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Engine problem?

Old Nov 3, 2021 | 04:24 PM
  #1  
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From: Warren
Engine problem?

So was just cruising along 60-70 mph omw home from work, all of a sudden starts to run like dogshit, like timing jumped like a ************. 🤔 So I thought detonation, but was very unsure bc it didn't sound anything like what everyone describes. So I need a little insight, can tiny detonations happen, I'm seeing no fluids engine isn't on fire like. Running good, turns to dogshit, slow down bc traffic jam, and dies. No popping, knocking, or pinging; just rough as ****.

So I was also just thinking, is it possible that I just lost my apex seals and didn't have a detonation at all?

Also wanted to note that I can freely rotate the shaft by hand if that matters.

Last edited by RollinHeavy; Nov 4, 2021 at 05:24 AM.
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Old Dec 15, 2021 | 08:34 AM
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From: Warren
Where to start

I'm not too familiar with timing on the rotaries so I'm not sure if I should start there. Or could it be a bad ignition problem bc it will not start up now, maybe ignition coil, plugs are less than a year old, wires about 2 years old they were upgraded ngk wires. I would love some insight.

88 gxl
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Old Dec 15, 2021 | 09:19 AM
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From: https://www2.mazda.com/en/100th/
Originally Posted by RollinHeavy
I'm not too familiar with timing on the rotaries so I'm not sure if I should start there. Or could it be a bad ignition problem bc it will not start up now, maybe ignition coil, plugs are less than a year old, wires about 2 years old they were upgraded ngk wires. I would love some insight.

88 gxl
the Lazy mans guide to a no start:
when you crank the thing does the tach needle bounce? if yes, then you need to check for fuel, you can usually smell it. these cars default to being flooded, so that is the direction to go in. there is a relay above the drivers right knee, and if you unplug it it shuts fuel off, and you can see what that does.
if no, if the ecu gets power, and an rpm signal it will output, so no tach needle bounce means no ignition and so you need to look at fuses and then the CAS
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Old Feb 9, 2022 | 04:05 PM
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From: Warren
Originally Posted by j9fd3s
the Lazy mans guide to a no start:
when you crank the thing does the tach needle bounce? if yes, then you need to check for fuel, you can usually smell it. these cars default to being flooded, so that is the direction to go in. there is a relay above the drivers right knee, and if you unplug it it shuts fuel off, and you can see what that does.
if no, if the ecu gets power, and an rpm signal it will output, so no tach needle bounce means no ignition and so you need to look at fuses and then the CAS

I've dealt with u flooding this car a numerous amount of times as I daily drove it thru 4 winters, I don't know if I would say that's the real issue here. I'm not saying it's not flooded but don't think that's the big fish. I have tried to de flood it a few times, it seems like it wants to start but no grab. I'm almost wondering if it could be my ignition coil.
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Old Feb 9, 2022 | 04:27 PM
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Go back to the basics.

are my apex seals blown? Check compression.
you can remove the leading spark plugs and crank and listen for 6 evenly spaced consistent pulses.
check for spark
check for fuel delivery
if no fuel, Jumper the fuel pump connector under the hood.

check all fuses.
check condition of the plugs.

Last edited by DR_Knight; Feb 9, 2022 at 04:30 PM.
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Old Feb 9, 2022 | 04:32 PM
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Kinda surprised it’s been 2 months since the initial problem… hoping you already did the steps i and j9 mentioned above.
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Old Feb 9, 2022 | 05:00 PM
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From: https://www2.mazda.com/en/100th/
Originally Posted by RollinHeavy
I've dealt with u flooding this car a numerous amount of times as I daily drove it thru 4 winters, I don't know if I would say that's the real issue here. I'm not saying it's not flooded but don't think that's the big fish. I have tried to de flood it a few times, it seems like it wants to start but no grab. I'm almost wondering if it could be my ignition coil.
step one was to see if it was flooded or not.

step two, if the tach doesn't bounce then you need to see if the ecu is getting power, if yes, then you look for an rpm signal

the idea is to fix the car with the least amount of work.
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Old Feb 9, 2022 | 07:16 PM
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Originally Posted by RollinHeavy
So was just cruising along 60-70 mph omw home from work, all of a sudden starts to run like dogshit, like timing jumped like a ************. 🤔 So I thought detonation, but was very unsure bc it didn't sound anything like what everyone describes. So I need a little insight, can tiny detonations happen,
first thing that comes to my mind is fuel pump and/or filter. the pump is easy enough to check for function and output. it never hurts to change the filter, so that's easy, too.
Also wanted to note that I can freely rotate the shaft by hand if that matters.
that's helpful. now you just need to check if you're getting signs of 6 functional chambers. you can either "shadetree" it and use your ears, or you can get an actual gauge and measure it.

is your car turbo? if not, i would shelf the detonation idea for a while. focus on the basic stuff like j9fd3s and DR_Knight have been suggesting from the start.
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