Gotcha, didn't mean to lead your thread astray. I didn't realize the valve would have exactly the same internals as a tire valve. Would have assumed they would use different rubber or something. Changing a valve stem is very easy so good to know.

 

Henrici,

Not a problem, I was actually responding to the NiteTrain who seemed to be indicating that the problem was the type of guage I used.

Since I had seen nothing regarding the valve having an internal failure after trying to read it, (it did not leak prior to this attempt, but had a total failure immediately upon the attempt) I wanted to let Everyone know about this failure mode and the easy fix.

Without the replacement valve stem and the tool, my dearly beloved Disco would be OUT OF COMMISSION AS WE SPEAK.

So hopefully this saves some of you a problem in the future. If you don't have the little replacement valve and the tool, you may want to pick one up before you mess with the test valve to avoid being stranded.

 

Spike, what is your take on this?

 

The reason they include all of those O-Rings in the fuel PSI gauge test kits is so you can hook it up and leave it connected while you do a test drive and not start a engine fire and burn up the car.

Yes there is supposed to be a cap over the stem, get a nice chrome one for a little "bling"

The round mechanical tire gauge will work just fine for the DIY're checking their fuel PSI in the driveway.
Just dont smoke and have a fire extinguisher handy.
Those rules hold true anytime you are working around fuel.

 

same way a gauge on a tire doesn't leak

 

I think nitetrain is just sayin he does not see how a tire gauge would not leak while testing fuel pressure. My gauge has a rubber seat that seals against the shrader valve. Yes, a little squirt(and I mean little) comes out when first pressed.

Danny, let us know how long them core's last. I was afraid what would happen if mine leaked after testing, but luckily didn't have to worry about it.

 

I tested mine just out of curiosity since I had changed the fuel pump assembly a few months ago and wanted to see what pressure I was getting. It was one of those round dial type guages that look like a little tire.

You can imagine my total horror when the damn thing first started bubbling then turned into a steady stream of fuel dumping on top of the engine. Prior to this it never leaked a drop, but I never messed with it either.

Glad I was in my driveway. I was going to walk to the Gas Station down the road to see if they could put in a new valve stem for me. They were great about it. Gave me a handful of extras. Wouldn't take any money either. When is the last time you had that happen.

The old one looked like hell when they took it out, new one works fine. I am sure the old one was original from it's appearance.

Lesson Learned: Have spare valve stems and tool on hand before trying test valve.Identical part internally. Never expected this to happen, but glad it was an easy fix. Just wanted to pass the info along to all of you.

Better to be prepared. I have had several fuel injected cars, but have never messed with any of the plumbing associated with same. Are these valve common to most cars?

I was also considering just blocking it off with a bolt if I could not get a valve stem to work, but that would have been another wild goose chase to find right size to use.

Just thankful it worked out so well. Thanks to Eric at Rovers North. He told me to get a tire valve stem since there is no replacement piece thru Land Rover.

I will put a cap on there real soon to keep foreign matter out, that may have been a major part of the problem, no cap.

 

All I'm going to say is, Spike is right about the fuel pressure test kits. I have never used a tire guage for testing fuel pressure. Not safe in my professional opinion. Not saying it won't work, but I wouldn't do it unless in a pinch. Just save a little money($12 at Harbor Freight and $30-40 for a better one at a parts store) and buy the tester. I also have never had a valve go bad on my. I can only guess that it broke because the tire guage may have pushed the valve core in too far, damaging the seal seats(my speculation). But there is no reason a tire guage wouldn't come in rel handy if you're stuck on the side of the road with a dead car and want to see if you have fuel pressure. I usually just push in the valve core and if fuel sprays out, I consider it good.

 

yeah, I wasn't trying to say he messed up his valve using a tire pressure gauge. I have no idea what it would do, I've never even considered using a tire gauge for that or seen anybody use one for that.

What I do know is when I check my tire pressure some air always escapes..air into the atmosphere..not a problem...low flash point gasoline on a hot engine..not so good.

 

Seriously, if it was me I would replace that valve stem. It may be working now, but the fuel may dissolve the oring away on the tire valve stem over time. Fuel will dissolve a lot of rubber compounds.

I'm not saying it will dissolve the oring on the valve stem, but it very well might. Last thing you want its to be driving around and the oring fails, spilling out fuel in your engine compartment and starting a fire.

If this was already brought up/resolved I'm sorry as I'm in a hurry and unable to read through the entire thread...