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Help with draining battery and other weird stuff

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titengo

15+ Year Contributor
50
0
May 24, 2006
Maunabo, Puerto_Rico
First of all excuse my english because it's not my primary language.

Second I've searched and read a lot but couldn't find the answer to my problem.

The car is a 95 GSX shell I bought missing the engine and engine harness. I had a 93 Talon turbo FWD with a 6 bolt to put in it. So after I put it in the car would start but it would never idle and missed a lot. The ECU was fried. I got it repaired and the car now starts fine and idles fine. The problem is it drains the battery very fast. So I started reading about battery draining and diagnostics posts. And went to test stuff in the car.

I've narrowed it down to the "TOP" 60A fuse in the engine and the mfi/mpi draining the battery. The battery works good on other cars and other batteries still drains on my car. The car stays on with out a battery and charges it well even on idle. Voltage at idle is at 13.xx. I wrote down the numbers but can't find the paper.

A lot of weird stuff is also happening that may be related(from what I've read here). First as soon as I connect the battery the mpi/mfi relay clicks. The power lock relay clicks but it doesn't move the locks. The AC turns on but the compressor doesn't kick in.

I'm not worried about the AC and the P/L. What bothers me is the battery drain. From what I could investigate it had a standalone (microtech or haltech)before. And I don't know if it has something to do with anything. Also I bought the harness from someone here and he told me it came from a running car. If I disconnect the 60A fuse and the mpi/mfi relay it does not drain the battery.

So I don't know what else to do to solve this. Any help would be appreciated. I almost always resolved everything from reading here but I cannot solve this.
 
Well do you have a multimeter? it would help you could take some readings off of the relay plug. Also some pics of the relay and plug along with any numerical values for the relay pins.
 
Also I bought the harness from someone here and he told me it came from a running car.
I assume this is a harness and ECU for a 95?
I assume the drain happens with the key off and the mpi relay activating?

If the answers to these is yes, the mpi relay activating is the problem (it should never activate with key off). The ECU turns the mpi relay on by putting a ground on ECU pin 38 (http://www.dsmtuners.com/forums/articles-tuning-ecu/281763-2g-turbo-ecu-pinout-w-wire-colors.html). So either the ECU is incorrectly grounding that blue-green wire, or it is shorting to ground somewhere, or the mpi relay is stuck on.

First test the mpi relay to see if it's stuck on. With relay removed, if pin 4 or 8 (both were connected to red-black wire) is connected (has continuity) to either pin 2 (red) or 3 (black-red), it is stuck and needs to be replaced. If not stuck on, then disconnect battery and then unplug the ECU and check if the relay's blue-green wire is being shorted to ground using a multimeter (in resistance mode). If not, you most likely have an ECU problem.
 
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Thanks for the responses.
Yes the harness is from a '95. And yes the drain its with the key in "off". Also when I turn the key to acc the fuel pump starts (even before the rewire). Also the car had in the radio area the tps connector to simulate something I was told.

I will do some tests again but is hard because it drains the battery very fast. If I connect the multimeter to the battery I can see the voltage dropping. This is a new battery and i don't want to ruin it.

Another thing the relay is from a hyundai excel because I couldn't find ona from an Eclipse
 
When you run your next set of tests you should also look to see if once you hook up the battery you get any dash lights like the check engine and so on. This could indicate that your ignition or accessory circuit is fired up when it shouldn't be which is kind of what it sounds like by you saying the ac and locks are activating. But any which way you look at it this shouldn't cause your battery to dye so quickly. I seen something similar happen when my buddy took out his radio and he left the wires to the harness hanging and the constant was touching the ignition.
 
Are you sure the pinout is the same?

No I don't know if it's the same. It's the only one I found that fits. It looks the same. Don't have those numbers either .

Zonerdck: It does something like that but no lights. From what I read in a post is that those circuits are connected together and when I open/close the locks it clicks but the don't move so that may be related.
 
I tested it and with the relay connected the voltmeter read 2A. When I disconnected it it dropped to 0.03 A.

Looking at the harness pin #4 & #8 got constant power, both red/black.
Pin #7 Black/white shows 12v with ignition.

I'm thinking it's the wrong relay because I can hear it click as soon as I plug it.
 
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Post pics of the connector and the relay. You said that two pins have constant and one has an ignition can you make a list for the plug with pin number next to wire color.
 
Here are the pictures. The first one is the relay I have in my car right now. The second one is the connector for the relay. Wires #4 & #8 got constant power. Wire #7 shows 12v with ignition. Wire #6 shows continuity.

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When you say...
Wire #6 shows continuity.
...you mean with ground?
If so thats a problem this wire should only receive ground when the ecu wants it to. Same with the white and red. If thats the case you could unplug the ecu and measure the wire again. If still ground then the wire itself is shorting to ground on something. If the ground goes away this tells you that the ecu is indeed the culprit. Doesn't necessarily mean the ecu is bad it just means that it is causing it to stay on.
 
No not at all I mean i measured resistance across the wire and there was resistance not infinity. The wire it's not shorting.
 
Well if that wire doesn't have a ground on it and the and the white/red doesn't have a ground then that relay is the issue. Did you check it with the battery plugged or unplugged? Also I looked for info on that relay but cant find a pinout so I would say swap it with a known good one.
 
That's what I'm going to do, but the relay is $75 new. I'll post back when I can get ahold of one.
 
So I bought the OEM relay and teh issues were gone. For future reference the one from the excel and other cars will start your car but it will drain your battery.

Thanks everyone for the responses.
 
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