I assumed tested the F/P at the connector under the ashtray.Hi, I have a 1991 MR2 turbo with a 4th gen 3sgte. Engine is fully rebuilt and engine harness from Doug (wiregap). Prior to getting the engine harness I was getting no power to the fuel. I was hoping the new harness might fix it so I can rule that out. The only problem I do have with this harness is that the obd scanner won’t turn on with it. My previous harness I was able to get codes. I replaced the efi relay and the COR still no power to the fuel pump. I only get 1v instead of the 12. I tested the starter relay and the ign relay all passed the testing procedure. I also checked all the fuses up front and replaced the 120a one. The starter is also new as well as the alternator. When I connected the fuel pump straight to the battery it would start right up without shutting off. So my car only starts with starter fluid or if I wire the fuel pump straight to battery. The only thing I changed prior to it not starting was the pipe that goes from the turbo to the side Intercooler. The connector that’s behind the driver seat is also plugged in, battery is also new. All the grounds are connected too, I sanded down the paint just Incase too. Anything else I should look for that could prevent power going to the fuel pump?
Thanks
No power to fuel pump
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Yeah I tested the connector under the ashtray, F/P turns on. The connector from the body harness that connects to the F/P isn’t getting the 12v, it only gets
1v while cranking
Ok so we need to determine where the 12V is going missing.
The fuel pump is powered from the fuse box in the engine bay with the Circuit Opening Relay.
First you need to determine that 12v is available with the key in the ON position to pin 2 of the relay.
It appears you have continuity between pin 1 of the C/OPN Relay and the fuel pump however still good to check it. Once you've done these checks come back to me and we can move onto the next bits to test.
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Just a bit of background on the system.
The pump will only run when the key is turned to START or the engine is running and the ECU controls the C/OPN Relay with the FC pin. It does not prime like other cars when you turn the key to ON.
The fuel pump is powered from the fuse box in the engine bay with the Circuit Opening Relay.
First you need to determine that 12v is available with the key in the ON position to pin 2 of the relay.
It appears you have continuity between pin 1 of the C/OPN Relay and the fuel pump however still good to check it. Once you've done these checks come back to me and we can move onto the next bits to test.
Just a bit of background on the system.
The pump will only run when the key is turned to START or the engine is running and the ECU controls the C/OPN Relay with the FC pin. It does not prime like other cars when you turn the key to ON.
I had a similar issue. The fuel pump would run with the paper clip at the diagnostic port. I found that the fuel pump resistor was bad. I had a spare resistor, but it can be bypassed to run full speed all the time.
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I tried it and it wouldn’t start.
I got the car with the swap in already but it ran and it drove. I installed the swap back in after getting the engine rebuilt. It started and drove after as well.
I was having a high idling problem though
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