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 Post subject: Hey all
PostPosted: Fri Apr 10, 2015 5:46 pm 
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Joined: Thu Apr 09, 2015 2:24 pm
Posts: 11
Hello all

New to the forum and to DSM's.

I just got a 1991 Mirage thats in pretty good shape. Tracking down a transmission issue with it but I am excited to begin tinkering.

This is my new baby. A 4G15 12v engine with a F4A21 4 speed automatic transmission. With only 111k miles on it seems to have been well cared for.
Image

I am looking for a MD739458 ECU, mine appears to burnt.
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After a few days researching it looks like some ECUs are interchangeable. The numbers I have come up with are MD161840 and MD160390. I am trying to find anyone with a used one before springing for a reman.

Anyway, will keep you all updated
Thanks
T


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 Post subject: Re: Hey all
PostPosted: Fri Apr 10, 2015 5:53 pm 
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The Silent Administrator
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Location: Ottawa, ON, Canada
I vote - replace the capacitors and clean the board with alcohol to prevent further acid damage. Then see what happens. If you have no spark, then there is another larger issue, but try those caps first.


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 Post subject: Re: Hey all
PostPosted: Fri Apr 10, 2015 8:03 pm 
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Location: Stantonsburg, NC
Welcome! Also note that a 1g dsm ecu (1.8 4G37) will work as long as you swap out the maf, throttle body and injectors at the same time. It'll give you a little more power as well. I seem to have better luck finding these in good shape for some reason.

_________________
93 Mitsubishi Expo LRV 1.8/manual
95 Eagle Summit DL Coupe 1.5/manual
01 Mitsubishi Mirage ES Sedan 1.8/manual


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 Post subject: Re: Hey all
PostPosted: Sat Apr 11, 2015 1:10 am 
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Thanks guys

This is just the info I am looking for. Moar power, up from that head snapping 92hp!

I cleaned off the leakage around that capacitor and will hook up the ECU tomorrow and see if that worked. I can get a new cap and solder it in if not and go from there.

The car has spark, runs great. Just the trans is stuck in limp mode. I am going to get a new valve cover gasket tomorrow to do a valve adjustment as the lash seems tight on #3 cylinder. and check the upper internals.

Next up will be a timing belt as I have no idea when or if it has been done. Better safe than sorry.


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 Post subject: Re: Hey all
PostPosted: Wed Apr 15, 2015 7:24 pm 
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Well, still stuck in limp mode.

I went and replaced the bad capacitor.
Image

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Car still starts right up and runs just fine. Not sure the ECU is even bad at this point. Only way to tell at this point is to replace it with a known good one I would think.

Starting to think its either a solenoid or something else is wrong with this transmission.

Digging around the wiring abit more now that the weather has gotten better.

Ran into a plug under the air can that is not plugged into anything. Everything else looks like it goes where its supposed to.
Image
The main plug in and the 2 solenoid plugs look good.
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They go to a junction on the wheel well.
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Image

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That purple plug in goes to the fuse box. There are no extra wires anywhere so not sure what it went to. Looks like extra power for? The green solenoid wires go to the plug in junction on the wheel well. They are trace out and appear plugged into the right spots.

Not sure where to go at this point. Any ideas would be appreciated

Thanks
T


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 Post subject: Re: Hey all
PostPosted: Wed Apr 15, 2015 7:48 pm 
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Posts: 7515
Location: Stantonsburg, NC
Time for a manual swap 8) . That unused plug with the tape on it is for the backup lights for a manual trans. I was shocked to see that when I did my manual swap last summer.

_________________
93 Mitsubishi Expo LRV 1.8/manual
95 Eagle Summit DL Coupe 1.5/manual
01 Mitsubishi Mirage ES Sedan 1.8/manual


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 Post subject: Re: Hey all
PostPosted: Wed Apr 15, 2015 8:15 pm 
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Would love to put a manual in!

What all would I need for that?

clutch pedal and linkage
transmission F5A21??
transmission linkage
shifter
hydraulic clutch slave cylinder?
clutch
throwout bearing

Any change to the flywheel?

Would like to look factory if at all possible. I have read up on a few swap articles but they were for AWD I think.

Thanks
T


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 Post subject: Re: Hey all
PostPosted: Wed Apr 15, 2015 11:26 pm 
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CSM Junkie

Joined: Sun Sep 02, 2012 9:52 am
Posts: 552
Location: Astoria OR
That bay is pretty clean :D.

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Black 1989 Colt GT with 4g61t. 200k miles and climbing. Rebuilt 2.0 in the works.....
14b, 450cc's, 3" exhaust, small fmic, all running on megasquirt version: DIYPNP
White 1992 colt-vista wagon 2.4, awd, auto (daily)
Keane


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 Post subject: Re: Hey all
PostPosted: Thu Apr 16, 2015 1:28 am 
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Ya, the whole car is pretty nice. Purdy...just dont shift gears atm. Already enjoying working on it tho.

Image


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 Post subject: Re: Hey all
PostPosted: Thu Apr 16, 2015 7:24 am 
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Location: Stantonsburg, NC
Your best bet is to find a manual 3g csm at the yard. I'd hold out for a 5 speed though, the 4 speeds are junk from what I've seen.

You'll need the trans, mounts, shifter and cables, clutch and brake pedal assemblies, master and slave cylinders and the lines that connect them together, flywheel, clutch (buy new), starter plate and possibly the starter and all bolts you removed during the process.

It's kind of a pain to swap it depending on your skill level but well worth it IMO. Makes these cars so much more fun to drive even with the 1.5L engine.

You can also use a 5 speed trans from a 93-96 mirage with the 1.5 but it's cable and not hydraulic. The only issue with this is that you'd need a cable clutch and brake pedal setup from a 4 speed csm. I have this trans in my 3g and love it.

_________________
93 Mitsubishi Expo LRV 1.8/manual
95 Eagle Summit DL Coupe 1.5/manual
01 Mitsubishi Mirage ES Sedan 1.8/manual


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 Post subject: Re: Hey all
PostPosted: Thu Apr 16, 2015 7:45 pm 
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Posts: 11
Update
1991 Mitsubishi Mirage 3G 1.5L w/F4A21 Automatic Transmission
TCU #MD739458 ECU #MD160390
Found and fixed ECU burst capacitor

Image

Image
ECU left TCU right

Image
ECU leakage

After fixing the burst cap on the ECU and cleaning both boards again I reinstalled and I still am stuck in limp mode... Just a gut feeling but I am thinking my TCU and ECU are not the problem. Is there anyway to test these boards when they are out?
Going to order a solenoid pack today and replace those and see where that gets me if anywhere. If its not the solenoids then I am going to have to consider dropping the trans and either do a complete rebuild or swap out to a manual trans.

Would like to get this fixed at least to DD mode so I can take my time collecting parts for swaps and upgraded performance.


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 Post subject: Re: Hey all
PostPosted: Thu Apr 16, 2015 8:40 pm 
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The Silent Administrator
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Location: Ottawa, ON, Canada
Does this help?

http://www.lilevo.com/mirage/89-92%20Co ... tdiag1.pdf


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 Post subject: Re: Hey all
PostPosted: Thu Apr 16, 2015 10:14 pm 
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Posts: 11
Very much so! All the ohm readings and continuity testing flow charts for the solenoids I was looking for.

Thanks a lot.
T


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 Post subject: Re: Hey all
PostPosted: Fri Apr 17, 2015 2:00 pm 
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Joined: Sat May 14, 2005 11:15 pm
Posts: 7515
Location: Stantonsburg, NC
The fact that the case is painted a grey color and there are markings on it leads me to believe it was either rebuilt or a used one from a junkyard. A stock one is just plain aluminum, no paint.

I have one here with 53k on it but there is an axle stub stuck in the diff. I tried everything to remove it with no luck and since I bought the car with a seized engine that prompted me to just go ahead and do an engine swap and manual trans swap.

I still have the trans although its been sitting out in the weather for months but if there's any parts you need they're yours for the price of shipping. I was only holding onto it because some of the local yards charge a core fee when you buy a trans so I was going to use it the next time that comes up.

_________________
93 Mitsubishi Expo LRV 1.8/manual
95 Eagle Summit DL Coupe 1.5/manual
01 Mitsubishi Mirage ES Sedan 1.8/manual


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