Posts: 88
My VIN: 2729
I'm trying to diagnose my engine problems, as you do, and read on the forum that the fuel pump normally primes for a few seconds before you crank the engine. Although when I turn my key to the second position, when all the cluster lights get power, my fuel pump runs continuously. I have the new combo pump from DMC and a new rpm relay so I don't think they're the problem. Is this supposed to happen?
Location: Vancouver, BC
Posts: 3,385
My VIN: thirty two 'o five
Club(s): (PNDC)
A lot of POs tend to bypass the inertia switch when it fails and run 12v to the pump off ignition. Are your electronics stock?
Dave
Here, somewhere.
Posts: 88
My VIN: 2729
Yes, my inertia switch is bypassed. Guess it's time to get a new one.
Location: Northern NJ
Posts: 8,579
My VIN: 10757 1st place Concourse 1998
The inertia switch is not what powers the fuel pump, it can only shut it off in case of an accident. The RPM relay is what tells the pump when to run. If the pump runs continuously when the motor is NOT running the RPM relay and/or fuel pump are not hooked up correctly.
David Teitelbaum
Location: Orlando, Florida
Posts: 2,734
My VIN: 01643
Club(s): (DCF) (DCO) (DCUK)
Dave is right, all the inertia switch does is breaks the circuit when the switch is triggered. It doesn't have an influence on priming (unless of course it's tripped, in which case there will be no priming at all).
Location: Vancouver, BC
Posts: 3,385
My VIN: thirty two 'o five
Club(s): (PNDC)
I have seen cars with power and ground run from the relay compartment all the way to the pump, obviously due to a PO working around a failed inertia switch. Obviously if the OP doesn't have any PO wiring hacks that isn't the issue. I'm not arguing the purpose of function of the inertia switch.
Dave
Here, somewhere.
Location: Orlando, Florida
Posts: 2,734
My VIN: 01643
Club(s): (DCF) (DCO) (DCUK)
I agree with you on this one. I actually know people that have run direct wires to the pump. In that regard, yes, if you notice something odd about the inertia switch, there may be some larger system change at work.Originally Posted by sdg3205
Location: Vancouver, BC
Posts: 3,385
My VIN: thirty two 'o five
Club(s): (PNDC)
The OP has another thread about a wiring mess. My guess is the relay is probably fine and there are some wacky work-arounds to sort out.
Dave
Here, somewhere.
Posts: 88
My VIN: 2729
I was comparing the wires from my RPM relay to the wiring diagram and noticed that the Lambda relay looks to be wired incorrectly. All of the wires are there but they don't match with the positions shown in the diagram.
Lambda.jpg Capture.PNG
Is it supposed to look like this?
Location: Leonardtown, MD
Posts: 9,005
My VIN: 03572
My schematic shows the brown and green/yellow swapped from that diagram. So it looks like that diagram is wrong and your relay is wired correct.
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Dave M vin 03572
