My 2007 CX-7 runs like crap, Backfires, Stalls, Blows Black Smoke (Solution Included)

[ottoblotto]

i read this and thought it was a great story to share. it was originally posted by Mitch on another site so credit goes to him. (pm'd him to join up here)




My 2007 CX-7 runs like ****, Backfires, Stalls, Blows Black Smoke (Solution Included)
Hi

Here is my rant (more like a story, a very TRUE story)


Almost 2 years ago when I purchased my 2007 CX-7, the car would run like **** in cold weather (below 25 F roughly). It would sputter, blow smoke, backfire and stall. Then on would come the check engine light. I took it to my mechanic and he told me there were codes his scan tool can't see and to go to the dealer. The dealer after 2 hours of diagnostics came to the conclusion it was the High Pressure Fuel Pump and a coil pack and possibly the turbo. He proceeded to tell me only the turbo was under warranty (my full warranty expired only months earlier) and the rest wasn't covered by power train warranty (it is after 2008 model I was told) and cost was $1100 + labor for the fuel pump and whatever for the coil pack + labor.

After much thought and analyzing the symptoms mentally, Looking at the flows on my other turbo charged car (Jeep turbo diesel) I told him to give it an oil change with the correct synthetic oil (follow manual) he suggested I was nuts, I suggested he did not know how to properly diagnose a vehicle ( Service manager was not happy, nor was the mechanic or the foreman).

Well he did the oil change and drove it around and all the symptoms and DTC's disappeared. Car drove like new, no smoke, turbo operated properly. Dealer looked at me asked why? (really)

Well I said to him that I purchased the vehicle used and that it made sense that the dealer gave it an oil change. Knowing how cheap a dealer would want to be, used low grade conventional oil. Well seeing that this problem only happenned when it was really cold (25 farenheit or less) conventional cheap oil is as thick as molasses. My thought being that when you step on the pedal, the injectors spray fuel (very rich mix) the turbo can't spool up properly so the engine sputters, blows black smoke and backfires because its too rich. The backfire trips the knock sensor, trips the DTC and the chain begins.

I am not saying that this will fix all situations. Just to question what you are told by any mechanic and don't think they know what they are talking about all the time. A scan tool can only suggest what the failure is with the trigger being something unrelated to the symptoms. Even honest mechanics (like good doctors) make mistakes.

(OIL IS NOT OIL, change it often, use the right oil)

I got out of there for an $80.00 oil change because I challenged the mechanic, the foreman and the service manager (none of whon like being told by a customer they were wrong). Those problems and symptoms never came back

I saw the service manager this week (a year later) and he told me that he applied my solution to a dozen vehicles in the past year and solved 5 vehicles issues because the car owners went to Jiffy Lube for the $30 oil change. To this day there is no mention of it in any tech bulletins from Mazda that I am aware of.

Thanks to the owners, moderators and members of this site. Without people like you, we would not have these resources to possibly help in the diagnosis of our issues or share in the enjoyment of our chosen vehicles.

CHEERS

Mitch

[jstcruzin]

Nice story and SO true sometimes. Some, not all mechanics, that I have come across think they know more than you or always have the correct answer because you arent in their shoes. After all you brought it to them, right? And who are you, the customer to question? The best ones really listen and are willing to try and work with you for a simple solution rather than against you and ripping your car apart to make more money.

I hope they toss you a bone if and when you go back.

Originally Posted by ottoblotto Thanks to the owners, moderators and members of this site. Without people like you, we would not have these resources to possibly help in the diagnosis of our issues or share in the enjoyment of our chosen vehicles.

I second this ^^^^^^

[bscar]

Not very many service writers know what the hell they're talking about

[dajuice27]

Good looking out cuz!