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Crank but no bang. Main relay?

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Old 08-29-2021, 10:49 PM
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Default Crank but no bang. Main relay?

So a little background I have a 95 turbo car on megasquirt. Has been running and driving for a few months now but the clutch started slipping and the weather got bad here in Arizona so I put it away for a while.
Havnt started it in a month or so but I got around to doing the clutch this weekend. Got it all back together and went to start it to make sure everything was good and no start.
Cranks just fine but I don't think I'm getting any fuel. I can't hear the pump prime with the key on or during cranking. I was reading it could be the main relay but I just don't understand how it could just stop working while it was just sitting.
Is there any way to test the main relay before I spend the money on a new one? And if I do need a new one is it worth the money to get the upgraded FM one?

Just confused and any advice would be greatly appreciated.
thanks guys.
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Old 08-30-2021, 06:05 AM
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Open the relay box and have someone turn the key on while you listen to it. If no click, it is bad. They can go bad sitting.
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Old 08-30-2021, 06:09 AM
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Do you have cranking sensor sync? Pluggin in and verifying all your sensors are working is probably good first step
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Old 08-30-2021, 09:36 AM
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Originally Posted by olderguy
Open the relay box and have someone turn the key on while you listen to it. If no click, it is bad. They can go bad sitting.
I definitely couldnt hear it clicking by myself but I'll have someone come turn the key so I can put my ear to it. I'll update later after work today!
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Old 08-30-2021, 09:37 AM
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Originally Posted by themonkeyman
Do you have cranking sensor sync? Pluggin in and verifying all your sensors are working is probably good first step
What is cranking sensor sync?
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Old 09-01-2021, 09:27 AM
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To confirm, pull the main relay out and jumper the switched contacts (not the coil contacts). If the car fires up, your relay be toast.
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Old 09-01-2021, 10:46 AM
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Okay I made a second post on this for unknown reasons but anyway. So I tried to jump the relay to no avail Idk if I did it wrong but I tried a relay because I had ordered one anyway and that didn't work. I plugged my laptop in to see if megasquirt would tell me anything (again idk why I thought that would help) and I couldn't connect to the ecu. So I don't think I'm getting ecu power. Any ideas as to why I wouldn't have ecu power? Where does the ecu get its power from? Did I somehow blow a fuse?
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Old 09-01-2021, 11:20 AM
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It’s gets power from the main relay. Check for 12v like I said in the other thread at the ecu. If nothing there, check at an injector. If nothing there, check at the relay. If nothing there, check at the main fuse in the engine bay fuse box.
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Old 09-01-2021, 11:24 AM
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Originally Posted by curly
It’s gets power from the main relay. Check for 12v like I said in the other thread at the ecu. If nothing there, check at an injector. If nothing there, check at the relay. If nothing there, check at the main fuse in the engine bay fuse box.
sounds good. I will check after I get off work and update.
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Old 09-01-2021, 01:50 PM
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Originally Posted by curly
It’s gets power from the main relay. Check for 12v like I said in the other thread at the ecu. If nothing there, check at an injector. If nothing there, check at the relay. If nothing there, check at the main fuse in the engine bay fuse box.
Okay. So I check all the fuses in the car again but to be sure. Everything checked good except the engine fuse in the cabin which is for the cooling fan. Oops.
Anyway. Checked power at the ECU and nothing. Checked at the number 1 injector and nothing. Check at the main relay in the engine bay and nothing. But I I have power at the main fuse in the engine bay. I checked the white and red stripe wire on the main relay with no voltage but the white and green stripe wire does have voltage. I will attach pictures.

Where should I go from here?

Thanks again for dealing with my newbness


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Old 09-01-2021, 03:34 PM
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White green is directly from the fuel injection fuse.

If you had B+ on the white/red, you wouldn't have this problem. Bridge these two pins and everything should work.

The other two, black and black/white, are what trigger the relay. Black should be grounded. Black/white comes from the engine fuse, and is hot in run or start.
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Old 09-01-2021, 03:51 PM
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Originally Posted by curly
White green is directly from the fuel injection fuse.

If you had B+ on the white/red, you wouldn't have this problem. Bridge these two pins and everything should work.

The other two, black and black/white, are what trigger the relay. Black should be grounded. Black/white comes from the engine fuse, and is hot in run or start.
Well it's funny you say that...
While I was waiting for you to respond I ran to autozone to grab a fuse because I figured it be good to have working fuses and right as I got back I saw your reply🤦‍♂️.
Started up like nothing. I really appreciate the help. @curly
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