Yesterday in about 98 degree weather I was going down the interstate when someone waived me over and said whenever I'd give it gas smoke would come out from under the car from somewhere up front on our 1996 XJS 4.0L and about that same time the check engine light had came on even though all the gauges showed OK. About 1/4th mile up the road I pulled over and looked and nothing was smoking or leaking and everything was full. So I got back on the road and she ran fine with no more smoke and 10 miles up I pulled into a parts store who checked codes for me and the only code was P0411, but everything appeared to be fine so we cleared the code and it's ran fine and normal ever since including over 150 miles I drove it today also in near 100 degree temps and all kinds of mixed driving.


The code is for an incorrect flow in the secondary air injection system.

Anyone have a clue what that was all about?


A little extra background; Once before back when we first bought it I noticed it smoking seemingly from under the front somewhere when we first got on the interstate once (in fact the day we bought it, 30 mins after we bought it) but it stopped on it's own, never turned on the check engine light, and everything was fine when I checked it (but that's scary when you just bought a car and flew out of state to get it). Even called the original owner who said it'd never done that before. At the time I chalked it off to him having over-sprayed tire cleaner or something onto the exhaust that was just burning off since he'd paid a detail shop to clean it up before selling it and they laid on the tire shine a bit thick including up in the fender wells. Now I'm wondering if that wasn't related to this as the smoke looked identical.

 

Check the black, electric air pump (P/N LHE1545AD) on the front of the engine. They are known to crap out. IF it does have to be replaced replace the check valve (P/N EBC11499) mounted under the intake manifold connected to the air pump by one of the two black hoses on the air pump. What happens is that the check valve breaks down taking the air pump with it. You can't replace one without replacing the other. The air pump itself is used on GM cars of the same vintage.

 

Well I was just out looking it over again and discovered there are two hoses coming from the back of the air pump, one is formed, the other is a flexible type (looks like an accordion all down it's length) and I discovered that one is not connected to anything. It was just laying down under there loose, even still has the hose clamp on the end of it... Question is, where does it connect? I couldn't find anything for it to connect to that I could see or feel and a web-search looking for a diagram of the system didn't yield any results.

Anyone knows where the other end of that hose goes?

 

SouthernGypsy,

I think it's part 8, air pump to air cleaner:

Air Injection Pump-4.0 Litre - Parts For XJS from (V)179737 to (V)226645 | Jaguar Heritage Parts UK

If in doubt, just look at jaguar's website .

Paul

 

There should be a hose connection on the leaving side of your air filter section. Can't recall exactly where it is. I replaced my air pump a month after I bought mine two years ago. Did not replace the check valve. With the hose off the back of the pump, start the car and no exhaust coming out the hose check valve is good.

 

The air injection pump cited by ptjs1 is not the correct one. The two links I've copied are for the check valve and the air pump.


Air Injection Pipes-4.0 Litre-From (V)194775 - Parts For XJS from (V)179737 to (V)226645 | Jaguar Heritage Parts UK


Air Pump and Mounting-4.0 Litre - Parts For XJS from (V)179737 to (V)226645 | Jaguar Heritage Parts UK

 

Thanks, found it on the air cleaner. The last place I expected it to be.

 

I started the car and there is nothing coming out of the hose at idle.

 

SouthernGypsy,

Apols for misleading you! Fortunately over here, we don't have to worry about any of that energy-sapping emissions stuff!

Paul