Installed O/R H...Wont stay started...WTF???

[95.0Stang]

Hey,

Just installed an O/R H-pipe on my 94 GT, and the thing will not stay running... well not ALL the time, when I first start the car it runs fine, and idles fine right between 800-900rpms, then I drive it, and the first thing it does is stop at the first stop sign, WTF is going on???

I brought the car home, and disconected the battery for about 5-7 minutes, and thought that would help for some reason...no such luck, I have to sit at stop lights and kind of rev the motor to keep the car running...WHY?

What confuses me is that I did this same mod on a 95 GT I had about 3 years ago, and never had this problem...

Help!

And I have tightened the nuts as much as possible, how do I get rid if two tiny exhasut leaks??? Would air tools help?

Jared

 

[Synned]

Hey,

Just installed an O/R H-pipe on my 94 GT, and the thing will not stay running... well not ALL the time, when I first start the car it runs fine, and idles fine right between 800-900rpms, then I drive it, and the first thing it does is stop at the first stop sign, WTF is going on???

I brought the car home, and disconected the battery for about 5-7 minutes, and thought that would help for some reason...no such luck, I have to sit at stop lights and kind of rev the motor to keep the car running...WHY?

What confuses me is that I did this same mod on a 95 GT I had about 3 years ago, and never had this problem...

Help!

And I have tightened the nuts as much as possible, how do I get rid if two tiny exhasut leaks??? Would air tools help?

Jared

An exhaust leak wouldn't cause that...sounds like you forgot to plug in your o2's or forgot about them completely, they jump into play like 2 minutes after you start the car.

 

[jtb19nh]

+1 on the o2's

 

[Bosko5.0]

did you remember to put the O2s back in and hook them up?

 

[95.0Stang]

An exhaust leak wouldn't cause that...sounds like you forgot to plug in your o2's or forgot about them completely, they jump into play like 2 minutes after you start the car.

O2s are securely back in the H-pipe...should I have put a mil eliminator in?

 

[Synned]

O2s are securely back in the H-pipe...should I have put a mil eliminator in?

No, they should be put in the new H, they should function the same, they are before the cats. If they are hooked up correctly...I don't even know what else it could be.

 

[95.0Stang]

they are in the new H, and plugged in...I dont get it...do I need new o2s now?

 

[tjh566]

when i installed my h-ipe when i dropped the old one out it feel onto an 02 sensor and it didnt look damged but a CE light came on, maybe it got damaged somehow.

 

[HISSIN50]

Did you accidentally disconect the VSS?

 

[95.0Stang]

Did you accidentally disconect the VSS?

WTF is that?

 

[HISSIN50]

VSS is the vehicle speed sensor. You noted an issue when coming to a stop. The VSS works with the computer and IAC to create a rolling idle around 1200 RPM to help prevent stalling.

 

[gunmetal5.0]

It hooks up to the tranny.

 

[95.0Stang]

I guess I need a picture...got one handy?

 

[final5-0]

I guess I need a picture...got one handy?

Its on the side of the trans near the back ... You can't miss it

Just look to see if you got a plug on the trans that don't got a a wire on it

or

Just look to see if you got a dangling plug thats not hooked up to something

btw ... This thread in N O T worthless just because it ain't got no pics

Pics ... Pics ... Pics ...

Just get under there and put the two of em together

Grady

 

[95.0Stang]

I have loosenend and reinstalled everything so far and to no avail. I checked the intake and one of the bands I took loose to unhook the egr was loose. thought that would be the fix. tightened everything back up, unhooked the battery for 10 minutes to let the computer reset, and I am still dying?

Come on :SNSign: help me out here, I can not seem to figure this out at all!!!

 

[94-302-vert]

What happens if you let the car idle for 5-10 minutes.... does it jsut keep idling or does it die on you?

I am thinking that if the cats were pretty much dead then they were giving a lot of backpressure that you do not have now. This could be a problem for the computer to learn....

As for the exhaust leaks... welcome to the club. First make sure visually you are well alighned.... then What I have found that works pretty well is to get the exhaust hot and re-tighten the bolts HOT... Usually takes a few times but has worked for me pretty well. I actually gotta re-do this again...

 

[final5-0]

Jared

The prob has to be with something you messed with while doing this
recent project

Go back and check EVERYTHING you messed with to see if something
is not like it should be

Exhaust leaks around those ball & socket joints can sometimes be
caused from not keeping the bracket even as you tighten it up
causing more pressure on one side of the connection than the other.

Sounds like something to do with when you go into closed loop

If it is something along these lines ... Seems like you would
generate some codes

Can you use a multi meter to check and see if you got good
activity with each O2?

Grady

 

[davins130]

def. sounds like you have some exhaust leaks, which are bringing in air that is then read by the o2's and messes up your idle because the computer thinks your running lean and then compensated for it. keep messing with the header to h-pipe flange until that leak goes away, and make sure you didnt strip out a bolt or anything because those things are extremly rusty.

 

[95.0Stang]

also thinking about buying new flanges, they aree $6 at advanced

 

[WhiteCobra95]

Did you ever remove your induction tubing/MAF? When I installed my headers and h-pipe, I yanked the air pump and had to pull the induction out. If you forgot to reconnect the maf/iat harness that could cause the problem, especially if you have other modes (i.e. after-market cam).

Even if you have exhaust leaks, they would just drive the system rich, they shouldn't cause your car to stall. (Stock closed loop fuel system typically only allow +/- 20% correction, which isn't going to flood out the engine regardless of a huge leak.)

I would suggest checking all sensor connections like Grady reccomended - TPS, MAF, IAT, ECT, IAC, O2's, etc.. If everything is cool, you might look at your IAC motor itself. If the car has a lot of miles and the cats were partially plugged, the IAC could have been operating in a different position than where it's at now, and the lower opening position is partially plugged. You could clean it out, or take the chance on installing a new one.

My car ran fine after the headers and O/R H-pipe install with one exception; the car repeatedly goes into stall saver mode when the A/C kick on. Every time the compressor engages at idle, the rpm drops down to about 500rpm, the compressor disengages, and then the engine flares just over 1,000. Cruising there's no issue. I rarely use it, so I haven't looked into fixing it yet. I suspect that it might have something to do with the change in load after removing the smog pump, or that I capped off the EGR tube at both ends.

Good luck man!