Hi all. I am very sad and upset. I recently bought my 1990 Nissan Skyline GTR R32 from the second owner with only 20,000 kilometers on the odometer and they are true miles. Well my car no longer idols/drives right. It now has only 22,357 kilometers. I was driving it and I noticed that when I went to change gears and took my foot off the gas the car would slow down as if I was pulling something and I heard a very faint noise. Well I went to my destination then on my way back I got on her a little when then got back to the state speed limit the car drove fine for about 1 mile. Then the car started acting funny. It felt as if I had no power. I look at my boost gauge and I couldn't go into positive boost. My oil gauge was normal and so was my temp gauge. I made it to an exit and parked in a gas station. Me and my girl went into Bojangles got some food, then smoked some cigs then I start her back up to see how she would run. She started right up and the car idols at 1 but if I would rev her up she would fall down to 0 bog and slowly work back up to 1 and idol fine. The engine didn't make any odd noises and didn't knock so I put on my hazards and drove her home very slowly. I made it home. Now she sits in my garage.
Since I have gotten her home here is what I have done to try to figure out what is wrong with her.
I used the obd1 port and pulled the code for maf sensor so I started her up and I unplugged the top maf for turbo nearest to firewall and the car stalled. I plug it back in and start her up again. Then I unplug the front turbo maf and the car didn't stall she kept running. I googled about the maf and I took it apart resoldered the 4 connection for the plug. I reinstalled it plug her up start her up unplug it and she stalled. I then disconnect the lead battery terminal for 10 minutes. After ten minutes I rescan her and I get code 55 which is no malfunction! I was so happy I thought I fixed my problem. I start her up and she idols fine but still I rev her up she drops to 0 bog her way back up to 1 rpm.
I drove her around the block and I can't boost at all. She will hit 1 that's it. Oh yeah before this problem occurred she would backfire when I would change gears. And when I rev her up she spits out thick black grime.
Here is what I know about my cars set up. I have a cat back exhaust, a turbo timer, a manual boost controller, two blow off valves and I think the rest of the car is stock. I had the boost set to 12. So she would boost higher then 12. The blow off valves are in front of the driver wheel inside the bumper and I can't make out the name of them. I did notice some things capped off in the engine bay.
I looked for bad vacuum lines, I check the intercooler piping for loose connections and found none. I can't get to the blow off valves to see if they ar stuck open. I removed the boost controller to see if that was the problem but it didn't make a difference.
Can anyone tell me how to diagnose what my problem is? Can I go buy a scanner from somewhere that would tell me what's wrong? Should I take it to Nissan? I need help I paid a very pretty penny for this car and I want to fix it but I am not sure what the problem is.
Pic of something I found today two cut hoses and one other disconnected hose with metal pipe.