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So ever since I had the drop in fuel pressure which I have not mechanically tested yet my fuel economy has steadily went down since then. Have not had the chance to hand calculate yet but lie o meter says it went from 16.8 to 14.3. I picked up a tester today so I’ll be able to rest idle pressure soon. Where do I hook up the tester? 

 

The pressure went went down and then back up to 17 18 at idle and 12 13 wot. 

 

Used to be 19 20 at idle and 15 16 wot before the drop. 

 

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I got my pop tester and injector adapter off of eBay. Made in India. Nothing wrong with the adapter. The pop tester works, but it's junk. I had to retrofit a different pressure gauge on because it was out to lunch. Leaked like a bastard, but I got it reasonably sealed up. It serves it's purpose, but I'd like a better one. I'm still fighting with the seller to replace the "off-valve". But, it was reasonably cheap, so meh. You get what you pay for and I can set up my own injectors.

 

I don't have the links right now, but I posted links a while ago where I got them from. Should be around. Don't have time now but I'll look later.

  • Owner
7 hours ago, kzimmer said:

I got my pop tester and injector adapter off of eBay. Made in India.

 

There isn't very much I would buy off of EBay... I've seen way too many people cheated there. 

 

3 hours ago, Mopar1973Man said:

 

There isn't very much I would buy off of EBay... I've seen way too many people cheated there. 

 

 

Agreed. I don't mind taking a risk now and then for personal stuff, hobbies, etc. If I need something for work, business purposes, etc that's different.

  • Author

Defiantly something wrong with he truck. It’s running a little rough at idle and wot and fuel psi dropped to 9 11 at wot and 16 at idle. Plan is too test fuel pressure and either pull the trigger on new injectors or try to have someone test them. Any other suggestions? 

  • Owner
1 hour ago, Marcus2000monster said:

One other  question. Are new connecting tubes  necessary for new injectors? 

 

Not really, unless visible damage is seen at either mating end. I do suggest new o-rings for them though.

  • Author

Looking to buy a fuel pressure tester. Will a 12 mm banjo bolt adapter work where the stock banjo is too test pressure??

  • Owner

I would move that back to the stock filter at the bottom. Get away from the VP44 if possible. 

 

The thing is you'll find that your pressure might be good at idle but crappy under load. The stock fuel lines and banjo's are known for being restrictive. Might be better off calling Eric at Vulcan Performance and get a full 1/2" fuel system for the truck and then you'll be better off. 

  • Author
10 minutes ago, Mopar1973Man said:

I would move that back to the stock filter at the bottom. Get away from the VP44 if possible. 

 

The thing is you'll find that your pressure might be good at idle but crappy under load. The stock fuel lines and banjo's are known for being restrictive. Might be better off calling Eric at Vulcan Performance and get a full 1/2" fuel system for the truck and then you'll be better off. 

If I find out that my lp is bad I’ll be getting a dtt assasin mechanical pump with half inch lines. Until then I have to test and find out if it’s bad or not. So would you hook up at test port on filter canister?

  • Owner

Crap. That's a PITA. So I would test at the VP44 for the temporary time.

 

Still, you are going to find that stock lines are going to drop the pressure way too much. Back in the day stock powered without a tuner at all. I had to upgrade to 1/2" lines and move the stock lift pump back near the fuel tank to just barely keep the pressure above 12 PSI. Then when I added the Edge Comp I had to upgrade to the AirDog 150. 

3 hours ago, Marcus2000monster said:

So would you hook up at test port on filter canister?

If you're able to hook up there I don't see why not it's before VP and after your lift pump

  • Author
3 hours ago, Mopar1973Man said:

Crap. That's a PITA. So I would test at the VP44 for the temporary time.

 

Still, you are going to find that stock lines are going to drop the pressure way too much. Back in the day stock powered without a tuner at all. I had to upgrade to 1/2" lines and move the stock lift pump back near the fuel tank to just barely keep the pressure above 12 PSI. Then when I added the Edge Comp I had to upgrade to the AirDog 150. 

I will try to test in both places. If the lp isn’t bad which I suspect it is I’ll upgrade fuel lines and banjos. I think it’s the lp because of drop in psi but it could be injectors too. 

  • Owner

Remember suction air leaks will draw air in all the time and never leak fuel out. The other part of that is the air that does leak into the fuel system will retard the timing of the injection event and reduce MPG's as well. Suction leaks can be tested by pressurizing the fuel tank. So I would get the truck running and quickly shut down the engine. Then using a shop vacuum on the discharge side to blow air into the tank. Have a second person hunt around the suction side of the lines for fuel weeping out. 

  • Author

http://www.jegs.com/i/Bosch-Actron/885/CP7838/10002/-1

 

Is this tester ok for Diesel engines? 

2 minutes ago, Mopar1973Man said:

Remember suction air leaks will draw air in all the time and never leak fuel out. The other part of that is the air that does leak into the fuel system will retard the timing of the injection event and reduce MPG's as well. Suction leaks can be tested by pressurizing the fuel tank. So I would get the truck running and quickly shut down the engine. Then using a shop vacuum on the discharge side to blow air into the tank. Have a second person hunt around the suction side of the lines for fuel weeping out. 

Where to blow the air in?

  • Owner
1 minute ago, Marcus2000monster said:

http://www.jegs.com/i/Bosch-Actron/885/CP7838/10002/-1

 

Is this tester ok for Diesel engines? 

 

Won't work you can't read the pressure while driving. Idle pressure is only the half of the story. 

 

This one will work.

http://www.vulcanperformance.com/VPMAX-Fuel-Pressure-Tester-Test-Gauge-Schrader-p/fpt.htm

 

2 minutes ago, Marcus2000monster said:

Where to blow the air in?

 

2 minutes ago, Marcus2000monster said:

Then using a shop vacuum on the discharge side to blow air into the FUEL tank.

 

Edited... :doh:

  • Author
2 hours ago, Mopar1973Man said:

Remember suction air leaks will draw air in all the time and never leak fuel out. The other part of that is the air that does leak into the fuel system will retard the timing of the injection event and reduce MPG's as well. Suction leaks can be tested by pressurizing the fuel tank. So I would get the truck running and quickly shut down the engine. Then using a shop vacuum on the discharge side to blow air into the tank. Have a second person hunt around the suction side of the lines for fuel weeping out. 

Where do you pipe the air in on the tank?

12 minutes ago, Marcus2000monster said:

Where do you pipe the air in on the tank?

Lol. The same place you put fuel in it. I usually just wrap/stuff a rag in around the hose and place it in the fuel inlet and turn it on. Won’t take long at all to pressurize the tank. 

Also, while injectors could be causing you an issue, I don’t for see that being your cause for reduced fuel pressure, as you are reading pressure pre injection event. I could see your truck running poorly from the injectors, but I don’t think they would pull your pressure down like that. Does your pressure drop the same at idle and just tapping the throttle or only under actual drive load?

 I think your LP is giving up the ghost. 

  • Author
15 minutes ago, Gamble said:

Lol. The same place you put fuel in it. I usually just wrap/stuff a rag in around the hose and place it in the fuel inlet and turn it on. Won’t take long at all to pressurize the tank. 

Also, while injectors could be causing you an issue, I don’t for see that being your cause for reduced fuel pressure, as you are reading pressure pre injection event. I could see your truck running poorly from the injectors, but I don’t think they would pull your pressure down like that. Does your pressure drop the same at idle and just tapping the throttle or only under actual drive load?

 I think your LP is giving up the ghost. 

I’m thinkin the same... 

I believe it drops maybe 1 or 2 psi when tapping the throttle.