Thread: CELs back, Right Steps?

Just want to get opinions if this sounds like a proper way to go about solving the issue i'm having. I have a 96 200sx (ECU/Harness) plugged up to a GA out of a 98 (has that extra EVAP crap) and right now its throwing codes P0400 (EGR Flow Malfunction) and P0170 (Fuel Trim Malfunction Bank 1). It was code free for a few months after swap, then started with this P0400 code one day. Was on for about a 2 weeks then was off one day when I started my car. It stayed off for about 3 weeks or so, then at a red light a few days ago came back on with that Fuel Trim code.

Things i've done.
I quickly checked for blockage in the EGR tube, didnt see anything. EGR Valve works (engine bogs when you manually press it in). Also both O2 sensors and CAT are less than a year old.

Does this sound like a proper way to go about solving. From what I know P0170 is usually related to the MAF.
1. Clean the MAF (or I can replace it with another spare I have laying around)
2. Fresh/Clean Air Filter
3. Double check all EGR hoses are not cracked, bad and not blocked
4. Replace EGR Solenoid

Feel free to throw in a few more suggestions and things I should try. I need this to pass emissions again (eventually) so EGR block off is not an option.

Can someone help me real quick with the vacuum lines for the EGR. I think i got it correctly (on my 1998 GA) but have 2 questions. First theres this hose (first picture) coming from the back of the intake manfold (its #2 on the diagram below) says it goes to the Absolute Pressure Sensor, which I dont recall ever existing? Where should I plug it, it has vacuum coming from it. (you can see in the picture where I currently have it plugged into so it isnt a vac leak).


Second issue is where does the hose that come from the top of the EGRC-Solenoid Valve go? (#9 in the diagram) It shows it going to a "T" hose splitter, which i have it plugged into, but where do the 2 ends go? I have one plugged into the intake right after the MAF and well you can see im holding the other end which i dunno what to do with. I thought maybe it went to where the hose is plugged into in the previous picture. But i can unplug that or there a vac leak. Theres no vac leak (i dont think) the way I have it now, but what happens when EGR valve opens.....






***EDIT***
For the time being till I can figure this out, I just took out the T and extra hose (i'm holding) and ran hose from that barb on top of the Selonoid into the intake.

Will I run into any problems doing this?

Did you switch everything to pre 97.should only have the evap purge solenoid along with corresponding egr hardware form pre 97 they might be slightly diff.pre 97 intake mani correctml?you need 95-97 evap hose diagram.top of my head im pretty sure top port is intake but please don't quote me on tyat.

You will make ur ecu trip balls when this isnt setup correctly. I might have a 96 diagram at my house thatll hepp you out I can. Shoot it to you when im home in the evening

Cool thanks.

The way I originally ran it all worked for awhile then the CEL came on for P0400 (EGR Flow Malfuc) for about 2 weeks one day after I got gas when i started the car. Then one day i went to leave work and when i started the car it was off for a good 3 or 4 weeks. Then on my way into work one day at a red light it came back on along with that Fuel Trim Malfuc code this time. Been on since (few days before original post) but this is what I found out. The thing that was throwing me off was the "Absolute Pressure Sensor" (its that standalone box right above the #2 in the diagram). Apparently i forgot to grab it off the firewall when I did the engine swap so that hose had no where to go and being a vacuum it needed to have a home. What I did was got a screw and plugged up that hose, freeing up the place where I had it plugged into on top of intake manifold (Reference first picture above for what I mean about where it was going). The hose from the top of the solenoid goes to that T splitter and one end goes into the intake and the other goes up to the top of the manifold where I originally had that Absolute Pressure Sensor hose plugged in (Again reference first picture above for what i mean). Far as i can tell its all ran properly now, but the CEL is still on so I dont know for sure yet.

I assume if i ran the hose's per 1996, i'd be plugging up a couple more hoses coming from on top of the intake manifold (from EVAP stuff)

Absolute pressure sensor. Like we were talking about, I've never heard of that thing before ever. Damn emissions stuff!

Yeah, you see it up there in that diagram. Eric @LikeTheMovies helped me figure it out. Showed me a picture of his SEL before he deleted it. Didnt realize it was connected to the firewall, thats why i couldn't find it lol, sneaky bastard. So as far as it being connected right, i think im good, but whether or not it will work is unknown so far. Since none of that EVAP shit has any purpose (since im using the 96 harness/ecu no plugs for any of it) i hope it will still flow properly.

Otherwise I assume ill have to run it like the 96 and be plugging up a whole bunch of things on top of the manifold, which i was hoping i didnt have to do