? on fitting size

[Steve Roseman]

I am currently in the process of hooking up an idiot light for my fuel pressure for peace of mind and just to have another gizmo. I plan on hooking the sending unit into the plug hole on the top of the banjo bolt on the output side of the fuel filter housing. If you are still with me, I was wondering if this is metric thread or npt and what size.

If it's npt I would guess it at 1/8". But knowing these trucks it's metric. I would appreciate any help.

 

[HEMI®Dart]

I believe it's a metric thread. It's alot smaller than 1/8" NPT too. I bought the adapter from TST that screws into the air bleed port, then opens up to a 1/8" NPT female thread. This may be the easist way to go.



TST's adapter: http://www.tstproducts.com/service_tools.html

 

[Cooker]

I foget the size, I can look if you definitely need it. I too ordered the adapter from TST.



For grins, I checked at a local fitting/hydralic shop to get the same fitting TST sells. Price was $15 w/ a minimum order qty. of 3

 

[Steve Roseman]

Thanks Guys,

The sending unit I ordered has metric threads, I think it's #10-1 or something like that. I'll find out tomorrow afternoon when my Napa dealer gets it in. I'm hoping it will work, the book says it closes below 17. 5-21 lbs. Should tell me of filter restriction or start of gelling.

 

[illflem]

Steve, I believe it is 10-1 Metric. I've never messed with an idiot light type sender on a 12 valve, but without a snubber on a electric gauge sender or a mechanical gauge the pulsations from the lift pump are so wild that the gauge will bounce rapidly from 0 to 40. If your idiot light behaves like a strobe light you will know what's up. I would recommend disconnecting the sender right away if it does this till you get a snubber, it will self destruct in short order. I also found on my '95s that unless your sender is very small there just isn't enough room to attach the sender right to the bleed screw port. You will either have to run a hose from the filter top to your sender or do what I did - tap a port on the injection pump inlet banjo bolt. This a better location space wise anyway and you will still be able to easily use your bleed screw for bleeding. Good luck, would like to hear how you fare.

 

[Deezul1]

Do not attach anything to the top of the filter housing such as a sender, the vibration will snap it off. (been there done that) I used TSTs fitting and attached a hose to it and then to the sender and it works fine. To get a ground for the sender I screwed it into a tee with the hose on the other end of the tee and then took an 1/8 " pipe plug and drilled and tapped it for 6-32, screwed it into the tee and fastened my wire that way. Didnt drill clear through.

 

[Steve Roseman]

Illflem and Deezul 1,

Thank you for your input. I will take your ideas into consideration while trying this. It's always easier to learn from someone else's experiences, many times it's cheaper too

I did find out the bleed bolt is a metric 6 and an adaptor from 6 to 10 is about impossible to find. The thought of a tapped banjo bolt went through my mind but that's as far as I got.

I might have to get hold of TST and order a fitting, also thought of contacting Cummins about a banjo bolt. I'll let you know how it goes.

 

[illflem]

Steve, it's really no big deal to tap the head of the banjo bolt to whatever thread you want. Doubt if Cummins has one that has been tapped but Geno's does, they are 1/8" pipe thread though.

 

[Steve Roseman]

I am starting to get things figured out . Before it got too dark to see, I went out and popped the hood to take another look at things. I hate to get started on something late in the day since I leave for work awful early in the morning. Anyway, I was looking at the banjo bolt with the bypass valve and it got my curiosity up. I went ahead and pulled it out, sure enough the bypass valve is the same thread as my sending unit. I pulled the inlet banjo bolt off to make sure it was threaded the same and it is, had red stuff run out all over the drive That's a whole different story.

I figured I could tap the inlet bolt, or get another outlet bolt and drill the passages bigger. I don't mind tapping, just might not be able to find the right size tap.

Will update tomorrow if I find out more.

 

[illflem]

Steve, NAPA can get you the tap, they've been able to come up with some real oddballs for me. Or maybe someone out there has worn out overflow valve to donate...

 

[Steve Roseman]

I picked up the tap today, my Napa dealer didn't have one in stock but a local farm supply store did. Will be drilling it out tonight

Will let you know how it goes.

 

[Steve Roseman]

Well, it might be me with the worn out overflow valve

I tapped the banjo bolt and installed the sender, but can't seem to get the pressure I need. I can hear the relay chatter at an idle, but at 1500 rpm it won't engage it. I don't have a regular guage to see what the actual pressure is.

I haven't noticed any lack of power but maybe I have more on tap just waiting for the right pressure.

TST says the pressure is about 20 at idle and 30-35 at cruising speed, my sending unit is rated 17. 5-21.

I'm going to check Geno's web site for pricing on the overflow if I can find it.

 

[Cooker]

Piers has the absolute best price on an overflow valve.

www.piersdiesel.com



I don't even know if Geno's sells them.



Before you buy one, I would check the pressure with a regular analog gauge first. This will ensure that your sending unit is functioning properly, and it might save you $45. Also I think it is good to have a idea of where your numbers are at vs. and "idiot light" (No offense. I'm sure you know what I mean. )

 

[illflem]

Steve, the chattering you hear is probably due to the pulsations from the lift pump, you really need to use a snubber or needle valve to restrict the flow. Check your mail.

 

[Steve Roseman]

Thanks Cooker, no offense taken. I prefer actual guages, but I figured the fuel pressure was something I didn't need to monitor constantly. I just wanted something to alert me of a pressure problem, I also didn't want any fuel lines running into the cab or another guage to clutter things up.

Illflem, I believe you're right on the pulsating of the lift pump. I guess you can say "I told you so! ".

I dropped you a return mail.

I just love a good challenge!