avoiding them when I bought my mine a couple of years ago.
 

·
KOG
Joined
·
6,994 Posts
Yep, upper intake plenum. You'll need a new gasket for that and use your torque wrench when putting it back on.
 

·
Super Moderator
Joined
·
13,926 Posts
Discussion Starter #8
Well; it was the alternator; yanked it off, G/G took it down, had it tested, stone dead, brought back a reman and I reinstalled it. Recharged battery and van started right up with no 'rude' warning lights. :)

I 'cheated' pulling the alt off: loosened the top bracket and slightly bent it and disconnected the AC line junction block at the firewall (no Freon issue since it all leaked out a month ago). I still have to finish tightening up a few bolts but that'll be later today once I wake up.
 

·
Registered
Joined
·
136 Posts
Some advice for others:

Try whacking alternator with a wrench, my failing one responded to that.

Voltmeter to use on battery terminals is good thing.

Knowledge of how to read codes is helpful (somewhere in Allpar no doubt is explanation of how to get codes and list of them, IIRC alternator failure will result in a code saying that ECM cannot control field or such, as the ECM includes voltage regulator function).

There is a voltmeter on the dash in at least some vehicles, but marks are not properly made. Nevertheless, you should see the pointer move at least one mark from not running to running and charging (from ~12v to ~14v).
 

·
Super Moderator
Joined
·
13,926 Posts
Discussion Starter #11
Some advice for others:

Try whacking alternator with a wrench, my failing one responded to that.

Voltmeter to use on battery terminals is good thing.

Knowledge of how to read codes is helpful (somewhere in Allpar no doubt is explanation of how to get codes and list of them, IIRC alternator failure will result in a code saying that ECM cannot control field or such, as the ECM includes voltage regulator function).

There is a voltmeter on the dash in at least some vehicles, but marks are not properly made. Nevertheless, you should see the pointer move at least one mark from not running to running and charging (from ~12v to ~14v).
No alt gauge on my van; just a warning light and buzzer plus the 'Check Engine' light also came on. Needless to say; I plopped a reman alternator in there and the charging system is now working. :)
 
  • Like
Reactions: BlackSheep01
1 - 11 of 11 Posts
Top