I’m experiencing a strange issue with my 2010 Mazda6 that is extremely unsettling on a day-to-day basis. When I’m at very low RPMs and foot off the gas my RPMs jump insanely high when turning the steering wheel causing me to panic brake. I have no idea what’s going on.
My regular RPMs when idling is around 700
When I’m in Drive or Reverse with my foot off the gas, RPMs go up slightly to around 750 (normal expectation)
But if I turn my steering wheel in either direction, very often the RPMs spike up to 1500 causing the car to jump. Although this NEVER happens if my steering wheel remains straightened out.
For some reason this is more prominent when the car is on an incline (ie, hill, parking garage…etc)
This has also occurred when I’m in Neutral as well and I start moving my steering around, spikes up to 1500
I understand that it is entirely normal for the ECU to increase RPMs a bit when turning the steering wheel, but not to this insane level. Anyone have any advice/suggestions for me? Thanks!
You can borrow a scanner for free from Auto Zone (etc.). Even if you don’t want to act on it yourself the knowledge prepares you for dealing with a mechanic.
Gotcha, thanks. If I get my hands on one of these, anything in the live data I should pay attention to? There’s no codes coming through my OBD2 reader and no check engine light.
Oh sorry, I do have a OBD2 live data scanner with me. Just wondering if there might be certain fields/statistics in the output I should keep an eye on when this issue happens? Thanks!
Small update - Looks life if I disconnect the power steering pressure switch, the issue disappears completely. I think my first step is to replace the power steering pressure sensor, for now I’m driving with it disconnected.
Turning the steering wheel places an extra load on the engine from the power steering pump. Most modern car automatically increase the idle rpm to compensate for the extra load when the steering wheel is turned. How that’s done varies car to car. On my older Corolla, thepower steering pump has an air valve which opens when the steering wheel is turned. The open air valve directs more air into the engine, same as pressing on the throttle pedal a little. With more recent vintages, the computer detects when the steering wheel is being turned via a power steering fluid pressure switch. When the switch says the steering wheel is being turned, the computer increases the idle rpm using an electric motor controlled throttle valve.
ok,yes I understand that.
fully understand that revs rise to compensate for usage.
what I’m experiencing is the car starts up and idles fine (cleaned carb,components are working) but once you turn it over compensates and can rev 1000rpm over the 900rpm it was idling at.then hunts or fluctuates rapidly.
I’ve switched out the pump switch .carried out relearns but still it happens.
pull the signal wire from the switch and no symptoms.
The big clue is when you disconnect the PS pump pressure switch, the symptom goes away. This suggests that when that switch indicates the PS pressure is high, the idle rpm is not increasing the correct amount. I have no experience w/your car, but it likely uses an electric motor to control the throttle valve and the idle rpm. Something appears wrong with that function. Ideas
Electric-motor fault
Gunk is preventing electric motor from setting throttle valve in correct position
Computer is confused, doesn’t know the actual position of the throttle valve , throttle position sensor fault, etc.
The second one, gunk in throttle body, seems the most likely.
no sorry,apologies
cleaned throttle body.
I’ve been typing carb clean and my fone has changed what I was meant to say.
used carb cleaner.sprayed air lines,throttle body,butterfly both sides etc etc.cleaned sensor connections etc.
I currently have p/s on pump un hooked (suggested by mitsubishi themselves as they dont know)
on top I’m having a performance issue .have done for awhile.im bit lost as I’ve gone back and forth with almost everything attached to the block.
I’m even having boost issues.went from factory solenoid,to after market,to manual t controller and no matter what I do it wont go higher then 7psi.(gauge) my other airtrek has none of these issues.yes I have two financial mistakes .but I love them too much and cost me too much .lol.
bit lost now… going as far as swapping out egr or blank plating it.
A shop might know of a way to make the computer think the high pressure switch has activated, without turning the steering wheel. Might provide a clue.
I doubt this has anything to do w/EGR. Not saying you don’t have an EGR problem, but this isn’t it. Can’t say if this would work on your car, but I test my vehicles’ EGR systems by applying vacuum to the EGR vacuum input at warm idle. If EGR valve is working, the engine will stall. If it doesn’t stall, usually the problem is the EGR passages are clogged w/soot, not the EGR valve itself.
A pro-level scan tool might be able to command the throttle valve to different positions that you could verify by looking at it, seems like that might be a fruitful test for this problem. High idle rpm can be caused by a fault in the pcv system, including something as simple as a faulty pcv valve. Have you tried testing for vacuum system leaks using starter fluid?
