1G No Crank No Start

[livedsm4g63]

Wanted to get everyones opinion. Im about done throwing my car together and Im running into an issue for a no crank no start. This means when I go to start the car, I turn the key to start and all I hear is a click coming from behind the radio. I believe it to be the mpi relay.

Knowing this I went and replaced the ignition switch, starter relay and unplugged my clutch switch to find the same outcome.

Thinking outside the box I went ahead and turned the key to the on position and jumped the starter signal prong (located on the starter) to the battery, what do you know, the engine started to turn over!

So with that being said, other then the starter relay and the ignition switch, what would cause no power to the starter signal wire? Anyone have a schematic?

I can always run a fuse to toggle to push button. Just a thought. Ideas?

 

[shinzon]

If you can get the car to start by applying battery voltage to the signal terminal on the starter, then you've narrowed down to a problem somewhere upstream of the starter. Off the top of my head, this could be the starter relay, clutch safety switch, wiring, or the ignition itself. Since the clutch safety switch is on the ground side of the starter relay, what I'd do is connect a volt meter at the clutch safety switch and confirm you're getting voltage on one side with the engine cranking, and with the clutch depressed you should have no voltage on either side.

If the clutch switch tests good, you'll have to take voltage measurements at the starter relay. With the key in the start posistion and clutch pedal depressed, you should have battery voltage on pin 3. If you do, it's a problem with the wiring harness heading out to the starter, or the signal connector on the harness. If you don't have voltage it's the relay or the ignition switch.

To narrow between the two, check for voltage on pin 2, the control side feed, or pin 4, the load side feed (they're spliced from the same wire). If you do have voltage with the key in the crank posistion, it's the relay. If you don't, it's the ignition switch or wiring in the column/dash.

If you car has anti-theft, that could be the fault too.

1g service manuals can be found here:
http://www.dsmtuners.com/threads/download-the-1g-service-manuals.344490/

 

[boostdawd]

If it worked before then retrace all your steps. May be something as simple as a missing ground.

 

[livedsm4g63]

If it worked before then retrace all your steps. May be something as simple as a missing ground.

Negative, was a shell I picked up. Everything powers just no voltage to the starter signal switch.

To shinzon:
Unplugging the clutch switch takes this out of the equation. I just find it weird that the MPI relay clicks however nothing happens. Ill be picking up new leads tomorrow for the multimeter so I can start tracing.

 

[shinzon]

To shinzon:
Unplugging the clutch switch takes this out of the equation. I just find it weird that the MPI relay clicks however nothing happens. Ill be picking up new leads tomorrow for the multimeter so I can start tracing.

Yup, I had the clutch switch backwards in my head. I was conflating the load side of an A/T starter relay, which is open in the off position, with a M/T starter relay, which is closed in the off position, probably designed this way so that if the clutch switch fails one can still start the car. Rest of what I said about the terminals at the starter relay to check still holds though.

Does your car have anti-theft? If so, there's another relay on the clutch safety switch circuit that you'll need to check too (or just disconnect the grounding location for the clutch safety switch). You can see that in the 90-91 electrical manual I linked to.

I don't like jumping relays because if you get the pins wrong you could fry something, but if you're comfortable with doing that, you could bypass the starter relay by jumping pin 3 with pin 4, which takes the anti-theft, clutch switch, and the starter relay out of the equation, leaving only the ignition switch, wiring, and signal connector.

The MPI relay powers many things in the ignition and fuel injection systems and is controlled by the ECU, so if your MPI relay is clicking (once when you turn the key on) that means your ECU is doing its job there. MPI relay is on a different circuit than the starter though, so it wouldn't have anything to do with your signal problem. ECU has no control of the starter either.