Is there any way to tell if my L-jet brain is dead without swapping it Options

[jd74914]

Hi guys, heres the problem.

A few months ago my car was running great. I had just rebuilt the engine and put everything back on. After fixing some grounding problems it ran perfectly.

Then, I went on vacation, came back and did some welding and forgot to unhook the brain when I unhooked the battery. After this the car wouldn't start. It wasn't getting any fuel. The coil also got really warm at one point, so I replaced it with another known good, new one I had. Now with the new coil, and a new fuel pump (I also had a known good pump) put in, the car still won't start.

It turns over fine, but it won't even run for a second on the cold start valve (IMG:style_emoticons/default/sad.gif)

Is there a problem with the brain or is there something else I should look for? I can't think of any other things to go bad. (IMG:style_emoticons/default/idea.gif) I'm pretty sure the points are good.

Its a 74 L-Jet BTW

[bd1308]

alright here's what you need to do:

After the system was installed in my car, nothing worked.

The Ignition turns the IGN relay on the relay board, which feed power to the dual relay.

with the car off, you should be able to open the dual relay and press down either relay--one should turn the fuel pump on, and the other should turn the FI computer on (click! goes all injectors once)

when you turn the key, you should hear two relays ( or more I forgot)

one should turn on on the relay board, and one you should hear from the dual relay--if your dual relay doesnt click, its either bad or you need to check the relay board (on the 914).

i have a dual relay i can send you for testing--its in not prefect shape, but it'll do for testing and you wont have to open yours.

[ClayPerrine]

The Ignition turns the IGN relay on the relay board, which feed power to the dual relay.

Britt.. I hate to do this but the above statement is WRONG!


You can pull every relay out of the relay board on an L-Jet car and it will still run. NONE of them have anything to do with the injection.

The double relay is powered off the heavy red wire that comes from it and attaches directly to the battery positive lead.

The fuel pump is powered 2 ways, one by the starter circuit when the engine is cranking. That signal is obtained by connecting the yellow wire on the engine harness to one of the 2 rearmost spade connectors on the 4 pin relay board connector. Both of the rear pins are connected together. (And a trivia item, you can connect a remote starter button to those connectors and feed battery voltage to them to get the engine to crank).

The second way is when enough air is moving through the air flow meter, it closes a contact that turns on the fuel pump via the double relay.