High Comp B16 won't fire.....
06-15-2009, 11:39 AM
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Re: High Comp B16 won't fire.....
Likely, the clips are where they should be, unless he removed all traces of wire wrap, as the length is usually a good indicator of which clip belongs to which injector, albeit, it's still possible of course that they're not hooked up correctly, I just doubt it really.
Where the "fun" could have come into play, is the injector resistor box, this is where (if any) injector misordering has come into play. It may be incorrectly wired as to create a misorder of sorts.
Though, yes, running the stock high impedence injectors with the resistor box could damage your injector drivers ("these" are found in the ECU itself not the injectors) due to incorrect impedence, despite the more likely case is that the injector simply wont open.
Did Shawn assemble the head and longblock? If so, then I'm no longer concerned about the build at all.
Pull the rail/injector assembly out from the intake manifold, pull the ignition wires and see if they are injecting fuel.
Where the "fun" could have come into play, is the injector resistor box, this is where (if any) injector misordering has come into play. It may be incorrectly wired as to create a misorder of sorts.
Though, yes, running the stock high impedence injectors with the resistor box could damage your injector drivers ("these" are found in the ECU itself not the injectors) due to incorrect impedence, despite the more likely case is that the injector simply wont open.
Did Shawn assemble the head and longblock? If so, then I'm no longer concerned about the build at all.
Pull the rail/injector assembly out from the intake manifold, pull the ignition wires and see if they are injecting fuel.
As for misordering the clips themselves, its definately not an issue. I KNOW I have the clips in the proper order however. Thank you though.
What is a "noid light"? Are you checking that you have a pulse (switching to ground while active) on the ECU side, and are you checking that you have constant 12V power to all the injectors on their input side..?
That's exactly backwards. Injector drivers are only damaged by overcurrent or overvoltage, and the overvoltage is not a factor here (and is very well protected against usually). Adding more resistance (with a resistor box) in series with high impedance injectors only lowers the injector current even more, so there is even less chance of damaging the injector drivers.
If the injector drivers are damaged, they didn't get that way while using high impedance injectors in any configuration unless there was a wiring error.
That's exactly backwards. Injector drivers are only damaged by overcurrent or overvoltage, and the overvoltage is not a factor here (and is very well protected against usually). Adding more resistance (with a resistor box) in series with high impedance injectors only lowers the injector current even more, so there is even less chance of damaging the injector drivers.
If the injector drivers are damaged, they didn't get that way while using high impedance injectors in any configuration unless there was a wiring error.
06-15-2009, 12:21 PM
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Re: High Comp B16 won't fire.....
Those test lights are crap by the way, and are almost worthless as a troubleshooting tool. Use a multimeter so you can actually get useful information that can help you.
You you aren't actually sure whether the ECU is turning the injectors on I assume. All four injectors get power all the time, and the ECU completes the circuit to ground to turn on the injector. So if you're just looking for 12V at the injectors, all you know is that they are getting power; you don't know if they are getting turned on by the ECU or not.
It's possible you have a problem with the OBD0-OBD1 harness or have the wrong harness. I think there are a few OBD0 connector pinouts if I remember correctly, but I'm assuming you know enough about your car to get the correct one so I don't think that would be a problem.
You you aren't actually sure whether the ECU is turning the injectors on I assume. All four injectors get power all the time, and the ECU completes the circuit to ground to turn on the injector. So if you're just looking for 12V at the injectors, all you know is that they are getting power; you don't know if they are getting turned on by the ECU or not.
It's possible you have a problem with the OBD0-OBD1 harness or have the wrong harness. I think there are a few OBD0 connector pinouts if I remember correctly, but I'm assuming you know enough about your car to get the correct one so I don't think that would be a problem.
06-15-2009, 12:48 PM
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Re: High Comp B16 won't fire.....
yes there are 2 different non obd pinouts, i ran into this problem doing my mpfi swap when i was installing my ls motor into me ef sedan, i guess i had like the shit magnet of that years wiring which was alot rarer than the others and had to research for about 20 minutes to find my correct wiring info. it was only a few wires different, but it stopped the car from starting.
But just looking at the big picture right now, coule there possibly be a timing issue since you had to pull the head and such, i would go ahead and double check to make sure everything is good.
But just looking at the big picture right now, coule there possibly be a timing issue since you had to pull the head and such, i would go ahead and double check to make sure everything is good.
06-15-2009, 01:01 PM
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Re: High Comp B16 won't fire.....
Those test lights are crap by the way, and are almost worthless as a troubleshooting tool. Use a multimeter so you can actually get useful information that can help you.
You you aren't actually sure whether the ECU is turning the injectors on I assume. All four injectors get power all the time, and the ECU completes the circuit to ground to turn on the injector. So if you're just looking for 12V at the injectors, all you know is that they are getting power; you don't know if they are getting turned on by the ECU or not.
It's possible you have a problem with the OBD0-OBD1 harness or have the wrong harness. I think there are a few OBD0 connector pinouts if I remember correctly, but I'm assuming you know enough about your car to get the correct one so I don't think that would be a problem.
You you aren't actually sure whether the ECU is turning the injectors on I assume. All four injectors get power all the time, and the ECU completes the circuit to ground to turn on the injector. So if you're just looking for 12V at the injectors, all you know is that they are getting power; you don't know if they are getting turned on by the ECU or not.
It's possible you have a problem with the OBD0-OBD1 harness or have the wrong harness. I think there are a few OBD0 connector pinouts if I remember correctly, but I'm assuming you know enough about your car to get the correct one so I don't think that would be a problem.
And if those things really are crap, guess it's time to retire it and pull out the multi-meter. Is there any particular impedence or voltage I should be checking when determining whether the ECU has turned them on or not? And if the measurement at the injector clip is merely that of 12 volts(indicating that the current is closed as you said), how do I read the problem? Sorry if these questions seem dumb, but there are definately some areas when it comes to doing this, that I could be better
yes there are 2 different non obd pinouts, i ran into this problem doing my mpfi swap when i was installing my ls motor into me ef sedan, i guess i had like the shit magnet of that years wiring which was alot rarer than the others and had to research for about 20 minutes to find my correct wiring info. it was only a few wires different, but it stopped the car from starting.
But just looking at the big picture right now, coule there possibly be a timing issue since you had to pull the head and such, i would go ahead and double check to make sure everything is good.
But just looking at the big picture right now, coule there possibly be a timing issue since you had to pull the head and such, i would go ahead and double check to make sure everything is good.
Thanks again.
06-15-2009, 01:58 PM
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Re: High Comp B16 won't fire.....
So one side of the injector will have constant 12V power, and one will be switched to ground by the ECU. So when the injector is turned on, one side will have power and one side will be grounded through the ECU. If you look at this with a multimeter, say between the ECU side of the injector and ground, you will see a changing voltage reading somewhere between ground and 12V. It will basically be a square wave on the ECU side, but the multimeter will average it out to some voltage reading because it can't actually display a square wave. This is when the engine is cranking/running obviously.
06-15-2009, 04:55 PM
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Re: High Comp B16 won't fire.....
That's exactly backwards. Injector drivers are only damaged by overcurrent or overvoltage, and the overvoltage is not a factor here (and is very well protected against usually). Adding more resistance (with a resistor box) in series with high impedance injectors only lowers the injector current even more, so there is even less chance of damaging the injector drivers.
If the injector drivers are damaged, they didn't get that way while using high impedance injectors in any configuration unless there was a wiring error.
If the injector drivers are damaged, they didn't get that way while using high impedance injectors in any configuration unless there was a wiring error.
Rt = R1 + R2 + etc.
I (current) = E (or V, Voltage) / R (Rt in this case)
Ah well, serves me right for multitasking this subject at the time of discussing SWR's/Reflected power on another forum, where regardless of higher or lower impedence, any deviation from expected impedence would damage the circuit. But, injectors aren't RF driven so beside the point. Sorry about that, I screwed up on this topic.
Square waves Fabrik, come on now.. peeps would need to pull their trusty oscilloscopes. Next up, spectrum analyzers.
Would still check to ensure the wiring of the box was correct, as it seems things haven't worked since the box was placed in-line/series.
06-15-2009, 05:30 PM
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Re: High Comp B16 won't fire.....
it was an 89 dx sedan, i dont know what was up with it, if it was made earlier in the model year or later, but all the info that i found on a regular search for mpfi swap wasnt adding up cause my wires were in different spots and the pinout was different, after finding that it was different, i just looked up the pinouts on the ecu i was using and correlated it with the wires ran from the engine bay and it worked, just had to depin and repin wires, that werent the same as the majority of peoples depin and move. it was just weird.
06-15-2009, 08:00 PM
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Re: High Comp B16 won't fire.....
You don't need fancy test equipment, you just need a multimeter and a basic understanding of what you're seeing. If you want to know if the injectors are firing, you don't care about the waveform, only that they're firing and should give some slightly changing voltage that is less than the supply voltage. I'm just trying to make people understand why they're seeing what they see.
I can tell you exactly what you should do and what you should see, but that doesn't do anything to help understand why you should do that and why you should see that. You haven't increased your understanding at all unless you know why.
Last edited by Fabrik8; 06-15-2009 at 08:04 PM.
06-16-2009, 04:33 AM
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Re: High Comp B16 won't fire.....
That's why I was saying the multimeter would average (the square wave) out to be a voltage somewhere between 0 and 12V. It doesn't really matter what it is, you're just looking for a voltage that is more than zero and less than whatever voltage is feeding the injectors.
You don't need fancy test equipment, you just need a multimeter and a basic understanding of what you're seeing. If you want to know if the injectors are firing, you don't care about the waveform, only that they're firing and should give some slightly changing voltage that is less than the supply voltage. I'm just trying to make people understand why they're seeing what they see.
I can tell you exactly what you should do and what you should see, but that doesn't do anything to help understand why you should do that and why you should see that. You haven't increased your understanding at all unless you know why.
You don't need fancy test equipment, you just need a multimeter and a basic understanding of what you're seeing. If you want to know if the injectors are firing, you don't care about the waveform, only that they're firing and should give some slightly changing voltage that is less than the supply voltage. I'm just trying to make people understand why they're seeing what they see.
I can tell you exactly what you should do and what you should see, but that doesn't do anything to help understand why you should do that and why you should see that. You haven't increased your understanding at all unless you know why.
Any other off-the-wall, awkward possible causes though? I just dont get why the fuel system worked on the way over there, and now, won't lol
EDIT: I must spread some reputation around.
Either way, I'm going to try and whip out the old multi-meter tonight and see what kind of readings I can get. Thanks again everyone.
Last edited by Subie2Honda; 06-16-2009 at 04:39 AM.