AusS2000

I confirmed that the relay is the problem. I put a multimeter on the connector whilst still plugged in and the relay is getting the trigger voltage but not outputting the 12V. I pulled the plug and put 12V to the output and the fuel pump fired right up.

I pulled the relay and disassembled. All the solder joints look good.

I couldn't source a replacement relay so will have to buy the whole unit from Honda.

One thought though. I'm using a Walbro 255lph fuel pump (and I now have a spare). I wonder if the current it draws is too much for the relay and that is what burnt it out? Perhaps I should install a slave relay off the standard relay.

BTW, all the documentation above shows pin 4 as the output to the fuel pump. Surprisingly my relay has no pin 4. The output is pin 7.

Reborn56

Wow Justin that is some good info
Is that the electronic helms book?

Also Auss2000 was this problem intermittent or did it just stop feeding 12v altogether??
I had the same problem replaced fuel pump and fuel pump assembly and havent had that problem since.


Marcus

AusS2000

The problem occurred and stayed that way. No intermittency.

I bought a new fuel pump but the problem has turned out to be switching not the pump itself.

Anyone wanna spare Walbro 255lph pump?

chairmnofthboard

did you try moving the connections and plugging the relay back in? Just to rule out bad connection.

Crappy feeling isn't it, when the car just DIES.

AusS2000

I did try playing the connections but no luck.

AusS2000

Hmmm, so I replaced the fuel pump and that wasn't it.

I ordered and waited 3 weeks for a PGMFI relay and that didn't fix it.

This should have been the clue. A15 doesn't need to be high for the fuel pump to work. It needs to go to ground!

I noticed something else too. A clicking under the hood. Turns out it was coming from coil 4. Swapping coils didn't change it so it was a wiring problem.

Well, actually an ECU problem. I swapped back in the OEM ECU and the fuel pump fired up fine and the clicking was no longer present. Hooked up an laptop and it sees the AEM but won't connect.

Looks like I'm in for a new AEM EMS.

Reborn56

Your aem was bad huh?

JustinC

Yeah that is the electronics helms book. It is very detailed.

AusS2000

I just realised I should have finalised this thread.

I spoke to AEM. They knew what the problem was. They said send it back, they would repair and return it (to Australia BTW). Total cost $50.

S2oooNvegas

This thread should be a sticky. Its very helpful. This is an odd ass hard as hell problem to find.
Just had an aem EMS car quit on me today, 2nd time since we built it. PGMFI relay clickin all wildly and fuel pump of course going off and on with it. Then it quit 100%. No fuel pump action.
Going over these connectors again now. Hoping its not the EMS.