Hey guys. A buddy of mine just installed a Fuel Pressure gauge and did it a little different than I did. He used a banjo fitting to connect his sending unit right to the top of his CP3. The thing is, he told me that the banjo still has about 3 or 4 threads showing out of the CP3. It only took about 4 threads because of the compression threads. The banjo did not seat all the way into the top of the CP3. Is this normal? Where else could he have ran this banfo fitting for a better fit? He said due to the threads, if he tries to take the fitting out, it will either strip the banjo threads or the pump. Help me/him out a little. Where else could it have been ran?

 

Anyone? At all?

 

From your math, it looks like the fitting has 8 threads on it, and you got 4 of them threaded, which should be more than enough. You are talking about Pipe Thread, right?

Or

Are you talking about the bolt that goes through teh banjo fitting, and you only got 4 threads on teh bolt, and the banjo did not seat? If that is the case, you are gonna leak fuel.

Just your description is a little hard to follow

 

Sorry, pipe thread is correct. I am use to calling it compression threads. The Railroad (who I work for) uses pipe threads on most of our equipment, and we have called it compression thread for years. Just one of those deals. Yes, he said he only got 4 out of the 8 threads on the banjo fitting itself to go into the top of the CP3. He was basically wondering if that was enough, and if thier would have been a better way to have intalled it. I told him that where he mounted it, it might vibrate lose.

 

4 threads will be fine. Obviously, if it is pipe thread, he will need some type of sealant on the threads, like Teflon Paste, or Teflon Tape. Some people don't like teflon tape on fuel fittings, as they think it will get into the lines and clog stuff up. However, if you know what you are doing, and start the tape JUST above that first thread, you will be OK.

 

With all this being said, is he going to have problems with that sending unit being directly attatched to his CP3 due to vibration? Where SHOULD he have ran it? I have my at my canister which I think is a better location. Other than thos two, were else would have been a good spot. Pics would be great as well. Thanks

 

have mine on the cp3 also. Easy place to install, and the point is to know fuel pressure at cp3 to tell if filter is clogged or lift pump is dead, so right on the cp3 seems like the best spot to me, but anywhere down stream of the filter is fine.

 

Yes, you can get into problems with virbations mounted on the CP3. What you can do and what alot of people do is:

Take your fitting, screw into CP3. Attach a 3-6" piece of rubber hose to that fitting and then attach your gauge to the hose. The rubber isolates the gauge from teh Cp3 and teh vibration

 

I have had my pressure gauge connected to the top of the CP3 for years with no problems. The first time I did it there was a lot of pump noise transmitted back into the cab. Fixed it two ways. First, I made a really tiny oriface in the 90 degree fitting at the CP3. Then I connected a short piece of rubber hose between the CP3 and the line into the cab.
The oriface does two things. First, it isolates the pulses, vibration etc from the pump to the gauge. Second, if by some remote chance the gauge or the line going to it spring a leak, the amount of diesel getting into the cab is not going to be nearly as much as a a full line.