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Somebody help me please!!! I have a 75 Monza Towne Coupe with the original 2.3 L four banger and 4 speed tranny. Last year i go the wild idea to to put a new stereo system into it (yes I did cut the dash and yes I now regret it). I had to get a new battery then ran all the wiring and checked to make sure the radio and speakers worked before I put it all back together- everything was fine so I went ahead and got everything installed and was ready to go intimidate my neighbors with classic 60's and 70's rock and roll. I cranked the motor but it would not start, then noticed that the dome light was not on and the radio would not work. I have talked with several mechanics and the consensus is that it is probably an electrical problem and i am at a complete loss on which direction to go from here. I used the cigarette lighter wiring to power the radio and as I said it had worked but now it does not. I have all the wiring diagrams and have combed over them so many times they need a shot of rogaine now. Any ideas or suggestions? Right now I am so befuzzled I can't think straight-

The lighter and dome light are on the same fuse, so I presume you've blown that one; but that should not have any effect on the car's ignition. So I have to ask what other wires did you splice into for the stereo installation? Normally, on the stereo there is a yellow bat+ wire that you would have hooked to the orange lighter wire, plus a red acc+ wire that should have been hooked to the yellow radio accessory feed wire in the dash. A possible problem would be If you somehow ended up with that red hooked to something else that has blown another fuse. The only fuse that would prevent starting would be the fuel pump feed. Not sure if this will help, but here's a link to the wiring diagram for your car-
download/file.php?id=4692

Does a 4 cyl Monza use a mechanical fuel pump or electric?

As I recall, the early ones with the 2.3 Vega motor were electric and the later 2.5 Duke motors had mechanical.

orange fusible link ok?

Can you see fuel squirt in carb? is there a strong smell of gas? did the spark plug wire show it's getting spark?

Replaced some 20 amp fuses that were broken and checked my wiring and did get the dome light to come back on and the radio to work. Still can't get it to start and I am pretty sure my fuel pump is not working so will be getting more fuses (25 amp, 10 amp, 4 amp, and every other amp I find) and see if that solves the problem. And the beat goes on....

Here's a quick thing you can do to help track down the problem; find the oil pressure/fuel pump safety switch under the hood. It has 3 large wires- pink (ignition) purple (start) and blue (fuel pump). If you place a jumper between the pink and blue terminals, you should be able to hear the fuel pump run when you turn on the key.

To start some of the rides I have worked on after sitting I usually prime the carb by filling the carb through the vent in the main opening with a small funnel this way I don't have to wait (and crank) until fuel catches up but be careful of splash as it can catch fire pretty easily. Don't ask, names and dates have been changed to protect the stupid (me ) No H-Bodies were harmed during this act of less than brilliant behavior! This will remove the fuel pump from the equation for a few moments like ten seconds of running, and can help identify/isolate issues. Harry

Where does the hanging black wire go?

Still can't get it to start- it will crank and crank but I do not hear the fuel pump when it does so thinking that might be the problem. I replaced all the fuses, checked every connection I could find including the oil pressure/fuel pump safety switch and am stumped!!! There is a connection in the picture below that shows a black wire coming out from behind the fuse block but have no idea where it goes. I also looked through my pile of parts and did find what looked like a jumper wire- it is maybe two inches long and has a flat metal plug on both ends. If this a jumper wire where would I plug it in or how would I use it? Needless to say my mechanical and diagnostic skills are virtually none existent and am at a total loss as to what to do now. Help!!!

Been going over my Monza again to see why it still will not start- I finally found the oil pressure switch connector but don't see where and what it plugs into. Maybe the picture might help-

If you look back at my last post, I suggested putting a jumper wire between the pink and blue. Then check for fuel pump operation.

I am such a dork!!!! I remember you saying use the jumper wire between the blue and pink but it never occurred to me to use the connector plug. Just went in the garage and used the little blue jumper I been carrying around with me and stuck it in the holes on the connector and it fired up on the second try. Love that sound!!! What do I need to do now- do I keep using the jumper wire or what? I am ready to take my baby out for a spin!! Thanks Spencer- you da MAN!!!

You need to connect that connector to the oil pressure switch. I don't know where it is on a 4 banger but it has to be somewhere where the connector will reach. It should screw into the block into a oil pressure passage. It prevents the fuel pump from running when the oil pressure is either too low or in the event of a accident when the engine stalls. Don't bypass it long-term, hook it up correctly to keep everything safe as designed.