Archived New alternator -- still no charge

[KMahnke]

Ok guys I need help! Been out of a truck for a week now waiting on a new alternator to come. Old thread https://www.turbodieselregister.com...n-1998-5-2002/189417-random-voltage-drop.html New one finally came today and put it in... . no luck, same problem... no charge. I had to jump start it because the batteries didnt have enough to get it to crank. I ordered a brand new DENSO Part # 2110135 from rock auto. I was looking on the forums and found this site Alternators and in the fine print it mentions that the Denso will not replace the Bosch alternator because it doesnt fit... the old one off the truck is a Bosch. I got the new Denso in no problem, the hot lead was was moved over slightly on the new one but not enough for the wire not to reach. Did I get the wrong alternator or does my problem go deeper?





Thanks for the help!

 

[LandShark]

Are you having any other problems with the truck? Any codes? Does the tach work? Any other malfunction lights? Which truck? Is it the 01 or the 95?

With a full charge, the batteries will run the truck a day or two with no problem. IF YOU ARE IN A pinch, it's easy to hook up a external regulator to keep the batteries charged.

 

[Missouri Mule]

Charging system: There is a EVR (electronic voltage regulator) inside of PCM it gets input from the Battery temp sensor and the ASD relay and determines alternator charging rate.

Battery temp sensor under driver's battery tray it of course sends temp readings to EVR.

ASD relay is in PDC it sends line voltage to EVR it is turned on by engine speed sensor, on your truck the crank position sensor probalbly turns it on.

If these two items are working then it is either your alternator or EVR.



This is the way it works on a 96.



Your Alternator question.

If all the wires/ connectors fit in the right places it should charge.



As Landshark stated you can put a remote regulator on. It can permament or used to test alternator to pin point the EVR as the culprit.

If the EVR is found to be bad you can buy a new PCM or leave the remote regulator on.

 

[KMahnke]

This is happening on the '01. Tach still works, no other lights or problems with the truck. The 2 codes that were coming up are :



P1682 (G) Charging System Voltage Too Low Battery voltage sense input below target charging voltage

during engine operation and no significant change in

voltage detected during active test of generator output

circuit.



P1693 (M) DTC Detected in PCM/ECM or DTC



I have ran the truck a few times since it stopped charging so I do believe thats why the batteries are dead.



As far as a remote regulator, how would I go about setting one up?



Thanks for the help!

 

[JFaughn]

I've not been a big fan of the external regulator , unless you can prove through testing that the PCM is bad , even then I would keep an eye out for a very cheap PCM as the truck ran with the external .
But being that you are talking about the 01 , I would spend a lot more , time & money to " not " put in the external reg. , more often than not its a connection problem , get some good testing done to find the problem , the newer trucks with the more involve electronics , becomes a longer chain of events when want to start engineer .
The different manufactures of alt. s is less of the same , as an example , you have an-other charging problem on the road , most alt. s & starters are rebuilt , what may happen is the place you go to will not give you a core value on a different alt. , so you end up paying more the next time , now the savings are gone .
I've been wrenching for over 30 yrs , I do not see a need for them to make some things more involved , have an alt with a reg on the fender well if not internal reg. , putting it in the PCM is an example of the new definition of an old term , preventive maintainace = preventing you from maintaining .

 

[John - K5AWO]

Be sure and check the alternator fuse

I had the same symptoms and also enjoyed? buying a new alternator only to find that did not fix it up.

Turns out, the fuse between the battery and the alternator was blown. If memory serves, it is a 130 amp fuse? At least it is a big honker and cost me a bundle to replace at retail because the truck was "out yonder somewhere".

Here were my symptoms in addition to what you have mentioned. Battery voltage way low, with engine running, the alternator output voltage was 30+ volts. Ergo, something must be wrong between the alternator and the battery. How can you have 30 volts on the alternator and a dead battery, right?

Unfortunately, I was not driving the truck and was trouble shooting the thing by telephone with the driver of the truck.

end result: I have a used, good alternator, a new alternator on the truck and a new alternator fuse.

 

[Missouri Mule]

Forgot about fuse in PDC.

 

[RON'S RAM]

Not sure if the 01 is the same as the 97, but I had the same problem and it ended up being a blown fuse. I could only find a new one from the dealer, so I bought a spare just in case. Test for voltage right at the alternator. Mine also was putting out close to 30 volts at the alternator but nothing at the batteries. The fuse is wired between the alternator & batteries. Once the fuse was replaced, alternator output was back to around 13-14 volts.

I never found any problem as to why the fuse blew.

Good luck.

 

[KMahnke]

Checked the fuse and the only one I found was in the fuse box under the hood, 140 amp and was still good.

 

[59crd]

Check for the wiring harness that is up by the engine dipstick tube up by the intake elbow to not be rub through if the wiring grounds it will blow a fuse and cause a not charge condition, this took me a while to find but it fixed my buddys 01, I found that the fuse that would blow was a 30 amp engine control in the pdc, If memory serves, well that fixed my problem.

 

[RON'S RAM]

Checked the fuse and the only one I found was in the fuse box under the hood, 140 amp and was still good.

Did you test for voltage at the alternator?