1991 xjs v12 injection pipe noise

This is a dozy. Anyone ever replace air injection pipe on the passenger side that runs along and below/beneath the motor from rear to the front… the pipe has rotted through and mechanic says he never has replaced such a pipe a it is rare for the pipe to rot. They can’t find the pipe new or used as I write this comment. Unfortunately this is as specific as I can be with the hope that someone might have had similar problem and know where such a pipe can be located. Mechanic says he doesn’t know if its a 4 or 10 hr. job.
Any info is appreciated
chaz

Not that rare for it to rust out, actually. It’s just that most of us just toss the air pump over the hedge and abandon the rusty pipe in place.

On my '83, I left the pipe in place until I had the engine out to replace the transmission, when I removed it. I dunno how you’d get a new one in without similar effort.

As far as obtaining the pipe itself, I dunno. I’d suggest you make one, possibly using the tips off the old one. It is, in fact, just a pipe.

Is it noisy when left in and any effect on the engine or other?

The small tubes going into the top of the engine go into the exhaust ports. If left open, you’d get exhaust noises out of them. However, there’s a T where the pipe connects from below that has a standard GM check valve in it, and its purpose is to allow pumped air in but block any exhaust from coming out. If it works, you shouldn’t get much sound from the exhaust ports.

There’s also the air pump itself. If it’s running, I suppose the pumped air coming through openings in that pipe might make noise.

So, do what the rest of us do. Toss the air pump over the hedge, mount an idler pulley or a GM CS130 alternator in its place to keep the tension on the A/C compressor belt, and remove all the plumbing on the top of the engine and plug the 12 little ports. Abandon the pipe across the lower right side of the engine in place.

Much appreciated. will pass on to my mechanic and see if that’s an alternative to his conclusion.

Sorry for the delayed response. This is an exhaust pipe. It is noisy (like a tapping valve ) when under a load. I thought it was valve noise, but mechanic says it from the exhaust pipe. I went to have converters checked and repairman notice air escaping from area rear of motor. Seemingly hard or maybe impossible to replace with same. mechnic says he’s never replaced one before.

Chaz,
This is the kind of thing having the XJ-S Jaguar Parts Catalogue and knowing the right part number are good for. The Jaguar part number for that Air Pipe is C46337. I just typed “Jaguar C46337” in Google and found a few places that might carry it in the USA. You didn’t mention where you live, so if you live in someplace other than the USA it might be more challenging to find it. The possible USA sources that I quickly found were Welsh Enterprises and Jagbits. You will have to contact them to see if they have one in stock.

Kirby mentioned that some owners do away with the emissions equipment. I live in California where 4 of my 6 Jaguars are required to pass emissons test every two years. The test includes a visual inspection to make sure that I haven’t removed anything like the air pump, air rails, etc. So although some have removed equipment like this, other have not either because they can’t or they prefer not to modify their cars from how they came from the factory.

Paul

Paul, I believe initially (like 17 days ago in the original post) Chaz thought he had a rusted thru air injection pipe. It seems like as of 4 hours ago, the problem may be with the exhaust pipe. From his post a few hours ago, I would guess there is a leak where the exhaust manifold connects to the down pipe. IIFC, there is some type of donut that fits in between the two items ?? SD Faircloth