no spark and more

[IdahoKidd]

Hi guys,

I am brand new to this forum and brand new to Zcars although I have years of fooling with cars, mostly old-really old Volvo's. Here is the short version of a long story. I just inherited a 77 280z in pretty good condition (good condition is always relative). The guy had fooled with it for years off and on trying to get it to run but was too stubborn to ask for help so I am not certain everything is where it is supposed to be. I bought a second 77z that is complete but the motor is seized. I bought it to have a life size reference manual and as spare parts.

So, there is no spark from the coil when cranking. Power to the coil. And here is the catch. When you turn the key to the off position, it fires the coil wire just one time. You can turn the key on and off repeatedly and get the spark, just not when it cranks. I ran into this very same problem years ago on a different vehicle and for the life of me I can't remember the cause or the cure. Any help?

Second question. I have figured out that the fuel pump doesn't work until the car is running. I really want to flush out the fuel from the lines before firing it up. I hasn't run for 10 years, but ran fine then. How do I fool the fuel pump into working so I can push the fuel out of the lines and replace it with fresh from the tank?

Thanks in advance.

Leonard

[1rad280]

that weird im having the same problem

[IdahoKidd]

Okay, it is coming back to me. A bad magnetic pickup coil gives this problem, both in Chevy v8's and apparantly 280z's. I didn't have a second pickup coil ( I think it says something like ignition control in the book I found), the little black box that bolts on the side of the distributor, but I did have a complete different distributor that didn't have the box. Put it in and pretty blue sparks everywhere.

However, for the life of me I can get the fuel pump to work. I can't find the fuel pump relay under the hood nor anything even looking remotely close. Any help on getting the pump to work? Where do I look, how do I jump it or bypass the relay?

Thanks,

Leonard

[Curtis240Z]

The oil pressure sender holds out the fuel pump until there is sufficient pressure, indicating the engine is running. You can try bypassing the sender which should let the fuel pump relay stay energized.

[tstewart]

If you don't have it already, the factory service manual for your car can be downloaded at http://www.xenons30.com/reference.html. This may help with your troubleshooting.

[IdahoKidd]

I still can't find the relay(s) and they are definately not under the hood. I found a Chilton and a Haynes manual and while I recognize they aren't the best, they are what I currently have. Tony posted the link for the manual above but my computer just sets there with a blank screen so I will fool with it later. Both of these manuals seem pretty certain the relays are on the inner fender of the passenger side. Neither car, 11/76 production and 5/77 production. I have unhooked the oil sender, the cold start valve, individually, together, nothing. It appears I will be pulling the pump out this morning and try to resolve it backwards.

Leonard

[skunkbud280Z]

Let the fuel pump live and let live, and just:

Disconnect the feed line just forward of the fuel damper and under the hood where the metal rails begin and blow the lines clean with an air compressor. About 40psi through the lines and they were clean in seconds. Return line was already disconnected at the fuel tank as I took the fuel tank off, so I only had to disconnect that line up front.

You said the fuel pump works only when the car is running, but I'm guessing you meant the pump works only when the car is cranking?

I was told by two separate sources that the pump actuates when the key is merely turned to the "On" position, but the FSM quickly clarified that this is not the case. It pumps in the "Start" position, when the engine is running obviously, and it has an emergency shut off feature if/when the engine stalls, I suppose to prevent fires in the case of wrecks etc.

[1rad280]

move the wires around under the right side of the dash above the fuse block. mine has a short wire that cause it no to pump or crank.just a hunch

Edited September 6, 2008 by 1rad280

[sblake01]

On a 75-77, this is the algorithm for fuel pump operation:

[IdahoKidd]

So here is the latest....

The car does not run, didn't when I got it, still don't.

There is power to the fuel pump all of the time. Key off, doesn't matter, power all of the time. There is power to both sides of the injector plug all of the time. Key off, doesn't matter. I found the relays on the inside of the fender in the passenger compartment, took all of them out and replaced all of them from the donor car. Didn't help a thing. There is power to one side of the cold start injector and it does function when triggered with jump wires but not during the crank cycle. With starter fluid, the engine does fire and bable briefly. Any thoughts?

Leonard