Rough start up on Mazda 3

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Mazda3LA

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Mar 26, 2011
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Wake Forest NC
Hi everyone,

I recently had my oil changed and fuel injectors cleaned on my 2007 Mazda 3. The next morning when I had these services completed I turned on my car and drove. It seems to now run a little rougher in the beginning when cold. once the engine heats up the car runs better. Could this issue be from the fuel injectors being cleaned or the oil change?

Thanks in advance
 
I doubt the oil change would have anything to do with it....I'd think the FI cleaning is the culprit.
 
Perhaps something has been unpluged. Were the injectors removed? If so check the electrical lead going to each injector.
 
I usually have them cleaned every 30k miles. I don't know how they cleaned them. I take the car to a nearby repair shop that has done work on my car before without any issues. I'll take it back to them tomorrow to see whats going on.
 
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I've NEVER gotten a injector "cleaned".

This is with my first injected vehicle that I bought in 1986 and went 394,000 miles before it died (and ran perfectly all that time with excellent MPG throughout its life) to my current vehicle with 244,000 miles. Both domestic and foreign vehicles with all engine types.

Just buy gas from a gas station that sees business and injector cleaner in a bottle every 15-20k miles.


Yes check with them and have them make it right. And that should not incl any more $$ wasted. Your vehicle is very young in miles to have ANY injector issues.

Take care, bill
 
Originally Posted By: Mazda3LA
I usually have them cleaned every 30k miles. I don't know how they cleaned them. I take the car to a nearby repair shop that has done work on my car before without any issues. I'll take it back to them tomorrow to see whats going on.


Ask them how they were cleaned.
 
The best way to keep injectors clean is to use top tier gas that has good additive levels and ocassionally add Techron to the fuel tank. That and drive plenty of highway miles help.

Cleaning injectors such as through the fuel rail is not really a normal maintenance thing. It's best done if there is a noticable problem, hard starting, rough idle, performance decline, misfire and/or injector balance test indicates injector deposits.
 
Originally Posted By: buster
Originally Posted By: Mazda3LA
I usually have them cleaned every 30k miles. I don't know how they cleaned them. I take the car to a nearby repair shop that has done work on my car before without any issues. I'll take it back to them tomorrow to see whats going on.


Ask them how they were cleaned.


+1
 
Definitely sounds like they either left some electrical connector loose, or perhaps they damaged the schraeder valve when they made the connection to the fuel rail. Maybe it is loosing a little bit of pressure.
 
Maybe it is relearning idle parameters. Tell the service place of the problem immediately, but it MAY clear itself up after a few days.
The throttle body and idle air valve should be cleaned real nice, too. This fixes all sorts of idle problems.
 
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If they unplugged the battery, you need to have the computer re-learn the throttle position. Here's how to do this:

(0) Make sure car is cold, doing this in the morning after car has been sitting all night is best.
(1) Unplug the battery, hold the brake pedal for 30 seconds or so to clear the ECU.
(2) Plug battery back. Start car.
(3) Don't touch the gas. Wait for it to get to full temperature (needle in the middle of the gauge) and idle to slow.
(4) Stop engine.
(5) Restart engine, wait for idle to settle.

Since the throttle is electronic it needs to be re-calibrated every time the ECU gets cleared. Normal driving will NOT recalibrate it, I've run into this myself on my g/f's car.
 
My two Japanese cars calibrate the throttle closed position automatically in 10 seconds without the odd requirement to wait until it warms up fully at only idle speed.
 
This is why cleaning injectors with snake oil in the gas is a bad idea. All it does is knock anything that might be in their lose and clog the injectors.

I never touch gas injectors until their is a problem, they don't get dirty that's what the fuel filter is for. On diesels if I suspect their is a problem I yank them and have a diesel injection shop go threw and properly clean any with a poor spray pattern.

See if it works its way threw, if not start trouble shooting which injector it might be. Luckily on that car you don't have to many.
 
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Originally Posted By: mechtech2
Maybe it is relearning idle parameters. Tell the service place of the problem immediately, but it MAY clear itself up after a few days.
The throttle body and idle air valve should be cleaned real nice, too. This fixes all sorts of idle problems.


This is most likely the problem if the shop disconnected the battery, which would be a normal procedure if they used one of those injector cleaners that you have to spray through the throttle body. Mazda 3 uses a fly by wire throttle with no idle control valve, so once the battery is disconnected, all parameters that were compensating for dirty throttle plate will be reset to original spec. Cleaning the throttle body should get rid of this problem.
 
Originally Posted By: Kiwi_ME
My two Japanese cars calibrate the throttle closed position automatically in 10 seconds without the odd requirement to wait until it warms up fully at only idle speed.
Yap. This has happened on all other cars I've owned. All I know is that when I reset the ECU in my g/f's car, no amount of normal driving would recalibrate the idle and it would idle funny while warming up, it would "hunt" for the right RPM at stop lights and such, but only while cold, once warm it was fine. Doing the procedure I mentioned got rid of the problem entirely.
 
Thanks a lot for all of your responses. Took it to the shop on Saturday and had the mechanic test drive. He felt the vibration. Looks like I misdiagnosed it. It felt more like a vibration when at cold start than a rough start. He took a look at the car to see if any wiring was loose and noticed that one of the motor mounts was cracked which was causing it to vibrate. Drove it this morning and car felt much better.

Thanks again for all of the responses.
 
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