this automatic has timing chain rattle for about 5000 miles, it is now idleing low about 700rpm. Is there a way to increase idle RPM?
Thank You,
Barry

 

There is no idle adjustment on fuel injected engines.

The IAC(idle air control) Valve is computer operated and very very accurate, usually within 5 RPM of "target" idle

Automatic do idle higher after warm up than manuals, usually 750 in Park and 800 In Gear

If idle is at or above 1,000 on cold start and then slowly drops as engine warms up then IAC Valve, ECT sensor and computer are working

Doesn't read like an IAC Valve issue but could be, I would clean it since it is free to do so

Good read here on that: How to: IAC valve cleaning thread (w/pics) | Ford Explorer and Ford Ranger Forums - Serious Explorations

 

if you know you have a timing chain on the way out, replace it asap.

If you do not replace it you will one day soon wish you had.

Chances are once you get a new chain kit installed the idle may fix itself.

BTW can you post a video clip of this suspected timing chain noise?

My Ranger 2.3 DOHC with 141K that I have been working towards getting on the road has a noise once warmed up that sounds like it could be from a worn chain.

I have been saving up my money to get it done since my back and neck will not allow me to do it myself.

here is a clip of my trucks engine you can here the noise once I rev it up slightly towards the end of the video.

on occasion I can here this noise slightly at idle but it only shows up once it is warmed up where the temperature gauge is at the half way mark.

The weird thing is the noise seems to go away once I shut the engine off and and disconnect the serpentine belt.

which caused me to find a noisy alternator, Belt tensioner, fan clutch drive bearing in the front timing cover and a noisy water pump.
even after replacing all of those parts the engine still has the same noise I have been trying to track down.

Yet all the other noises I found went away with each part that I replaced.

The only thing I can figure is I am not running the engine long enough with the belt off
to duplicate the noise ( to avoid overheating )

or the lack of load on the engine from the belt being off causes the timing chain to stop making noise.

and yes I pulled each spark plug wire one by one which made no change in the sound.


here is a much longer video that shows the noise either going away or at least getting quieter once the belt is removed.