924Board.org

jrrhdmust · Joined: 19 Mar 2008 Posts: 180 Location: Middle Georgia

Well as some of you have read in other posts my 924 died on me leaving me on the side of the road.

I believe it is a fuel issue, in that I can spray starter fluid in the intake and it will fire. It turns over fine.

I replaced the Fuel Pump Relay, when I turn the ignition on I can feel it actuate in my hand, and I have voltage coming out the back to the appropriate places. I have ohmd out the fuel injector wiring, fuel injectors themselves, and I have power to the fuel injectors. I have another DME computer that I have substituted in. Lastly, I replaced the reference sensor and the speed sensor on the fly wheel, and checked continuity accross them from the DME connector.

I have also replaced the fuel filter, and when I jumper the fuel pump on the return line I have the 85ml in 30 sec.

I am planning on pulling the cap on the end of the rail to check pressure accross the rail. Short of that, I am out of ideas.

Any ideas on what to check are most welcome
_________________
67 Mercury Cougar XR7 under Restoration
71 VW Superbeetle Completed Resto 11/07
73 Mustang Mach 1 10 Year old restoration

Paul · Posted: Fri May 23, 2008 11:34 am Post subject:

Which hose do you believe is the return line?

Which one is the fuel pressure regulator?

Which one is the fuel pressure damper?

_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

jrrhdmust · Joined: 19 Mar 2008 Posts: 180 Location: Middle Georgia

[quote="Paul"]Which hose do you believe is the return line?

Which one is the fuel pressure regulator?

Which one is the fuel pressure damper?

quote]

My understanding is that the pressure regulator is closest to the firewall. The return line comes from it and from there is where I took the measurement for the 85 ml in 30 sec. The damper is on the front of the rail towards the front of the car.

I pulled the nut and ball on the end of the fuel rail, guess what? No pressure, I had a couple of drips of fuel come out but that is it. I borrowed a set of fuel pressure guages and I am going to set them up on the end of the rail, jumpre the fuel pump relay to get the fule pump to operate and see what kind of pressure I have.

I am thinking at the very least I need either a new pressure regulator or a check valve given my expereince pulling the nut and ball bearing from the end of the rail.

Also, I got the idea to clamp off the return line, and try to start the car. This time I could smell a little bit of fuel, but the car did not catch.

Thanks for your assistance!
_________________
67 Mercury Cougar XR7 under Restoration
71 VW Superbeetle Completed Resto 11/07
73 Mustang Mach 1 10 Year old restoration

jrrhdmust · Joined: 19 Mar 2008 Posts: 180 Location: Middle Georgia

Well I put a pressure gage on the fuel rail. It showed 31 PSI with the pump jumpered. I could not start it to see what it would be since the car does not run. I also clamped off the return line and watched the pressure gage go above 80, so I am sure the pump is working correctly. I also shut off the pump and let the car sit, and after an hour I still had 30 PSI on the rail, so the check valve is good.

I have ordered a new pressure regulator since mine was slightly off, but it seems like the fuel injectors would still fire.
_________________
67 Mercury Cougar XR7 under Restoration
71 VW Superbeetle Completed Resto 11/07
73 Mustang Mach 1 10 Year old restoration

Paul · Posted: Thu May 29, 2008 9:45 am Post subject:

Pull the electrical plug on one of the injectors and try to start it.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

jrrhdmust · Joined: 19 Mar 2008 Posts: 180 Location: Middle Georgia

I actually did that by accident. I was verifying I had power to the injectors, so I pulled one and had a friend turn the car over. It still did not start.

Thanks though!
_________________
67 Mercury Cougar XR7 under Restoration
71 VW Superbeetle Completed Resto 11/07
73 Mustang Mach 1 10 Year old restoration

Paul · Posted: Fri May 30, 2008 9:32 am Post subject:

Any chance you have water in the fuel?
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

bcblase · Joined: 23 Oct 2007 Posts: 574 Location: Winchester, VA

Have you checked the Mass Air Flow (MAF) meter? I had to reset the wiper arm on my car to get the idle to steady out. It might be worth cracking it open and checking for problems.

The electrical connector on the MAF or the TPS can be a potential issue.

Also, you might want to check the seals in the throttle body and the vacuum lines.

Hope this helps,
BC
_________________
1987 Porsche 924S - track toy
1986 Mercedes 190E 2.3-16v - autocross
2007 F-150 5.4L Lariat Supercrew - tow beast
1994 Volvo 850 Race Wagon - 24 Hours of Lemons Car
2001 BMW 325xi - daily driver

jrrhdmust · Joined: 19 Mar 2008 Posts: 180 Location: Middle Georgia

I checked the sensor.

I do have a question: Has anyone checked the voltage to the injectors. If I disconnect all of the injectors, I have 12v, if just one injector is connected it drops to 3.5v and with three connected it drops to 1.7 volts. It doesn't matter which ones are connected or which one I am checking the voltage on.

I purchased another computer - used - but I would really doubt they both have the same problem.
_________________
67 Mercury Cougar XR7 under Restoration
71 VW Superbeetle Completed Resto 11/07
73 Mustang Mach 1 10 Year old restoration