Idle Speed

[kirby]

Hi everyone

I'm new to this having just bought a Rav4 GX 1995 petrol auto. Problem is idle speed seems too high, about 1000 and very slight fluctuation when warm. Goes down to 800 when put in drive. I've cleaned the idle control valve, no difference. I should add I have no problem with too low a speed or stalling and she seems to otherwise run as sweet as the proverbial nut! Any hints or tips would be greatly appreciated.

[anchorman]

Welcome to the forum.

Is the heated rear screen turned off? It will lift the idle speed the same as turning the wheel and having the air-con on. Other than that I don't think its adjustable but bothy might have something in his manual.

[warlock]

i've got the same problem with my 2001 rav nrg

with a 1AZ-FE engine

when starting from cold it idles at 2000 rpm

until it reaches operating temp any help would be appreciated

i've also cleaned the idle control valve

[kirby]

Thanks for your responce Anchorman. I've just checked the rear screen heater and it's not that. Chap at work suggested a vacuum leak, I've tried pulling pushing and squeezing all the hoses I can see but it dos'nt get better or worse. Maybe the EGR valve?

[anchorman]

Thanks for your responce Anchorman. I've just checked the rear screen heater and it's not that. Chap at work suggested a vacuum leak, I've tried pulling pushing and squeezing all the hoses I can see but it dos'nt get better or worse. Maybe the EGR valve?

I don't have any 4.1 info and the stuff I do have is mainly diesel. However, I do have some info on the brand new VVTi and that suggests a problem with the throttle body (the bit of the intake with the throttle butterfly in it). Most of the diagnostic revolves around electronics but it does suggest looking for leaks and damaged gaskets on the engine side of the throttle body.

An old trick for locating leaks on the inlet side is to have a spray around with some WD40. If any of the vapour gets pulled into the intake through the leak the engine will race. It doesn't do any harm (don't spray it directly onto the exhaust manifold) but you can progressively home in on the leak.

I hope this helps

Good luck

[geomowat]

Chap at work suggested a vacuum leak, I've tried pulling pushing and squeezing all the hoses I can see but it dos'nt get better or worse. Maybe the EGR valve?

Ditto to all your previous postings. I was talking to a Toyota Mechanic today who was gloomy about the Idle Air Control Valve (IAC) as its replacement is expensive (did not suggest a figure). It could be the PCM not sending it the correct signals, but this is far less likely than the IAC not doing the right thing with the correct signal.

that suggests a problem with the throttle body (the bit of the intake with the throttle butterfly in it). Most of the diagnostic revolves around electronics but it does suggest looking for leaks and damaged gaskets on the engine side of the throttle body.

Agree with this and it would be downstream of the butterfly (other than the bypass function of the IAC, which of course, is designed to supply a metered leak).

An old trick for locating leaks on the inlet side is to have a spray around with some WD40. If any of the vapour gets pulled into the intake through the leak the engine will race. It doesn't do any harm (don't spray it directly onto the exhaust manifold) but you can progressively home in on the leak.

This did not reveal anything in my case, but this is a good trick that often does work. As my increased idle is only when fully warm (1,300 - 1,400 rpm), one has to be a little bit careful where the overspray goes!

When inspecting mine, I was suspicious about a pair of valves (one with a dot and 4 on it the other with 2 & 3) on the bulkhead, one of which seemed to have something broken off it (an earlier posting which even Bothy could not identify!), the mechanic I was nattering to today confirmed that one was physically damaged and they are Vacuum Valves. He followed up this confirmation by telling me not to bother trying anything else to find the reason for the higher idle for the moment as when either of these valves was not functioning correctly, it played havoc with all sorts of tickover situations as did most types of vacuum leak into the plethora of vacuum pipes.

Good luck,

George