first things first i need to tell a story...
i bought my first cav...97 z24 5spd, it came with 270CC RC engineering injectors already installed on the car.

i never not once had any difficulty with the injectors...i never ran boost or n2o..the car ran just fine n/a w/ the injectors, put down 151.4hp with a few mods.

ive since bought a 98 z24 auto...it had a blown motor when purchased, i built a new engine...put it in, and since my 5spd car has been lets just say "sitting" so i decided to use the injectors off it....

i took the stock fuel rail/lines off the 98 auto car to polish them...i took the FPR off and painted/polished it...i then put the rc injectors in the rail and wired them up

tonight i put the rail/lines/fpr/injectors all together and bolted it up..it was DONE.

now comes the totally F'D up part....when i plugged my injector harness into the main wiring loom the injectors kicked on and started spraying fricken gas into the cylinders...before i realized wtf was going on the intake mani. was full of gas and so was the #3 cylinder (and when i say full i mean FULL) *******AND...some weird crap....i already had the fuel pump fuse removed from the under-hood fuse box...AND the f/p-injec. fuse out of the dash fuse panel...and some how it still sprayed gas.

my ? is...how could this even happen-why are the injectors spraying fuel out LET ALONE spraying with all fuel fuses REMOVED-and i mean this is ALL 4 of them spraying like no tommarrow...FULL BORE PRESSURE.

did i wire something wrong? i am pretty positive i wired the starter and battery and alternator wires correctly.

is the FPR messed up...when i took it all apart did i mess some sort of adjustment up?

tommarrow im going to disc. the rail/lines/injectors and use a stock rail etc off a different car and see if maybe the FPR is whats not working correctly.

thanks for a help in advance!!!

My guess would be the 97 injectors are low impedance, and the 98 are high impedance or the other way around. One of the two is saturated, while the other is peak/hold. When you put the 97 injectors into the 98 the problem your having is that the signal going to them is wrong at the PCM side. If you swap pcm's it should work ok.

Just currious, i thought the injectors on the 97 were bottom feed with the ones on the 98 top feed? Am i mistaken here?

mid 99+ are high impedence. the 96-mid 99 were low impedence.

If he would have had high and low impedence injectors, the Rc injectors wouldn't fit.



Gilles
2.3 Ho

wow that really makes no sense whatsoever. I really have no idea, how there could be any kind of pressure going with the car off in a dry rail? the onlything I can think of is that some how your pump is staying on, and your accidently grounding out your injectors, that would explain them cliping.

I really dont know.


"boobs now with Riboflabin"

well i know for a fact that the pump isnt on...you'd be able to hear it running (you know that hummm from down below lol) so yeah the pump isnt whats doing it

we all thought it was just the system filling the rail and getting ready to go....but why the darn heck would the injectors open up? i mean if u had the car all ready to go etc and then tried starting it...youd fricken have one HELL of an explosion...i mean ID pry die!!!!

we cant be dieing over here lol...
so yeah, im still gonna try the stock stuff and see



Black 97' Z24
Blacked Out and Lovin' It...
"Z Yaaaa"

the pump has to be on in order to get that much fuel into the intake and motor


and since you just instaled the injectors there shouldnt have been any pressure in the system

welp...
tried a different rail/injectors/FPR all together, still did the same damn thing.

we un-hooked the fuel line that goes directly into the fuel rail...put the battery terminal on...and she squirted all over.

my dad and i are convinced that some how the fuel pump is on all the time, and so are the injectors...
but WTF? the fuel pump fuse is OUT the f/p-inj. fuse is OUT

HOW CAN THE PUMP BE RUNNING?!

I read the entire fuel injection section in the Haynes manual-not a damn bit of good that did, no info. pertaining to this sort of situation

i have the GM starter relay re-call installed on my car...could this have ANYTHING to do with the problems im having?




Black 97' Z24
Blacked Out and Lovin' It...
"Z Yaaaa"

Did the car run ok before you swapped injectors? That would eliminate shorted circuits.

My guess is that either the pcm or something is commanding the fuelpump to run, but without a fuse im not sure how that is possible.

If i had the car in front of me i could help you figure it out. Are you sure it's gas from the injectors and not water. My guess would be to eliminate the fuses one by one, until the pump stops pumping, maybe its mislabeled.

well...i have no idea if the car ran, i never saw it run MYSELF...i heard that it ran fine before the previous owner blew the engine up.

yes-im 100% sure its gas...i tapped 4 pop bottles to the injectors to make sure that the gas no longer goes into the cylinders etc.

i'll try the taking all the fuses out theory.



Black 97' Z24
Blacked Out and Lovin' It...
"Z Yaaaa"

there has to be a wire shorted to power for the fuel pump


or the fuel pump relay is stuck on


or the pcm is constantly giving the signal to the fuel pump relay , and if there is a pcm or short to power of some kind it might also becausing the injectors to get signaled on

just start by unplugging the plug at the back of the car. Its under the rear seat area (under the car)..... that will cut all power to the fuel pump.

Then figure out what happened to the original engine....... could be possible this is how it went.......

is the key on or off? make sure its key off to start.


To me, sounds like a ECM problem....... and maybe you pulled the wrong relay?





SPD RCR Z - '02 Z24 420whp
SLO GOAT - '04 GTO 305whp
W41 BOI - '78 Buick Opel Isuzu W41 Swap

ok...well i really dont need to try and unplugg the fuel pump because obviously its gonna keep it from powering up as it doesnt have any. i just dont see a reason to do that cuz i know it wont have power for sure.

tonight i found something that i was very damn sure was the problem...there is a wiring harness...that comes out of the back of the fuse box in the engine bay..runs down the fender well and into the main harness (located right beneath the air box) i looked around at it and noticed (2) PINK severed wires. it looked as though the air box was rubbing on the harness or something cuz there was a big red wire with some of the plastic (a tiny portion) wire covering was torn off...i tapped that up real well and re-connected both of the small pink wires.

it did nothing...i was for sure this was the frickn problem when i saw those severed wires...but i even tried hooking together the pink wires opposite of the way i already had, AND hooking them together...not 1 of the 3 ways worked-the injectors still sprayed.

as for the relay...(if its even a relay? i thought it was just a fuse) i pulled the one under the hood that says "fuel pump" on the cover. and the "f/p-inj." fuse out of the dash fuse box.

the key was OUT of the car...all i gotta do is touch the terminal to the battery with the injectors plugged in and SPRAY.

god i am so frustrated right now idk what to do, tommarrow im calling my local GM dealership and asking for a mechanic. hopefully they can tell me whats up.

thanks for everyone's help already, i really appreciate it



Black 97' Z24
Blacked Out and Lovin' It...
"Z Yaaaa"

This could be how the other engine went, but calm down and take a deep breath.

Unplug the battery, unplug the pcm. Do you still get spray?

Next, start eliminating sensors out of the loop if you dont get spray with the pcm plugged in. I had a similar issue except it was a quad driver module error. Turns out my cruise control module shorted, and triggered everything on the qdm it was on. I'm thinking something on the injector circuit is triggering voltage across the injector wires to be constantly on.

But it does sound as though the fuel pump is still getting fuel and pumping, it may not be loud but its pumping. Also your injectors are open, which suggusts to me that theres something triggering it. PCM's usually ground an injector to complete the circuit, so thats why i suggust you check your pcm grounds also. If you remove the connectors from the pcm, and touch battery to power and still have spray then something is grounding out.

*SOLVED*

ok...im a MORON...i started thinking long and hard...my ignorance had gotten the better of me when i was saying "ohh i hooked the starter up right for sure!"

WRONG-i had one of the wiring connectors (one with 4 tiny wires on one ring) hooked up to the positive terminal on the starter....i took it off and put it on a ground-WAM FIXED!!!!

i guess it was the fuel pump grounding unit..what a fricken moron i am.

sorry to inconvience anyone on here for my stupidity.

thanks for everyone's help though!



Black 97' Z24
Blacked Out and Lovin' It...
"Z Yaaaa"

also be careful with all that fuel and playing with the battery one lil spark and we will need another memorial.

glad you got it figured out