Mitsubishi 3000GT & Dodge Stealth Forum banner
41 - 54 of 54 Posts

· Science, bitch!
1992 VR4
Joined
·
964 Posts
Read about chrome ECU here: http://chromedecu.org/?page_id=684

Almost everyone with a TT 3S wants to mod at some point. If you ever want more performance, there are several options, including chrome.

However, it sounds like you have the proficiency to do the repairs yourself. Just be aware that since you don’t have a test rig, you might end up chasing your tail if your repairs aren’t 100% or there is some other damage you don’t find. These cars are old and especially the 1G computers are known weak points. A remanufactured ECU will be cheaper and suffice if the remanufacturing process was done correctly. The cost of a reman ECU might approach 50% of a chrome ECU (or be close to equal if you get a used chrome ECU), so plan accordingly.


Sent from my iPhone using Tapatalk
 

· Registered
Joined
·
41 Posts
Discussion Starter · #42 ·
Sounds like you have tools and knowledge to do the radial capacitor replacements. Knowing that, I’d say just do replacement, clean around C6 and pins for side-boards, then just try ECU to see if it works correctly.

I understand you wanting to do it yourself and could save yourself a lot of money, at worst you’d just have to send it in for repair or replace (as you said) if your repair doesn’t correct it. I’ve fixed my ECU, TCU and Tach by simply doing the same, though I did have to buy a spare used TCU just to see where trace went that was completely burnt away when capacitor burnt up along with burning hole in PCB of my original board. Repaired trace, replaced capacitors in both units, now have one in car and a working spare.

If you don’t have correct capacitors or a electronics store near by where you could purchase them, you could just order set from 3SX for $8.96 that comes with an extra 47 µF that wouldn’t be needed in your TT ECU.
💪 (y) I always try and fix my stuff myself I will not go to a auto shop or stealership unless the sun is falling out of the sky. An added benifit is you get to learn how everything works.

That Capacitor kit from 3SX seems pretty convenient... I am going to look through my spare circuit boards and components first though before I pull the trigger on that.

How is 3SX for shipping times? I live in Vancouver Canada, just wondering if I did go the 3SX route how long (roughly) of a wait I would I be in for?



Read about chrome ECU here: http://chromedecu.org/?page_id=684

Almost everyone with a TT 3S wants to mod at some point. If you ever want more performance, there are several options, including chrome.

However, it sounds like you have the proficiency to do the repairs yourself. Just be aware that since you don’t have a test rig, you might end up chasing your tail if your repairs aren’t 100% or there is some other damage you don’t find. These cars are old and especially the 1G computers are known weak points. A remanufactured ECU will be cheaper and suffice if the remanufacturing process was done correctly. The cost of a reman ECU might approach 50% of a chrome ECU (or be close to equal if you get a used chrome ECU), so plan accordingly.
One day when I do start adding performance parts (it will happen sooner than later), then I will probably do the CHROME ecu, Wide Band 02, FPR, Speed Density, Cat-Back (or full) exhaust, higher cc Injectors, stand-alone MSI ignition, TIEN coil-over suspension, custom made & shaped intercooler piping, etc, etc... oh I can dream. One day when I have the money to do these things I will, and I can't wait until thar time lol.

Already have a Stage 2 clutch lol. Had it installed after I destroyed the clutch on the car shortly after I bought it 10 or 13 years ago when I was in my early 20's. I didnt know much about cars at all back then, so soon after that I got a truck and put my Dodge Stealth into storage under cover for about a decade. I am glad I 'took it off the road' when I did or else, I may not have still had the chance to drive the car today. probably would have crashed it or something would have went wrong due to my lack of understanding of cars at the time...

But alas! Back to reality!
 

· Registered
Joined
·
79 Posts
💪 (y) I always try and fix my stuff myself I will not go to a auto shop or stealership unless the sun is falling out of the sky. An added benifit is you get to learn how everything works.

That Capacitor kit from 3SX seems pretty convenient... I am going to look through my spare circuit boards and components first though before I pull the trigger on that.

How is 3SX for shipping times? I live in Vancouver Canada, just wondering if I did go the 3SX route how long (roughly) of a wait I would I be in for?





One day when I do start adding performance parts (it will happen sooner than later), then I will probably do the CHROME ecu, Wide Band 02, FPR, Speed Density, Cat-Back (or full) exhaust, higher cc Injectors, stand-alone MSI ignition, TIEN coil-over suspension, custom made & shaped intercooler piping, etc, etc... oh I can dream. One day when I have the money to do these things I will, and I can't wait until thar time lol.

Already have a Stage 2 clutch lol. Had it installed after I destroyed the clutch on the car shortly after I bought it 10 or 13 years ago when I was in my early 20's. I didnt know much about cars at all back then, so soon after that I got a truck and put my Dodge Stealth into storage under cover for about a decade. I am glad I 'took it off the road' when I did or else, I may not have still had the chance to drive the car today. probably would have crashed it or something would have went wrong due to my lack of understanding of cars at the time...

But alas! Back to reality!
Sorry I confused you saying FP speed relay. I call it that because most posts here or on internet using just FP relay are referring to the MFI. Remember non-TT 3000GTs don't have the FP speed relay so they say FP relay for the MFI frequently.
As far as your ECU, the damaged area you have involving the C6 capacitor is fairly common in 1st gens pics posted over the years. It can be associated with no starts, shutting down when hot suddenly, and MFI relay just clicking on and off. The C6 capacitor and board pads around it are usually burnt like yours. I doubt its just the acid-electrolyte fluid as that usually runs downhill towards the base of the small upright board you show with corroded leads since that side of ECU is mounted down. When you find pics of rebuilt ECUs of MD159965 -966s you see the C6 capacitor often replaced with different type of (not ceramic) capacitor of the same value...I can't give you value. There are kits for 3000gt ECUs like you mentioned that include the electrolytic capacitors but also include the C6s. 1991-1993 Mitsubishi 3000GT / Stealth ECU ECM Capacitor Kit w/ C6 SMD (N/A + TT) | eBay. This one is like $14.99.
To answer your question on testing relay, I would do as I suggested in my last post...pull the relay off the harness and jump the connector between port 2 and port 5 on the connector and start the car...it is testing the entire low speed circuit at once. If it keeps running then you can go back and test part by part the low speed circuit to repair it or just bypass it.
 

· Registered
Joined
·
79 Posts
Sorry I confused you saying FP speed relay. I call it that because most posts here or on internet using just FP relay are referring to the MFI. Remember non-TT 3000GTs don't have the FP speed relay so they say FP relay for the MFI frequently.
As far as your ECU, the damaged area you have involving the C6 capacitor is fairly common in 1st gens pics posted over the years. It can be associated with no starts, shutting down when hot suddenly, and MFI relay just clicking on and off. The C6 capacitor and board pads around it are usually burnt like yours. I doubt its just the acid-electrolyte fluid as that usually runs downhill towards the base of the small upright board you show with corroded leads since that side of ECU is mounted down. When you find pics of rebuilt ECUs of MD159965 -966s you see the C6 capacitor often replaced with different type of (not ceramic) capacitor of the same value...I can't give you value. There are kits for 3000gt ECUs like you mentioned that include the electrolytic capacitors but also include the C6s. 1991-1993 Mitsubishi 3000GT / Stealth ECU ECM Capacitor Kit w/ C6 SMD (N/A + TT) | eBay. This one is like $14.99.
To answer your question on testing relay, I would do as I suggested in my last post...pull the relay off the harness and jump the connector between port 2 and port 5 on the connector and start the car...it is testing the entire low speed circuit at once. If it keeps running then you can go back and test part by part the low speed circuit to repair it or just bypass it.
You said you've got electronics background and multimeter. On your ECU board, you need to put your meter on diode setting and check the silicon diode D104...it looks cooked..surface shiny cooked and all markings burned off...should look just like D104 and read about the same..around 0.6 -0.8V forward. Also,be sure to check resistor R125...950-1050 ohms. If any read off spec,realize you may need to lift one end leg off board and re-check em. Its a 4 layer board: traces on top, on bottom, and a few traces on two other layers between for 5v and ground traces.
 

· Registered
Joined
·
79 Posts
EDITED: You said you've got electronics background and multimeter. On your ECU board, you need to put your meter on diode setting and check the silicon diode D103...it looks cooked..surface is shiny with all white markings burned off...it should look just like D104 which is the identical component. Both should measure about the same...around 0.5 -0.7V forward is good. Also,be sure to check resistor R125...950-1050 ohms. Also check D8 surface mount diode If any read off spec,realize you may need to unsolder n lift one end leg of the component off the board and re-check measurement. Its a 4 layer board: traces on top, on bottom, and a few traces on two other layers between for 5v and ground traces.
 

· Lovbyts
Joined
·
4,503 Posts

· Registered
Joined
·
41 Posts
Discussion Starter · #52 · (Edited)
Great company to deal. Family business! They've been operating since 1998. Incredible 1 day turnaround. a+ communication. 5 year warranty. Good value, the total cost for repair & return is $250(usd). Being as I live in Canada, I had to pay an extra $50 for International expedited shipping; this is to be expected and props to Foreign Auto ECU Repair for communicating this to me almost immediately during our first talks. Here is a link to they're service: Remanufactured Engine Computers w/ 5 yr warranty - 800 241 6689

One repaired ECU:
 
41 - 54 of 54 Posts
Top