mbz

You're welcome! ?

I suspect this may be the case as well from the PO's mechanics notes about adjusting it to "run lean" for smog check. I also considered the EGR as a possible culprit, but didn't want to muddy the thread as it was getting muddied up pretty well. Hoses on injectors and fuel rail were all recently replaced with new hoses by PO's mechanic. Thanks for the word of caution. Might just cut the hoses off at FPR if easier than trying to remove and reuse. Replacement high pressure fuel injection hose is not that expensive ($5.25-ish per foot).

Yes that's one of the alternate / OE part numbers listed for the part on the Rock Auto site. I went ahead and ordered it, comes with a 3 year / 36,000 mi. warranty. If it's the wrong part, I'll just send it back for a refund. Hopefully it's the right part and a direct swap out that I can do next weekend or sooner as time permits. Will keep you posted. Thank you again for all your help and patience, I appreciate it very much.

I'm looking at this one: https://www.rockauto.com/en/moreinfo.php?pk=46963&cc=1209226&jsn=1

Fo' sho! The lifetime warranty from O'Reily is tempting for $30 bux more.... how often do these FPRs fail?

Will do once I get the FPR swapped out and engine idles and rev's better. Trying to get the excess fuel pressure under control first.

OK thank you. I'll order one today and install when next available opportunity to work on car. Purchasing question / advice solicitation: Buy the $50 FPR from Rock Auto or spend $30 more and get one from O'Reily with a lifetime warranty? Or any other purchasing suggestions / recommendations?

Hi Dave WM, Yes the fuel pressure gauge is inline right after the fuel filter going into the fuel rail. (easier access) OK so I just disabled starter, disconnected electrical to CSV, and held the key to the START position. The fuel pressure gauge reads 43.5 psi

Dave WM, here it is: Fuel Pressure with fuel return line disconnected and Engine Running: 41.5 psi So just short of taking the FPR out and testing it, this is most likely a failed FPR....? (like 99% chance)? If so, I'm thinking I'll just order one and swap it out and see if that fixes the issue. Is the FPR something that would take some time to fail and would cause the engine to run rich and gradually increase fuel pressure until the FPR ultimately fails?

Dave WM: To be clear, with the fuel return line disconnected and draining into a bucket, if the fuel pressure is still high (like 38-40 psi), then there is a clog somewhere in the fuel rail to the return line? (most likely a failed FPR?) AND, if the fuel pressure is normal (36 psi), then it would indicate a clog in the metal fuel return lines that run under the car. Is that right? Also regarding FPR test with compressed air, I do not have an air compressor. It would cost me less to just order the FPR and swap it out at this point. (providing it is the most likely culprit for the high fuel pressure)

This video...?

AND, if the fuel pressure is normal (36 psi), then it would indicate a clog in the metal fuel return lines that run under the car. Is that right?

So, to be clear, with the fuel return line disconnected and draining into a bucket, if the fuel pressure is still high (like 38-40 psi), then there is a clog somewhere in the fuel rail to the return line? AND, if the fuel pressure is normal (36 psi), then it would indicate a clog in the metal fuel return lines that run under the car. Is that right?

Can I do this at the hose the connects to the metal return line by the fuel filter? I ask because of the easy access it would be preferable.

About how much gas should I expect to have to collect? 2 gallons? 5 gallons? More?

Which test should I perform first? I don't have a vacuum gauge but can have one in about 30 minutes.

Just re-tested this and got the following results: Engine OFF / Key OFF = 12.52 volts Engine ON / Motor Running = 12.70 - 13.00 volts (fluctuates)

OK Guys, here's the results, ALL of the readings below are with the NEW BATERY installed: Checking the vacuum on the fuel pressure regulator (FPR) as it affects the fuel pressure while the engine is running. 0). New Battery Voltage Reading: Everything OFF = 12.48 Volts, Engine Running = 12.12 Volts 1). Fuel Pressure PUMP ONLY = 29 psi. (see photo 1) [This seems VERY ODD considering last test with old battery was 35.5 psi] 2). Fuel pressure reading while the engine is running = 41 psi (see photo 2) [PRESSURE UP] 3). Fuel Pressure with FPR Vac. line disconnected = 44.5 psi (see photo 3) [PRESSURE UP] 4). Fuel Pressure while Sucking on the vacuum hose from the FPR = 40 psi (see photo 4 & video) [PRESSURE DOWN] 5). Fuel Pressure while Blowing on the vacuum hose from the FPR = 44.5 psi (see photo 5) [PRESSURE UP / NC] 4 Fuel Pressure Suck On FPR Vac Line New Battery.MOV

Got the new battery in today, $110 at Costco for an Interstate Battery with 3 year warranty. Will do other tests tomorrow.

Yes I get it. And I appreciate the help. I'm confident we'll get it sorted out soon enough. Thank you!

? YES, It's CHEAP but not THAT CHEAP! ? It reads zero when disconnected.

OK Got it. Will run tests and return results at next opportunity. It may not be until the weekend.

Well the gauge is a Harbor Freight special, so I don't know how "good" it is, but it seems to be functioning good enough.

OK So just to be sure I have this right, should I run the tests AFTER installing a new battery, or just when I have them time?

OK but I'm, already getting 38.5 PSI with the vacuum line to the FPR connected. I'm not sure what would change to make that number go down to 30 PSI.....? I'll run the tests anyway, but just not understanding why it would all of a sudden go down to 30 PSI when it's already been shown to be at 38.5 PSI with the FPR vacuum line connected. Also, I have the fuel pressure gauge connected just after the fuel filter for easy access..... should I have it connected somewhere else for a more accurate reading?