Tonight after work I noticed an odd electrical problem. While the heep was warming up before I take off I noticed that if I tried to roll down two windows (or all four) the engine rpm would drop about 100 rpm from idle and the volt gauge would drop to what I would say is the 10 volt mark.

Does this mean my Alt is weak and not charging 100% at idle or is the battery weak and in need of replacement?

This is a preliminary question before I have the Alt and battery bench tested, just wanted to know what direction I should be going in.

On a side note when coming to a stop, once I get below 15mph, the high idle drops and the engine feels like it wants to stall. If I release the brakes slightly while stopping it does not seem to do it as harsh. Is this a brake booster issue or more of a vacuum issue?

Thanks for reading this far.

 

If your alt is working right,this should not happen,you can take the battery out of the car while it running and will be fine,I would look at alt first.

 

I thought the alt as well, should be an easy swap. Time to price a replacement.

 

I know it is not for everyone,but I buy all mine from the jy,alt,starters,etc. $20,and why I am there I get a spare,I look for the best ones,just bought a starter that is almost new,just so I have a spare,i hate paying for new or rebuilt parts.

 

X 3 on the alternator. I have two other suggestions for you, though. Check your battery cables and alternator wiring at all connections for cleanliness and security. Also, I don't recommend disconnecting and removing the battery on any newer vehicle while it is running. I used to do this on my Pre 1970's Chevys all the time to test the alternator but, I tried it on a 1980 Toyota and the power spike fried the coil, ignition module and voltage regulator the instant I pulled the battery cable. With the XJ being a vehicle with electronic ignition and fuel injection, I think that would just be a really bad idea. Just my two cents. There are safer ways to troubleshoot.

 

No plans on pulling the cables while its running. I arc'd a starter with a wrench and about made work in my shorts.

I was thinking about a jy part. I have been using mypartshop.com and can find them for about $40 in my area. But thats for non u-pull type yards.

First thing in the morning I will go through all the cables and grounds. Get some new wire and redo most of it. Going to get the battery tested and replace if needed and track down a new/used alt.

Let you know how it goes.

 

My statement about pulling the battery was to make a point that your car when running depends on the alt,I always use a dvom or snap on scanner for testing. If you have a dvom just see where the volts are,13,5 to 14 would be good,battery should be about 12.6,when not running.

 

sorry dude man sounds like the alt. have fun fixing

 

kind of stinks, because you have to go at it from the bottom up

 

Pulley on the Alt was bad. Replaced Alt and the belt while I was in there. All is better now. Thanks guys!

 

Good deal