Honda / Acura K20a K24a Engine Forum banner

1 - 20 of 59 Posts

·
Registered
Joined
·
33 Posts
Discussion Starter #1
Hi so I recently bought a stock ep3 and there is a code saying that there is a misfire in cylinder one. I checked for spark and that's all good. Compression is good. I check the fuel Injectors and cylinder 1 Injector was clogged and not working so I replaced it and I still have a misfire in cylinder one so I check to see if the fuel injectors were getting power and they were all getting power instead of the first one. I'm stuck here since I'm not sure how I should fix the issue. Would it be a relay or fuse or something else? If so wouldn't the other fuel injectors not work as well?

All help is appreciated, thank you for reading.
( First post sorry if it's posted in wrong area )
 

·
Arouse the DAMPFHAMMER!
Joined
·
6,265 Posts
...I replaced it and I still have a misfire in cylinder one so I check to see if the fuel injectors were getting power and they were all getting power instead of the first one. I'm stuck here since I'm not sure how I should fix the issue. Would it be a relay or fuse or something else? If so wouldn't the other fuel injectors not work as well?
Welcome to K20a.org TrippinSuzuki!

Do you have an Oscilloscope? If so I recommend you to measure the injector pulse. Sounds like wiring has an issue or even the driver of the injector. Alternatively, if you have a budy around with an K20A2, you can check the second by swapping the ECU's for testing. It would also condense the failure grid down to the wiring of the injector.
 

·
Registered
Joined
·
33 Posts
Discussion Starter #3
Welcome to K20a.org TrippinSuzuki!

Do you have an Oscilloscope? If so I recommend you to measure the injector pulse. Sounds like wiring has an issue or even the driver of the injector. Alternatively, if you have a budy around with an K20A2, you can check the second by swapping the ECU's for testing. It would also condense the failure grid down to the wiring of the injector.
I don't know any Honda guys in my area ( central New Jersey ). I have a feeling that the 2 wires one brown one yellow, that goes to the fuel injector is bad somewhere so I have been opening up the harness looking for where it has power and where it doesn't, I'll probably just run some new wires but I haven't found where there is power on those wires yet.
 

·
Registered
Joined
·
47 Posts
I don't know any Honda guys in my area ( central New Jersey ). I have a feeling that the 2 wires one brown one yellow, that goes to the fuel injector is bad somewhere so I have been opening up the harness looking for where it has power and where it doesn't, I'll probably just run some new wires but I haven't found where there is power on those wires yet.
This is where the injector pulse reader comes in. You plug it into the harness at the injector and it will light up when power is sent to the injector. If it pulses like the others the wires are OK. You can also use a test light.. look at this video.
 

·
Registered
Joined
·
33 Posts
Discussion Starter #5
This is where the injector pulse reader comes in. You plug it into the harness at the injector and it will light up when power is sent to the injector. If it pulses like the others the wires are OK. You can also use a test light.. look at this video.
Yeah I did the test light right now, there seems to be power coming into it but there is no ground pulse. Does this mean the computer is bad?
 

·
Registered
Joined
·
47 Posts
Yeah I did the test light right now, there seems to be power coming into it but there is no ground pulse. Does this mean the computer is bad?
Fuel injection has a dedicated ground either on the top of the valve cover front of engine or two behind the fuel rail/injectors... check that.
 

·
Registered
Joined
·
33 Posts
Discussion Starter #7
Fuel injection has a dedicated ground either on the top of the valve cover front of engine or two behind the fuel rail/injectors... check that.
Checked grounds one of the grounds that grounds the engine to the chassis or something was cut so I fixed it. I checked the pulse again and this time the pulse looks to be a solid light, when I switch to a different injector it is a pulse the way it should be. Car also idles kind of rough now revs to 2000 and goes back to 1500 then back up to 2000.
 

·
Registered
Joined
·
47 Posts
Checked grounds one of the grounds that grounds the engine to the chassis or something was cut so I fixed it. I checked the pulse again and this time the pulse looks to be a solid light, when I switch to a different injector it is a pulse the way it should be. Car also idles kind of rough now revs to 2000 and goes back to 1500 then back up to 2000.
The idle issue sounds like a idle air control valve to me?
Is it still misfiring?
 

·
Registered
Joined
·
33 Posts
Discussion Starter #9
The idle issue sounds like a idle air control valve to me?
Is it still misfiring?
Yes cylinder 1 is still misfiring, the Injector is not getting a pulse signal for some reason, I am going to track down the wire to the ecu and see if the ecu is giving out a pulse or if the ecu is bad. If what I'm gonna do isn't the correct thing than please redirect me.
 

·
Registered
Joined
·
33 Posts
Discussion Starter #11
Could it also be my cam sensor? But if the cam sensor wasn't working wouldn't all the cylinders have problems?
 

·
Arouse the DAMPFHAMMER!
Joined
·
6,265 Posts
I don't know any Honda guys in my area ( central New Jersey ). I have a feeling that the 2 wires one brown one yellow, that goes to the fuel injector is bad somewhere so I have been opening up the harness looking for where it has power and where it doesn't, I'll probably just run some new wires but I haven't found where there is power on those wires yet.
Mmmhhh...did you ping (ohmic restistance measurement) the the two wires from ECU pin all the way up to the connector already if they are in a healthy condition?

It is easy like that, if you have no oszi, to condense it down to the source of failure:
  1. swap the injectors by one cylinder #, so that #1 is #2 and ...#4 is #1. If the problems still is alive and move you know it's the injector.
  2. ping the wires (all). If all wires are ok, you know the injector or ECU are the issue
  3. measure the injector resitances of all, if one has loosen his resistance, swap it for a new one
  4. If the issue is still there, you have only two option: ground of #1 is not ok, what would be scary if #2-#4 see it or #1 ECU injector driver is dead
  5. Check the ground, refurbish it and test the system again. If it doesn't work you can assume the ECU driver circuit is not ok -> order an used PRB ECU
A PRB ECU is about 300 USD, a simplest Oszi is about 200 USD. It is your decision what will come first ;).
 

·
Registered
Joined
·
33 Posts
Discussion Starter #14
Mmmhhh...did you ping (ohmic restistance measurement) the the two wires from ECU pin all the way up to the connector already if they are in a healthy condition?

It is easy like that, if you have no oszi, to condense it down to the source of failure:
  1. swap the injectors by one cylinder #, so that #1 is #2 and ...#4 is #1. If the problems still is alive and move you know it's the injector.
  2. ping the wires (all). If all wires are ok, you know the injector or ECU are the issue
  3. measure the injector resitances of all, if one has loosen his resistance, swap it for a new one
  4. If the issue is still there, you have only two option: ground of #1 is not ok, what would be scary if #2-#4 see it or #1 ECU injector driver is dead
  5. Check the ground, refurbish it and test the system again. If it doesn't work you can assume the ECU driver circuit is not ok -> order an used PRB ECU
A PRB ECU is about 300 USD, a simplest Oszi is about 200 USD. It is your decision what will come first ;).
I'm not sure which wire on the connector would be for pulsing a ground to the injector, if I did I could check if it is the ecu or the wire at fault, if you know could you show me which one? Thanks for the reply.
 

·
Registered
Joined
·
33 Posts
Discussion Starter #16
No pulse from the ecu :( guess it's gonna need to be replaced. Do I have to look for an ep3 ecu or will a rsx one work?
 

·
Registered
Joined
·
77 Posts
What are you testing ecu injector pulse with? Needs to be something very fast reacting to pick up the pulse. Preferably led test light
 

·
Registered
Joined
·
33 Posts
Discussion Starter #18
What are you testing ecu injector pulse with? Needs to be something very fast reacting to pick up the pulse. Preferably led test light
Yeah I'm using a test light. I'll open up the ecu tomorrow and see if anything wrong with it, maybe use a electronic cleaner spray. ( Car has also been having more and more trouble starting the more I diagnosis it )
 

·
Registered
Joined
·
77 Posts
Is it LED the test light? Incandescent bulb won't pick up the low duty cycle of an injector pulse. Also double check there polarity on your LED if that is what you're using.
 

·
Registered
Joined
·
33 Posts
Discussion Starter #20
Is it LED the test light? Incandescent bulb won't pick up the low duty cycle of an injector pulse. Also double check there polarity on your LED if that is what you're using.
I was using a incandescent but I'll try with a led as well, the incandescent had no problem picking up the good ( working )fuel injector wires pulse.
 
1 - 20 of 59 Posts
Top