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914World.com _ 914World Garage _ Stuck Fuel pressure regulator?
Posted by: pete000 Jun 30 2015, 04:20 PM
74 1.8 L-Jet
Has any one ever had a fuel pressure regulator get stuck from sitting dry?
My car has been on jack stands for 4 years. and I finally got all the fuel lines back in.
No fuel was going to the fuel rails. I tested the pump and its pumping just fine but no fuel seems to get past the pressure regulator. I took it apart and soaked it in gas and bench tested it with the pump and it seems to be flowing good now. I also checked the cold start valve, fuel rails, and they are not blocked.
Have to put it all back in and see.
Seems like it just got stuck and would not allow fuel flow. Possible?
Posted by: jcd914 Jun 30 2015, 04:46 PM
Fuel Pressure Regulator is at the end of the fuel loop and would not stop fuel from getting to the injectors.
Fuel goes from tank to pump to injectors to press reg to tank.
If it were stuck close fuel pressure would max out at what ever the pump could generate (on my explorer that about 100psi).
If it were stuck open the fuel pressure would be very low.
Jim
Posted by: jim_hoyland Jun 30 2015, 05:52 PM
My L-Jet has an in-line fuel pressure gauge mounted by the CSV. It really helps in diagnosing l-Jet issues when the motor quits all of a sudden. If engine quits and fuel pressure gage still reads 30 or so, the problem is not fuel related. If it dies and fuel pressure is zero, then it,s most likely a dual relay connection, ground or pump issue.
Posted by: Dave_Darling Jun 30 2015, 06:38 PM
If you hook up the FPR backwards, you'll have very high fuel pressure because the regulator will act as a plug in the line. BTDT.
--DD
Posted by: McMark Jun 30 2015, 09:57 PM
What Dave said.
Posted by: pete000 Jun 30 2015, 10:08 PM
I thought I might have it backwards, but it wasn't. It is correct.
Would it take time to pump out all the air in the lines?
I didn't run the pump for very long.
I was tripping it on by using the air flapper.
I will try to fun the pump with the line open at the end of the loop to get all the air out.
Posted by: McMark Jul 1 2015, 01:23 PM
Takes 20-45seconds to get fuel through, and then another 60s to purge all the air. Then check for leaks.
Posted by: worn Jul 1 2015, 01:37 PM
74 1.8 L-Jet
Has any one ever had a fuel pressure regulator get stuck from sitting dry?
My car has been on jack stands for 4 years. and I finally got all the fuel lines back in.
No fuel was going to the fuel rails. I tested the pump and its pumping just fine but no fuel seems to get past the pressure regulator. I took it apart and soaked it in gas and bench tested it with the pump and it seems to be flowing good now. I also checked the cold start valve, fuel rails, and they are not blocked.
Have to put it all back in and see.
Seems like it just got stuck and would not allow fuel flow. Possible?
I got a car that had sat for more than a decade. Drove it home from Baltimore with 90 PSI straight from the pump. It ran very poorly and scared the crap out of me as the trucks passed me on the Pennsylvania turnpike. Yeah, they can get stuck. I freed it up, but not trusting it, replaced it nonetheless.
The gas gauge did the same thing. Reading down to half full. It fixed itself, but not without me having to frequently fill a car to be on the safe side with an engine that didn't want to start. Of course the do gear had come loose too...
Posted by: Jeff Bowlsby Jul 1 2015, 01:57 PM
Sounds more like you switched your fuel supply/return lines where they enter the engine bay. Common mistake.
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