Manager Forum

I will be looking at several diagnostic items on this, but Mazdas are new to me. I have codes p0351, 0352, 0353, 0354 and p0355 stored. I am assuming these are related to the specific cylinders, but can not seem to verify this. Customer states engine was running fine, then she went to pass a vehicle on highway and engine died like turned off the key. Would restart but appears to be running off of about 2 or 3 cylinders. The back coils appear to be a challenge to get to. So far I have disconnected the front coils, and there was no change in engine operation for #s 4 and 5. When I disconnected #6, the engine died (I am assuming #6 was one of the cylinders that was running properly) I have not done this test on the back of the engine. Does anyone know how to identify which cylinders are missfiring when the engine is running? Scan tool data only shows "Missfire detected yes/no" and does not specify which cylinders, unless the codes listed above are the ones. But the codes are history. I would like to know which ones are missfiring NOW. Ideas?

Well, I didn't look this vehicle up on my scan tool but it would seem to me that on datastream with your scan tool you should be able to view which cylinders are misfiring. If not, I would next be using mode 6 for further diagnostic help.

hth

I am unfamiliar with "mode 6" as my background is 90% GM. I am also not sure if my scan tool covers this, as I have not seen anything that indicated a "mode 6" I have the Maxi DAS DS 708 scanner.

This is basically a ford. Can you "lie" to your scanner and make it believe you are working on a ford? At that point you should have cylinder contribution test.

Jeff @ Able Auto wrote:This is basically a ford. Can you "lie" to your scanner and make it believe you are working on a ford? At that point you should have cylinder contribution test.

I forgot about that possibility. Sometimes it works and sometimes it doesn't.

Hmmm, I will have to try that. Should I select any particular model Ford?

Its and escape. I am not familiar with your scanner. I think a tech 2 shows mode 6.

Customer notified me that she had just refueled shortly prior to this problem. I am having a fuel sample pulled now, but I am unsure if a fuel induced missfire would set these codes? I was under the impression that these codes were an electrical issue.

Fuel sample is normal, nothing unusual there. It seems like the engine in running barely off of two cylinders, #1 and #6. The other 4 do not respond when the coil is disconnected. Have looked at the harness near the ECM where it bends at a pretty tight angle, but nothing OBVIOUS is seen.

Just out of curiosity, we swapped the #6 coil with the #5 coil and cleared codes. Restarted vehicle and same codes came back, so I don't feel like I have bad coils. I am suspecting a bad ECM or wiring at this point.

All this happened after a hard load. I would look at that angle. Have never seen it one of these but look at the crank or cam sensor. If i remember correctly there was an issue with the crank sensor. I would also check pcm to see if it's in limp.

Well I found a lot of articles and a bulletin after doing a bit of research and it says there is a problem with EMI from spark plugs causing coil failure and PCM failure. Per Mazda, they say in the bulletin to replace the plugs, coils, and PCM. Customer nearly had a heart attack on my sales floor after hearing the quote. Decided to take the vehicle and try to trade it in.