Fuel Injectors not Firing?
 

Hi everyone. I thought I'd make a post this morning before I start my next round of diagnostics to see if anyone else has an idea as to what is happening with my car.

For those who haven't followed along, I just rebuilt a BRZ and while the engine was out I turbo'd it. The car ran just fine before the engine was removed, but after I put the engine back in all it does is crank over.

I sprayed some carb cleaner into the MAF hole and the engine started right up - sounded great. But the engine is not getting fuel so it dies after about 5 seconds.

I replaced the fuel pump with a Deatschwerks model and have fuel pressure the entire way up to the 2 pressurized feed lines on the fuel rails. But when I disconnect the fuel return line it is bone dry.

Right now I am going to rob the injector computer off another BRZ and see if that fixes the problem. Nothing has changed to this car where it should have this issue now when it didn't exist before. Does anyone have any ideas as to what is causing this issue or how to resolve it?

The third line isn't a fuel return line, it's part of the evap system and shouldn't be filled with liquid anyway, so that's not out of the ordinary. Also the fuel injector computer may or may not be the solution. From my experience (which isn't great but still) tuning my own car, on startup only the port injectors fire, at least for the first few seconds and up to minutes depending on how warmed up it is. During cranking only port injectors fire also. Did you replace injectors? A failed DI computer should also throw a code, so try pulling them and see if you get anything.

Good to know it's an evap line and not a fuel line. When I went to search for a vacuum diagram for this car I couldn't find one..

I replaced the injector computer with one from another (working) BRZ and there was no change. I can crank the engine over and over again without any smell of fuel from the tail pipes. I am getting codes, but only for the O2 sensor aside from the 4 permanent codes that were stored before the car was ripped apart - but the parts that threw those codes have been replaced (cam position sensor, O2 sensor, and coolant has been filled so no more coolant temp sensor).

I have not replaced any injectors, nor have I touched this part of the engine at all. I just disconnected it and re-connected it upon install.

So right now it seems as though none of my injectors are firing? I have re-checked the harness connectors a dozen times (on the back of the engine) and they are securely connected.

I went through all my fuses and one that says "EFI HTR" was blown, so I replaced it. Still no change.

All engine grounds are connected in the factory positions with the factory "E" bolts.

These are all the codes that were stored in the ECU when I went to fire it up:

P0108 - Manifold Absolute Pressure / Barometric Pressure Circuit High Input
P0113 - Intake Air Temperature Circuit High Input
P0118 - Engine Coolant Temperature Circuit High Input
P0123 - Throttle / Pedal Position Sensor / Switch "A" Circuit High Input
P0193 - Fuel Rail Pressure Sensor Circuit High Input
P0198 - Engine Oil Temperature Sensor High
P0223 - Throttle / Pedal Position Sensor / Switch "B" Circuit High Input
P0328 - Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)
P0333 - Knock Sensor 2 Circuit High Input (Bank 2)
P0340 - Camshaft Position Sensor Circuit Malfunction
P0345 - Camshaft Position Sensor "A" Circuit (Bank 2)
B2321 - Lost Communication with Driver Door Power Window ECU
U0100 - Lost Communication with ECM / PCM "A"
U0122 - Lost Communication with Vehicle Dynamics Control Module
U0140 - Lost Communication with Body Control Module


MAP - replaced with Omni 4 bar MAP sensor.
Engine coolant - coolant was low when the auction fired it up causing code
Cam Sensor - 2 replaced due to broken connectors



After clearing the DTC's and re-starting it a few times, all I have now is a single O2 sensor code and a P1604 - Startability Malfunction with a 5 step diagnostic process testing EVERYTHING under the sun in this car...

Does anyone know how to check the Engine immobiliser system?

Did you retune for the MAP sensor? Who tuned the car? Starting tables are based on the MAP sensor. If you don't account for it, absolutely it will not start.

You are my F***ING HERO! I threw the stock MAP sensor back on (as it hasn't been tuned yet - that's the next thing to do after I got it running) and VROOM started right up. Idled like crap for about 2 minutes as I kept my foot on the throttle, then stabilized and now it idles like normal.

THANK YOU KINDLY SIR!

Almost time to: :burnrubber:

All Codes Cleared - No more Check Engine Light!

Yup, that will do it. Although stupid, the ECU looks for MAP sensor calibration as part of the initiation sequence and if the values are wrong, it won't start, or start and just quickly die.


The fuel system is returnless stock.

Good to know it fired right up!

Glad to hear it worked! My guess would be there's not enough flow to accurately use the MAF or maybe it's the non-linear region of the injectors. Either way, the cranking tables are hard coded for each mode (which I don't know what the modes mean but either way); for each MAP value, open injectors for X amount of time. Putting in an different sensor probably made the ECU think MAP was pulling a lot of vacuum since the scaling is much larger, thus injecting little to no fuel :thumbsup:

It's still been idling really rough when I turn it on (after the initial time it ran well). I can turn on the car and it dies within 3-5 seconds, over and over again. But if I feather the throttle and manage to keep the engine alive for more than 15 seconds, suddenly the ECU kicks in and drives the RPM's up to 1500 for a minute and then drops it down to 600-700 where the engine idles very stable. I can then warm it up and if I turn it off then back on again, it dies unless I feather the throttle.

What I'm doing now is I've disconnected the negative terminal on the battery to reset the ECU. It's too late now and my neighbors would be driven crazy if I ran it, so I will wait till tomorrow to see if this has made any change. I'm also getting an intermittent O2 sensor code, so I'm getting that ordered from the dealer as well.

That seems odd, stock tune? Startup timing is different and typically a little rougher since it's -15 degrees timing for cat warmup, it's what makes the really loud noises on aftermarket exhausts unless it's tuned out. Anything else changed on the engine, intake, etc?

what turbo kit? if its a blow through maf kit you are going from stock (draw through, which the stock tune is calibrated for), to a blow through reading. which could be why it wont run right

This just saved me from selling the car after an embarrassing amount of diagnostics. Thank you lol

Hey quick question,

I'm having an issue with one of my cylinders, number 2 to be exact. swapped the Coil and replaced the plugs, still an issue. Might be a fuel rail issue, but I was doing some work and I think I might have borked the Fuel Injector Module. I was thinking of grabbing another used Fuel injector module and testing to see if that fixes the two error codes I was getting in relation to that.

Question for you is when you were successful with getting your car to start, was it running with the Fuel injector you grabbed from the other car? or did you roll back to the ecu you had in the car originally before putting back the MAP Sensor?

Thanks in advance.

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