Stuttering At Wot At 4k Rpms. S/c Motor

Tonto674

New Member
Dec 19, 2016
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0
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Hi everyone, currently t/s an issue with my 2v.
Car specs(short):
Built 2v 4.6 Vortech S/C downsized pulley pushing 18 psi
Fuel: 2 Ford GT pumps lined to two FPDM supplied by BAP with the wire upgrade.

History:
Has driven fine for about a year since the finish of the build and tune. Last weekend went on a 100 mile ish drive and parked it till the next weekend.
Drove it to work one day and the car died on me. Found one of the connectors going from the relay to the BAP burned up. Replaced the connector and drove it home. The next day I realized I couldn't go WOT past 4000 rpm without it stuttering and backfiring.

Attempts to fix so far:
Cleaned MAF and Air filter, replaced Fuel filter, checked voltages on BAP(17+ volts), checked voltages to fuel pumps(17+ volts).
Planning on replacing o2 sensors next.

Interpretation of graphs: Graphs show a clear decline in fuel pressure in regards to rpm increasing. Looking for more suggestions and thoughts.

Thanks guys!
FP.jpg
fpdc.jpg
issue.jpg
ltft alone.jpg
ltft.jpg
ltft1 alone2.jpg
o2 voltage.jpg
pump voltage.jpg
stft.jpg
stft1 alone.jpg
 
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wmburns

SN Certified Technician
Aug 14, 2009
5,890
519
204
Houston Texas
Confirm that the fuel rail pressure sensor is boost referenced. Is the intake vacuum reference line connected and leak free? Is there any evidence of raw gas in the line?

What has been done to rule out a ruptured FRPS?

Has the FRPS pressure reading always been soooooooo low? Should be around 40 PSI. Even at the starting point it's only 20 PSI.
 

Tonto674

New Member
Dec 19, 2016
4
0
1
33
I just pulled the vaccuum line off and checked if it was wet. I know it isn't much diagnostic effort on the FRPS but it was all I knew how to do.

Edit:
https://www.svtperformance.com/forums/threads/boost-hose-to-frps.842444/
http://www.moddedmustangs.com/forums/99-04/196752-there-way-tell-if-frps-bad-2.html

I just read these two links and I am going to check the lines for any smell of gas. It looks like replacing the FRPS will be a safe bet all around. I will also make sure to zip tie all my vacuum line connections.
 
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