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Discussion Starter #1
So at idle I have 18psi. At wot it drops to 3psi. Sometimes at idle it has only 7 and then will just back to 18 after a few. Could it be that I streched out the pressure spring or could need a new one. Thanks for the help
 

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So at idle I have 18psi. At wot it drops to 3psi. Sometimes at idle it has only 7 and then will just back to 18 after a few. Could it be that I streched out the pressure spring or could need a new one. Thanks for the help
First things first:

1. Have you confirmed your gauge is reading correctly? Electric are known to read low under load or erratic when going south, or if you have an isolator that is leaking. These are, by far, the biggest issues we see concerning pressure with the FASS.

2. Restriction. Have you tried to see if the filters needed service or is your in-tank pick up getting restricted? I would try our 5 gallon bucket test and see if your readings improve.

It this a FASS (with 2 filters) or HPFP (Just the pump)? I don’t recommend stretching the spring as it will cause uneven loading and premature failure over time. I do think we need to start there.
 

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I have the 150. I have the pressure in the additude monitor and I cant find any leaks. The filters are new. Whats the bucket test, how do I check the in-tank pickup, and where I get a new spring because this seemed to happen at around the same time I played with the spring. Thanks for all the help Dan
 

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I have the 150. I have the pressure in the additude monitor and I cant find any leaks. The filters are new. Whats the bucket test, how do I check the in-tank pickup, and where I get a new spring because this seemed to happen at around the same time I played with the spring. Thanks for all the help Dan
Man....double check that sending unit.....been down this road with them several times.

As for the bucket test......Run the truck at idle and run up to wot and note pressures. Then you get a bucket...unhook the return line of the FASS at the fillter neck. Place line in bucket and run the pump. Fill bucket about halfway or so. Then unhook the suction line from the tank and place in the bucket. Run the pump and truck and note fuel pressure and such. If pressure are solid after the bucket test, i would pull the tank and inspect. When you are done, hook up return line and leave suction line in bucket. suck fuel out (Dont air lock the FASS though...you might need to crack the fuel filter to reprime if this happens...no biggie).


Use our dealer locator on our web site to find a close dealer to you. (Use any really...just a drop ship). You need a PS-1002 for about 13-15 PSI or PS-1020 for about 18-20 PSI.
 

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Discussion Starter #5
Just so im straight on this the return goes to the filler neck and the suction goes to the tank correct and also do you have any online dealers. Thanks alot
 

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Just so im straight on this the return goes to the filler neck and the suction goes to the tank correct and also do you have any online dealers. Thanks alot
That's Correct, you can use the FASS to load and Unload the test bucket as well.

We are not an "Online Dealer" but can help you when Dan is out of the office.
 

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Discussion Starter #7
Should I give you guys a call
 

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If you are in trouble feel free to call, we are not all over the phones this late but if we see your call we will be glad to help
 

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I will be giving you a call in the AM to get some parts
 

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2001 24 valve,my 95 pump only runs 14/15 at idle but drops fast to 8/10psi on light throttle up and 0/2psi wide open.:CRY:I tried a different sending unit same.I was wondering if I went to a 1/2" line fump to filter instead of the 3/8" it came with? I would like a stronger spring just to try or do I need a 150 pump?I use a WS 1001 stand alone for a pre strainer.
:popcorn:
 

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1/2" line is not going to make a diffrence on a good pump. These pumps are rated at the given GPH with the 3/8 line.

I am running the 150 pump and cannot pull it down past 13psi at WOT but I am only in the mid 500's on rwhp...
 

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2001 24 valve,my 95 pump only runs 14/15 at idle but drops fast to 8/10psi on light throttle up and 0/2psi wide open.:CRY:I tried a different sending unit same.I was wondering if I went to a 1/2" line fump to filter instead of the 3/8" it came with? I would like a stronger spring just to try or do I need a 150 pump?I use a WS 1001 stand alone for a pre strainer.
:popcorn:
OK.....i still like to always see a mechanical gauge used to test for pressure in these situations when troubleshooting a electric gauge. Just good practice.

Can you duplicate this issue at idle by just flooring the accelerator? If you can, pull the suction line off at the outlet of the WS-1001 filter head you are using and place into a can or jar of fuel (Don’t need a lot for an HPFP). See if you can duplicate the issue while sucking out of this fuel source.

If the gauge is confirmed good and the bucket test shows a drop still, I would think we might have some debris in the pumps regulator that is holding it open. OR could have a spring issue.

How new is this pump? Got a SN?

Running ½" line is not going to help you with this issue. 3/8" line will flow anything that your truck will need.
 

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Pump is 6 months old,I do not have the SN handy. I think I will blow back the siphon to see if it's strainer is partially restricted.Where is the bypass located in this pump?
Its internal and not servicable unless you cut the wire. This is not really an issue unless you got real crazy with the teflon tape or didnt use our prestrainer. That is about the only time I see issue with debris that causes pressure probs.
 

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Well used high pressure to backflush the siphon tube and still no luck.If you have it in neutral with the box on #3 stick it to the floor real quick & let off 10 psi is what it drops to.:popcorn:
Have you tried the 5 gallon bucket test yet or sucking out of a jar of fuel?

If your suciton tube has a crack in it....blowing air back in the line will not do anything for you.....
 

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I just installed a fass 150 4 weeks ago pressure was reading 16 all the time with a 1 to 2 psi drop when i hogged on it and now it is reading 5 all the time. What might be the problem? it didnt drop all together, it dropped like 2 1/2 psi per day. Now steady at 5. Please help.:CRY:
 

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I just installed a fass 150 4 weeks ago pressure was reading 16 all the time with a 1 to 2 psi drop when i hogged on it and now it is reading 5 all the time. What might be the problem? it didnt drop all together, it dropped like 2 1/2 psi per day. Now steady at 5. Please help.:CRY:
Most likely your gauge set up..... have you checked it?

We installed a FASS 150/150 Friday, the gauge set up was not touched.... It read only 7-8 PSI after install and bleed session.

After we re-primed the gauge side of the isolator the truck showed 17PSI
 
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