I have a custom build on almost completely stock everything. Just trying to get it running at this point.

Issue... Injectors are not opening.

Have tried two sets, so its not the injectors. I have fuel at the pump and rail. The resistor box is connected and correct from what I can see.

What can cause the injectors to not want to fire? Cam angle sensor?, crank angle sensor?, any thing else I can check? I just don't know where else to look to trouble shoot. I do have 12v at the injectors.

 

Do u have fuel @ the fuel rail??!?!?

 

I do have fuel at the rail. Just the injectors are not opening.

 

Voltage at the injectors?
Check at the ecu to see if the injectors are getting grounded.
All sensors connected?
Getting a valid crank/cam signal?
Any DTCs in the ecu?

 

I have 12v at the injectors.
Not sure how to check ground at ecu for the injectors.
Yes, all the sensors are connected.
How can i check for valid crank/cam? I know if I unplug one or the other I lose spark so there working to some degree.
No check engine lighs yet while cranking.

 

Its a ground up build so it can really be anything but when it comes to injectors i don't know where else to look.



- If i have spark, can a problem at the crank or cam sensors shut off the injectors?

- Is there some way to put a volt meter to the resister box to check to see if that's the issue?

- Is there anything in the fuel pump housing that could keep the injectors from firing, keeping in mind that the pump is pumping?

- i've checked over every fuse in the car, but is there a fuse or relay directly in relation to the injectors that i can try and replace?

 

I dont particularly know how its setup, but I know holding the gas down while cranking the car kills the injectors, could there be something wrong with whatever may do this?

Sorry I cant be of more help

 

^ TPS Maybe, i can take a look at it and see if i notice anything odd.

 

Unplug the injector connector hook up a digital multi meter to check dc voltage and probe the positive and negative side of the connector, crank the engine and the voltage should fluctuate from battery voltage to 0 voltage.

 

^ With the key on its 12v, and while cranking it drops to 7v and bounces around a constant 7v to 7.5v on my cheap reader.

It never dropped below 7v. If its supposed to drop to 0v then what could be wrong? I've been over my grounds and I'm not seeing anything that I've missed.

 

Your meter is reading 7v due to averaging the 14 and 0 volts sounds like the injectors are pulsing.

Have you messed with anything related to the injectors? Have you verified fuel pressure?

 

What are you using for a Fuel regulator. What's fuel pressure?

 

It's always something simple... She's running finally. Thanks guys.


Turns out it was the.fuel pump. I used the plug assembly from an evo 10 and apparently the wires are reversed. I had tested that already once before but I guess I didn't crank it long enough. She had fuel in the rail so I just assumed. Was a long day yesterday and just needed anouther perspective to get me back on track.

Thanks guys.


A truely one of a kind Evo build thread to come very soon.

 

For future reference just because fuel is in the rail or there is fuel flow does not mean it is sufficient, fuel pressure needs to be checked.

 

^ True

Ya i have a fuel regulator with gauge that i honestly probably don't need but i bypassed it at the first sign of an issue. When i checked the rail initially the feed line blew off the rail when i unbolted it tricking me into thinking it wasn't a pump issue. The pump was running, had fuel pressure in the rail, and the spark plugs and injector tips were dry. The fuel stopped at the injectors so assumed that was the issue.

I had thought about pulling the feed line and simply just testing it into a cup but with everything that was going on, i got excited and simply skipped the first step to trouble shooting it.

Its always something simple, oh well. Just glad shes running and lets hope my world first motor holds together long enough to put down some numbers. lol