Piston knocking/slapping when the truck accelerates from around 1200RPM @40MPH.
First things First: I'm using 91 to 93 oct Gas since day 1.
It started doing it uphill, since the transmission shifts too soon, sometimes when going uphill the RPM's drop
under 2000. When I step on the pedal to accelerate it . .. Piston knocking right away for a few seconds, then it stops. Whenever the truck goes under the 1200RPM and I need to accelerate again, it knocks. And I'm not confusing this sound with the valve sound (the sewing machine sound) that Toyota still saying that "it's normal". I know what piston knock/slap is and that sound can't be confused. At first I thought I was a casual thing, but it started to doing it even on the Highway.
According to the advantages of an Atkinson Engine: piston knocking is virtually "impossible" or less likely to happen because of the Direct Injection system. When fuel injection happens inside the chamber it is supposed to cool it down to prevent pre-ignition due to overheating. I hope to got this right. Well, if it is not a matter of high temperatures at the combustion chamber, then could it be a too lean air/fuel mixture. And this could explain that hesitation feeling when accelerating/lugging the engine. We know now that there's an under power feeling due to the transmission shifting too soon to higher gears, but this might a stacking issue as well.
Things I found weird....MPG. Frequently this truck is giving me more than 28MPG. That's weird. I mean, or something is f.ckd up, or the MPG calculations are wrong or the ECU just want to save fuel or run the truck with air only ?
I took the truck to the dealer, and guess what ? They didn't find a thing and they've stated that my truck is on spec. I'm taking it back to the dealer again an try to contact Toyota corp. because this is something that needs to be addressed and fixed accordingly.
I'm posting this complaint here because I haven't heard of this before and I really don't know if this is an isolated issue, but the truth is it is not acceptable on a new car.
A D V E R T I S E M E N T S
2nd Complaint I've got on my "new" truck.
Piston knocking/slapping when the truck accelerates from around 1200RPM @40MPH.
First things First: I'm using 91 to 93 oct Gas since day 1.
It started doing it uphill, since the transmission shifts too soon, sometimes when going uphill the RPM's drop under 2000. When I step on the pedal to accelerate it . .. Piston knocking right away for a few seconds, then it stops. Whenever the truck goes under the 1200RPM and I need to accelerate again, it knocks. And I'm not confusing this sound with the valve sound (the sewing machine sound) that Toyota still saying that "it's normal". I know what piston knock/slap is and that sound can't be confused. At first I thought I was a casual thing, but it started to doing it even on the Highway.
According to the advantages of an Atkinson Engine: piston knocking is virtually "impossible" or less likely to happen because of the Direct Injection system. When fuel injection happens inside the chamber it is supposed to cool it down to prevent pre-ignition due to overheating. I hope to got this right. Well, if it is not a matter of high temperatures at the combustion chamber, then could it be a too lean air/fuel mixture. And this could explain that hesitation feeling when accelerating/lugging the engine. We know now that there's an under power feeling due to the transmission shifting too soon to higher gears, but this might a stacking issue as well.
Things I found weird....MPG. Frequently this truck is giving me more than 28MPG. That's weird. I mean, or something is f.ckd up, or the MPG calculations are wrong or the ECU just want to save fuel or run the truck with air only ?
I took the truck to the dealer, and guess what ? They didn't find a thing and they've stated that my truck is on spec. I'm taking it back to the dealer again an try to contact Toyota corp. because this is something that needs to be addressed and fixed accordingly.
I'm posting this complaint here because I haven't heard of this before and I really don't know if this is an isolated issue, but the truth is it is not acceptable on a new car.
- ciscom, Caguas, Puerto Rico