MikeTyson8MyKids

iTrader: (1)

So are the O2 sensors showing it running very rich? What are your fuel trims like?

RIWWP

iTrader: (2)

I was just pointed to this thread, and I see there are a few calls for me previously.

The original compression test sheet is acceptable, if not exactly normal. Ignore the 17 and 30 psi references, and look at the 200 and count the lines. the thicker line next to the 17 and the 30 is the 8th line from the bottom/top, also known as the 'middle' line. If we assume that the 200psi at the top line is accurate, then there is no way that the 17 and the 30 would be at the same point on the chart to, just doesn't make sense. However, if we assume that those numbers aren't important to the scale, and use the middle line as '100psi', then those results (one peak for each face in sequence, you can see the front rotor face with the problem as the lower peak for every 3 peak.

The PSI numbers are then about 96/97/90psi for the front rotor, and 100/98/97 for the rear rotor (rough numbers eyeballing an average, assuming every horizontal line is 12.5psi, which is 1/8th of 100)

The Rear rotor also shows what I think is the time, of 0.167 seconds per vertical line. Assuming that is true, the math looks like the RPM of the test was about 239rpm. A really rough eyeball guess, but it looks like just about 1 peak every 1.5 vertical lines.

So that means that the compression conversion would be something just about like:
Front: 7.1/7.1/6.7
Rear: 7.3/7.2/7.1
@ 250rpm
at sea level

Again, REALLY rough. If my guess on RPM is too high, then the numbers are better. If my guess on RPM is low, then the numbers are even worse. If the test wasn't done at sea level, then the numbers get even better.

So the engine isn't stellar, and one face may very well be failing, but there hasn't been a SINGLE reference about hard hot starts, so I am inclined to think that my number guesses are lower than they actually are.


Fernando, I would take a good hard long look at your fuel pump. Hook up a fuel pressure gauge and go for a drive. See if the fuel pressure starts falling off when you start seeing power problems. The factory fuel pump can start failing as early as about 50,000 miles, with 60,000 miles being a fairly common occurance (right about 100,000kms). Most last longer, but failing then is still seen quite frequently. When they do tend to fail, "about 20 minutes" of driving is exceedingly common for when they start to cut out on a given drive.


A drop in fuel pressure from the fuel pump overheating could be generating a lean running condition which will sap power by itself, and ECU trying to correct it will continue making the situtation worse.

Fernando Lopes

Hi MikeTyson8MyKids,

I don't know. These were replaced is all I know. But what outputs they are giving to the ECU I am not sure. I guess it does require some ECU monitoring and maybe my mechanic doesn't have the results for this.

Anyway car is moving to a Mazda dealer and I will request them to check this.

Hi RIWWP,

Thank you very much for your feedback.

As far as I understood, it seems that one of the rotors has definitely a problem. To be sure of this I want to repeat the compression test from another Mazda dealer and ask them to provide the results on the correct form.

The car has indeed hot start problems but from what i read this was due to the poor starter motor. When hot I just have to keep the key on the ignition few more seconds before the car is started.

I will ask the Mazda mechanic to check the fuel pump following your input and check the result.

MikeTyson8MyKids

iTrader: (1)

Let us know how it goes.

04Green

iTrader: (1)

I like the idea of getting the CAT out of the way.

It seems your mechanic is talking about the oxygen sensor. The one in the CAT just checks to see if the CAT is bad. The one further forward is how the ECU monitors the engine. If that one is bad, most bets are off.

With all the work, has the battery been disconnected for any period of time to reset the ECU. Or, 20 brake stomp it? That many changes, without the ECU reset, will leave the computer trying to figure out what is going on after it stabilized on something. This could result in a lot of fuel going through the engine, as it was rich to just keep alive before.

My thoughts? CAT, if that test worked out, and fuel pump. Mine ran a heck of a lot better with a new one.

Best I got right now.

Brady Black

I seem to have a similar problem. My car will get me to and from work just fine (I live about 5 miles away), but I am nervous to drive anywhere outside of town. My typical symptoms start with the coolant light coming on but not staying on (My coolant level is fine. I check it nearly every time I drive just to make sure). I then get a huge loss of power. The car will have a hard time doing 60 MPH in 6th gear. I've noticed that the problem seems to be more persistent in hot weather. Shortly after the loss of power several lights on my right instrument cluster will illuminate (I believe its the battery, oil, and one other light in that area) and the car will die. My oil level is fine. Took the car to Mazda and they had a "rotary specialist" work on it. The mechanically self admittedly has never seen the inside of a rotary engine.

I will try and figure out a way to post the diagnostics report. The mechanic said that I would need a new engine because the apex seals. The report said loss of vacuum on both rotors with the voltage dropping as the engine heated up.

Is this similar to the problem you have?
Does anyone have any input?

Brady Black

Here is the report.

RIWWP

iTrader: (2)

I do not suspect an engine problem.

Every single symptom you just mentioned has one thing in common: voltage drop.

I have never heard of an engine failure causing dash cluster lights to come on at the same time, but they do come on with voltage problems. Voltage problems could also be reducing fuel flow, affecting AFR signals, affecting ignition coil output, etc...

For somewhere less than $6,000, I recommend that you clean your battery terminals, battery clamps, and all grounding points first, and see what that gets you. Grounding problems are a common cause of voltage drops, dash lights, etc...

The next step is to test the alternator, to see if you aren't actually charging it well, so while driving, you are powering everything off the battery, until it finally drops voltage too low to sustain everything, and systems start shutting down.