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Discussion Starter #1
Alright so I made a post about this before with no reply or any luck so I'm going to try again. I have a 1993 Mitsubishi 3000gt vr4. Its running rough and giving a CEL 25. I have replaced the ecu, maf, and the maf plug with no change or luck. Car doesn't run any better or any worse with it unplugged or plugged in. What other approach should I make to solve this issue? Also I have a SAFC that came with the car. It wasn't hooked up though and I don't know if it ever was. I do have a boost controller hooked up but I currently have no boost.
 

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I have my scanmaster 3 hooked up in it and the only code its giving me is 25. Iv changed my MAF with two other ones known to work and even changed my plug.
I have also swapped out my ECU and it didn't make a difference. the strangest thing about any of it is my car is running with out injectors 1 3 and 5 and is running rich.
 

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I have also swapped out my ECU and it didn't make a difference. the strangest thing about any of it is my car is running with out injectors 1 3 and 5 and is running rich.
it's only running on 3 cylinders? What makes you say it's rich?

I have my scanmaster 3 hooked up in it and the only code its giving me is 25. Iv changed my MAF with two other ones known to work and even changed my plug.
What is the Baro voltage in scan data?
 

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Discussion Starter #6
it's only running on 3 cylinders? What makes you say it's rich?


What is the Baro voltage in scan data?
I believe it be running on 3 cylinders because before we connected the scanmaster we thought maybe it was fuel related or spark related so we unplugged each injector and it never changed on any of them and my husband was like screw it and unplugged all of them at once and it didn't change how it idled at all. And we had a friend who is helping my husband with engine swapped test the voltage of the plugs and he said they all read fine but I dont know what the voltage was. We also checked the voltage on the MAF plug and they all seemed good. I can't remember what they were either mainly because my husband checked that part and everything seemed to be right voltage wise. But when we went to check the ECUs voltage to each thing the voltage meter broke so we connected the scanmaster and thats when we seen the code 25 and started swapping parts out with known good ones and it never changed.
 

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I believe it be running on 3 cylinders because before we connected the scanmaster we thought maybe it was fuel related or spark related so we unplugged each injector and it never changed on any of them and my husband was like screw it and unplugged all of them at once and it didn't change how it idled at all. And we had a friend who is helping my husband with engine swapped test the voltage of the plugs and he said they all read fine but I dont know what the voltage was. We also checked the voltage on the MAF plug and they all seemed good. I can't remember what they were either mainly because my husband checked that part and everything seemed to be right voltage wise. But when we went to check the ECUs voltage to each thing the voltage meter broke so we connected the scanmaster and thats when we seen the code 25 and started swapping parts out with known good ones and it never changed.
Oh and I believe it to be running rich because of the smell when its idling/revving. It also smokes white smoke which I know could be valve stem steals and oil burning. I'm thinking of pulling the head to see if blown the gasket but either way I dont think that would explain the CEL 25. And honestly I dont want to start pulling the engine apart unless I really have to.
 

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Discussion Starter #8
I also currently dont have a battery in it because my husband jacked it for his car 🤦‍♀️ and wont let me use it. Soooooo I dont know the baro voltage. And honestly I'm still trying to figure out how to use to scanmaster completely which I haven't gotten to mess with since he took the battery. I gotta buy a new one.
 

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Discussion Starter #11
You push the mode button to scroll through the data parameters. You're looking for "BAr"
Gotcha alright well when it stops raining and what now I'll get the battery from my old man and see what it is. He said somthing about knock about last night and I have no understanding on what exactly knock is on the scanmaster. What should that be at? Hopfully I'll get the chance to look tonight at the BAr and stuff. Is there anything else I should look at while i will have the battery? I wish this thing would let me upload the video of the car running.
 

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The crazy knock readings are definitely odd, and are either a software glitch or some really weird interference. I'd want to scroll through the other data perimeters and see if any others are going nuts. (I kinda expect the baro readings to have a problem but I'm wondering if there's a global issue going on that could be causing you grief.) I'd want to check the ECU grounds also.

As far as the running on 3 cylinders, you need to find out what's missing... It's either got a spark problem, fuel problem, timing problem, or fuel problem.

Give us some history on what has been done to the car, and what you know and don't know...? what work has been done recently? when was the last time it ran? what has changed since the last time it ran?
 

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Discussion Starter #13
The crazy knock readings are definitely odd, and are either a software glitch or some really weird interference. I'd want to scroll through the other data perimeters and see if any others are going nuts. (I kinda expect the baro readings to have a problem but I'm wondering if there's a global issue going on that could be causing you grief.) I'd want to check the ECU grounds also.

As far as the running on 3 cylinders, you need to find out what's missing... It's either got a spark problem, fuel problem, timing problem, or fuel problem.

Give us some history on what has been done to the car, and what you know and don't know...? what work has been done recently? when was the last time it ran? what has changed since the last time it ran?
Honestly we couldn't get any information on the history of the car and as for what all has been done we dont even know either apparently the people who had it before us bought it the way it is and then we got it. Not sure how long they had it or anything. I know it has aftermarket turbos, dual front mount intercooler pipping, not sure if the safc was ever plugged in or not, came with AEM ecu but it's a four plug not a three so I dont even know why the guy had it for it and I couldn't information on it. When we got the car the guy said he had no idea what all was done to the car and he said the car just needed to be tuned because of the aem ecu which wasn't even connected in it plus i dont see how he would have plugged it. But aside from the aftermarket intercooler and turbos( which aren't any bigger then stock just suppose spoil faster or somthing other. They are td04 but are suppose to be better the stock and spoil better.) They did vacuum delete and had the boost controller half way hooked up which we finished. We have swapped out between two ecus and 3 MAFs and even changed out the MAF plug.
This picture was taken before we did much anything.
285282

Now when it comes to spark we did check the sparkplug and stuff of that nature which all were fine. Also I checked the timing and it was right on point. Now for the fuel part I dont know where to begin because the front 3 dont work. I have no clue where to start on why they dont work. I do how ever plan to check the ECU pins to each front injector and the maf and also finish installing the air/fuel gauge.
All we know about this cars history is it's from south Carolina and the man we got it from bought it running the way it is now and had no idea on how to work on these car and knew little to nothing about them so after it sat for a while he decided to sell it. Of course we didn't find any of that till we got home with car that night and was able to get it to start. Also what do you mean by a global issue?
 

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By "global issue" Larry probably means if something crucial is the culprit affecting many other things, such as an MFI relay, bad ECS computer, or bad IAC killing each ECU. It will help us better to help you by explaining how exactly you are testing or checking things and what exact values or observations are being made. If it is easier, record a video of the car idling, do a walkaround, and cycle through the Scanmaster 3's parameters.

Also, is that small port at the back of the upper intake plenum just vacant and open, or do you usually have something plumbed to it? If not, get a vacuum cap for that.
 

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Discussion Starter #15
By "global issue" Larry probably means if something crucial is the culprit affecting many other things, such as an MFI relay, bad ECS computer, or bad IAC killing each ECU. It will help us better to help you by explaining how exactly you are testing or checking things and what exact values or observations are being made. If it is easier, record a video of the car idling, do a walkaround, and cycle through the Scanmaster 3's parameters.

Also, is that small port at the back of the upper intake plenum just vacant and open, or do you usually have something plumbed to it? If not, get a vacuum cap for that.
We will put the battery in it this weekend and record the parameters. I'm pretty sure a few of them are actually off but I dont know enough about what they should be to know that to be fact. That picture was when we brought the car home, we have done a lot of corrections on it since that picture. That nipple has been capped until I get a different boost gauge to install then that's where itll go. Other ports have been capped as well. We ran lines from the FPR to the front of the TB with a t going to the BOV. The two WG lines are together with a T going to the boost valve then going to the rear nipple on the y pipe. Everything else has been capped. We tested the plug on the MAF with a multimeter in volts. I compared the results to a post I found on another thread on here and they weren't all completely accurate some were higher and some were lower. I tested continuity on the ground I believe it was pin 5 and the result was -0. We also changed the MFI with another one and it didn't change anything. I haven't checked the IAC but I think it's safe to say that's not my issue but I also plan to test that this weekend just in case. The car has coilovers without ECS so I'm not sure if that computer matters but I dont know much about that stuff since the ECS has never worked in any of our cars.
 

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Discussion Starter #17
This is all the readings on my scanmaster
 

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The rest. As you can see, the BAr reads 0 not sure if that's saying it's just not reading it or what. We used a noid light to test the injector pulse on the front 3 injector and they do infect have a good pulse. It's actually not the front 3 now.. it's just the first 2 from the left. I don't know if they are shooting gas or not I haven't gotten that far with it yet. I had some other injectors laying around that were known to be good but not sure if they are for tt or not. They are orange. Installed them and no change so probably not tt injectors. Pulled all the plugs on the front head and recapped them and also checked to make sure they were getting spark and everything is good with that. I did a compression test on the front head while I had the spark plugs out and all 3 cylinders have a compression of 150. Tomorrow I'm going to swap injectors off the other tt and see if that makes a change but the thing is it should be showing a CEL for injectors if they weren't working. Unless they are clogged I guess. But I uploaded all the scanmaster readings at idle the way it idles at the very moment. I hope yall can check them out to see if anything is off to you guys.
 

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