How fast should FP fall.......

S

supraguy31

New Member
May 10, 2005
626
0
0
Pembroke, NC
Ok all, I have read the TRSM and I know that there is a time limit to how fast you loose FP on these Motors.

My Question is how fast should FP fall if you dont have the Fuel Pulsation Dampner installed.

IE.... FPD bypass Kit
MKIV Fuel Pump
Aeromitive FPR set at 40 psi vacuum line on.

Reason Im asking is that Im eliminating some boost Issues that Im having and this is one thing that I noticed that didnt seem right, I set my Turbo timer for 30 Seconds, and once the engine Shuts off, the fuel pressure goes straight to 0, Doesnt hesitate at all, I heard that its suppose to drop a little but then stop and after time it slowly bleeds out but mine doesnt do any of that.

Just picking your brains to see weather this is an Issue that needs to be Addressed or this is something normal since the Fuel Dulsation Dampner has been removed. Having boost Issues where Im not getting the correct A/F while boost is rising.....

Thanks
Robert
 
jdub

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
SM Expert
Feb 10, 2006
10,730
1
38
Valley of the Sun
Yes...it's an issue and needs to be fixed. The fuel system should hold at least 21 psi for 5 minutes.
 
apexi287

apexi287

New Member
Jul 24, 2005
401
0
0
Knoxville, TN
The fuel pressure after key is off should hold residual pressure, it'll drop a couple psi but shouldn't drop directly to zero. The dampener will not effect pressure it just helps reduce(dampen) vibrations within the fuel lines. Test your FPR and if you are able to do a pressure balance test of your injectors that will show you if any of them are leaking as well.

By any chance was your fuel pump used, did this happen after you installed the pump? If so that could also be the culprit if everything else is ok. From the sounds of it your have pressure issues not just after the key is off as well. But that's definitely an issue you need to address before something else goes!
 
grimreaper

grimreaper

New Member
Jul 2, 2008
2,180
0
0
Dallas
aeromotive regulators arent designed to hold rest pressure and wont. according to their tech dept. they dont offer one that does.
 
johnd

johnd

Supramania Contributor
Dec 4, 2007
278
0
0
Ont. CA.
Guys, I have a aeromotive fpr on my 1j with no dampner and it always holds pressure for a while.
 
shaeff

shaeff

Kurt is FTMFW x2!!!!
Staff member
Super Moderator
Mar 30, 2005
10,588
10
38
Around
Same here. Aeromotive AFPR. It holds pressure for a bit after I shut the car down. It's been so long since I've had the car running that I can't remember how much pressure and for how long, but I distinctly remember it holding pressure.
 
S

supraguy31

New Member
May 10, 2005
626
0
0
Pembroke, NC
Well, Maybe thats why Im always smelling fumes coming into the car. At one minute, I look at the Gauge and its reading 33 psi, and then later on, I start the car up and look at the gauge again and its reading 40psi. I have a Megan FPR that I can installed and see what that one does.
 
S

supraguy31

New Member
May 10, 2005
626
0
0
Pembroke, NC
Well, I went out and Pulled the Aeromotive off and Installed my Megan FPR back on, Started the car up and Set the FP to 40psi Vacuum line off, Plug the line back in and it dropped to around 34 psi, with turbo timer set for 30 Seconds, I turned the car off and watched the FPR, Once the car shut down, the FP dropped to about 23 psi and just sit there for a little and then it Extremely slow started to bleed out. No more fume smell so hopefully that did the trick. Now if my FP was a problem then I guess I need to get back out on the road and do some more Data logging with the MAFT Pro to verify things.
 
shaeff

shaeff

Kurt is FTMFW x2!!!!
Staff member
Super Moderator
Mar 30, 2005
10,588
10
38
Around
Is it an authentic Aeromotive, or a cheap knockoff? Could be the diaphragm?
 
S

supraguy31

New Member
May 10, 2005
626
0
0
Pembroke, NC
Well I bought it from a member of the forum as he had it in the for sale section. I was insured that it was an original but I cant tell the Difference between the 2 of them. Its now sitting in the garage on my shelf so if there is a way to tell then by all means tell me.

It came with the FPR, Gauge, fittings and Braided Lines (Both of them) and the Fitting for the fuel rail.
 
grimreaper

grimreaper

New Member
Jul 2, 2008
2,180
0
0
Dallas
a liquid filled gauge will read different readings at different temps. you have to vent it to get accurate readings. Assuming you didnt know this and reused the same gauge
 
S

supraguy31

New Member
May 10, 2005
626
0
0
Pembroke, NC
grimreaper;1206174 said:
a liquid filled gauge will read different readings at different temps. you have to vent it to get accurate readings. Assuming you didnt know this and reused the same gauge
Click to expand...

The gauge was already installed on the FPR when it came in. I didnt do anything to it other than install all the fittings into the Fuel rail and connect everything up and then set the FP. I think that is when I started to get that fume smell but dont Quote me on that. I dont have it anymore as I went back outside about an Hour ago and did the test again. Rock solid 21-23 psi after shut down and it didnt move any at all. I went ahead and shut to hood and came on back into the house as its cold and Windy tonight.
 
S

supraguy31

New Member
May 10, 2005
626
0
0
Pembroke, NC
Mine looks Exactly like the one on the Left. Has the Aeromotive name on it also. I dont really want to take it apart. I will take a pic of it when I get home and show everyone.

Got out this morning and did a Quick boost run, Instead of A/F dropped once Im maxed out at set Boost, My A/F dropped around 6 PSI but went straight to 10.3 or so. Now time to make adjustments again and get this thing going.
 
You must log in or register to reply here.
Top Bottom