low idle/stalling since new exhaust install

[93 r1]

I just put a turbo back exhaust from Road Race Engineering on my girlfriends 99 GST. Everything went together great and it sounds pretty good.

Problem is...now when driving and slowing/downshifting to come to a stop the RPM drops down really low(<400) and will then go up to about 600 but occasionally it will stall out instead of going back to the normal idle. It re-starts immediately when it does stall out though. I checked to make sure all vac. lines were connected, checked brake booster vac line, & cleaned out the MAS plug. None of that helped at all.

Everything else seems fine. Nothing really abnormal. Its just kind of wierd that it happened right after I installed the exhaust. Anyone have any good ideas.

BTW...the only mods are 3" turbo back exhaust w/high flow cat, and Apexi intake.

 

[93 r1]

The BOV is not vented to the atmosphere. All connections are tight

 

[93 r1]

any ideas?

 

[brcewane]

You might want to check your BISS screw http://www.vfaq.com/mods/BISS-1G.html

 

[allwheelTSI]

a bad ISC could be the cause of that..

 

[Black95TSIawd]

did u ground ur exhaust again if not your oxygen sensor is not functioning properly

 

[93 r1]

There wasn't any ground strap on it before. Should there be one?

 

[Black95TSIawd]

yea

strap a wire from the downpipe to anything u can find a ground on. Makes the O2 work properly

 

[maxperformance]

i just ordered the Apexi cat back exhaust for my 95 GST, when i was underneath the car looking at the ugly stock exhaust i saw one of the o2 sensors, i know im going to haveto take that off. With the new cat back exhaust will there be a place on the Apexi to plug the o2 sensor in? I dont understand what im gonna haveto do with the o2 sensor after i unplug it.

 

[FourG63 97GST]

I dont remember seeing a ground on mine when i took it off
and i dont have a ground now.

whats the manifold made of?
since its all connected wont that ground it?

 

[shadow1]

The exhaust gaskets and rubber hangers prevent adequate exhaust grounds without the ground strap. I've read on other forums that it eliminates ground noise on the O2 sensor since the O2 sensor has its own ground wire. If the factory went to the trouble and expense to put it there, than it definitely has a purpose.

 

[ABK]

is the 99gst with a stock turbo?
I think you are having problems because of your 3" exhaust. I know too big of exhaust on the car will cause major spool problems and stalling problems

 

[ABK]

is the 99gst with a stock turbo?
I think you are having problems because of your 3" exhaust. I know too big of exhaust on the car will cause major spool problems and stalling problems

 

[spyder20]

Originally posted by maxperformance
i just ordered the Apexi cat back exhaust for my 95 GST, when i was underneath the car looking at the ugly stock exhaust i saw one of the o2 sensors, i know im going to haveto take that off. With the new cat back exhaust will there be a place on the Apexi to plug the o2 sensor in? I dont understand what im gonna haveto do with the o2 sensor after i unplug it.

I put a 3" turbo back on my Talon and eliminated the rear o2 sensor. There is a VFAQ on the circuit to build so that you don't get a CEL. I have the diagram on my laptop as well if you can find it. Its only a few pieces, the most important part is to get a power resistor for the heater wires so that the power is dissipated. The circuit is really straight forward and easy to build....email me if you're unsure of what to do...

 

[doug]

Originally posted by 93 r1
Problem is...now when driving and slowing/downshifting to come to a stop the RPM drops down really low(<400) and will then go up to about 600 but occasionally it will stall out instead of going back to the normal idle.

Did you perhaps disconnect the battery when you were installing the exhaust? It may be that the ECU just got reset and is taking a while to "relearn" the fuel trims and stuff. That's how mine is whenever I disconnect the battery. It sometimes takes a day or two to return to normal.