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Discussion Starter #1 (Edited)
Everyone should know that testing their fuel pressure during WOT is the not only the best way to determine if there is any issue with the fuel system but it is often the cheapest, quickest and easiest.

Unfortunately, many of you silly noobs think its a nearly insurmountable task and its last thing you'd ever do when diagnosing a suspected fuel system issue. I think it was Quennan that posted the other day that if you asked someone on the forum to test their WOT fuel pressure it was as if you asked them to do advanced calculus. Its not hard, in fact, its very easy and NO you don't have to buy some dumbass ricer in car Gauge.

IMO you should have the means to test fuel pressure at the fuel rail BEFORE you ever think about installing a fuel pump.


First off, get yourself a decent gauge. No liquid filled, cheap pos 1/2" diameter play toy you find on most regulators. Get a real gauge- 2.5" diameter or bigger, 100psi minimum. Every autoparts store has one type or another in stock and you'll find them all over Ebay. Should be less than $40

Even this cheapo from Harbor Freight will do:


If you have a 2003 Srt-4 you're pretty much done. This is because 2003s already have a schrader valve port on their fuel rails.

On 2004-2005, most guys are completely stumped and dumbfounded as to how they could ever tested their fuel pressure at the rail since is no pressure port there. But don't you think Mopar had a plan for this?!?! If you simply look in the Factory Service manual, you'll see Mopar's nifty solution--> Miller Tool 6539.

A quick Google search finds the EXACT part you need for less than $35 :wah?!:

Miller Tool 6539


You're not quite done yet. You really need to see the gauge while driving but most gauge kits you'll find for less than $50 only have ~2ft hose, which won't get the gauge out from under the hood. Don't give up yet noob, hope is not lost.

Luckily, old R12 refrigerant hoses use exactly the same fittings and are practically indestructible.
(size 3/16 45deg flare, 3/8-24 thread) IT IS NOT, I REPEAT, IT IS NOT AN -4!!! THE PROPER SIZE IS 3/16 45DEG FLARE

A 3/16 45degree flare splice from your local hardware store
+ a $10, 36" long R-12 A/C hose either new or off an old A/C charging set works great to extend the fuel pressure gauge to where ever you need it. I prefer just to tape it to the windshield to test WOT fuel pressure.
 

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Discussion Starter #2 (Edited)

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Nice thread Duster.

While we're on the subject, which fuel pressure gauge would you recommend for a permanent display in cabin? I have an empty spot on my triple pillar I'd like to fill......fuel pressure seems to be the next on my list (Scangauge and Wideband fill the other two).
 

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Discussion Starter #6
While we're on the subject, which fuel pressure gauge would you recommend for a permanent display in cabin?
None.

I don't think a permanently mounted fuel pressure gauge is worth spending money on. imo most remote senders aren't particularly accurate.
 

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Sticky!!!!

Good info...kinda sad that people modding their cars don't already know this stuff...
 

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think found the 044 psi max, she wont hold anything more than high 70s to redline on E85 -8 line boomba rail and 1150s it will SPIKE 83-85 than fall to 80 quickly than slowly fall to mid 70s closer to redline, Guess she needs another to hold that kinda psi. :/ dual 044s comming soon.
 

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Discussion Starter #12 (Edited)
think found the 044 psi max, she won't hold anything more than high 70s to redline on E85 -8 line boomba rail and 1150s it will SPIKE 83-85 than fall to 80 quickly than slowly fall to mid 70s closer to redline, Guess she needs another to hold that kinda psi. :/ dual 044s coming soon.
No, 85psi is nothing for an 044. At 85psi the 044 should be pumping out 400lb/hr. Are you sure the rest of the fuel system can meet that flow rate?

You may have other issues such as a restriction between the pump and rail or restriction at the pump's inlet. Testing fuel pressure right at the pump's outlet will tell you if everything between the pump and rail are sufficient.
 

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Great thread! It's something I've never needed to check but always wondered how to do being that I have an 05'. Way to keep the community informed, Dave!
 

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No, 85psi is nothing for an 044. At 85psi the 044 should be pumping out 400lb/hr. Are you sure the rest of the fuel system can meet that flow rate?

You may have other issues such as a restriction between the pump and rail or restriction at the pump's inlet. Testing fuel pressure right at the pump's outlet will tell you if everything between the pump and rail are sufficient.
Why would fuel psi slowly ramp down as rpms climb? ill see mid 80s than slowly trickle down to high 70s by redline.

my sensor is on my a1000 FPR. and ive ramped the fuel psi BASE to 85 psi, and it holds just fine at idle.
 

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no leaks, but that was done with 03 rail, i since got a boomba with fittings, and never got to test it, being my input snapped lol.

when i get back im doing dual 044s and sump, new rewire with 8-6 gauge wire and relays.
 
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