Problem with Edelbrock/msd LSX conversion

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Feb 28, 2009 | 11:12 PM

Deeavi

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From: Bowman, SC

Problem with Edelbrock/msd LSX conversion

I also posted this in the fuel injection forum I need some help with a project.

We have a 98 Camaro that we are changing from efi and going to a Demon carb and Edelbrock intake. It came with a MSD ignition/timing controler. I am bypassing the ignition and fuel injection harness, but want to leave the factory computer for other functions. I installed a "Race Pumps" fuel pressure regulator designed for use with an efi pump and carb. The (racetronics)pump on the car is fairly new

After setting everything up the fuel pump seems to quit pumping after intial startup. When I turn the key on. The fuel pump initializes and the pressure gauge reads correctly, then goes down quickly. Then the carb will run out of gas in few minutes and the engine shuts down. I can turn the switch off and back on the it does the same thing. There were no problem with fuel delivery before the swap.

Also my cooling fans are not turning on.

Any ideas? Appreciate any help!

Feb 28, 2009 | 11:16 PM

Deeavi

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From: Bowman, SC

I was just informed that the fuel pump requires an rpm signal. Since the crank sensor and the cam sensor pulg into the msd harness, I am not sure how to resolve this issue

I am not sure about the fans either.

Need some ideas for a work-around if possible?

Thanks!

Feb 28, 2009 | 11:42 PM

Frost

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From: Richmond VA

There are a few work arounds. Run your fuel pump off of an IGN ON ckt and it will run as long as key is on. That or either buy the connectors or jump into the harness and get the crank sensor back to the pcm.

Feb 28, 2009 | 11:46 PM

Frost

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From: Richmond VA

The relay trigger wire is found in the BLUE PCM connector. It's number 37, dark green wire with white. Check it with a DMM at key-on to make sure it switched +12 to the wire and not a ground so that you know what you need to feed it.

Mar 1, 2009 | 10:38 AM

Deeavi

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From: Bowman, SC

Thanks for the reply.

I think that I am going to try and find a connector to jump the circuit back into the pcm harness like you said.

Mar 1, 2009 | 04:45 PM

Deeavi

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From: Bowman, SC

Quote:

Originally Posted by Frost

To give you an update, I made a connector and tied the crank sensor output into the stock PCM crank sensor connector, and everything works. Fuel, tach, etc.

Now it seems my Race Pumps fuel pressure regulator cannot handle the pressure from the efi pump. It is designed to do just that, but I may have to put two regulators. I don't want to change my pump out unless I have to.