Installed off road X pipe... now car wont idle..

[Schlodes]

I installed my off road X pipe today. Exhaust consists of equal shorties, the off road X, straight thrus, and stainless tails out to the back. Motor is internally bone stock BTW.

Car pulls a bit more up top in 4th. But it now idles @ 5-600 RPM, lopes like it has a B 303 cam, and wants to die off, surges at idle... check engine light came on just before I gave up for today. Everything is plugged in and tight [02s etc.....]. Played with idle a little [was idling perfect this morning with stock H pipe on] but nothing will cure it. It idles like a pig that wants to die. I didnt change anything else, just the X pipe.

Starting to think that this may be a bit too much exhaust for a bone stock motor???, but lots of you guys are running the catless stuff, with straight thru type muffs or MAC pro dump setups and are fine. So I figured this would be too.

Sounds like a damn indy car at WOT , too bad it has to come off For the 10 RWHP its worth, I can't tolerate the car idling like that Unless anyone has any ideas..

Anyone run into the same problem?

Discouraged Thanks.

 

[4dStang]

I don't see how exhaust can cause your poor idle. I have comletly new exhaust with eq lenth hdrs, hpipe and flows and my idle did not change one bit. I would check your plug wires and make sure they are all on and in the right order and then check your timing. Start with the basics before you rip stuff out. I have run open headers before and it had no effect on idle! There is something else wrong.


Chris

 

[88stangmangt]

pull the codes before you take it off your 02's might be dead. if so buy new ones and it is fixed.

 

[Schlodes]

Plug wires are all good... never had to touch them to do the job.

02 sensors are brand new with maybe 5000 KMs on them

I'll screw with it in the morning after work. I have a diagnostic scan tool I can toss on it to see what the code is...

Other than that I am lost.. I've gone over everything.

 

[65ShelbyClone]

I'll screw with it in the morning after work. I have a diagnostic scan tool I can toss on it to see what the code is...

Or you can just use an analog voltmeter or a test light.

I put full exhaust on my car before it had any engine mods and it didnt change the way it ran. I'm thinking your O2 signals just arent getting to the computer somehow. Code scanning will tell you that, though.

 

[willys1]

I put an off rd h- pipe on mine,at times it does lope like it has a cam,but it still idles between 6-700 rpm.

 

[RydeOn]

Mine has always purred. Never had any idle probs. My x pipe was my first mod. Is the smog pump tube on good?

 

[Matts89LX5.0]

smog pump pipe was what I was thinking as well.

Matt

 

[Jeff Cardwell]

Hey Schlodes
I did not have a problem with mine once I put a cap on the air injection tube on the X-pipe. Now my car sounds like a 5-speed at idle. Hope this helps.

Jeff Cardwell
www.ThunderValleyMustangs.com

 

[1991vert]

i had the same problem after i put it on. did you reset your computer? it fixed mine and it idles fine. hope this helps

edit: make sure your air tube on your xpipe is either connected to your smogpump or PLUGGED. after all that is done, let the car sit for like 10 mins maybe idling and let it get used to it. after you reset the comp you should be set.

 

[Schlodes]

Thanks for all the replies!

I had all the stuff everyone mentioned covered.

I was so puzzled [pissed off more] I took a sick day from work and went at it again last night.. no sleep from working the night before and staying up all day Figured out what it was... There was 2 things really but the 1 big thing caused the not wanting to idle. The other just made the car idle rougher.. it sort of always has.

First thing.. I noticed the problem occured once the car fully warmed up and went into closed loop [EEC goes into closed at 180*?]. It would almost immediately just die down and want to stall once it got up around 180*.. Anyway.. The 02 bungs on the X pipe were really deep in the way that the element for the sensor was barely even exposed to any exhaust. I did notice it when I was putting the pipe on the first time but never gave it much thought. Last night I went and looked at the stock H pipe. I grabbed a sensor and screwed it in then looked in the pipe, then did the same thing with the X pipe, and it wasn't even close. So, I cut about 1/4" off each 02 bung [with a hacksaw followed by a file to straighten - was desperate], re installed the pipe, reset the ECM then went out and drove the car around. MOre I drove the better it seemed to get. I let the car idle today while I cleaned out the garage, and it idled ok but still sort of rough. [this leads up to the 2nd thing].

The 65mm throttle body I have has a provision, but no actual hole, for the metal elbow, so you can hook the plastic hard line up to the oil fill tube on the valve cover. So for a while I just had a breather on there. I decided today [been meaning to for a while] to drill it out and re install the hard line. Once I did that I had to reset the idle [back the throttle stop off a bunch] as the car was now up around 1100 RPM idling with the hard line installed. Set the idle and the car idles nice now, dead on 700 RPM or so. I came to the conclusion that the breather was one giant vacuum leak [starting at the PCV valve] *thanks Mr. Yount for explaining that one a while back!*

Everything is happy in LX land again.. for now