1g MAS Help

[Kyogie12]

So i recently picked up a 91 GSX but it needed a head gasket so half the engine was appart. I finished assembling everything back to their respective places, except i ran into an issue when it came to the intake and the MAS. The wiring harness from the engine was clipped and capped, and the harness from the intake was yet clipped and capped. I called the guy i bought the car from and asked what was up, he said he was gonna put on a 2g MAS but never got around to it. So i rewired them all back together. Startered her up and....REALLY rough idle that dies most of the time. Essentially what happens when the MAS isn't working right. Now i noticed there is a connector where the harness splits into a "Y" shape. One side goes to the MAS connector on the intake and the other is a plug. Now i cannot find for the life of me where this plug goes...any help would be appreciated! And if that would be the cause of the rough idle? Thanks!

 

[dsmdeliveryboy]

So i recently picked up a 91 GSX but it needed a head gasket so half the engine was appart. I finished assembling everything back to their respective places, except i ran into an issue when it came to the intake and the MAS. The wiring harness from the engine was clipped and capped, and the harness from the intake was yet clipped and capped. I called the guy i bought the car from and asked what was up, he said he was gonna put on a 2g MAS but never got around to it. So i rewired them all back together. Startered her up and....REALLY rough idle that dies most of the time. Essentially what happens when the MAS isn't working right. Now i noticed there is a connector where the harness splits into a "Y" shape. One side goes to the MAS connector on the intake and the other is a plug. Now i cannot find for the life of me where this plug goes...any help would be appreciated! And if that would be the cause of the rough idle? Thanks!

Check the wiring for it on vfaq

 

[RoasT BeeF]

I am fairly certain the other connector should connect to the coolant overflow bottle. It wont cause a rough idle.

I would start with double checking the maf wiring to make sure you have connected the correct wires to each other. Some of those colors become harder to tell apart with age. Also make sure you have good connections! Use solder and heat shrink if possible.

Since the engine was disassembled when you got it there could be a hand ful of other things causing the problem as well. If there is a CEL it will be the easiest way to track down the problem.

 

[turbo laser]

does the plug have two nipples on it, cause it maybe the boost control solenoid. On my 1g that is what splits from the harness with. I unplugged mine and took the vacuum lines off, but i have a manual boost controller

 

[CardShark]

So i recently picked up a 91 GSX but it needed a head gasket so half the engine was appart. I finished assembling everything back to their respective places, except i ran into an issue when it came to the intake and the MAS. The wiring harness from the engine was clipped and capped, and the harness from the intake was yet clipped and capped. I called the guy i bought the car from and asked what was up, he said he was gonna put on a 2g MAS but never got around to it. So i rewired them all back together. Startered her up and....REALLY rough idle that dies most of the time. Essentially what happens when the MAS isn't working right.

Since your engine was apart, there is a ton of things that could be wrong causing your rough idle....definitely doesn't have to be your MAF. That being said, it could be your MAF so double check your wiring and then swap in another 1G MAF to check if it is the culprit.

Now i noticed there is a connector where the harness splits into a "Y" shape. One side goes to the MAS connector on the intake and the other is a plug. Now i cannot find for the life of me where this plug goes...any help would be appreciated! And if that would be the cause of the rough idle? Thanks!

This connector is not what is causing your trouble. I can't remember exactly what this is but there is no component/sensor in that area that will cause a really rough idle as you are describing.

 

[Kyogie12]

I double checked everything and realized the idiot before me had the BOV dumping to the atmosphere :/ so i'm gonna fix that first and see what that does for me...

 

[AlaskanDsm]

It should be a night and day difference once the BOV tube is replaced. There could still be other issues but this is DEFINETELY the right place to start haha.

 

[Kyogie12]

Hahaha yeah I can't believe i missed that one...I just figured that the guy wouldn't have it venting to the atmosphere because he knew what he was talking about when it came to DSMs...haha

 

[AlaskanDsm]

My advice would be to assume nothing and inspect everything. He probably sold it to go to a honda

 

[Kyogie12]

Hahahahahaha funny you should say that. The story goes like this. I bought a 91 Talon TSI about a month back, while driving it home the engine seized up (balance shaft i think) so the motor was shot. Instead of rebuilding I was gonna buy a new one from a guy in Florda from a guy "named" Jason Castelos but he scammed me and I love 800 bucks (essentially the rest of my budget money at the time). So i was sitting with a broken talon. Well the original owner of that talon (title was still in his name, it passed through 2 people then me and none of us changed the title) wanted it back so he traded me his 88 CRX Si for it. I HATE hondas so I traded that to the guy i got the 91 GSX from and now i'm in the situation i'm in haha.

More bad news...i put on a dump tube and the car still idles like shit. I did however hear a vacuum leak somewhere from the intake manifold :/ so i gotta investigate that. Also my headers get REALLY hot within seconds and start smoking...thoughts?