Alternator

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Well guys, go figure, just when I was about to order my 16cm turbo housing, and think about some new tires, I find a new problem. I went to the hardware store today and found that the voltmeter was reading lower than normal. When I got home, I hooked up a tester and it said that the alternator wasn't charging.
So here's the question, has anyone else's quit at 133,000, or is there anything I can do to save it, or if you bought a new one how much? I guess this is kind of an urgent thing I need to tend to since the battery won't last too long turnin' over that big motor.
I really want that housing, and new tires, and...
Thanks

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'93 D350 2wd Club Cab 5-speed,133,000 miles,K&N, Amsoil throughout, Borgeson Steering Shaft,Isspro gauges (Tach,EGT,Boost,Engine Oil Temp. )

 

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Chris,

I would look for a reliable Starter / Altenator shop and have them go over it. I haven't had that problem on mine yet, but on my other vehicles that's what I end up doing.

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'93 LE W250 5spd 3. 54 White Reg Cab
180,000 Miles 04/11/00

 

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I was going to look for a rebuild kit for mine as it eats voltage regulators (in '89 the regulator is external on the firewall). the lights flicker at idle and when I changed the serpentine belt, the alternator did not spin too freely.
Does anyone know where you can get one??Part #'s??

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Jason's Lil' Mack - 89 D250LE 2WD 5Spd 3. 55 Reg Cab. K&N,"tweaked pump", 3. 5" Exst straight,E&M Custom seats. Bosch H4, PIAA 80W/80W HdLites. Bosch 100W Driving. Bosch 55W Fogs.
218,000 miles (355,000 Kms)
7450 Hrs.

 

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Well, I just put a new alternator on,... and no change. The gauge is still reading low. Any suggestions on things to check?

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'93 D350 2wd Club Cab 5-speed,133,000 miles,K&N, Amsoil throughout, Borgeson Steering Shaft,Isspro gauges (Tach,EGT,Boost,Engine Oil Temp. )

 

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Yo, I just finished a dual Optima battery installation and noted the same thing, voltage lower than usual. After driving a few miles, the voltage came up. I figure that the mass of two batteries in parallel lowered the resistance enough that even though the amps were going in, it took longer for the voltage to rise. It seems fine now.

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'93 D-250 Club Cab, Emerald Green & Gold, 5-speed w Gear Vendors OD, 77K , ASC Sun Roof, Horton Fan, Transfer-Flo 45 gal tank/toolbox combo,PIAA Pro 90 Driving lites, 16cm turbo housing, fuel pressure adjusted by James Ray, '96 chrome wheels, Hella headlights Pre-luber, Fuel filter relocated, Chrome kit
May Madness registration committee 97,98,99,TDR ; December Dieselfest winner, 98;
Nationals 99

 

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Chris the voltage regulation on the 92,93 trucks is controled by the engine control module located behind the battery. On the front of the engine there is a wire running up from the harmonic ballancer, this is coming from the engine speed sensor. Follow the cable up there will be a connector near the top of the engine. Check for a good connection. The engine control module uses this signal to control the field voltage to the alternator.
Hope this helps.
Gene
92 350 4x4

 

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Ditto on the engine speed sensor. It lets the PCM know that the engine is running so that the AUTOMATIC SHUTDOWN RELAY will close and permit the field circuit to energize. The PCM then reguates the voltage. If the sensor is bad it will not be obvious unless you have a factory tach. The tach will not operate or the needle will bounce if the sensor is bad. Perform the following checks:
NOTE: Since you just replaced the generator you may save time by going to step 4.

1) See that battery voltage is present at the generator output terminal (terminal D). This will tell you if there is a good connection or not between the generator and battery.

2) Check that the generator ground wire (terminal A) is secure.

3) If both of those things check out, disconnect the black two wire connector near the generator. The wire colors from this connector to the generator are Dark Green and Dark Blue. Connect battery positive to the Dark Blue wire at the connector and then connect another wire to the Dark Green wire at the connector and with the engine running AT IDLE momentarily ground that wire and see if the voltmeter shows an increase. If it does the generator is good if not it's bad. If good reconnect the connector.

At this point the problem is that the field of the generator is not being energized.

4) The Auto Shut Down relay is located on the drivers side fenderwall and has four wires going to it. They are RED, DARK BLUE, DARK BLUE WITH YELLOW STRIPE and DARK GREEN WITH A ORANGE STRIPE. Find this relay and remove it from its connector. Jumper the RED wire to the DARK GREEN WITH ORANGE STRIPE wire. If your charging system operates either the relay is bad or it is not being triggered by the PCM. To determine which check that with the engine running there is power to the DARK BLUE wire, if none (this is very unlikely) there is bad wiring between the ignition switch and the relay. Reinstall the relay and with the engine running at idle connect a wire from the DARK BLUE WITH YELLOW STRIPE wire to ground. If the Charging system now works the PCM is either bad (not likely) or the engine speed sensor is bad (likely, I just replaced mine at 125K). If the charging system does not work the relay is bad.

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'93 W350 Club Cab, 5 sp. , Factory Options: LE, 4. 10, LS, 7600 lb. rear springs, tachometer, front stabilizer bar. Mods: Banks stinger plus, Linex bedliner, 25,000 lb gooseneck, 10,000 lb receiver, Tekonsha brake controller.
'Power Wagon' injectors to be installed!

 

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First off, thanks for your replies members! Mark, I followed your directions and came to the conclusion that the relay was bad. However I just got off the phone with 3 different Dodge dealers that don't even list an Auto Shut Down relay for a Diesel. They have numbers for gassers, but no Diesel.
What am I to do?

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'93 D350 2wd Club Cab 5-speed,133,000 miles,K&N, Amsoil throughout, Borgeson Steering Shaft,Isspro gauges (Tach,EGT,Boost,Engine Oil Temp. )

 

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Chris I have three relays mounted in the engine compartment near the battery. The one mount on the single bracket is pn 4443977, the other two are mounted together on another bracket this is pn 4638271.
Good luck
Gene
92 350 4x4

 

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Thanks so much Gene! Ahh, the part numbers. I guess that I was a little upset when I wrote that last post. I forgot to write that my relay doesn't have a part number on it anywhere. So the dealers were just going on the description, but they were very helpful, and I probably could of got one without the part number. But part numbers never hurt anyone!
All of this aside, I think I might of found the problem. You know how it goes, one of those small, easy, kick-yourself-in-the-butt-because-its-such-an-easy-small-thing-that-you-didn't-double-check things!!!! Anyway, I'll keep you posted. And as always, it seems that I couldn't solve any of my problems without the membership! Thanks again!

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'93 D350 2wd Club Cab 5-speed,133,000 miles,K&N, Amsoil throughout, Borgeson Steering Shaft,Isspro gauges (Tach,EGT,Boost,Engine Oil Temp. )

 

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Mark,
I installed tachometer but it won't work, you seem to understand the engine speed sensor, my truck is auto and uses the sensor to control the overdrive and charging system, the overdrive and charging system both work fine but the tach won't, could this still be the speed sensor?
Thanks in advance, HAPPY RAMMIN!!!
Caleb Reese

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1993 LE W250 4x4 CC,Auto,3. 5's,Limited slip. Diamondplate,K&N,Egt,Boost,trans temp VDO Vision series, BD 3 1/2" Exhaust.
Preparing to B. O. M. B.

 

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Members, now for the SOLUTION!, I think. Yesterday when I was scratching my head sitting in the drivers seat, motor running, getting ready to leave, I got out of the cab, lifted the hood, and reached for that speed sensor connection in front of that first valve cover. I juggled it a little and went around to the drivers side just to see if the gauge had moved, well it DID! So I think that it was the culprit. That would also explain why the BLUE W/YELLOW STRIPE wasn't hot which made me think that the ASD relay was bad.
If I have some time tomorrow, I'm going to put the old alternator back on and see if it was just that speed sensor connection. Which I hope is the case.
I think that I know why the connection wasn't good, however I'll explain that later.
As always, A BIG THANKS to all members!

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'93 D350 2wd Club Cab 5-speed,133,000 miles,K&N, Amsoil throughout, Borgeson Steering Shaft,Isspro gauges (Tach,EGT,Boost,Engine Oil Temp. )

 

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Hey Chris and Boatpuller!

Glad you found the loose connection Chris. It's interesting about the dealer not being able to find the ASD in the part look up. The 93 service manual does not call it out in the underhood PHOTOGRAPH for the diesel but instead has a "fuel pump relay" (which the diesel does not really have) shown as the most forward relay on the drivers side. This should be shown as the ASD. Bad cataloging.

Boatpuller, if your charging system works your engine speed sensor is good.

Four wires go to the tach. The colors on the truck side of the tach connection are BLACK (ground). ORANGE (power for the light-this is variable voltage positive). RED (12V positive). GRAY WITH LIGHT BLUE STRIPE (PCM).

Check that the BLACK wire is grounded and that the RED wire has 12V present with the engine running. The same fuse used for the turn signal flasher (fuse 9) feeds the tach.

If that checks out either the tach is defective or the PCM is at fault.

From what I see from the wiring diagram the tach works by the PCM rapidly (the exact rate depending on the engine speed) grounding/ungrounding the GRAY/LIGHT BLUE wire which causes a DC current to flow through the tach in pulses. In turn those pulses are counted by the tach and the RPM are displayed.

To test the tach try disconnecting its connector and jumpering 12V to the tach wire that matches up to the RED wire on the truck connector (this may also be a red wire on the tach side of the connector). Then connect a length of wire to the tach wire that corresponds to the GRAY/LIGHT BLUE wire and VERY RAPIDLY, as fast as you can, touch that wire to ground REPEATEDLY. This should simulate the PCM operation.
If the needle of the tach moves the tach is good and for some reason the section of the PCM that controls the tach is bad.
A new PCM would have to be installed. If the tach does not respond then it is defective. In all the above I am assuming that the tach is a MOPAR unit or an aftermarket unit that is designed to hook directly into the Dodge wiring harness connector. Definitely check the TACH SIDE wiring to make sure it is located in its connector (supplied with tach) properly so as to match the right wire on the truck side of the connector.

I wish you a working tachometer!




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'93 W350 Club Cab, 5 sp. , Factory Options: LE, 4. 10, LS, 7600 lb. rear springs, tachometer, front stabilizer bar. Mods: Banks stinger plus, Linex bedliner, 25,000 lb gooseneck, 10,000 lb receiver, Tekonsha brake controller.
'Power Wagon' injectors to be installed!

 

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Mark,
Thank you very much for the info, I think you have explained my problem to me, I ordered a VDO Vision series tach, their tech support person told me that he had info from Chrysler that the tach pulse is 100HZ@3000 RPM,which he said is the same as a 4cylinder gas ignition, he was assuming that the pulse was a voltage pulse not a ground pulse, he said that their tach needed at least 5volts for signaling. So now I have a brand new tachometer that I can't use and probably can't return because I have had it for to long. At least now I can start saving up for a MOPAR tach so that I can have one that operates, and quit wasting time trying to make the one I have work.
Thanks and HAPPY RAMMIN,
Caleb

 

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Hi Caleb.

I got to thinking about the what VDO said and they are probably right about the PCM providing positive voltage pulses to the tach. When I read the wiring diagram I interpreted the PCM completing the circuit to ground (that is, being electrically between the load and ground) for the tach as it does for almost all of the outputs it gives. If VDO is wrong none of their tachs would work when hooked into the Dodge harness.

It seems worthwhile to determine if the tach works. I am not surprised at all when new stuff doesn't work; upset, yes; surprised, no.

Knowing how the tach operates you can check it as follows:

1) Disconnect tach connector from the truck wiring harness.

2) Connect its ground wire to a GOOD ground.

3) Connect its 12V wire to KNOWN 12V.

4) Connect a wire to the signal wire. Leave hanging free.

5) Connect one more wire to KNOWN 12V. Leave hanging free but not touching any ground.

6) VERY rapidly strike the two free wires together repeatedly. Close to 10 Hz should be possible this way which corresponds to 300 rpm.

If the tach works this way something in your truck is defective (wiring, PCM). If the tach doesn't work-Ship it back!!!

The MOPAR tach p/n is 82400711. Price was $142. 00 (list) in Sept. '98. It is a quality unit (liquid damped movement) with a face and needle that exactly match the other gages.

I hope this additional info helps.