Starting issue no spark no fuel
Starting issue no spark no fuel Okay guys I am getting no spark and no fuel. The rails do have pressure just not spraying fuel. I have checked the ground and power to the pcm with a test light and they do have power and ground. is there anything in particular I need to look for or check out? I did the harness btw. i scanned the pcm and the map works the tps works and thermostate and iac works according to the scanner. what do I look for now besides pulling the whole harness out. any advice would be great. thanks for any advice or comments.
srun
srun
Originally Posted by kairles
as k5tpi asked in your other thread have you removed VATS, also is the ECM getting an RPM signel?
Launching!
Joined: Oct 2004
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The crank angle sensor will do that to you. It is a reluctor type sensor. If you have a multimeter put it on ac voltage auto range and you should see a voltage when you crank the engine. Sorry, have no idea what the voltage should be but I would think it would be at least one volt. Might compare the voltage output with something like the vss output from the tranny.
Last edited by RFERG43; Apr 25, 2006 at 09:05 AM.
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Originally Posted by AceHaag
what is your pcm out of year and model? it may help in figuring out your problem.
the pcm is a 99 and the harness is out of a camero of the same year
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First thing I would do is solve the fuel problem. Sounds like you have things wired way wrong or something. Fuel pump should at least prime when you cycle the key. I'd try to jumper across the fuel pump relay and see what happens.
Originally Posted by kossuth
First thing I would do is solve the fuel problem. Sounds like you have things wired way wrong or something. Fuel pump should at least prime when you cycle the key. I'd try to jumper across the fuel pump relay and see what happens.
the pcm doesn't control the fuel pumps in my car. also the wiring is mostley the same as when i got it out of the other car. does anyone have diragram for the fuel injector connector and whats suppose to be hot also the coil packs. i'll go over the wiring again tonight. I'm sure the crank and cam sensor are working now. I see rpm when i bump the starter.
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From: Detroit, MI - Camp Pendleton, CA
The PCM should always activate the fuel pump. It is a 12v feed to the fuel pump relay, which will prime for 2 seconds and then shut off. Then when cranking it will reactivate. So you should have:
1) 2 power feeds, 1 switched off the PCM
That switched should power the coil to close the relay.
2)1 constant ground on the other side of the coil (control circuit)
4)power feed to the pump when the relay is closed.
On my car, the old setup was a ground to close the relay. I had to cut it and constant ground it then cut the control circuit power feed that was activated by the PCM.
Once you have fuel pressure I would then worry about the other problems. Jump 12v to the relay to see of the pump kicks, if not then your other relay wiring is wrong. If it does activate however then your PCM isn't outputting the 12v power feed to the relay and you either have a bad power feed (probably constant 12v orange wire) or a bad ground.
Look on your scanner again and see you have a RPM signal on the scanner. Yes the PCM does output a tach signal, but that is after the PCM converts it from the input the crank signal give the PCM. If you have no crank signal input from the sensor then your PCM will not fire the coils or the injectors. Vats also disables the injector pulse width after 2 seconds when it does not recongnize a passlock key input from the BCM. Figure out fuel then let us know. -Alex
1) 2 power feeds, 1 switched off the PCM
That switched should power the coil to close the relay.
2)1 constant ground on the other side of the coil (control circuit)
4)power feed to the pump when the relay is closed.
On my car, the old setup was a ground to close the relay. I had to cut it and constant ground it then cut the control circuit power feed that was activated by the PCM.
Once you have fuel pressure I would then worry about the other problems. Jump 12v to the relay to see of the pump kicks, if not then your other relay wiring is wrong. If it does activate however then your PCM isn't outputting the 12v power feed to the relay and you either have a bad power feed (probably constant 12v orange wire) or a bad ground.
Look on your scanner again and see you have a RPM signal on the scanner. Yes the PCM does output a tach signal, but that is after the PCM converts it from the input the crank signal give the PCM. If you have no crank signal input from the sensor then your PCM will not fire the coils or the injectors. Vats also disables the injector pulse width after 2 seconds when it does not recongnize a passlock key input from the BCM. Figure out fuel then let us know. -Alex
first thing i would do would be open the HPtuners scanner, and turn the key on.
assuming i connect with the scanner, i would then watch the "RPM" gauge in the scanner and crank the engine.
if the crank sensor is on right, working, then you should see some RPM..... if it doesnt, the PCM does not realize the motor is turning, it does not fire spark and it does not fire the injectors.
also, the injectors and coils are powered off of two fuses, one for each bank.. check thoes.
thoes two things would be where id start.
assuming i connect with the scanner, i would then watch the "RPM" gauge in the scanner and crank the engine.
if the crank sensor is on right, working, then you should see some RPM..... if it doesnt, the PCM does not realize the motor is turning, it does not fire spark and it does not fire the injectors.
also, the injectors and coils are powered off of two fuses, one for each bank.. check thoes.
thoes two things would be where id start.
Ok, the PCM supplies a ground signal to both the coil packs and the injectors for "fire" them off. Like we said though get your fuel pump figured out. That is a must. It doesn't matter what you are using for your pump. As for what injector wires do what do you have a wiring diagram? If not go here www.alldatadiy.com and sign up. You can get pretty much the entire factory diagram online. Anyways, your pink wires on both the coil pack and injectors is a switched hot wire. This wire must be hot not only when the key is on but when the starter is cranking too. Make sure it it hot when cranking. I've seen people make that mistake before and wonder why it won't start. Any wire for the fuel injectors that has a black tracer (IE stripe) on it then that is the ground signal coming from the PCM. Hope this helps some
I don't get it. Does the ECM have to power the fuel pump? Will the ECM not powering the fuel pump make it not pulse the injectors?
sounds like the ECM doesn't know the motor is running/cranking. he has pressure at the rails just the injectors aren't firing.
sounds like the ECM doesn't know the motor is running/cranking. he has pressure at the rails just the injectors aren't firing.
Originally Posted by kairles
I don't get it. Does the ECM have to power the fuel pump? Will the ECM not powering the fuel pump make it not pulse the injectors?
sounds like the ECM doesn't know the motor is running/cranking. he has pressure at the rails just the injectors aren't firing.
sounds like the ECM doesn't know the motor is running/cranking. he has pressure at the rails just the injectors aren't firing.
Originally Posted by red90cobra
this is what i was trying to figure out also but everyone say i need to hook the pump up to the pcm. also i do get rpm when cranking. i do not get power to the injector connectors, i am going to check on that one. thanks for the help. the reason for the pcm not controlling the pcm is I have a auto rod 7 switch panel mounted on the cage. i figured i did not need to hook up the pump to the pcm. will it not run without it.
Joined: Sep 2004
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From: Downers Grove, IL
Originally Posted by red90cobra
i figured i did not need to hook up the pump to the pcm. will it not run without it.
i think i might of gotten it down it cranked for a whoppin 5 seconds and died. and when i went to restart the battery was low. I'm gonna put the battery on the charger we'll see what happens tomarrow. thanks for everyones help.
