Bad exhaust leak.. Run in Speed Density?

[Poda]

The Fleetwood has a bad exhaust leak upstream of the left 02 sensor from the exhaust manifold flange. It's tripping a lean code which I'm sure is causing the PCM to add fuel to the left bank of cylinders. Car's running like garbage.

It's freezing up here, and I won't get around to replacing the flange gasket for a little while (no room in garage = PITA..) - question is, I know it's not ideal but if I reset the PCM, unplug the MAF and run in Speed Density will I be better off? Other than a MIL, and slightly worse mileage, I'm assuming the car will at least run a little smoother..

EDit: it occurs to me that unplugging the O2 sensor and forcing it into closed loop might be a better alternative until I can get the gasket done..

[KW Baraka]

Originally Posted by Poda

The Fleetwood has a bad exhaust leak upstream of the left 02 sensor from the exhaust manifold flange. It's tripping a lean code which I'm sure is causing the PCM to add fuel to the left bank of cylinders. Car's running like garbage.

It's freezing up here, and I won't get around to replacing the flange gasket for a little while (no room in garage = PITA..) - question is, I know it's not ideal but if I reset the PCM, unplug the MAF and run in Speed Density will I be better off? Other than a MIL, and slightly worse mileage, I'm assuming the car will at least run a little smoother..

EDit: it occurs to me that unplugging the O2 sensor and forcing it into closed loop might be a better alternative until I can get the gasket done..

Are you sure the gasket's blown out?

Maybe the manifold bolt(s) just needs to be torqued to spec......

KW

[steveo]

yeah i'd just run it in open loop. but it's already doing that for you -- a lean code causes immediate open loop operation. no need to unplug anything.

go easy on it though, a leak that large at the flange will cause excess heat on that cyl. wouldn't want you to torch a valve or anything..

[Poda]

Originally Posted by KW Baraka

Are you sure the gasket's blown out?

Maybe the manifold bolt(s) just needs to be torqued to spec......

KW

Thanks for the advice guys..

Yeah, I know the gasket's blown out - I can feel it leaking there..

On the flip side, is there any kind of goop that would withstand the temperatures that I can apply to the flange as a temp fix until it gets warm enough for me to do it, or find a nice warm garage?

[steveo]

you can loosen the bolts, squeeze a bunch of high temp o2 safe rtv in there, let it cure, then come back and retighten it. that might buy you a few weeks or a month.

or there are some ceramic and silicate exhaust joint sealers, they are the color of bird shit, and they dry into a hard crust. you could just squeeze a bunch of that and it would, at the very least, reduce the size of the leak

but it'd be just as easy to replace the gasket. you do realize you dont have to actually remove the manifold to replace the gasket, right? removing the bolts is the only hard part, just because it's so tight in there. you just have to pull it away enough to get a gasket scraper in there, you might not even have to loosen the connection to the y-pipe. it's not a bad job.

[Poda]

You're right - at that stage I might as well just do it properly..

[KW Baraka]

Originally Posted by Poda

.....Yeah, I know the gasket's blown out - I can feel it leaking there.. ......

Yeah......you'll be able to feel it leaking if you had loose bolt(s) there, too.

Before doing anything else......get in there with a wrench and try tightening the bolts.

Been there many times.....done that many times.......

KW