LT1-LT4 Modifications 1993-97 Gen II Small Block V8

passenger side injectors not working??? help please?

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Old 03-30-2009, 05:47 PM
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Default passenger side injectors not working??? help please?

well a week ago i made a thread about and po300 code on my car got some great response and all seemed like ignition at the time. I changed all of the ignition parts on the list i was given still throughing the same engine light. So today i went with a screw driver to give the injectors a listen and all of my passenger side injectors make no sound and i beleive they are not fireing based on how the motor sounds thats the problem now. has anyone had that problem i ask cuz i am wondering if it the regulator, rail , or the the injectors them self or just a wireing issue. any information would be much appriciated thanks.
Old 03-30-2009, 05:53 PM
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There would be no doubt that it wasn't firing on 1/2 the motor, if it wasn't. She'd barely be running. Did you try disconnecting all the injectors on that side, one by one, listening for change?
Old 03-30-2009, 06:03 PM
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no i didnt try that yet im kinda scared to run it with this going on it runs like **** but not that bad thats why i dont understand wat is going on cuz i cant hear them tick at all compared to the drivers side and its open headers and i can hear it in the exhaust tone it sounds good on the drivers side but real bad on the pass almost knocking or lean sounding like spark knock
Old 03-30-2009, 06:11 PM
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Originally Posted by somlt1
no i didnt try that yet im kinda scared to run it with this going on it runs like **** but not that bad thats why i dont understand wat is going on cuz i cant hear them tick at all compared to the drivers side and its open headers and i can hear it in the exhaust tone it sounds good on the drivers side but real bad on the pass almost knocking or lean sounding like spark knock
Maybe an o2 sensor if the problem seems bank specific.
Try doing what was mention and disconnect one injector at a time. Idle should drop slightly with each injector unplugged.
Old 03-30-2009, 06:16 PM
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What year is this car? The car could run on four cylinders, I've seen it.

Are you certain it's one side, not every other one? Do a check with a noid light.

You have two fuses for the injectors. The injectors get full voltage all the time and the PCM applies a ground as needed. This allows the PCM to "see" 12 volts through the injectors and let's it constantly check them.

This might help: http://shbox.com/1/smfi_devices_injectors.jpg
Old 03-30-2009, 06:18 PM
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o2sensors are brand new to i bought those when i did my header two years ago but ive maybe put five hundred miles on it sinse then ill check it with that side dissconected
Old 03-30-2009, 06:20 PM
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Well if you have open headers, then it'd be easy to check! Put your hand down there on the side that's not 'firing'. If there's a substantial amount of heat (compare to the other side) then you know at least some cyl are firing. Otherwise that bank is essentially just an air pump and the air should only be warm from the whole engine and the compression of the air in the cyl. That header's collector should also be pretty wet with fuel. If you have a temperature gun, you could even measure the temp at the collector on each side and compare.
Old 03-30-2009, 06:23 PM
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Originally Posted by Formula350
If you have a temperature gun, you could even measure the temp at the collector on each side and compare.
I found that this actually works pretty well.
Old 03-30-2009, 07:32 PM
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Originally Posted by Paul Bell
What year is this car? The car could run on four cylinders, I've seen it.

Are you certain it's one side, not every other one? Do a check with a noid light.

You have two fuses for the injectors. The injectors get full voltage all the time and the PCM applies a ground as needed. This allows the PCM to "see" 12 volts through the injectors and let's it constantly check them.

This might help: http://shbox.com/1/smfi_devices_injectors.jpg
its a 97 and i tryed to look for two fuses and only found one im getting and noid light from my buddy later to chech the volts
Old 03-30-2009, 07:44 PM
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Originally Posted by somlt1
its a 97 and i tryed to look for two fuses and only found one im getting and noid light from my buddy later to chech the volts
Hey man, diggin your wheels. have bigger pictures?
Old 03-30-2009, 07:46 PM
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OK. I don't think the 97's injector harness's were much different. The noid light will flash to indicate it's getting power and the PCM is calling for injector pulse.
Old 03-30-2009, 07:48 PM
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Originally Posted by nik1703
Hey man, diggin your wheels. have bigger pictures?
i have a couple more pics in my garage the fronts look good they are pro stars the backs are only ok they are a off brand and not really the rite back spacing so im saving up to buy the maching prostars
Old 03-30-2009, 07:52 PM
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Originally Posted by Paul Bell
OK. I don't think the 97's injector harness's were much different. The noid light will flash to indicate it's getting power and the PCM is calling for injector pulse.
so if the pulse isnt supplyed by a working injector the pcm will set the po300. ill give it a check tomarow with the light and see if there is power supplied. the other thing you said is that there are two fuses for the injectors i only found one injector fuse in the engine compartment fuse block
Old 03-30-2009, 07:58 PM
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Originally Posted by somlt1
so if the pulse isnt supplyed by a working injector the pcm will set the po300. ill give it a check tomarow with the light and see if there is power supplied. the other thing you said is that there are two fuses for the injectors i only found one injector fuse in the engine compartment fuse block
is there a fuse that i missed?
Old 03-31-2009, 01:38 AM
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In the fuse block under the hood is the injector fuse(s). After trying to look at a '97 owners manual downloaded from shoebox, I'm thinking there's only one fuse. If after testing with the noid light it's still no good, I'd re-plug the connectors at the PCM. You could probe each injector plug to confirm each one is getting full 12V.
Old 03-31-2009, 04:44 PM
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Originally Posted by Paul Bell
In the fuse block under the hood is the injector fuse(s). After trying to look at a '97 owners manual downloaded from shoebox, I'm thinking there's only one fuse. If after testing with the noid light it's still no good, I'd re-plug the connectors at the PCM. You could probe each injector plug to confirm each one is getting full 12V.
yeah i agree and i will be testing it with my freind thats a chevy tech he thinks it the pcm because its bank specific so i will probably be calling pcm for less in the near future for a new one it sucks cuz i just got it tuned by speed inc a year or so ago. but we will see wat the noid testers says thank you all for all your help



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