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fail safe for no injector pulse?

Kenny_Kline

Well-known member
Joined
Dec 27, 2007
Messages
789
Location
Seekonk, MA
Is there a fail safe that would prevent the ECU from providing injector pulse? If not, it may look like I have a bad ECU (injector driver in ECU) but its unlikely considering the ECU just came back from ECMlink today.

Just a quick recap: I get spark (1&4 fire together and 2&3 fire together) so clearly the CAS is working but I tested it anyways and I get power, ground, and 2 5v references output to the ECU and confirmed the signals input into the ECU at the ECU plug so wiring is good. I tested ground pulse at ECU side and ECU is not putting out ground pulse for any injectors. Its either a bad ECU or something is telling the ECU to not pulse the ground but I have no idea what that could be. TPS is working correctly, fuel pump activates correctly, MPI relay tests good.
 

tektic

Well-known member
Joined
Dec 19, 2012
Messages
1,497
Location
ronkonkoma, ny
As far as I know the only thing that could cut fuel while you spark working is the upper airflow threshold.

I had the fuel cut parameter set to 00 instead of FF So as soon as it came out of cranking it would die because it hit fuel cut as soon as airflow was over 00. That's the only thing I can think of.

You should test the injector pin out of the ecu if you didn't already do so, to rule out bad wiring.

So if everything is stock you may have a bad maf. In theory it could be reading above the air threshold.
 

Kenny_Kline

Well-known member
Joined
Dec 27, 2007
Messages
789
Location
Seekonk, MA
I did test the ECU injector wires at the ECU plug side and no pulse. I also checked the input of crank and cam signals at the ECU side and it's getting the signal so I ruled out wiring.

I'm on SD. Omni 4bar and GM IAT. At this point I'm turning the crank by hand unbolted to test now. I'm on a new build and although motor primed, I'm not trying to crank over anymore than I have until I confirm injector pulse from ECU.
 

tektic

Well-known member
Joined
Dec 19, 2012
Messages
1,497
Location
ronkonkoma, ny
I think it's a software problem. Check your fuel cut settings. If the map sensor is calibrated correctly... ect.
 

presterone

Well-known member
Joined
Jan 23, 2012
Messages
514
Location
brunswick maine
CEL come one with key on engine off? This just happened to me recently everything checked out except injector ground pulse
 
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