Gasoline in Air Cleaner Housing

Ahoy !
V12; 5.3L with Automatic trans; 1992 XJS Convertible; LHD
(Not sure if this question belongs here in V12 or in XJS).

Any guesses on how raw gasoline may have gotten into the Air Cleaner housing ?

I removed the driver’s side (LHD. B bank, I believe.) air cleaner housing to replace the air filter element and got a palm full of raw gasoline. Air filter element had an egg-sized hole blown through it.

I did not experience any back fire during the less than 100 miles (city & highway) that I drove the car. So, I am assuming the hole was a perk that came with the car. Engine seemed to run fine. Used car - don’t know the history.

I’ve not tried to re-start the engine. I have changed engine oil & filter. Oil did not look nor smell outstandingly “fuel diluted”.

I’ve not yet been able to remove the air cleaner housing to have look at the throttle. (Rusted nut & stud on the front support bracket, of course.)

Richard Cielec
Greater Metro Chicago, Illinois; U.S.A.

Disconnect the vacuum line that connects to the fuel pressure regulator and see if you have raw gas there. A ruptured FPR diaphragm will allow gas into the intake manifold, which I suppose could make it’s way to the air cleaner housing.

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Thanks. I’ll check later today. Hope it’s not the Fuel Pressure Regulator re: No Longer Available. I think BMW and Volvo applications have FPR’s that look similar (Internet search; have not have any in-hand) but are not the 2.5 bar spec. of the V12.

Richard Cielec
Greater Metro Chicago, Illlinois; U.S.A.

Check Welsh Enterprises. EAC 1284. Ah, It’s a '92. Never mind!

I wasn’t aware that FPRs were hard to come by?

I recently worked with Richard on servicing the injectors on this engine… His vehicle has only one FPR (EBC3387) mounted at the front of the A bank fuel rail. . The vacuum hose from that FPR has a solenoid valve and a delay valve fitted, shown as part of the “hot start system” at SNG Barrett site. The vacuum hose would most likely fit to the driver side intake manifold, but is not confirmed.

Richard needs to verify that the plumbing shown at SNG Barrett, is in fact, the plumbing on his vehicle.

The gas leak is on the B bank side coming from the air box. I have suggested that Richard needs to determine what piping/plumbing is entering the B bank air box. Maybe someone here has that information.

SD Faircloth

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So the B side side intake manifold, correct?

Understand. I cannot think of anything that would introduce fuel into the air box. Grasping at straws, I was thinking that if a large amount of fuel was getting into the intake, it could make its way to the airbox. Admittedly seem like a long shot.

The only thing I can think of on the B airbox is the PVC setup. But at the moment I cannot think of how raw gas enters the PVC system. Assuming connections are correct.`

Edit: Just occurred to me that the vac lines for tank vapor purge are plumbed on the B-side, right at the throttle butterfly, I believe. If the charcoal canister is full of gas it could maybe wind up at the butterfly and run down into the airbox…

I will be very interested to see how this plays out.

Well…I said that wrong. Thinking of too many things. I meant to say, I think the vac hose on the A bank FPR (passenger side) would logically ? be fitted to the A bank intake manifold., but where it fits is not confirmed. Again, keeping in mind there is but only one FPR on this specific engine. SD

Agreed and makes sense.

That’s another point I’d like to dig into, but I don’t want to totally hijack this thread. I’ve heard of eliminating the A bank FPR, and seen that done, but not the B bank FPR. If I’m visualizing this correctly, I don’t understand how any pressure can be built in the fuel rail, if the outlet is unregulated.

I’m with you. Not sure I understand how the FPR works in this setup. Found an example of a '92 V12 with this setup on a YouTube video… Link below. Look beginning at +/- 1:42 on the video.

1992 Jaguar XJS V12 Coupe - Walk Around - Autosport Designs - YouTube

SD Faircloth

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Of course, in proper Jaguar fashion, on this year model and this engine, Jag decided to switch things around. The fuel feed line connects at the front of the fuel rail on the B bank side of the engine, and the fuel line is connected to the FPR at the front of the fuel rail on the A bank side.

Trust I got the link embedded properly. SD

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CORRECTION…that should read…and the RETURN fuel line is connected to the FPR at the front of the fuel rail on the A bank side. SD

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Hello, Bob:
Thanks. But those FPRs at Rock Auto, having the horizontal fitting, are not correct for my car. Hope this Barratt link works. See Item #2.

Richard Cielec
Greater Metro Chicago, Illinois; U.S.A.

Got it. Yeah your fuel rail is a different design than I thought it was. Thanks for the clarification!