Engine vibrates

RAJ SUNDAR

MEMBER
2000 MAZDA PROTEGE
1.6L
4 CYL
2WD
AUTOMATIC
180,000 MILES

Spark plugs are covered with soot. Did the following but no success:

Replaced the spark plugs.
Replaced the coils.
Replaced the fuel pump.

Two coils, one sitting on spark plug 2 sparks 2 and 3 and the other one sitting on spark plug 4 sparks 1 and 4. The new spark plugs keep on getting covered with soot. The vibration is steady.(Even and continuous)

There is spark in all 4. One of the pin in both coil connectors has 12v current.

The in tank fuel filter is not replaced. The compression in all 4 cylinders is around 180 PSI.

Can it be the fuel filter or the fuel regulator giving the problem? Please answer

4 Replies

MOTOR MASTER

MECHANIC
279 POSTS

Hello my name is Dave.

The fuel filter would not cause this problem, however the fuel pressure regulator is one possible cause. But before we go throwing parts at it we need to first find out if there are any trouble codes stored in the computer. If the plugs are getting black soot on them then the computer should be reading a run rich condition. There are a lot of reasons it could be running rich so we really need to check for the codes. Here is a link to our tutorial on retrieving any trouble codes that may be stored in the computer:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

If you can find any codes stored and get back to us with the results we will be glad to help you narrow down the culprit. I would highly recommend getting this resolved as quickly as possible since if it keeps being driven under these conditions then it will clog the catalytic converter, if it hasn't already

We look forward to hearing back from you and thank you for using 2CarPros!

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Monday, February 8th, 2021 AT 3:26 AM

RAJ SUNDAR

MEMBER
36 POSTS

Hi Dave,

I am very sorry for the delayed reply. I had a problem in scanning the vehicle. It's OBD1 (17 pins) and the MIL is never on in this vehicle. I think the LED is burnt. So I bought an adaptor to connect with my code reader. Unfortunately It didn't work. I get "Linking Error" message. Then I bought a LED test light and diagnosed the vehicle. I get 2 codes 21 and 22, sometimes I don't get 22 but I get 21 and 23. My interpretation is correct if only 2 digit codes were generated. I wonder whether there are 4 digit OBD1 codes. If yes, then my code will be 0102 or 0103.

I usually buy these tools from ebay and it took couple of weeks to receive them.

Where do you think the problem is? Thanks in advance for your suggestion.

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Wednesday, March 3rd, 2021 AT 8:08 AM

KEN L

MASTER CERTIFIED MECHANIC
47,690 POSTS

Are all the spark plugs sooted that same or is one more than the others? Can you please shoot a quick video with your phone so we can see what's going on? that would be great. You can upload it here with your response. You could have a clogged catalytic converter. these guides should help us:

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

and

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please run down these guides and report back.

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Friday, March 5th, 2021 AT 8:50 PM

RAJ SUNDAR

MEMBER
36 POSTS

Hi Ken,

Again I apologize for the late reply. I bought two new coils for this vehicle from eBay and replaced the existing coils. Now the car is working good.

The mistake that I did earlier was that I changed the coils with junk yard ones. Unfortunately one of them was also faulty.

Another mistake that I did was that I was reading the error codes without clearing the previously recorded codes. Before installing new coils, I cleared the codes and did the diagnostic test and there were no codes.

Earlier, when I checked the coils for spark, I had spark from all coils. The car was running good for a short time only. So I suspected the coils and wanted to fit new coils.

I also like to share some of my findings on this vehicle.
There is no CEL in these models. The only way to read the error codes is using led test light method. The EOBD codes are 4 digits.

I thank Dave and you for taking interest to answer my question. The videos with instructions of your web site were very useful.

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Saturday, March 20th, 2021 AT 12:55 AM