injector 4

 

Callisto, if you think there is still some kind of unsolved problem, what should I be looking for or testing?

Intake manifold was oily, does this point to something wrong with pcv system or its built in catch can on the engine?

Or since the engine is at 112k miles, it is normal build up?

 

Back to doing a proper compression test including a wet test, then comparing all the results and you may need to do a *cylinder leak down test(*more then likely)!


*A leak down test will pinpoint if the problem is head or short block.

 

After I get the engine back together I will perform a proper compression test.

Can you layout the exact procedure you would like me to follow

The link below seems to have a different procedure then what you elude to.

compression_inspection-1201.html

They make no mention of how many times to crank, and want me to hold the acclerator pedal down.

You say 5 revolutions, or do you mean 5 compression strokes for the cylinder being tested? 5 revolutions on a 4 stroke engine would give you like 1 poof into the meter.

lay it out precise, so you don't have to say my test is null and void.

 

remove all spark plugs.
It would be better but not necessary to disconnect the ECU
use a screw in spark plug hole compression gauge. Make sure you add a tiny bit of wd40 or engine oil on the compression gauge o-ring or seal.
Now here is the learning part....... if you don't have a simple remote starter switch. set the gauge on the wiper are so you can see the gauge face while sitting in the driver seat. When to push the start bottom watch the needle carefully. Each time the piston comes up on the compression stroke the needle will move in a positive or higher-pressure direction. Count this event 5 times no more no less. And write down the number.
This will give to the base line of all 4 cylinders.

*The misunderstanding is and the difference between total or maximum built cold compression vs maximum compression measure at close to operating temperatures. Don't worry about this for now. basic how to instruction most all do not account for the 2 basic ways of compression testing.


*DO NOT worry or try in any way to alter the Throttle body plate.


I generally as a rule don't explain that there are a couple fundamental ways of performing a compression test on forums. If this were not a Mazda forum and say a Ford Pony or Camaro forum there would be countless debates from mostly DIY about this simple procedure. And as we all know DIY know more then some one that built Performance engines for a living once. rolmao.

 

I can see why cylinder 2 is misfiring.

 

nice! ^^^^^^^^^^^^^^^^

 

I put the engine back together. Car is running well.

No misfire counts on any cylinders now.

Long term fuel trim at idle is down to .8

Low end torque is nice and strong.

CALLISTO, so here is the question, did I cause this P0302 misfire because i used E85 for a year?

Or was this just par for the course for 112k mile engine?

 

While I'm not able to comment on if it was the sole reason the misfire started, I wouldn't run E85 on the car anymore...

 

E85 really needs a ECU calibration to be not only effective but to make sure the ECU does not get anomalies fueling issues that the programing tries to correct. E85 was never designed in a factory Mazda ECU programing.

I think I have said many times for a street driven (noncompetitive) vehicle E85 has more shorting coming then benefits (if really any).

On an observance.... when performing Dyno runs with anyone using E85 it was almost impossible even setting up careful DELTAs to get same run results. Even on the same.
You can also see this on the limited (based on how many did the tests) back-to-back Dyno runs and looking at the results even when SAE smoothing was used.