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1G Alternator trouble still

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Joseph90talon

Proven Member
35
3
Aug 18, 2015
Paw paw, Michigan
Steps I've done on my 1990 eagle talon to trouble shoot altanator not charging issue
1.checked and added grounds
2. Altanator relay replaced
3. Altanator fuse replaced
4. Battery tested (good)
5.altanaror replaced ( also had it tested. test results were good)

Voltage readings with key off on the back of the altanator

B+ cables attached to battery then stud on back of altanator 11.8 volts

L terminal (black and white wire) no voltage

S terminal (yellow wire) 11.8 volts

Voltage readings with key on the ON POSITION

B+ terminal cables attached to battery then back of stud on altanator 11.8 volts

L terminal (black and white wire) 2.2 volts

S terminal (yellow wire) 11.8 c

voltage readings in back of alternator with car running.

B+ cables attached to from battery to stud on alternator 11.8 volts

L terminal (back and white wire) 11.8 volts

S terminal (yellow wire) 11.8 volts

The cars stock with No system or crazy wired accessories. The computer does look to have some wires spliced on it not sure what that's about. Also my tach does not work. I just bought this car with a blown motor just got it back up and running. This stupid electrical issue is all that's stopping me from hitting the pavement
Any help would be GREATLY APPRECIATED guys!!
 
Is the charging warning light functioning? Does it come on with the ignition on car off? Does it go off once the car is started?

With the car running, you should see charging voltage at the L terminal. It sounds to me like you're only seeing battery voltage there, which obviously would mean the alt is not charging (sounds like you figured that much out already). What that does seem to indicate though, is the wiring from the ignition switch through the alt relay seems to be working. If the charging light is functioning correctly as well, that half of the circuit would appear to be good.

I know you said you tested/changed the alt, but it seems like that's where your issue may be.

Also, 11.8V would indicate you battery is dead as hell. Fully charge the battery, and then test the system. You should be seeing right around 12.6V on a fully charged battery (car off). You should see somewhere around 14V give or take while charging. The charging voltage should fluctuate with RPM.

Here's a good reference for testing if you haven't already seen this. It basically outlines pretty much everything I just said: http://www.galantvr4.org/docs/1g_charging_starting_system.pdf
 
Yes the battery warning light comes on when key is in the ON position. When car starts the battery light disappears. As far as the altanator goes the first one I bought I had them test it twice it passed both times I still had them replace it with another then also had them test it the machine also said it passed.
 
Looking back at your test results, with the key on and engine off, you should have battery voltage at the L terminal. You said the warning light comes on, so that's good. Can you confirm you have battery voltage on pin 2 of the alternator relay with the key on engine off?
 
I currently have an alt problem as well, but trying to chime in. For some reason on mine on a warm start it doesnt charge UNTIL i rev the engine up pass 3 or 4k rpm...then it begins and stays charging. I will change the alternator on mine, but to my problem my assumption is the alternator is bad or more so the voltage regulator. To your problem, have you tried reving it? I would say try a new alternator, if anything you can return it. GL
 
From my understanding On second gens theres 4 things that can mess with the alternator. The fuse, there's a relay by your coolant reservoir the low battery light indicator and the ECM.
 
Our cars have self exciting alternators(after 2500rpm). If it is not charging once you blimp the throttle, you need a new alternator. If it doesnt charge without reving you have a wire issue. Its as simple as that.
 
I apologize I tried to do a voltage test in the dark this morning be4 work and it was incorrect.. I do have battery voltage at the altanator relay 12.7 at the battery and 12.7 at the altanator relay
 
Well man, you have power everywhere in the circuit where and when you should except for the B terminal on the alternator. Can you verify that when you put a meter probe on the Alt B terminal and also on the battery - with the car running you only get battery voltage, and the voltage doesn't change with RPM?

At this point, You've pretty much ruled out everything. The alternator is the only thing left. Do you have a known good alt you could swap in? I know you said your current alt was tested, but the alt itself is really the only thing left.
 
With new and reman alternators, if it doesnt excite after 2500rpms its shot. Get a new one. Like I said inmy previous post, our alternators(majority of them) dont need any special wires to start charging.

The simple fact that voltage isnt rising with rpm(assuming charging cable has a good connection) is a dead giveaway. I've been told on several occasion at parts stores that my bad alternator was good. I've also received brand new DOA alternators. Most of those parts guys dont know shit.
 
Portum had a pic of a second gen on his profile pick so I just assumed that's what he had then you chimmed in lasthop05 so I wasn't sure if it was just second gen alternators that started charging after a free rev of 2800 or if that diagnosis covered my 1st gen as well..so I guess time to break out the pocket book for a oem alternator LOL Ill update the thread when I get the oem one on.
 
^Yeah, I agree. I'd say your alternator is the issue. I've also had DOA alternators out of the box.
 
Hey guys! Sorry it took so long for a update. During my alternator trouble I noticed my timing belt looked a lil sketchy so I decided to do a timing belt and water pump replacement also. Anyway back on subject I got the Saturn alternator wired up and mounted and she's now charging at 13.7 volts .
 
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