Mitsubishi 3000GT & Dodge Stealth Forum banner

141 - 151 of 151 Posts

·
Registered
1991 VR4
Joined
·
1,280 Posts
Why do you feel like you need to replace the original fuel lines? I am still on original lines to/from filter in the engine bay on my 91 with over 300,000 miles and they look file, and i'm even running E85 now. I may replace the return so i can add a flex fuel sensor but they aren't brittle or anything.
 

·
Premium Member
1995 Mitsubishi 3000GT VR-4
Joined
·
136 Posts
Discussion Starter · #142 ·
Mainly just piece of mind and PM. I agree they're in fine enough shape, especially given their age. My return line immediately off of the FPR is a bit beaten up, and some of the semi-rigid plastic sheathing is breaking away where the pair of them pass through the metal guide below the throttle body, but I'm not concerned about any immanent failures. I like the idea of stepping up to AN fittings wherever possible for better serviceability too.
 

·
Registered
1991 VR4
Joined
·
1,280 Posts
Mainly just piece of mind and PM. I agree they're in fine enough shape, especially given their age. My return line immediately off of the FPR is a bit beaten up, and some of the semi-rigid plastic sheathing is breaking away where the pair of them pass through the metal guide below the throttle body, but I'm not concerned about any immanent failures. I like the idea of stepping up to AN fittings wherever possible for better serviceability too.
Fair point, there are AN conversion kits available as well. I know 3sx has some, maybe other vendors. My plastic sheathing is deteriorating as well. I may get some other type of heat shielding for a new return line. Don't forget the fuel filter while you are in there if you haven't already (new copper washers with it) :)
 

·
Premium Member
1995 Mitsubishi 3000GT VR-4
Joined
·
136 Posts
Discussion Starter · #144 ·
Fair point, there are AN conversion kits available as well. I know 3sx has some, maybe other vendors. My plastic sheathing is deteriorating as well. I may get some other type of heat shielding for a new return line. Don't forget the fuel filter while you are in there if you haven't already (new copper washers with it) :)
Yes, I did the filter a while back -YEARS ago in fact- but it's accumulated approximately ZERO miles/hours of run time since install :) Speaking of replacing these lines as a means of preventative maintenance, the reason I had to replace the long line from the tank to the filter with a SS braided hose was because I kinked my c-shaped line while trying to get in there and replace the filter.
 

·
Premium Member
1995 Mitsubishi 3000GT VR-4
Joined
·
136 Posts
Discussion Starter · #145 ·
I finished getting everything installed late last night! It's looking like a whole engine again!





Hoping that flooding the FPR solenoid with gasoline didn't hurt it. I ran through all of the book tests for it. It passed the functional checks based on allowing/blocking negative pressure when energizing it. It's reading a little high however on the coil resistance check (over 60 OHMS measured, allowable range is 36-46 OHMS). I don't think that should be an issue, but I've got a gauge in the cabin now to watch fuel pressure so if it starts acting up I would think I'd see something at that point.



Stinks I couldn't fire it up last night, but my replacement FPR should arrive today. I've triple checked all my lines and connections and I think I'm all set to start it up right after R&R'ing the new regulator. I hope it starts after all this work. I'm sure I'll have to step through all the idle adjustments and rigging procedures since I overhauled the throttle body, but those should be straight forward. My mother is coming down to visit on Friday -first time seeing her since the zombie apocalypse. I didn't want her to see Dad's GT laid up like a barn find. With any luck I'll be able to get it off the stands and cleaned up before she arrives.

 

·
Premium Member
1995 Mitsubishi 3000GT VR-4
Joined
·
136 Posts
Discussion Starter · #146 · (Edited)
Well O’Reilly’s screwed me. The FPR never arrived. The store blamed the website, and the website blamed the store. So that was canceled and I looked elsewhere. Fortunately, my mother’s trip down to visit was taking her right through Concord, NC on Friday morning. So I made a call to 3SX and arranged for her to pick up the fuel rail adapter for the AEM Honda-style FPR (AVM-25-303BK). I lost a day in the process, but was left with a much better setup in the end. The AEM unit allows for clocking of the vacuum reference line and the outlet (return) port fitting going back to the tank. I ended up routing the vacuum line under/behind the three connector bracket off the plenum, and the return port I set shooting straight out in line with the fuel rail. The fit is a little tight with the breather line going between the valve cover and the intake bubble, but everything was able to be routed without any issues.



A quick hotwire of the pump to pressure check, leak check, and set the spring tension, and I was ready for a first start attempt!


I didn’t realize I rambled while checking things out for almost 10 minutes; I can save you some viewing time and just say it started up and checked out fine. I mentioned in the video after it started that the fuel pressure was low, but actually after I shut down and checked the book it appeared to be right on the money. So I cleared out the tools, dropped it off the stands, and loaded up for a test drive.


Drum roll……..

……..

It works!

………

………

………

………

At getting tickets! But that’s about it. :(



It’s still having all the drivability issues as far as hesitating and stumbling on takeoff. As soon as you’re over the hump and into closed loop mode, it still rips and is a ton of fun. Which is how I got the ticket :) It was a dumb place, but I caught a green arrow and goosed it good onto a street I never should have been doing that on at that time of night. Good thing the cop came right after me so I only had a chance to get up to 70. He was cool about it. I let him know I was on a test drive after working on it all evening, which was evident with all the tools I had with me in the passenger seat. I think at that time of night they’re glad anytime they have a stop where the driver hasn’t been drinking. I didn’t have my license, either because I forgot to grab it when I loaded up and left straight from the garage. He gave me a warning for not having that, and bumped the speed down to six over (51 in a 45).

But yeah all the issues remain. It’s probably been O2 sensors this entire time and I’m just not good enough at reading the logs in EvoScan. I will say though that there were a lot of suspicious things in those logs that made me question everything I was seeing with the five-volt sensors. I assumed weird behavior in parameters like the inlet temp, knock count, fuel pump mode, and things like that were related to issues with all the corroded and compromised wiring. Hopefully now when I start to get into the logs they’re show a more focused path towards an actual failed component or system.

I should be more depressed about it, but honestly with all I tore apart and rewired, I’m happy that I could still get it out and drive it for a bit. I was able to get it all cleaned up, and take my mom for a spin too, which was awesome.




I would have a new set of logs by now, but I need to familiarize myself again with the software, and I need to get it loaded onto a new computer. Since my last drive years ago, the laptop I was using has died, so I need to download and initialize everything to get EvoScan up and running again. I was never proficient in that software even back when I had it up and running, so I’ll be starting from scratch.

I’ve got a lot of reading to do. Does anyone know which version of EvoScan I should be using for a ’95 running a Chrome ECU? I know the download page for the software says that version 2.6 is best for 3S and DSM cars, but I don’t know if that’s still the case if I’m using a Chrome computer (the latest version is 2.9). I have a leak check to do as well since I had all the intake piping apart, and I need to install an electric fuel pressure gauge and a boost gauge so I can get that fuel pressure line out of the cabin.
 

·
Premium Member
1995 Mitsubishi 3000GT VR-4
Joined
·
136 Posts
Discussion Starter · #148 ·
OMG how did you get those wheels???

And ... 51 in a 45?? WTF
I believe my father found those when he was looking for a set of five-spoke '94 wheels to replace his six-spoke originals because they were flaking so bad. These were a pretty close match, and are still 18" instead of the 17" they offered in '94. I looked through his records, he got them in 2011 from partsgeek.com under part number ALY65744U85N. They don't show any hits now though for them under that number. He also got one wheel replaced after a bad pothole hit later that year from a site called wheelsandcaps.com under the same P/N. That site at least shows a listing for them still, but they're out of stock in all variants. Sorry.

And the 51 in a 45 was a favor by the cop. He had me clocked at 70. They do that a lot down here if you're nice to them and catch them in a good mood. I think that's as low as they can write them for, so that's there way of cutting you a break, but not quite as good as just giving you a warning. I think I can pay $50-$100 and take a four-hour class to avoid the rest of the fine and the point or two that it carries. But for $130, I'll pay it and be on my way.
 

·
Registered
1991 VR4
Joined
·
1,280 Posts
As soon as you’re over the hump and into closed loop mode, it still rips and is a ton of fun.

But yeah all the issues remain. It’s probably been O2 sensors this entire time and I’m just not good enough at reading the logs in EvoScan. I will say though that there were a lot of suspicious things in those logs that made me question everything I was seeing with the five-volt sensors. I assumed weird behavior in parameters like the inlet temp, knock count, fuel pump mode, and things like that were related to issues with all the corroded and compromised wiring. Hopefully now when I start to get into the logs they’re show a more focused path towards an actual failed component or system.
Do you mean into open loop mode? Closed loop is when you are using the NBO2s for fuel trims. Open loop is the higher throttle/load where you are not using the O2s and are just using MAF/fuel tables, etc. If you think the NBO2s are messed up and causing your issue in closed loop, you can always try unplugging them briefly and seeing if the car doesnt stumble in those low load/light accel situations.

If/when you have some logs, post them up and ill take a look. It's usually pretty easy to see if your O2s are cycling as they should.
 

·
Premium Member
1995 Mitsubishi 3000GT VR-4
Joined
·
136 Posts
Discussion Starter · #150 ·
Yeah I said that backwards. But what you described is what I meant. Poor control while operating at lower speed with the O2 sensors. It also has the hot-start stumbling issue too, and unfortunately I don't think they're related, so I have two big issues to try and resolve I think.
 

·
Registered
1991 VR4
Joined
·
1,280 Posts
Yeah I said that backwards. But what you described is what I meant. Poor control while operating at lower speed with the O2 sensors. It also has the hot-start stumbling issue too, and unfortunately I don't think they're related, so I have two big issues to try and resolve I think.
As to the hot start issue, you might just need to bypass/remove the fuel pressure control solenoid. Sometimes its operation isn't really compatible with a hotwired fuel pump and/or aftermarket AFPR. I removed mine like 10 years ago.

Read more here: Stealth 316 - Fuel Pressure Regulator Upgrade

"The fuel pressure control solenoid (or valve) is used by the engine control unit (ECU) only to increase fuel pressure during hot engine starts when there is a greater possibility of fuel vapor being generated in the fuel lines. When the air intake temperature exceeds 140ºF (60ºC) and the engine coolant temperature exceeds 194ºF (90ºC), the ECU uses the fuel pressure control solenoid (for up to two minutes) to allow outside air into the vacuum hoses to increase fuel pressure. In addition, the ECU increases fuel injector activation duration (richens the mixture). These two actions by the ECU are what I believe is a cause of the hot-engine hard-start condition I and many others have experienced on a hot summer day after turning the engine off for a short while. The engine acts like it is flooded for maybe a minute then runs fine. Because this is the only purpose of the fuel pressure control solenoid, I decided to remove it. I don't think there is much we can do about this part of the ECU programming short of going to stand-alone engine management. Owners that have removed the fuel pressure control solenoid, whether upgrading to an aftermarket FPR or not, have not reported problems related to this. I will update this web page if I encounter problems. If you decide to keep this solenoid, you need to modify the instructions that follow. "
 
141 - 151 of 151 Posts
Top