Mitsubishi Eclipse 3G Club banner
21 - 38 of 38 Posts

·
Registered
Joined
·
411 Posts
Discussion Starter · #21 ·
I assume you checked all associated fuses and relays, fusible link, etc?
I was looking at some fuse box diagrams and noticed there was a "generator relay", at least according to that diagram but dunno if its accurate or not. Change your alternator belt too if you haven't already, and make sure its adjusted properly.
Belt is new as well as the pulleys. Can you send me the page the generator relay is on? I don't see it.
 

·
Registered
Joined
·
411 Posts
Discussion Starter · #25 ·
No relay found in this whole car for the alternator. I just bought a new battery. I had the battery tested and the numbers came back screwy. The battery is a 540 CCA but, was tested shows 738amps! I also replaced negative battery terminal. I took the ground lug loose at the body and cleaned it and checked all the wires for the positive side and reinstalled my factory alternator. I threw my trickle charger on the new battery for safe measure. Also, I checked the two wires from the pig tail at the alternator to the plug in near the fuse box for continuity, all of which are good. It this doesn't fix it, I'll get 3 ft of ground cable and rebuild the ground to the back of the head. If this doesn't fix it, it's to the ECM we go (I really hope it doesn't get that far).
 

·
Registered
Joined
·
411 Posts
Discussion Starter · #27 ·
You've changed so much that, in the end, are you going to be able to pinpoint the original problem when its finally resolved?
Should via process of elimination. So I just started the car. Voltage is fluctuating depending on what loads are applied e.g AC, high beams. At the highest, I got 14.3 volts on my multimeter on the back of the alternator to ground. When I shut everything down and leave idling, the voltage drops to the point of setting off the battery and brake light again. So the rebuilt alternator and new battery did not correct the problem. I'll move on to the ground cable next. This is a pain in the epic ass.
 

·
Registered
Joined
·
411 Posts
Discussion Starter · #28 ·
OK, I can replicate this exact event EVERYTIME. Here we go! At idle speed, all voltage is within factory spec. IF I turn on the AC, high beams and any other load, the voltage increases as it should. NOW, here is where it gets screwy....Lets say I have 14.4 volts with all loads applied and shut off the aforementioned loads, then all of a sudden my voltage drops below factory spec and the battery/brake lights come on. After a few seconds, voltage builds back and the lights go out. What am I missing here? I have a new battery, my OEM alternator that has been rebuilt, all wiring is good, all voltage at the alternator pig tail is within spec (other than it does fluxuate some). The only thing I have not done is replace this negative battery cable and I intend to do that in the near future. Thoughts anyone? Im lost on this problem.
 

·
Registered
Joined
·
411 Posts
Discussion Starter · #29 ·
SHOP rebuilt OEM alternator is worse now than ever. Barely puts out 12 volts and the bearing is making a whirling noise. Just bit the bullet and ordered a FACTORY rebuilt alternator. I'm sick of dealing with this issue.
 

·
Registered
Joined
·
411 Posts
Discussion Starter · #32 ·
Ok, so I ordered the Denso alternator today. Should be here Friday. I was reading on the DSM 2g forum and it appears the 2 signal wires (FR and G) let the ECM monitor the electrical load on the charging system. If the ECM detects it needs more voltage, then the idle speed will increase for more voltage as the alternator makes more power with higher RPMs. This can be seen in our FSM as it states hold RPMs to 2500 when running most of the alternator test. So, while driving on the interstate this morning, crusing between 75mph and 80, the tach was showing about 2800rpms BUT, the voltage was bouncing all over the place and the batt/brake light came on. I called the shop that rebuilt it and he said it sounds exactly like a bad regulator and offered to give me my money back. I'm betting on a bad regulator right now.
 

·
Registered
2005 Spyder GT
Joined
·
721 Posts
I don't understand how a shop could rebuild an alternator WITHOUT checking the regulator, I mean, that's just bullshit!!! Its an electrical component FFS!!! I'd be real pissed and wouldn't use that shop again, EVER!!! IDK, perhaps the regulator was only failing when it got hot??? Anyway, I think you've found the problem and shouldn't have an issue with the Denso
 

·
Registered
Joined
·
411 Posts
Discussion Starter · #34 ·
I fairness to the shop, they use all new parts e.g diode pack, regulator and bearings. The first time, the diode pack blew and it was clearly seen. This time, it's the regulator possibly. I e used this same shop before with great results so I can't be mad at them for that. I've bought bad part right out of the box before and I know others that have done the same especially in recent years. We will see if this Denso alternator fixes the problem. After driving today, it was acting the same. Like the regulator wasn't built within the spec the 3g needs.
 

·
Registered
2005 Spyder GT
Joined
·
721 Posts
I fixed it! The voltage regulator was bad! Voltage from ground to B terminal (bolted wire) is 14.3 volts! Denso alternator fixed it.
Another member is having similar issues and I bet it will be fixed by using a quality alternator rather than a lot of the crap being sold nowadays.
I typically lean towards either Denso or Bosch electrical components when OEM aren't available.
 
21 - 38 of 38 Posts
Top