Misfire help

Hello,

Having a misfire in my 99 cobra.

Changed out spark plugs and coil packs, still an apparent misfire on bank 1 - passenger side.

When I unplug the fuel injector on driver side, the car acts normal and sounds different.

When I unplug ANY of the 4 fuel Injectors on bank 1 - passenger side, the car has NO change in sound or idle. What could this be?

Thanks for any help

Update. All injectors have 13 ohm resistance. All connectors getting 12v

Checked all fuses, everything seems good electrical wise

Is the EMF filter at the back of the head still connected?

01yellercobra said:

Is the EMF filter at the back of the head still connected?

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EMF filter? Do you have a pic of that?

It's a little black box looking thing. It bolts to the back of the head. I think it's the ground for the COPs.

01yellercobra said:

It's a little black box looking thing. It bolts to the back of the head. I think it's the ground for the COPs.

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I didn’t see that, and I can’t find anything online. Are you able to provide pics?

Starting to think the camshaft timing on that side is off. I’ve replaced everything minus fuel injectors and they are fairly new.

Time to open up the wallet….

Any codes?

5.0 Hatch said:

Any codes?

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None, but data logs show nothing firing on bank 1 according to my tuner. Has a noticeable misfire when idling

This should help you @austin21 ......







Check your radio noise capacitor #2.



Check ground off the PCM G201. Possible you have a bad PCM.

Vinnie_B said:

This should help you @austin21 ......


View attachment 1836712

View attachment 1836711


Check your radio noise capacitor #2.

Check ground off the PCM G201. Possible you have a bad PCM.

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You know what, this might be it. I was looking around the ECU/PCM earlier and did NOT see this ground anywhere. I will take another look tomorrow.



Found this picture on youtube.


For the radio noise capacitor #2, where is this located? I tried to look up and it may be near the coils?

austin21 said:

You know what, this might be it. I was looking around the ECU/PCM earlier and did NOT see this ground anywhere. I will take another look tomorrow.

View attachment 1836716

Found this picture on youtube.


For the radio noise capacitor #2, where is this located? I tried to look up and it may be near the coils?

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Looks like it's near the rear of the motor by the head bank 1.

Vinnie_B said:

Looks like it's near the rear of the motor by the head bank 1.

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thanks for your help, it is greatly appreciated.

Is this what the noise capacitor looks like?

austin21 said:

thanks for your help, it is greatly appreciated.

Is this what the noise capacitor looks like?

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No problem! Yes sir that would be it. I would also recommend pulling your PCM and sending it out to see if there is a issue with the hardware and/or software. I've sent many customers out to flagship 1. They are a reputable and trusted source for testing,rebuilding and selling preprogrammed modules. There link is below.

Vinnie_B said:

No problem! Yes sir that would be it. I would also recommend pulling your PCM and sending it out to see if there is a issue with the hardware and/or software. I've sent many customers out to flagship 1. They are a reputable and trusted source for testing,rebuilding and selling preprogrammed modules. There link is below.

Engine Control Modules | ECM | PCM | ECU

Flagship One is your trusted source for updated and pre-programmed engine control modules and module repairs. FREE LIFETIME WARRANTY & FREE SHIPPING. Shop Now!

www.fs1inc.com

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Checked ground for g201 and I had an ext4/ ground wire not connected. I scraped off the metal to ensure I had a good ground but no change.

Going to send PCM off to see if there’s any issues with it.

No change with g201 ground. Made sure it was a good ground also by using it as a ground and checking voltage on the 8 pin connector.

If the ECU is not the issue I’m almost certain it’s the camshaft timing. Car had a comp cams, valve springs done a year or two ago but car hasn’t been driven much.

austin21 said:

Going to send PCM off to see if there’s any issues with it.

No change with g201 ground. Made sure it was a good ground also by using it as a ground and checking voltage on the 8 pin connector.

If the ECU is not the issue I’m almost certain it’s the camshaft timing. Car had a comp cams, valve springs done a year or two ago but car hasn’t been driven much.

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Keep us updated @austin21.

Vinnie_B said:

Keep us updated @austin21.

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Wow what are the odds. My late father in law (who i inherited this car from) Actually bought this ECU from FS1 so they are going to RMA it for free. Thanks for the reccomendation

While i wait to hear back about the PCM - if the cars camshaft timing is off/missed , does this mean my motor is most likely hurt?

I uploaded a clip of the idle, unsure if anyone can hear the misfire or not

I think ive pretty much covered everything i can. I may get a noid tester which that should confirm that the injector is firing and communicating with the PCM.

Car isnt blowing any type of smoke or anything like that.

austin21 said:

if the cars camshaft timing is off/missed , does this mean my motor is most likely hurt?

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I wouldn't jump to any conclusions until you get your ignition issue resolved first than if still missing check with a qualified mechanic who can diagnose your mechanical camshaft components properly. Noid light is great for checking fuel injector signal from PCM.