[SOLVED] Injectors 1 and 2 not firing

While on a long trip my 2008 Mazdaspeed 3 suddenly lost power and the engine light turned on. Did a noid light test to find that injectors 1 and 2 were not firing. Tested continuity down the wire harness all the way to the ECM with no issues. I even replaced the ECM with a refurbished one and the problem is still there. The noid light shows one pulse then nothing for both injectors 1 and 2 and when doing the noid light test for 3 and 4 I noticed that the pulse seems to be getting weaker and weaker as I crank the engine. Anyone have any ideas?

 

Something may be in the harness. Time to tear into it.

 

Weird that conuinty is fine but noise light is acting hinky.

Have you had the injectors tested?

 

Fixed! It was the wire harness to ecm plug. I used a pun to check if the pins were getting contact and the injector 2 pin had no resistance while pushing in the pin. Took the plug apart and fixed the connector and it runs perfectly.

 

Hey mate. I'm having the exact same problem as you. What ecu plugs did you pull apart?

 

Based on the way he worded it it sounds like the giant connector going into the ECU right at the battery box. There are two connectors

 

Ah so you mean the injector drive module?

 

The connectors to the ECU. Big fat rectangle connector. It's bolted to the oem battery box.

 

No I mean exactly what I said ecu

 

The ecu is in my passenger footwell, I'm from Aus so right hand drive. There is no plugs on the battery box

 

Looks like the entire harness going to ecu here to me on this aus MPS. The PCM is in the passenger for well.

 

That's different to my 6 aswell. I don't have a battery box, just a battery tray. Under the tray is a heap of wires coming from ecu in footwell going into fusebox. If I know what the connects looked like that he rebuilt I'll be able to find them in mine

 

Please post a picture of under your hood

 

Engine bay is a bit messy, got fair bit pulled apart. Here's the bay and the footwell with my ecu

 

Wtf where is the ECU post your other pic

Is the previous owner relocated the ECU that wiring is probably your problem

 

It's right hand drive, the ecu is normally there for the Aus mps6
I just want to know what plug into the ecu he rebuilt haha

 

He did it's just attached not embedded, (fixed) definitely not pulling our leg. I learnt something today, pretty cool that it's in there.

I'd have to check shop manual to get exact pins for injectors unfortunately I won't have time to jump on the PC this weekend

 

I was drunk and trying to look at the pictures on my phone. I didn't see the second one

It wouldn't hurt to check all of the pidns on both of those connectors

Some people have managed to fix weird issues by simply unplugging the connectors and plugging them back in

 

Yeah Im being legit haha. Im not sure out of the 4 are the correct ones. I've unplugged everything and did a Noid light test and nothing changed. So I'm at a loss. I've narrowed the area down to that part of the loom or the ecu itself

 

When I had issues with mine Noid test was fine, however it was pin in the injector that was angled away from the female pin and not making contact with the harness connector. Bent it vertical and it was fine. This was after an injector cleaning