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Discussion Starter · #1 ·
I was driving my car a couple days ago in traffic and came to a stop and the engine died. I restarted it and from that time on it will not idle. It runs great with my foot in the accelerator and cruising but when i take my foot off the accelerator pedal it will die. I have looked at vacuum leaks, plugs, timing, TPS, MAS & Now the IAC ...Does anyone have any ideas...I thought about ECU next ?

Regards,
Rob
 

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Sounds to me like the Idle Control Compensator..very expensive about 350-400 U.S. $$

Try adjusting the idle and that should help..I've run mine without replacing compensator for about 2 years by adjusting idle up.
 

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Thanks for your ideas...I have since then removed the IAC from the bottom of the Throttle body Valve Assy. I found that it was pretty dirty and sooty, I cleaned it and reassembled and it idled great for about 1/2 hour then it started dropping off but it will idle now but only at about 300 RPM...So, I believe I'm looking in the right place now...Thanks again for your help

Regards,
Rob...
 

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Discussion Starter · #4 ·
Hi all I just fixed my 1993 Mitsubishi RVR Sportsgear 2.0 4G63 engine. It would idle rough and then sometimes the idle would just drop off to near nothing and die. Well, I removed and cleaned the Idle Speed Control (ISC)and it didn't make much of a difference, then I read a posting on www.mitsubishi-forums.com about the ECU Capacitors in many Mitsubishi cars C111 and C104 leaking. So, I am an electronics tech and thought this can't be too hard...and removed the ECU and replaced both of the electrolytic capacitors made by(Rubycon)C104 was a 50V 47UF 105 degrees cap and the other I believe was C109 16V 100UF cap but there are only 2 electrolytic capacitors on the whole circuit board. So, just replace them both they are real cheap. You can purchase them from MCM Electronics web site. After replacing them the car immediately started idling perfect!These 2 caps drive a transistor power circuit for the ISC to run properly. The ECU is very expensive! It's worth a look...

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Rob Swenson
 

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Mine has a problem with a flat spot on the throttle, at slow moving traffic position, it jolts like there is no throttle at all... I suspect it might be the TPS..
Would this be a likely problem?
It idles ok, but slightly under 1000 rpm.


BTW, Where can i find the ECU?
 

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Hi,

Can you tell me where can I find the Idle Speed Control? I would like to clean it up hoping to reduce the idle speed. Currently its 1000 rpm.
 

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I had the same problem with our early 90's RVR sportsgear. I took svendawg's advice and replaced all three capacitors on the circuit board. It would be tricky without an electronics background, but I managed to remove and replace all of them and get my car working normally again. The parts cost me seven bucks and six of that was shipping. It took about an hour of careful work as well. Getting the ECU in and out of the car proved to be the most frustrating part. I took pictures and am making a blog that I will post on myspace when complete. I'll repost when I'm done.

--Ray
 

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having read this thread i believe that my ecu needs these capacitor thingies replacing too, i look fwd to seeing your photos Ray...
 

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i believe that my ecu needs these capacitor thingies replacing to
Mine too.

Plan to do this next month once I have some bench time to play with the ECU. I would not recommend this kind of repair to someone who does not have any electronic repair skills. You at least need to have a solder iron, solder sucker, fibreglass brush and some idea what a capacitor is. Might be best if you just remove and bring into someone who has the gear & expeience.

I will take some pics when I do mine and post up a 'how to guide' for those that want to give it a go.

Jim
 

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Guys,

DSMers have been dealing this problem since late 90's :(. There is a very good VFAQ on this topic:

http://www.vfaq.com/mods/wayback/caps.htm

It appears that later model ECUs didn't have this problem (2G DSMs 95+ do not have leaky CAPs).

Oh, if anyone's ECU is beyond repair, I have an ECU from '95 LRV (2.4 egine) for $75 + shipping. But if they are anything like the DSM ECUs, 95's should be OK ;)
 

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Thanks for that, great write-up on the subject. I know you indicated that 95+ doesn't have the problem which is why I need to have a look being a 95 RVR. Simple enough to do and I'm sure I have the caps at work.

One additional note is that the ECU link is not for a RVR but a different model. I'm fairly sure the caps and fix will be the same but will check once I get mine out. I also noticed that the RVR ECU is mounted different than shown being flat on the floor rather than vertical.

Jim
 

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DSM ECU’s are mounted vertically, behind the radio. However Galant VR4s (the granddaddies of DSMs) have the same ECU mounted in the Passenger side kick-panel, just like LVR/RVR. The only thing that is different is the casing, the board itself is the same and it is interchangeable. In other words, do not put much significance to where ECU is mounted ;).

Also, 95 was a significant year for DSMs, new generation of car/electronics and ECU. That is when they went to the OBD2 ECU. Oddly enough, my ’95 Summit/LRV has OBD2. So it appears that Mitsu went to this style of ECU a year before they were mandated to do so the US Fed. Government (all 96+ cars were required to have it).

This made sense on DSMs, since they were redesigning the entire car, but appears out of place on a Summit/LRV, since there was no generation change from ’94 to ’95.
 

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OK, curiosity got the best of me and I pulled the ECU out of the RVR oever the weekend. The numbers on it are;

MD753881
GIT14671MI

Had a look at the board and there are two 47uf caps on it which look as good as new. I could test but would need to remove to do so. Question is now do I just replace the two caps anyway or leave as is?

Only problem I have with replacing the caps is a high wattage resistor mounted to the casing for heat abosorbtion. Can be a **** to dismount so would probably de-solder from board.

What would you recommend to do in this instance?

Jim

Jim
 

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Capacitors can look 100% normal while they are leaking and destroying your board! Does it smell “fishy”? One of the signs of leaky CAPs is fish odor (I am not kidding you!).
 

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Caps are fine and don't smell at all. Back of board is clean with no signs of corrosion. The two 47uf caps have a brown casing that is different than the 'blue' type but unsure if this means anything (ie higher temp rating).

I threw it back together and installed last night. Decided to not fix it if it wasn't broke. Easy enough to remove again and replace if I want to. Didn't have the right size & voltage caps anyway so would have to order. Took a couple of pics in case I need to get #,s, type, etc off board in future.

Jim
 
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