How to measure V6 fuel pressure

[ianM]

Hi all,

After suffering from a separated fuel filter, which has now been put back together, I was hoping to take a reading of my fuel pressure to check I've done it all properly.

I understand the V6 engines have a schrader valve somewhere you can use to measure the fuel pressure. However, I was just wondering if there were any pics or "how tos" about the steps you need to take, especially when it comes to depressurising the fuel system - without spraying petrol everywhere!

After a quick glance, the workshop manual doesn't mention a schrader valve at all - instead Rover suggest detaching one of the hoses, and then fitting your fuel pressure gauge in between, which seems much harder (and with much more potential for going wrong) than just using what's essentially a tyre pressure nozzle.

If anyone who's done this could point me in the right direction, it'd be hugely appreciated!

[vitesse]

I've got a fuel pressure gauge, used it quite often mostly just to eliminate fuel pressure problems.

Screws directly onto the Schrader valve and although I generally wrap some cloth around it, I'd say the petrol release is minimal, so forget about spraying everywhere. Helps if you leave it, after testing, connected for several hours so any pressure will have dropped a bit.

Regards

[ianM]

Originally Posted by vitesse

I've got a fuel pressure gauge, used it quite often mostly just to eliminate fuel pressure problems.

Screws directly onto the Schrader valve and although I generally wrap some cloth around it, I'd say the petrol release is minimal, so forget about spraying everywhere. Helps if you leave it, after testing, connected for several hours so any pressure will have dropped a bit.

Regards

Hi Vitesse,


Thanks for this - would you happen to have any pics of where the schrader valve actually is, please? I had a quick look the other day, but I couldn't obviously spot it! I heard it's under a blue cap - does that sound right?

[SD1too]

If you look just to the left of where the accelerator cable connects to the throttle linkage, that's where it should be.



Simon

[ianM]

Originally Posted by SD1too

If you look just to the left of where the accelerator cable connects to the throttle linkage, that's where it should be.



Simon

Oh, that's perfect - exactly what I was looking for! Thank you!

[ianM]

Well, I seem to have fallen at the first hurdle! I bought this https://www.ebay.co.uk/itm/134785734914 on ebay, but when attaching it to the Schrader port, it doesn't seem to depress the pin inside to let the fuel escape.

On a tyre, it works fine - screw it on, and just as you get to the end, there's a hiss and it starts to read the pressure. On the fuel Schradrer, however, the pin it needs to depress seems to have been recessed somewhat, and is sitting maybe 2mm recessed in from the end of the nozzle. As such, even when tightening my tester on, it never actually manages to depress the pin and take a reading.

Am I doing something wrong? Or is there something up with my valve (or tester)? Tried to attach some photos to show what I'm seeing!

[SD1too]

I've just been out to my car Ian and the Schrader valve looks the same as yours.

Sykes-Pickavant is a long established tool manufacturer. Its kit includes three adaptors for Schrader valves. It's eye-wateringly expensive though.

Simon

[vitesse]

Thought I'd join the club and check my valve too much like your photos, the top of the valve a couple of mm below the top.

Your kit looks similar to my own, except mine is non-branded. I need to use an adapter for mine, but as you've tried it on a normal tyre then you've got the size right.

Wondering if a valve removal tool might help, just unscrew the valve a couple of turns, or the one on the kit, you might loose a bit of petrol when it's unscrewed until you can re-tighten the valve.

Good luck