Question no start after major repairs.. ECM?

[toomanyfbodies]

i"m just completing building one car out of two. one was a bare shell and the other was a wrecked 97 z28. i've swapped every nut,bolt, and bracket. i'm at the point where the car should run however..... it cranks and has spark but not getting fuel. i jumped the relay on the pump and it will work but still no start. when i was doing the tear down i set off an alarmthat i didn't know it had and i unhooked the battery. didn't think anything of it. not sure if this has anything to do with it. the security light comes on and goes out briefly when the key is turned to run but i think thats normal?? however the service engine light never comes on at all. i plugged in the scan tool and it wont read anything..just says check connection. the wiring harness is all plug and play... 2 grounds under the dash (rechecked) 3 grounds under the hood (rechecked). any ideas?? how to test ECM? alarm reset??

[BLACK HAWK]

did you check the fuel pressure at the manifold? might be a bad fuel pump or the pick up hose disconnected in the tank.

[toomanyfbodies]

the pump doesn't even run unless i jump the relay... the car ran fine 3 weeks ago.

[BLACK HAWK]

well there you go, get that fixed

[steveo]

what year is the car you swapped all the stuff into? it's a '97 engine and harness? tell us more details. this is electrical we're talking about here, and if there are different years of cars involved, there might be some stuff you have to do

if it cranks, and it has spark, that means the opti should be working well enough, so.. it could be injector power, have you checked for constant injector power on the pink wires?.. or it could be the injector enable signal from the vats module is missing

if the VATS system isnt working properly, and you've bypassed the starter portion of it, you'll still get no fuel. pretty common thing in engine swaps. i wouldn't trust the security light..

a dead ecm is really rare. i ran into one on my car, but it was because of really shoddy wiring by the previous owner. mine still ran but wouldn't connect to the scanner...

[toomanyfbodies]

i bought a wrecked 97 z28 (hit hard in the back) and it ran drove fine. i then found a bare shell... i bought it with only a windshield and a couple clip nuts in the dash. BARE!! i then transfered EVERYTHING to the new shell. harness is complete and uncut and the motor and trans and suspension were transfered as one piece. the wreck had 30,000 EASY miles and all original and uncut. i did set off the alarm when i took it apart. now everything is back together and it cranks but doesn't start. will fire with a spray of gas in the intake so it has spark. the fuel pump does not run so i jumped a wire to "make" the pump run...still the car doesn't start so the injectors must not be getting pulse. i haven't tried to bypass the vats. from what i've read and seen in other cars that keeps the car from cranking which it does fine. i should also mention the dome lights dont shut off which brings me back to thinking the alarm but shouldn't a scan tool still read it? as well as the service engine light should still work??

[ddpowers22]

I had this issue (kinda) when I changed out my whole steering column. Crank and no start, then I figured out that the column I put in had a different key with a different chip in the key, which caused a security issue. All I did was bypass the security (VATS?) by putting in a resistor equal to the resistance measured from my old key chip. If you do some searching on here on how to bypass the security youll see what im talking about. Otherwise I can snap some pics when I get my car out of the shop.

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[steveo]

first thing is to check for +12 constant power on the pink wires to the injectors, key on, but not cranking

[toomanyfbodies]

pink wire has a constant 12.6 volts

[cocobolo95]

Pink injector wires will have power anytime key is on. You need to check the ground wires of the injectors. So use either a noid light or a 2 lead test light. One side to inj + and the other lead to inj -. Have assistant crank the engine. See if light blinks on and off while cranking. If yes, injector is opening. If no, injector is not opening.

Besides vats, there are silent codes that do not light the ses. opti low resolution pulse missing and 2 icm codes are major players. This is because,when set, these codes disable the fuel injectors and opti code also disables the fuel pump.

[toomanyfbodies]

no light flashing.... injectors are not opening...have power but no pulse ground.

[cocobolo95]

So the most likely suspects are either vats keeping the injectors from opening, or one of the silent codes is set keeping injectors from opening.

But, then you have things like bad pcm grounds or connectors that are bad or poorly connected that can affect injector ground from pcm. Since you had everything apart, I would check to make sure everything in the engine and pcm wire harness is in order also.

[toomanyfbodies]

yes...the injectors aren't opening, the fuel pump isn't cycling and the interior lights are on. makes me think it's in shutdown from the alarm but i've never seen one that the scan tool wouldn't read or even light the service engine light. so whats the secret to reset the alarm? i've been told use the keyless entry but that didn't do it. also been told to leave the key in the run posistion for 15 minutes and that wasn't it either. grounds and connections are all clean and good. does the vats control interior lights? fuel pump? injectors? everyone tells me that is wont even crank if thats my problem but it does

[steveo]

dont focus on the alarm too much, unless it's an aftermarket alarm, i doubt that's your issue

vats does two things; prevents cranking, and disables injectors. well, actually that's wrong. it doesnt disable the injectors, it ENABLES them with a pulse to the ecm if the resistor pellet matches.

it's common to bypass the disable for the starter, though, it may already be done and you dont know about it.

your '97 is a bit different than most, it has a body control module with most of the vats crap built in. earlier models had a seperate starter enable relay, yours doesn't.. it's in the BCM afaik

[steveo]

stupid question, are you sure the ECM plugs are in the right place, and all the interior plugs are tight? it is weird to not have fuel pump AND injectors. nothing involved with any aspect of the security system would disable the fuel pump prime.