PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

No injector pulse

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Old Mar 10, 2018 | 08:35 PM
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Default No injector pulse

I have a 94 s10 that i put a 03 5.3 engine in with the 94 4l60e trans. The computer is a 0411 (red/blue) that was flashed to disable VATS and a base guess tune for the performance parts on the engine (cam,Heads ect.). The wirring harness is made from the harness that came with the engine. I pulled it all apart took out what was not needed and fit it to my truck. Now as it stands I currantly have no o2 sensors plugged in , no coolant temp sensor, and none of the coils are plugged in at the moment. Every other sensor is new and plugged in. Now ive been through this harness a millon times making sure everything is correct. I have grounds I have ignition wires and hot all the time wires in correct spots no problems. Out of curiosity I tried to see if I was getting injector pulse and cranked the engine. however im not. Am I jumping the gun not having whats missing hooked up? or should I get one even with out those missing items. Its got readings for all the sensors I do have ( intake temp, thorttle % , RPM when cranking). Now I do not have anything for the pcms blue connector pin 34 to let it know I am in park but my understanding the computer does not need that one to run as it uses the signals from the pressure switches in the trans, and yes I do have a brake
switch signal done correctly with a relay. Any thoughts?
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Old Mar 11, 2018 | 12:03 AM
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I believe the injectors and the coils share ignition feeds, so it's possible that because you don't have the coils plugged in you haven't completed the circuit for the injectors. Just guessing...
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Old Mar 11, 2018 | 12:46 PM
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the injectors and coils have seperate voltage feeds and both are getting voltage key on and cranking. thanks for trying though. ok so i now have the upper o2s plugged in the coils plugged in and the coolant temp. So as of now everything to run is plugged in and my small scanner shows Intake temp, coolant temp, map reading, throttle % and RPM signal when cranking (about 120 rpm) still no pulse using a noid light plugged into injector plug. The computer has good grounds, ignition voltage key on and cranking and constant battery voltage where needed. the brake switch is holding voltage to pin 33 on blue connector once brake is pressed voltage goes to 0. the one thing im stuck on is what to do with the park signal on blue connector pin 34 i currantly have nothing on it as my understanding the computer uses the pressure switches in the trans to find the gear selected. is this true or should i have a ground input to this pin? i have only my little scanner today so i cant see anything more then basic data steam information. any thoughts on this park signal?

Last edited by bridawg; Mar 11, 2018 at 01:00 PM.
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Old Mar 15, 2018 | 02:00 PM
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do you have the file?

is it possible someone forgot to populate the VE table? does the fuel pump prime at initial key on and does it have spark? screw driver in end of lead against an earth? or clear lead adapter if you're fancy.
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Old Mar 15, 2018 | 02:31 PM
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Get a coolant temp sensor. Probably 40% of the fields/tables in the factory PCM rely on coolant temps. Some of the PCMs won't do anything without one.
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Old Mar 15, 2018 | 02:35 PM
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Maybe a stupid question, but doesn;t the ECU switch on the grounding side, not the voltage side? If so, would you see anything with a noid?

Edit - nevermind I just thought it through. In the tune, check for your prime pulse masses being zeroed out? I've seen that in tunes before
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Old Mar 15, 2018 | 10:15 PM
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Injectors fire off the cam sensor signal. Make sure its plugged in behind intake. Also the grounds at the rear of the intake.
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