This car had suffered from a persistent raw fuel smell coming from the engine bay, and while it was getting some body work done a couple of months ago, the body tech found what he described as a hose leading up to the bottom side of the area in which the intake manifold can be found. From the end of that hose, there was a steady drip of fuel, even with the car completely powered off.

We had been having issues getting the car to tune properly anyway, so I suspected a 32-year-old car probably needed new fuel injectors. I bought six and had them installed. This comes less than a year after having a brand-new cold-start injector installed. The six new fuel injectors seemed to fix the fuel smell problem, and mileage also improved a bit. I thought that was that.

Well, last week the smell came back on a Sunday, went away Mon-Wed, then came back on Thursday. On Thursday, I pulled into my brand-new garage after driving the car for a half-hour and shut it off. When I cranked it again 30 minutes later and backed out, I got out of the car and went to where it had been sitting in the garage to see if I could find any evidence of a leak. There were three puddles of fluid -- two of them water from the A/C condensation drains, and one that smelled strongly of gasoline but was oily when rubbed between my fingers. I suspect it was gasoline that had run down the outside of the motor and picked up oil residue before falling off the car.

If you're familiar with where the A/C condensation drain is on the vehicle, this gas/oil patch was about a foot forward of the right-side condensation drain. I'm estimating that places it dead between cylinders 3 and 4, on the cold (passenger's) side of the motor. Obviously I want to get this fixed before I stick it in a brand-new garage with three other cars.

My biggest question is, what IS this? Is there really a hose or nipple in the vicinity where fuel can leak out? If not, what is it likely to be? The top of the motor is dry, so this leak is coming from the bottom and I can't easily inspect it without getting the car up on a rack somewhere.

Jess

 

Coming off the a/c compressor is a fuel cooler with a couple of fuel hoses that might be leaking. These are often overlooked.

On GPs don't forget to check the small fuel hose at the very front of the cylinder head, often hidden beneath a crust of grease and dirt. It may not be the leak you're experiencing at the moment but it's worth checking anyhow

Cheers
DD

 

Is there a vacuum port on the bottom side of the intake that should be connected to something? The shop is saying they've found what looks like a vacuum nipple with no hose connected to it, and no hose in sight. Gas is dripping from the vacuum nipple off and on.

Jess

 

It's a drain, just cap it off.

What's dripping shouldn't be raw gasoline but, rather, oil vapors from the crank vent system that have condensed to liquid. I'm not sure how raw gasoline would/could be in the intake manifold unless you have an injector leaking

Cheers
DD

 

And all six injectors are new as of 6-8 weeks ago. I had the same thought you did and preemptively replaced them all.

Most worrisome is that I'm moving into a new house with a six-car (!) garage in about a month and this car will be in the same space as another vintage Jag, two other project cars, my XF and my wife's SUV. It will be attached to the house. Ergo, a car leaking raw gasoline onto the floor of the garage (which it was doing recently) is a fire hazard I don't want to have to deal with.

I did find a little oiliness mixed with the gas last week but figured that came from the gas dripping onto the block and picking up surface oil/grime before hitting the floor. The floor was just painted and completely clean of any prior contaminants, so it's not transfer from another source.

The shop if flummoxed right now as well. They can't find any dampness whatsoever from any fuel line. I've told them to replace every line they see if they have to. I hate problems I can't identify.

Jess

 

Maybe try this. Similar products/schemes work for AC freon leaks

 

I meant to post this earlier but got distracted.

Just a few days ago I had a major fuel leak in that area.

I was backing out of the shop, smelled gas, and noticed I was leaving a trail of raw gas on the floor. A peek underneath revealed a 24" puddle of gas. I grabbed something else to drive for the day.

Next day I started the car and there was no leak at all.

Long story short, it was leaking where the the rubber fuelis clamped to the fuel supply pipe. Roughly speaking the supply pipe enters the engine bay below, and inboard of, the battery. If I jostled the hose in 'just the right way' it would spurt fuel. My presumption is that my jostling emulated the movement of the engine at startup.

Anyhow, double check that hose. The leak would appear on the floor just as you described.

Cheers
DD

 

Update...

We checked the back of the compressor and all fuel lines. No leaks from any of those.

We capped off the nipple. That stopped the gas smell and puddles of gas (for now, at least; I've been fooled before). However, now we have a new problem: The car floods and is very hard to start, especially when hot. Now, starting is an involved procedure of sputtering, half-burned gas in the exhaust for a few seconds, and you really have to feather the throttle to get it to catch. Once it catches, then you have to manually hold an idle of around 2000 rpm until it burns off the excess fuel and smooths out.

This would seem to point to injector leakdown, but as I said above, I just bought six new injectors. It also has a brand-new cold-start injector installed.

The next step is going to be to disconnect the cold-start injector so at least we don't have it spraying more fuel into the system, and see how that works. But I'm sort of flummoxed at why (and how) we're continuing to get gas in the system. Either an injector is physically bad, or the car is holding it open somehow even with the key off. I've thought about coolant temp sensors (although mine is pretty new); I've thought about MAS, but once you get it past the first 10-20 seconds after starting, there are no issues running, driving, passing, cruising, anything. Mileage is great at 23 mpg highway. I was told to look for an air temperature sensor, but I can't find one available for an 87 V6 (all air temp sensors seem to be either for the 5.3 V12 or for the XJ40 motor, not the XK6).

The other issue is the idle is still up. This just started with the leak. They manually turned it down some, but with the car in park, it idles at 1500 (better than the 2000 it was idling at last week, I guess). With the car in gear and my foot on the gas, it idles at 1000. I may get them to turn it down again and see if that helps, but I doubt that would help the flood/rich problem on startup.

Jess

 

Some reading

XJ6 Series - EFI Rich Mixture

XJ 6 Series III 4.2 - Cold Start EFI Overfuelling

I'll come back later after coffee


Cheers
DD

 

Jess, have you put a fuel pressure gauge on the line from the pump and watched to see if the pressure leaks off? Shouldn't drop at all in a reasonable amount of time (5-10min).
Dave

 

Dave,

To my knowledge, the shop has not done that.

I'm still chuckling a bit at Doug's link above where the factory recommending going to Radio Shack and soldering a part into a harness.

Jess

 

But it works!

Many have reported better running after the 'cap mod' even if they didn't have the double-fueling problem


Cheers
DD

 

What happens if I just unplug the cold-start injector? Would that make a noticeable difference?

Jess

 

In warm weather you probably won't notice any difference. In cold weather it'll take a bit longer to start the engine.

If the cold start injector is leaking you'd have to remove the fuel hose and cap-off the nipple on the fuel rail.

The capacitor mod doesn't have any bearing on the cold start injector, by the way

Cheers
DD

 

I didn't know any Radio Shacks were left! I thought they all DIED a couple years ago!
(';')

 

Lost another better post !!

google says Radio shack still around.

Short version.

Carl