Help me figure out this starter issue on my S1 Elise

Help me work this out, some of this will be copied and pasted from a Euro forum I also posted on.

96 Elise running an SCS ECU with coil on plug conversion. I was flashing the ECU, and went to restart, and it wouldn't turn over. I got a loud click from the solenoid. Figure okay, starter is bad. Replace that. Same thing. Okay, maybe grounds are dirty. Clean those up, same thing. Motor will crank if I apply 12v directly to the starter spade. Check the ignition signal wire, shows 12v with the key turned to crank, when not connected to the starter. But once it's done up, nothing. Finally popped the cover off the MFRU (multifunction relay unit, it has the relays for the starter, fuel pump and ecu in one unit) to look at what the relays are actually doing. When the key is turned, the starter relay will click over, then immediately open back up. I can push the relay closed by hand and the car cranks but will not start. The relays for the ECU and fuel pump close as they should, and I can hear the pump prime. Immobilizer has been bypassed directly with the connector cut out. I haven't checked for direct spark yet, by pulling the coils and sticking plugs in to see if they light, that's probably the next step. I have some videos on this FB post in the S1 group https://www.facebook.com/reel/248118054925625 . I'm in the states, so a known good MFRU isn't exactly around the corner.

Weird twist, I noticed when it was cranking, my Davies water pump display would sort of light up occasionally even though I had pulled the fuses to it. When it sounded closer to starting, the display would look slightly brighter. I put the fuses back in, and she would start after manually closing the starter relay. Doesn't really make any sense....

Quote:Originally posted by ive
you can use two jump cables in series to connect battery ground pole to the engine block to check the ground path.

Just tried this. No difference.

I pulled the MFRU out and tested it by applying 12v directly to pins 4 and 6 of the input side, which closed the relay and checked for good continuity on output pins 5 and 7. That checked out.

I'm going to double check the actual connector for corrosion and/or a loose pin. Is the ground for this on the ECU ground bolt?

I'll double check for a solid 12v coming into the MFRU off the ignition switch with a multimeter.

Maybe I missed it in your post, but are you sure of the health of the battery? Specifically, could it have dropped too much during flashing and just not have enough juice?

In reply to cyow5 :

Yeah, its a newer battery (6 months), and is on a tender. The fact I can manually close the starter relay by hand and start the car leads me to believe that the battery isn't the issue.

fatallightning said:

In reply to cyow5 :

Yeah, its a newer battery (6 months), and is on a tender. The fact I can manually close the starter relay by hand and start the car leads me to believe that the battery isn't the issue.

Those are very low-demand operations though, then it fails to do the hardest part. I've had batteries die on a tender, so that *technically* doesn't answer my question. I'd at least have it tested or see if you can jump-start. 

Edit: Sorry, I misread what you were saying. I think I've got it now; carry on!