NEEDING HELP: Bad ECU or motor harness
 

Just finished buttoning up my fresh fully rebuilt motor. It runs on the rear primary injector only, no NOID on front primary injector. so you can image how rough it runs running on one injector. voltage tested injector clips and i get .4v readings on both front and rear primary injectors(im sure thats the wrong readings)..I just know that if I unplug the front injector clip NOTHING happens and if i pull the rear injector clip, the engine dies out. just to keep in mind, my harness has normal wear and tear or a burnt, old, heated up.. the injector clips are good still but the wires on it are going..

upon countless harness and ground checking making sure everyhing is in the right spot, adding grounds etc, I use a friends Apexi PFC. This is where it gets weird... First start, Runs perfectly, no roughness, but only for 2 SECONDS, then dies out, and will not start again, only way to get it to start again is to unplug/replug the PFC entirely.. I've gone back and forth (for hours) between ECU's and checking that my grounds and sensors are correct.


My Question is. What should my next step be? should i replace, add, fix, my computer, or harness. I'm afraid if i replace the ECU the harness could fry it? both are very pricey, and I just became broke after this rebuild... I need to make sure my next step is correct.. :thumbsup:

mods:
fresh built, from pineapple racing sponsor 0miles
large street port
Block Off Plate Kit
single turbo w/ 3" straight through pipe 10psi
apexi PFC

Re: NEEDING HELP: Bad ECU or motor harness
 

any suggestions/direction???

Re: NEEDING HELP: Bad ECU or motor harness
 

With the PFC; starts, runs, then dies is usually a PFC ground problem.

If the engine still has the original engine harness that requires the jumper harness for the fan control black relay to work; you NEED to replace it!


Any FD with an original engine harness MUST have it replaced as it is crap!

Re: NEEDING HELP: Bad ECU or motor harness
 

It could be so many things but I tend to agree with blackturbo's ECU grounding statement. That said, its really hard to diagnose the problem with the information given. Out of curiosity where are you grounding your multimeter when you're checking for voltage at the injector?

Also, I'm not trying to turn this into a sales pitch but I believe we do have a slightly used (read ~6000 mile) engine harness around at the shop, if you're looking for one that wont give you any headaches and just plugs in let me know.

Re: NEEDING HELP: Bad ECU or motor harness
 

Check the main loom earth that bolts to top of rear rota that is main earth that gives trouble