adams993

hey guys, so I have had my DACH Catless X pipes for about 2 months now. They sound WICKED....BUT, once the car is warmed up, I'll pull up to a stop light, and the revs will dipp really low, the ECU will try to compensate by throwing some revs at it...and then it'll be fine. Most of the times though, the car will just dip too low and die. Is there a way to get aroudn this? Turn up the idle? If so, how do I do this!?! THANKS!
ADAM
(P.S. the DACH pipes only have 2 of the 4 O2 sensors hooked up.)

ADAM

Gweedo

That is your problem. Your car is OBD2 and requires an O2 reading before and after the cats. If the second set of O2s are not hooked up your car most likely thinks it's lean and is dumping fuel to compensate. I'm surprised your are not getting a CEL.

John H

Adam

What mufflers are you using?

adams993

No CELs...and running RSR. The DACH pipes only allow for the pre-cat O2's to be plugged in.
ADAM

dpressley

Are the second o2 sensors still attached to the wiring and hung in the engine compartment somewhere?

Pete

dpressley

actually, come to think of it, it probably can't solved and you need to sell the pipe to me!

Gweedo

Sounds like those pipes are for a '95 OBD1 car.

Schnell 911

Have a second set of bungs welded into the bypass pipes so that you can thread back in the secondary O2 sensors. If they are in the circuit (feedback to ECU) and properly grounded, you shoild have no CEL issues or mixture / idling problems. Just my experience.

viperbob

I'm with Dannen.

Rick

I'm going to speculate that it's not actually related to the bypass pipes unless the secondary O2 sensors are disconnected. I had bypass pipes on one of my 993s for over 2000 miles without an issue. I had the secondar sensors pulled up into the engine compartment and wire tied out of the way...no issues.

Here's my suggestions:
1. Make sure the secondar sensors are still connected to the wiring harness and tied up somewhere in the engine compartment (not below).
2. Make sure your ISV is cleaned up.
3. I'd disconnect the battery for a reasonable time and then reconnect...start the car. This will reset everyththing to base code and may help.
4. Check for MAFS/throttle body adaptation (I can't explain this well at all but you can encounter issues if the gas pedal is pressed at all while the battery is disconnected - I'd PM/email Steve Weiner for details & process to resolve).

Cheers,

Rick

Gweedo

Don't the second set of O2s need to be "dummy" O2s that send a signal to the computer that says the exhaust is clean as opposed to "regular" O2s that will tell the computer that the cats are not working? I believe they call them "MIL Eliminators"

993inNC

Exactly, its not the X-pipes at all! THANKS ADAM ....for not contacting me about it first instead of blaming my product

What he needs to do is wire tie them to anything in the engine compartment that provides a ground (heater box above the bypass does just fine). What I bet he did was dosconnect the battery and the first time he took it out the car stalled. Should have worked itself out with in 20 miles.

adams993

Chris, you MUST be kidding me! I NEVER blamed the product! I said my car was dying since I got them, not blaming hte product, I'm sure this happens with ALL catless pipes. Geesh. ANYHOW, the secondary o2's are plugged in and hanging ziptied in the engine compartment. WHat is the ISV? How does one clean it!?! Any info is great! Chris, I DO NOT blame the pipes, I know it is a catless issue, not a DACH issue!
ADAM

adams993

As for the whole 20 miles workout....this is NOT the case man. The car runs fine UNTIL it is warmed up...THEN dies at every stoplight. I have driven over...hmmmm...500 miles with them I would estimate. The battery was disconnected while the car was in the body shop....and 500 miles have been logged since then. Still stalling.
ADAM

ppressle

The isv is a very good suggestion... Check out pcar for the diy or search the forums here. There has been lots of discussion about it.

I don't know if it matters, but you should probably try grounding the o2 sensors (the body) to see if that makes a difference.

(disclaimer, I have actually never had problem with an isv in the 993. Just read many posts.)

Pete