rb25swap cranks, has spark, injectors wont spray

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socalswapped
Posts: 3
Joined: Sun Jul 22, 2018 8:23 am
Car: s14 240sx

rb25swap cranks, has spark, injectors wont spray

Postby socalswapped » Sun Jul 22, 2018 9:29 am

Car sat for a few months and will no longer start. Rb25 stock ecu stock injectors q45 throttle body and aftermarket intake manifold. It cranks. I pulled the plugs and ran a temp ground from the plugs to battery and cranked it and they all fired. I pulled the fuel rail from the manifold and put paper towels in front of the injectors, cranked motor and none of them sprayed at all. The paper towels were bone dry. Fuel pump is priming. Fuel pressure with key on is 3kg/cm so like 42 psi and then slowly bleeds off. All injectors are getting 12v power. So its probably not the cas since the plugs are firing right? Could it be the maf? Mines the pink sticker 3 pin type, its getting 12v as well, is there any way to test it? Not really sure where to go from here any help would be very much appreciated. Cheers


socalswapped
Posts: 3
Joined: Sun Jul 22, 2018 8:23 am
Car: s14 240sx

Re: rb25swap cranks, has spark, injectors wont spray

Postby socalswapped » Sun Jul 22, 2018 12:19 pm

Edit: checked maf while plugged in key on with a blow dryer, it sends in between 0 and 4 something volts depending on how close the blow dryer was. Seems fine

wa-chiss
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Car: 1990 S13 H/C KA24E
2005 Toyota Sequoia
1976 Honda CB750F Super Sport
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Re: rb25swap cranks, has spark, injectors wont spray

Postby wa-chiss » Mon Jul 23, 2018 6:09 pm

ecm controls ground from the injectors. Grab a Noid Light and see if you have a ground signal. The light plugs into the injector connectors and flashes when the ecm grounds the circuit. If no flash when cranking the engine, I'd say the ECM is done. If there is a flash, your injectors are probably either clogged or electrically open.

socalswapped
Posts: 3
Joined: Sun Jul 22, 2018 8:23 am
Car: s14 240sx

Re: rb25swap cranks, has spark, injectors wont spray

Postby socalswapped » Mon Jul 23, 2018 7:50 pm

I did the noid light test and didnt get any flashes. I did it with a kit I got from o reilly which mentions gm connectors but one seemed to fit pretty tight so I used it, would that matter? I dont think so if not then I guess ill test the injectos and search more about the electrically open thing. Thanks bro, Ill post again when I find something else out.

wa-chiss
Posts: 2568
Joined: Mon Feb 20, 2006 10:23 pm
Car: 1990 S13 H/C KA24E
2005 Toyota Sequoia
1976 Honda CB750F Super Sport
Location: San Angelo, TX

Re: rb25swap cranks, has spark, injectors wont spray

Postby wa-chiss » Fri Aug 10, 2018 11:01 pm

Sorry, haven't really been on lately.

It won't matter what manufacturer they're made for, as long as it plugs in. Did you happen to flip the light around and try it again? They're polarity sensitive so you might have the light's ground on the wrong side of the injector connector.

Honestly, I would have a hard time believing all 6 injectors went out at the same time. I've seen it happen, but it's extremely rare.

flartius
Posts: 138
Joined: Sat Apr 01, 2017 9:19 pm
Car: 1996 - Nissan 240sx SE RB25DET
2008 - Yamaha YZF-R6 - SOLD
2007 - Ford F150 FX4
Location: Huntsville, AL

Re: rb25swap cranks, has spark, injectors wont spray

Postby flartius » Tue Aug 14, 2018 8:47 am

I'm with chiss, either the ECU isn't grounding the injectors to complete the circuit or you have a wiring issue. But again like chiss said, I would have a hard time thinking all six went out together, so I don't think it's bad injectors or a wiring issue.


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