Fuel pressure switch question

[rdragoo]

Hello all,
I have a M1008 that seems to take air after sitting overnight. I understand the fuel pressure switch can be a frequent culprit. Can someone explain to me what this switch does, and why it's ok to just remove it and plug that hole without replacing it?
Thanks,
Randy

 

[Jetnoise400]

Hi Randy,

First and foremost, I don't have any first hand experience with these little senders, and so I'm only repeating what others have relayed in their experiences... so take all this for what it's worth.

Here's how it was explained to me: The fuel pressure switch exists purely for the STE/ICE diagnostic equipment. What's that you ask? It's the gear that plugs into that great big round multipin connector under the dash. The switch sends fuel pressure info back to the STE/ICE unit for diagnosis purposes. The civvy trucks never had them.

As to if it's okay to pull it and plug the hole, dunno for sure. But it sounds reasonable that since it's a diagnostic item only and assuming you weren't planning to get the STE/ICE gear for your truck, it would still be okay to just remove it and plug the hole. Do at your own risk, your mileage may vary, etc, etc, etc.

Personally, I like to put back every part that it came with from the factory. So when and if the one on my M1009 ever starts to leak air, I'll replace rather than just remove.

Good luck, and report back what you decide to do... I'm curious.

 

[rdragoo]

Sean, from what you've said and what I've found, you're right. Can anyone with experience on this say what they've used to plug the hole with when removing this fuel pressure switch? I understand it's not threaded.

 

[gasser]

That is correct, it's not threaded. I have not plugged it, however I did replace one once. It's pretty straight forward. However, if you were to plug it, I would think that something like JB Weld - maybe?

-graham

 

[firefox]

Hi Randy,
They are plenty cheap enough. i believe I paid $20 from Owens Export.
Yes they are only used for the STE/ICE test gear.
I am not quite sure where the device leaks at, as I don't have mine apart right now.
I figured that plugging up the cavity with a new switch and O ring would make sure it got plugged up properly. It is not clear to me if it leaks through the wire passage or through a bleed hole in the cavity or elsewhere.

I got a PDF from Owens Export that describes the three models of switches that were used and their installation instructions, but the file was scanned in and is a little hard to read in places. I am going to include it here in the hopes that someone has some software to clean it up and post it back here.

 

[gasser]

Yup, I got mine from Owens as well - $20 bucks got me two of them.....

-graham

 

[Hasdrubal]

Hey, I had a similiar problem with my M1009. Would get it running,in morning fired then died.Drove me nuts, having to bleed the injectors etc.. It was a faulty vent in the fuel cap. When you park the vehicle open the cap to release pressure or vacuum, if it fires in the morning, it was the cap. Either replace it or drill a small hole in it .