2G Car driving funny

[MasterMatt209]

Side note: car does have a small 16g with no tune or anything this is how I bought the car. It also has an aftermarket BOV and an AFPR which is reading 43psi as it should

Finally got my 95 GSX drivable today and well it didn’t do so well. Car idles between 1200 and 1500, before it was at 2500 due to the stop screw keeping the throttle plate open. So first thing I noticed was the boost gauge while driving at any rpm was at the 3rd line rpm the bottom (stock boost gauge) and the car didn’t seem to wanna “go” gave it some gas and it was almost like I didn’t. And when coming to stoped the car would idle at a couple hundred rpm like 200-400. Even if I let off the gas while driving the idle would drop below maybe 900 and go back up. Can anyone help me figure out what’s going on? I tried to give the best info I can here.

 

[MasterMatt209]

Also, it seemed like it didn’t shift I didn’t go very far or fast. I had the TPS off when the throttle body was rebuilt. I’m pretty sure I read the tps tells the car when to shift so I’m guessing that’s adjusted wrong?

 

[Kenny07]

Well first thing is to fix the idle:
http://www.dsm.org/how-tos/tttt/tttt3.html

Lots of info in there.

Also you said you took of the TPS. I would assume that it was not put on “correctly”
Here’s how you do that:
http://www.dsmtuners.com/threads/how-to-adjust-the-throttle-position-sensor-tps.324431/


That should help iron out your idle

You should also do a boost leak test.

 

[MasterMatt209]

Well first thing is to fix the idle:
http://www.dsm.org/how-tos/tttt/tttt3.html

Lots of info in there.

Also you said you took of the TPS. I would assume that it was put on “correctly”
Here’s how you do that:
http://www.dsmtuners.com/threads/how-to-adjust-the-throttle-position-sensor-tps.324431/


That should help iron out your idle

Okay thank you I’ll look into those articles right now

 

[Vegas Smith]

I know you mentioned doing a blt earlier but did you actually pressure test the whole system and not just spray soapy water everywhere? When the car comes to a stop and the rpms drop, that's probably a poorly adjusted biss/isc as it doesn't have enough movement in the isc step motor to cleanly idle the car for a second.

1) get rid of all leaks by pressure testing until say 20psi (should leak slowly over a minute or so).

2) Set TPS

3)Set Biss screw by grounding timing then setting idle by adjusting biss screw.

 

[Mauispyder]

These weird problems are often huge air leaks after the MAF and in difficult to see areas like the intake manifold.

 

[AWD-Tony]

Was your base fuel pressure set with vacuum hose disconnected at operating temperature?

 

[AWD-Tony]

Are you venting BOV to atmosphere?

 

[JPenny]

Listen to what has been offered and assure the TPS and biss are set correctly..like tk106 asks if the bov is vented to atmosphere with persay a factory maf wouldn't the mixture be wrong after pedal?

 

[MasterMatt209]

I know you mentioned doing a blt earlier but did you actually pressure test the whole system and not just spray soapy water everywhere? When the car comes to a stop and the rpms drop, that's probably a poorly adjusted biss/isc as it doesn't have enough movement in the isc step motor to cleanly idle the car for a second.

1) get rid of all leaks by pressure testing until say 20psi (should leak slowly over a minute or so).

2) Set TPS

3)Set Biss screw by grounding timing then setting idle by adjusting biss screw.

Thanks man I’ll try everything suggested, I didn’t know you had to ground timing to set the biss I adjusted it correctly but didn’t ground to. Previous owner had the biss screwed all the way in.

 

[MasterMatt209]

Are you venting BOV to atmosphere?

I’ll get back to you on the fuel pressure, but when I got the car they had the maf blocked off and bov open. The guy had the stock the connector hose so it is now recirculated.

 

[Vegas Smith]

Yeah, you have to ground the timing so that the ecu doesn't keep changing the timing every millisecond which can change the idle.

 

[MasterMatt209]

Yeah, you have to ground the timing so that the ecu doesn't keep changing the timing every millisecond which can change the idle.

The walkthrough I just read involved an $1800 scan tool.. what’s up with that

 

[MasterMatt209]

Okay guys I have been starting the car everyday waiting for a check engine light cause I had the battery out a few times, it’s a misfire code so once I figure that out I’ll be into seeing what’s wrong.

 

[MasterMatt209]

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So when I take the vacuum off of the AFPR it reads 60. Here is a picture of what it reads with the line on, I think I was wrong when I said it read 43 I think I have the increments wrong. Anyways someone give me feedback thank you

 

[1990TSIAWDTALON]

Re-adjust that regulator for 43.5 with no vacuum.
The misfire can very well be a bad wire so put a set of plugs and wires on her.
While your in that area, check connections on the fuel injectors and all other sensors you can see.
Ground your timing tab and set base timing to 5*BTDC. Unground plug.
Set BISS screw to approx 1 1/2 turns to 2 turns out as a start and start over with the car at those base settings. A code reader will tell you which cylinder or multiple. I had 6 month old NGK wires go haywire so maintenance, maintenance........
You have a turbo car with a 1 to 1 rising regulator. It works with vacuum too. Set it without any vacuum on it at all and the vacuum and boost will give you the correct fuel pressure.

 

[MasterMatt209]

Re-adjust that regulator for 43.5 with no vacuum.
The misfire can very well be a bad wire so put a set of plugs and wires on her.
While your in that area, check connections on the fuel injectors and all other sensors you can see.
Ground your timing tab and set base timing to 5*BTDC. Unground plug.
Set BISS screw to approx 1 1/2 turns to 2 turns out as a start and start over with the car at those base settings. A code reader will tell you which cylinder or multiple. I had 6 month old NGK wires go haywire so maintenance, maintenance........
You have a turbo car with a 1 to 1 rising regulator. It works with vacuum too. Set it without any vacuum on it at all and the vacuum and boost will give you the correct fuel pressure.

Yeah it’s a cylinder one misfire, I was getting new plugs and wires anyways. I didn’t really understand the timing part, I don’t have any way to tune or anything. To set the fuel pressure do I just start the car and unhook the vacuum like then set it to around 43 psi?

 

[1990TSIAWDTALON]

Yep. That's the easy way. There is a fuel pump connector somewhere under your hood that will activate the pump with 12v applied but just make it easy and have all the tools ready to adjust the regulator. A allen hex key and a 5/8 or close to that. Loosen the jam nut, turn the allen head screw on the regulator IN and lower it to 43 then tighten the jam nut. Put the vacuum hose back on and it will lower the pressure because it sees vacuum. If it saw 10 lbs of boost, it would raise it 10 lbs.

 

[Vegas Smith]

Yeah it’s a cylinder one misfire, I was getting new plugs and wires anyways. I didn’t really understand the timing part, I don’t have any way to tune or anything. To set the fuel pressure do I just start the car and unhook the vacuum like then set it to around 43 psi?

Yes.

 

[MasterMatt209]

Yep. That's the easy way. There is a fuel pump connector somewhere under your hood that will activate the pump with 12v applied but just make it easy and have all the tools ready to adjust the regulator. A allen hex key and a 5/8 or close to that. Loosen the jam nut, turn the allen head screw on the regulator IN and lower it to 43 then tighten the jam nut. Put the vacuum hose back on and it will lower the pressure because it sees vacuum. If it saw 10 lbs of boost, it would raise it 10 lbs.

Okay thanks so I’ve got the AFPR correct now, I’m still sort of boggled by the BISS procedure when it comes to grounding the timing. Do I need special tools like a scanner and stuff?

 

[MasterMatt209]

Another update just took the car for a drive up my street very conservatively. The car now doesn’t jerk into hear it shifts smoothly so that’s very good I guess. But at one point when I was about to hit boost I hear a noise like air was just squeezing out through a hose, but it’s time for a boost leak test anyways like you guys said. Do I have to boost leak test through the turbo or is there another way like going through the intercooler? My tester doesn’t fit on while also haveing the intercooler piping on. Maybe I need a new tester

 

[1990TSIAWDTALON]

You can go through the intercooler but first just go around EVERY coupler and fitting and make sure they are all tight. Might just be a loose clamp but if you hear air, yep BLT time. I test from the turbo so I catch every link that might leak. You should be able to find it pretty easy.

 

[1990TSIAWDTALON]

Okay thanks so I’ve got the AFPR correct now, I’m still sort of boggled by the BISS procedure when it comes to grounding the timing. Do I need special tools like a scanner and stuff?

No special tools, I was just trying to get you in the ballpark. A simple wire grounding the timing terminal will work. I have a speaker wire with 2 alligator clips.

 

[MasterMatt209]

You can go through the intercooler but first just go around EVERY coupler and fitting and make sure they are all tight. Might just be a loose clamp but if you hear air, yep BLT time. I test from the turbo so I catch every link that might leak. You should be able to find it pretty easy.

Okay awesome. I know that the intercooler piping to turbo flange leaks but I’m not sure how to fix it, the gasket that’s on there now is like an exhaust gasket with the dimples and stuff is that the correct thing to use?

 

[MasterMatt209]

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This the timing ground?