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Drew
Drew, Super Mazda Tech.
Category: Mazda
Satisfied Customers: 2518
Experience:  19 yrs. experience. Mazda Senior Certified Tech, with Ford, Linc. & Merc. experience. ASE L1 Advanced Certified Master Tech.
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2004 mazda 3: sluggish..exhaust..intake manifold..3 coil packs

Customer Question

2004 Mazda6 3 liter v6 5spd, 90k miles, compression check all cylinders at 170+- lb., Motor runs sluggish, random backfiring from the exhaust (More like puffing) and intake manifold. I can pull the power lead from the 3 coil packs on front of engine and backfiring stops. Motor will then run on back three cylinders. When I plug them back in one at a time I get random misfiring and backfiring.

Help
Mike
Submitted: 5 years ago.
Category: Mazda
Expert:  Drew replied 5 years ago.

Welcome to Just Answer. My name is Drew and I will be glad to assist you.

 

Make sure you have the correct coil connected to the correct coil. Each coil connector will have a tag on the wiring harness that says COP4 COP5 COP6. Make sure all are corrected to the correct coil. #4 is closest to the belt and #6 is closest to the transmission.

If that does not resolve your concern, hit the reply button to let me know and I will give you additional diagnosis steps.

Thanks

Drew

Customer: replied 5 years ago.
The harness for the coils ( front and back) is made from the factory at a certain lengths. There is no way to plug the coils in the wrong order without taking the harness apart. I am confident that is not the problem. it would be pretty obvious if the factory harness was modified or changed.
Expert:  Drew replied 5 years ago.

Just check it to prove me wrong so we can move to the next step.


Thanks

Drew

Customer: replied 5 years ago.
Just confirmed that you cannot plug all of the coil leads in at the same time in the wrong order. The factory harness will only allow the connectors to be plugged in certain one way. The wires are all made to various lengths and end at each pre determined coil pack. Backfiring is random with no certain pattern.

Thanks
Expert:  Drew replied 5 years ago.
So you visually verified that each COP tag number is connected to the correct coil??
Customer: replied 5 years ago.
I see no tags on the wires, The coils are plugged into the proper connector on the harness. I am 100% positive.
Expert:  Drew replied 5 years ago.

OK.

 

I suggest that you clear the codes and test drive the vehicle and see if the check engine light will come on after 20 miles.

 

You should also check the fuel pressure.

 

Here is a list of items to check for your concern.

 

Thanks

Drew

 

Fuel line pressure: 430 - 510 kPa {4.4 - 5.2 kgf/sq.cm, 63 - 73 psi}

 

 

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Customer: replied 5 years ago.
Relist: Inaccurate answer.
I found problem today, It was not what the Master tech said
Expert:  Drew replied 5 years ago.

What was the cause for your concern and how did you repair it??

 

Please let me know.


Thanks

Drew

Customer: replied 5 years ago.
Car is fixed, Sorry I am not going to disclose what my hours of research and trouble shooting unveiled. I am just disappointed that I have to pay for this service when it did me no good.

Thanks anyway
Expert:  Drew replied 5 years ago.

Well then lets make a deal.

 

If you tell me what was the cause for your concern and what you did to repair it, I will submit a request for a refund of your deposit back.

This way I can learn from you and pass the information on to another customer like yourself that has the same concern.

Win Win situation for all.

Thanks

Drew