I am looking into making an adapter tee to measure the fuel pressure going into the inlet side of the TB using the existing fittings. It's for a 92 5.7 350 engine.I have tried to search and have seen some mods, but I wanted to get some more info for one I'm trying to make. I do know of the actron adapter. I own one, but they always leak on me and I'm tired of messing with them. I've tried a few, they all leak unless you hold them perfectly, so reading pressure is useless if it leaks. Not really interested in buying the other custom adapters that are/were available. Too expensive and seem harder to find these days.

I know the inlet fuel line is 3/8. Is that 3/8 npt? My idea is to take a 3/8 mnpt to 3/8 npt brass tee and just get a standard 1/4 npt gauge to thread into the tee. Seems easy enough, but I just wanted to make sure I have the thread sizes correct before I make any purchases.

Thank you

 

It’s saginaw fittings used on the fuel line. Just but a adapter that goes in place of the fuel filter to check or on the tb.

https://www.jegs.com/i/OEMTOOLS/693/27167B/10002/-1

 

I see. Not as straightforward as I thought then. The adapter you linked is the same one I have that leaks. I've used some that work only if you hold the gauge perfectly perpendicular to the fitting, and I have one that previously worked and just now shoots a geyser of fuel everywhere so I just got fed up with that adapter being unreliable. I've messed with new o-rings and all that. They leak at the part that allows the gauge to move independently of the adapter. Tired of getting a fuel bath.

I've found the other adapter that is essentially a longer version of the fitting that threads into the TB itself and has a hole tapped for a 1/8 npt gauge. But at $50+ bucks I wanted to see if there was a cheaper solution. Maybe not. Don't mind spending the money, but not if I didn't need to.

 

If your leaving the adapter on all the time your risking a potential fire.
this tool is for testing only a fuel gauge left on a vehicle all the time isn’t a smart idea.

 

I agree. I’ve read about people who do that and claim it’s ok, but I personally don’t agree with that.

I’m simply looking for a quality test adapter. The one that was linked is the one people use the most it seems, but they have always leaked on me. So I can’t even get one good reading out of the thing making it useless.

It seems like it’s a gamble with that adapter. Some people say it works great, and others have my experience.

 

Update:

Bought another one of those test adapters. Sprayed fuel everywhere from the swivel just like all the rest I've used. You have to hold it in a very particular way to get what I assume are o-rings to seat properly. Still, it dribbles fuel out the sides enough to not trust the reading I'm getting. I guess I may shell out and go with this:

Testing adapter

Not being able to do something as simple as testing the fuel pressure is just driving me crazy. Especially since on a van you need to unbolt the TB to put the adapter inline because the fuel line orientation won't allow for it while the TB is bolted on. You can't simply back the line off enough to put the adapter on. Anyway, I don't know how anyone has gotten any luck with those swivel adapters. I know it's not a user error. It doesn't leak at any of the fittings, just the sides of the swivel part.

 

You can do this;

 

That is awesome. I’ll eventually do this, thanks.

 

You will need to take your regulator apart to do this or you will fill it with aluminum chip.

 

For sure. I’ve had these apart so many times I’ve got it down to minutes haha. This is a mod that seems practical for long term. I’ve known of some that just seem sketchy to leave under the hood but this one looks legit. Thanks again.

 

Another tip is DON'T use that metal cap. I just put it on there so people would know what they're looking at. I replaced it with a plastic tire valve cap,I'd rather it sucked it down through the motor than the metal one if it were ever to rattle off.

 

That seems like a fantastic idea.
Probably the truest representation of the fuel pressure where it matters, too.

 

Thank You Sir,
I was rebuilding the TB and knew I was going to have to reset the pressure and didn't have one of those inline taps. I made the regulator adjustable too.


Next trick will be making a spring housing that is sealed and taps into the vacuum nipple for a VRFPR. Not sure if it's ever been done with a factory FPR so I may be crash test dummy. That TB is off the 305 that's in ol Smoky(my truck)and I'm not going to waste the effort on that one but eventually I'll be replacing that POS 305 with the blueprinted 355 that's in my '78 Elcamino. That engine will be getting a 454 TB.