Engine/Transmission (1994 - 1998) Fuel Pressure

[nfox]

I just purchased a new electronic fuel pressure gauge and was wondering where the best spot would be to tee the sender into the fuel line? The sender has 1/8 pipe thread on it. Is there a kit or something i can buy to hook the sender in the proper spot to read fuel pressure? How much pressure should i have at idle and under load?

 

[illflem]

The best way I've found is to remove, drill and tap a 1/8" port in the injector pump inlet banjo bolt. Geno's sells these for 24 valves, not sure if they work for 12s. If you can drill and tap your manifold for a pyro you will find the bolt a piece of cake. You will also have to snub and isolate your sender from the lift pump's pulsations and the engine's vibrations otherwise I guarantee the sender won't last long. An 1/8 needle valve, Grainger p/n 6MN31($3. 49) makes an excellent snubber. You can isolate the sender from the engine with a rubber grease gun hose from the auto parts, make sure the 1/8" ends on the hose are tapered. Don't use Teflon tape on anything, it will eventually leak, instead use anti-seize. Some senders need to be grounded, it won't happen if it's isolated with a hose, attach a ground wire to it with a hose clamp.

I'm sure there are other ways to do this, but after several trials and errors this is the method I've settled on. 20-25 psi is a good pressure to see. Under 18 or over 30 isn't good.

 

[nfox]

fuel pressure reading

Open to suggestions on where to read fuel pressure?

 

[A Johnson]

Originally posted by illflem

The best way I've found is to remove, drill and tap a 1/8" port in the injector pump inlet banjo bolt.



Nfox, follow illflems advice.



Illflem, as I always read your posts for words of wisdom, could you elaborate on the anti seize vs. teflon tape thing? Is this a rule of thumb for large pipe threads as well? Have you found that it works better than the liquid teflon sealers(pipe dope) also?

A Johnson

 

[illflem]

AJ, I learned the hard way that Teflon tape doesn't hold up well in automotive applications. It just doesn't do well with heat, vibration and fuel. The tape is also a real pain to remove if you have redo a fitting and don't want to introduce contamination. My feeling is the tape is best left for jobs with small pipe when you don't want to get dirty. I use anti-seize exclusively on vehicles, boiler and hydraulic fittings. Permatex #2 works great with fuel also but only in lower temp applications. For plumbing I use a product called Rector Seal #5 www.rectorseal.com/ , works great even with plastic pipe where some pipe dopes are a no-no, doesn't make a mess like liquid Teflon and is much cheaper. Just don't leave the lid off Rector Seal outside and walk away, for some reason bees love it and will steal it. I've even seen them cleaning the excess off pipe fittings. Teflon is more of a lubricant than a sealer, makes for ease in assembly/disassembly. When I put something together my hope is that I will never have to take it apart again. Doesn't always work that way though.

 

[nfox]

I liked illflems advise, i was just wondering if anybody else did it any differently.

 

[shendren]

i have not done it yet but i bought the adapter from tst. it goes on the outlet of the fuel filter i think.



scott

 

[A Johnson]

Illflem, thanks for the info.



Nfox, I also was going to suggest looking at a banjo on the fuel filter head and see what could be done there. A Johnson

 

[illflem]

Scott, I also started out with the adaptor from TST. Didn't even get halfway though the install before I didn't like it, my thought was the extra vibrating weight on the little screw in the aluminum housing was just the beginning of a leak. Plus I wouldn't have use of the bleed screw after a filter change. I still use the TST adaptor on other people's rigs to temporarily check the fuel pressure. Chose the injection pump banjo bolt location because it's has plenty of room around it and will never get in the way of anything.



IMO the only other good way to do it came from The Patriot. He drilled and tapped a 1/8" port into the top of his fuel filter housing. Nice spot but a little risky, if you somehow mess up it's far cheaper to replace the banjo bolt than the filter housing.

 

[nfox]

Banjo Bolt

How far do drill into the banjo bolt before i tap it? When i go to ground the fuel do i just wrap a wire around and clamp it to the sender and ground it to the battery?

 

[illflem]

Remove the bolt, don't loose the washers, and drill from the end of the bolt towards the head all the way though. The correct bit for a 1/8 tap will be a tight fit. The hollow shank of the bolt will keep your bit straight. Drill press or at least a vice will make things easier. Tap it from the head side, take care to keep the tap square to the bolt, use oil to lube. Turn the tap a half turn in then reverse to clear chips. You will be tapping tapered pipe thread, you don't want to tap too deep or the next fitting will be loose, remove the tap occasionally and try your next fitting, it should start easily and thread about half way in by hand. After you tap it make sure there are no burrs or chips, this is the clean side of the filter, you don't want any contamination. I find it easier to tighten in your snubber or needle valve to the bolt before replacing it on the pump, you could even connect the hose with sender all together before replacing the banjo bolt. Everything's easier out from under that crowded hood. Use anti-seize on all connections, no need for thread sealant on the banjo bolt, the washers do the sealing. If your sender indeed needs grounding, many don't, just connect a bare wire around a hose clamp on the sender to a nearby ground terminal to the body or engine, there are a few in the area, negative battery terminal will work also. Long answer for a short question, did I miss anything?

 

[dseabaugh]

I have found that Teflon tape voids many warranties as it does not break down and can plug holes, get into bearings, etc. If you must use teflon , always use the paste instead as it won't void most warranties.

 

[illflem]

I have a friend, brand new house with a brand new gas range with some burners that didn't work. Teflon tape debris had clogged up the valves.