Hello.
I have a cx5 diesel from 2014 and a problem with starting the car on a cold engine (longer time start), this happens after a big service (oil, filters, fuel filter,), before the service was ok. Thinking there is a problem with the fuel filter, so I exchanged him alone again and it was fine for three days the car started normally. After three days, the car again , cold engine for a long time start. I was in diagnostics in Mazda but did not find anything because he started to normally again, after which I noticed that he only has a problem when it's raining and sometimes as the temperature drops. after a few days of observation, it fires worse as it rains, there is no rain it is ok.
Maybe somebody help me with this problem.

 

Your Mass Air Flow Sensor could be the culprit. UN-plug it before the next cold/rainy day start and see if makes a difference. It's located in the plenum for the intake air where the cleaner/filter goes. "That Box".

 

if this sensor was damaged, then the computer should not show it? but I will try to do that of course, every advice is valuable to me in this problem

 

Understands that after disconnecting the sensor and starting the engine, the problem with the start will continue. is the sensor to be replaced?

 

If the MAF is flakey and causing this problem, we are trying to discover that by disconnecting it just before a "start-up" on a day where you believe you would have the trouble. You don't want to leave it disconnected past that start-up test. If it proves to be the cause then replace it. If not, no. Leave it in service and look elsewhere. Did you do this "big service" yourself when the problem started?

 

The problem started after the service I was doing in the garage. Sorry my English is a bit weak, you could explain to me, after the plug is unplugged, how the car should behave after starting with the plug unplugged, so I can see that it's not working

 

I would bring it back to the place where you had service and let them figure it out. Obviously, something they did is causing this problem.

 

I did, but they found nothing. The garage didn't find anything. My vehicle warranty company has found nothing Mazda service didn't find anything, after the car started up normally when I gave it back (it didn't rain)

After I pull the plug, what will be the symptoms so I know that the sensor is damaged?

 

I agree. This is one of those issues where you may need leave the vehicle with them until they can see the problem and fix it. They should lend you a loner vehicle for your inconvenience. Get aggressive. Ask to speak with the service manager. Don't take no for an answer. Don't just quietly go away. That's what they want!

 

I left the car at their place 3 times and every time they did something, and they gave back the car that worked for them (because it didn't rain) so I'm trying to find the problem myself, I'll wait for the rain and I'll do as you said, maybe you were right. Today I pressed down some rubber cable that also comes out of the intake manifold under the sensor and connects to a metal tube (it was poorly inserted) what it is. I'll let you know after it rains. Please watch this fast, maybe I can help you. You're the only one who's led me to the sensor