Mini 30amp fuse blowing. Lots threads. No ansers

[stig0000]

Hi all. Just got back from a week at fraser is. Another great week. Jeep wentwell again untill my 30amp engine ecu fuse keept blowing.

Bit of history. Few months ago when 4wd. When reved the ecu fuse would blow. Engine would idle fine tho once reved over 2-3000rpm. It would blow. Still drove it home tho it stoped blowing and couldent find anything at fualt

Then yesterday. It happend again. Alltho this time wile trying to tow a bogged pagero thru indian head. And if you no the place. Youd get the idear of the situation. Got towed out buy a mate and started fualt finding. After going thru countless fuses and rums. In 40deg heat. Finaly pinpointed it to be the aultenator. Disconect the reg off the back and drove perfict. Juust no aultinator. No problem have duel batterys and drove all the way back to the coast. After a google theres a heap of threads for this problem tho no fixes. Few say o2 sensors short tho not my problem. Im atm replacing the ault and then retesting. So if you get this problem this could be a fix.

[junglejuice]

Just for your info there isn't a regulator on the rear of the alternator, the black block is merely a moulding to hold the wiring in the desired place.....

[stig0000]

Ahh sweet. Thanks.

[Roler]

Did you get a chance to take some readings on the alternator?
Or any codes?

That first time it happened, was that in similar (warm/hot) conditions?
For some reason this makes me think of the thread we had not too long ago, relating to that battery temp sensor in the battery tray and the feedback to the ECU...

[stig0000]

Both were in low range and motor was working hard. I was pulling another car in very soft sand and first time was on a slippery hill 4wding. The first time I dident notice low voltage. Later on I will get codes from it. My temps weren't bending into the red tho both times it was very slow and lots of revs. Been worked. First time I let it cool down. Put a 15amp fuse in (last one left) and it ran like that for about 2 months. With in that time there was more 4wding.

I never new there was a bat temp sensors??

[Deezelweazel]

Just some background info:
If a 30Amp fuse is blowing, you have some serious short. These fuses are designed to handle up 1.5 times the current before they blow. This means in your case up to 45A.
Depending on your alternator (Nippon Denso or Delco Remy) ( related to the XJ model) you have an external regulator.
In the past update model this regulator is located- guess where? - in the ECU.

For this reason it is important to let the forum members know what XJ model you drive. Otherwise every fault diagnosis is just guessing...
If your regulator is shot. The cheapest exchange (You really don't want to buy an new ECU!) is to put an regulator directly behind your alternator.
But we don't know the model, so it is guessing again.

[layback40]

Originally Posted by Deezelweazel

Just some background info:
If a 30Amp fuse is blowing, you have some serious short. These fuses are designed to handle up 1.5 times the current before they blow. This means in your case up to 45A.
Depending on your alternator (Nippon Denso or Delco Remy) ( related to the XJ model) you have an external regulator.
In the past update model this regulator is located- guess where? - in the ECU.

For this reason it is important to let the forum members know what XJ model you drive. Otherwise every fault diagnosis is just guessing...
If your regulator is shot. The cheapest exchange (You really don't want to buy an new ECU!) is to put an regulator directly behind your alternator.
But we don't know the model, so it is guessing again.

Dont you just hate it with these people who wont put proper details about their jeep in their signature.
It doesnt matter what type of 4WD you were towing or where you were or what you were drinking. Your jeeps electrical system has no interest in these things.