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Greg, Technician
Category: Car
Satisfied Customers: 7129
Experience:  17 years Shop Owner /Technician. 27 years experience,
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Van Model: DA64 minivan Brand: Suzuki Every Gscan2 OBDII

Customer Question

Van Model: DA64 minivan
Brand: Suzuki EveryGscan2 OBDII shows fault code P0302-cylinder 2 misfire detected.
I tried the following ways:
1- Changed plug.
2- swapped injectors.
3- checked wire-ring.
4- changed cam sensor.
5- changed crank sensor.
6- Head valve grinned and new gasket fixed.
7- Changed ignittor.Please help. Thank you
Submitted: 1 year ago.
Category: Car
Expert:  Greg replied 1 year ago.

Hi .

Looking at all the parts changed looks like you covered all possibility's that the problem should be fixed .

But this we see quite often and all boils down to a bad catalytic converter .

Remove the up stream O2 sensor and do a exhaust back pressure test .

Is the misfire a hard misfire or just a slight misfire that comes and goes .

Do you have COP (coils on plugs) or HT wires .if wires check the spark on each four if the No. 2 is not strong like the other 3

replace wires .

Please do the back pressure test for a bad cat and get back to me if needed.

Rgds Greg.

Customer: replied 1 year ago.
Hello, Thank you for the reply.
How do I do a back pressure test? where is the oxygen sensor located? Catalytic converter is the barrel like thing in the exhaust pipe? Do I remove it and keep it open? How do i fix it back? by welding? Or do I need to clean the whole exhaust system?Misfire is hard. It's continuous.It's coils on plugs not wires. It's a 3 Piston engine. we changed all 3 coils to brand new coils and brand new plugs. 2nd piston is not working.Thank you.
Expert:  Greg replied 1 year ago.

For exhaust back pressure test you need a pressure gauge. Its checked at the first O2 sensor which you have to remove .

you should not have more than 1.5psi back pressure anything above is a bad cat .

no need to drill holes just remove the O2 sensor just after the exhaust manifold .

in same cases just removing the O2 sensor and starting the engine you will in some case

feel that the misfire has gone if this is the case remove the cat and replace if its the law in your area.Greg

Customer: replied 1 year ago.
I checked everything you asked its not above 1.5PSI and also the cat looks brand new. Nothing wrong with that.
Checked all piston compression and its all in normal level.
Removed the O2 sensor as you asked but still the misfire is their.
Anything else?
Customer: replied 1 year ago.
We even replaced the ECU with the same number but still the misfire is their.
Expert:  Greg replied 1 year ago.

Disconnet the O2 sensors .

Clear codes and start is misfire still there .

What was the compression reading all the same or one cylinder higher than the other two .

Do you have live data on your scan tool .if yes?

Get me the data at idle for :

Short fuel trim .MAF.

Then again at 2500rpm.


Customer: replied 1 year ago.
I did disconnect the O2 sensor and cleared the codes still the same fault code is their.
-- compression reading was all the same.
-- I have live data on my scan tool, I'll upload screenshots shortly, just confirm you need live data reading for :
- Short Fuel Trim
- Mass Air Flow
at idle and at 2500 RPM ?
-- I swapped injector in cylinder 1 with cylinder 2 and also the injector in cylinder 3 with cylinder 2. When i checked them all, always the injector in cylinder 2 is wet with petrol. So It's not burning right? All injectors are sparking too. So Do you think their might be some fault with electrical components or anything to do with electricity? When I remove the injectors and check for petrol spraying all the injectors do spray petrol well.Thank you
Expert:  Greg replied 1 year ago.

Sounds odd swap the spark plug 1 and 2 .id still code P0302 then spark to #2 is weak

Check that you have a strong spark on #2 as with #3 and 1 .

If compression is good ,spark is good fuel is good then i can only see a problem with the fuel mix to #2.

For live data copy yes as said idle then 2500rpm .


Customer: replied 1 year ago.
I also think it's a fuel mix issue, but how do I solve it or confirm it's an issue with it?
Please find attached screenshots from today's scan as per your request.Thank you
Expert:  Greg replied 1 year ago.

You need to get to operating temp as you are still in open loop .

Is this your idle speed .

What was the compression reading all the same or one cylinder higher than the other two .


Customer: replied 1 year ago.
you want me to take the readings again on operating temperature? compression on all cylinders are the same. I have sent you readings on both idle speed and 2500RPM. Please check. What else can I try? can it be an issue with the engine head?
Customer: replied 1 year ago.
What are the readings you are looking for? those are the screenshots attached before. Those are the readings that can be taken. MAF reading could not be found but short term trim fuel reading is their.
Customer: replied 1 year ago.
How do I check how the electricity and earth is coming from ECU, How can I take the electrical readings or pulse readings that are been sent to the three wires on the injectors. What are those three electrical wires connected to the injector? how do i check if it's working properly or how can I get the measurement? can i use a avometer for this?
Customer: replied 1 year ago.
Hello Mr.Greg How can I rate you when the issue is not solved yet. I'm not happy with your responses. Sorry to say that but I would like another expert to answer my questions please. I will rate you once you connect me with another expert.Thank you