Fuel Pressure Woes...

[npe3484]

First off, I'm reading my fuel pressure on a 0-60 psi Isspro Ev2 gauge. It's plumbed via a TorkTek snubber, then 3' of rubber hose, then the electronic sending unit which has a 0.018" orifice added to it. There's a brand new OEM lift pump on the truck, no fuel pre-heater, new filter, new pre-filter screen, new OEM rubber hose between the pre-filter and lift pump, and new OEM hard line from the ilft pump to the filter head.

Now for the problem... With the stock OFV installed and before I changed the lift pump, I had 15 psi at idle and single digit pressures under any throttle. With a new TorkTek OFV 010 installed I'm seeing 20-21 psi at idle. Taking off from a stop at any speed will pull the pressure down to ~7 psi. Keeping the pedal steady at about 1/2 throttle will allow the pressure to eventually climb back to the 15-20 psi range. If I let off the pedal completely and start coasting the pressure will jump up to 25-30 psi. Giving it throttle again will immediately drop it back to single digits.

I'm thinking I need to do the mods to my stock OFV and see if that changes anything. At least it will rule out the OFV completely. Any other suggestions?


By the way, even with the TorkTek snubber, 3' of rubber line, and a 0.018" orifice in the sending unit, I still get a fair amount of needle bounce at idle... :bang. Just a heads up for anyone looking to use his products on a 12v. I'm going to pick up a WeatherHead needle valve from Napa and install that instead of all the crap that Rob had me try. :doh:

 

[Big Blue24]

Are you feeding the factory lift pump with the factory hard line from the factory sending unit in the tank?

Might want to remove the factory sending unit and make sure it isn't full of build-up and grim. Also, the factory draw straw lines in the sending unit can rub and wear large holes over time. Thus you will suck air unless the tank is full of fuel.

 

[BRE]

Might want to remove the factory sending unit and make sure it isn't full of build-up and grim. Also, the factory draw straw lines in the sending unit can rub and wear large holes over time. Thus you will suck air unless the tank is full of fuel.

Interesting... I wonder if this might possibly be my problem or at least some of it...

 

[npe3484]

Are you feeding the factory lift pump with the factory hard line from the factory sending unit in the tank?

Might want to remove the factory sending unit and make sure it isn't full of build-up and grim. Also, the factory draw straw lines in the sending unit can rub and wear large holes over time. Thus you will suck air unless the tank is full of fuel.

Yessir. All factory from the tank to the lift pump. Not really looking forward to lifting the bed / dropping the tank :badidea:

 

[holsky]

Im running about 40psi at idle, full throttle it runs down to about 20-25 psi.. I bought one of those banjo bolts with the 1/8ntp threads in the head off ebay and put my sending unit in it and thats the bolt that feeds the p-pump.

 

[npe3484]

Im running about 40psi at idle, full throttle it runs down to about 20-25 psi.. I bought one of those banjo bolts with the 1/8ntp threads in the head off ebay and put my sending unit in it and thats the bolt that feeds the p-pump.

So, all you're telling me is that you bought a tapped banjo bolt? :what:

 

[holsky]

So, all you're telling me is that you bought a tapped banjo bolt? :what:

Haha yeah. I tryed to do it to my original one but didnt get it drilled straight enough and it leaked but then I found one on ebay and put it in and no problems.

 

[npe3484]

Haha yeah. I tryed to do it to my original one but didnt get it drilled straight enough and it leaked but then I found one on ebay and put it in and no problems.

Ok... So did I? Mine came from TorkTek.

 

[holsky]

I believe thats what mine was also. Had to pay 20 bucks for it!

I was acutally watching my fuel pressure and at full throttle my pressure actually goes up but never really levels out probably around 30-35. Around 1/4-1/2 throttle im running about 20-25 psi.'

EDIT: After re-reading your original post haha I did notice you said that you had one. But all i did was snubbed my electronic sending unit right to the banjo bolt and ran my wires right it to the gauge.

Ill try to get you a picture.

 

[npe3484]

But all i did was snubbed my electronic sending unit right to the banjo bolt and ran my wires right it to the gauge.

Ill try to get you a picture.

I tried that and got somewhere near a 10 psi needle swing between bounces! The way I have it set up now, the needle only bounces at idle, between 20-21 psi. I'd still like to eliminate all of the bounce.

Anyway, I'm much more concerned with my fuel pressure issues than I am with the gauge bouncing at idle.

 

[holsky]

Do you have a aftermarket fuel pump? (lift pump)

 

[Bponci]

Run a bucket test. Plumb a bucket of fuel and road test. If your pressure is ok then you know where to go. Condition. Cause. Correction. I live by the 3cs theory.

 

[npe3484]

Run a bucket test. Plumb a bucket of fuel and road test. If your pressure is ok then you know where to go. Condition. Cause. Correction. I live by the 3cs theory.

I can see this going horribly wrong. LOL First thing that popped into my head was driving down the road with a bucket full of fuel in the passenger seat.

Thanks for the suggestion, Brad. I'll give it a shot tomorrow if I'm not tied up with family stuff all day.

 

[biggy238]

I typed a bunch of stuff and then my comp ditched it.

Pull the bed up, Check where the lines drop down off the top of the tank. Pull the level sender. mine had worn two lines in the pickup where the sender wires were in contact with the poly/nylon pickup. I used a piece of truck air line and a bulkhead to make my own big bore pickup tube.

I replaced the screen at the bottom of the sender and on the preheater assembly. I don't even remember the pressure mine was running. I did end up with a bad reman napa pump and replaced it with a delphi from genos garage.

 

[npe3484]

Pull the bed up, Check where the lines drop down off the top of the tank. Pull the level sender. mine had worn two lines in the pickup where the sender wires were in contact with the poly/nylon pickup. I used a piece of truck air line and a bulkhead to make my own big bore pickup tube.

I replaced the screen at the bottom of the sender and on the preheater assembly. I don't even remember the pressure mine was running. I did end up with a bad reman napa pump and replaced it with a delphi from genos garage.

That's my plan. Do you think it's easier to drop the tank or tilt/lift the bed?

 

[npe3484]

Do you have a aftermarket fuel pump? (lift pump)

...

First off, I'm reading my fuel pressure on a 0-60 psi Isspro Ev2 gauge. It's plumbed via a TorkTek snubber, then 3' of rubber hose, then the electronic sending unit which has a 0.018" orifice added to it. There's a brand new OEM lift pump on the truck, no fuel pre-heater, new filter, new pre-filter screen, new OEM rubber hose between the pre-filter and lift pump, and new OEM hard line from the ilft pump to the filter head.

Now for the problem... With the stock OFV installed and before I changed the lift pump, I had 15 psi at idle and single digit pressures under any throttle. With a new TorkTek OFV 010 installed I'm seeing 20-21 psi at idle. Taking off from a stop at any speed will pull the pressure down to ~7 psi. Keeping the pedal steady at about 1/2 throttle will allow the pressure to eventually climb back to the 15-20 psi range. If I let off the pedal completely and start coasting the pressure will jump up to 25-30 psi. Giving it throttle again will immediately drop it back to single digits.

I'm thinking I need to do the mods to my stock OFV and see if that changes anything. At least it will rule out the OFV completely. Any other suggestions?


By the way, even with the TorkTek snubber, 3' of rubber line, and a 0.018" orifice in the sending unit, I still get a fair amount of needle bounce at idle... :bang. Just a heads up for anyone looking to use his products on a 12v. I'm going to pick up a WeatherHead needle valve from Napa and install that instead of all the crap that Rob had me try. :doh:

 

[OrangeNV]

drop the tank......depends how rusty the two strap bolts are. but spray them down a few days before, then use an impact gun

run the tank as dry as you can, leave a gas can in your truck while doing this so u dont run out, even 1 or 2 gallons sloshing back and forth can make one end real heavey when tilting it down.

i used a big floor jack (my truck is lifted) and it came down no problem

my dumb arse never poured out the 2 oe 3 gallon in the tank once i dropped it and put it back up on the jack - it all sloshed to one end and slid off the jack....

but imo it was a ton easier than lifting the bed, its a 1 person jo with a big enough jack

 

[biggy238]

Definately depends on what you have access too. I've only used cranes and track hoes to lift my bed when i needed. I haven't done the other so i can't speak for it.