Cold: - when i start the engine without touching the gas pedal, RPM are very low and a lot of vibrations. - does it immediately smoothen out if you then touch the gas pedal? - When i start the engine when i push the gas pedal (a very few), it starts perfectly. - and does it idle correctly thereafter? Hot: - when i start the engine without touching the gas pedal, it tries to start but do not. - When i start the engine when i push the gas pedal , it starts after a few seconds. - and does it idle correctly thereafter? I wouldn't worry about having to press the accelerator somewhat during hot starts as it is a fairly normal procedure. I wouldn't worry either if the answers to all of the above "red" questions is "yes". The "don't touch the accelerator" applies mainly for cold starts and also in the case of the ECU controlled IAC-s, like the ones on the 2.7. What you have a re some kind of mechanical idle control devices that appear to sense intake vacuum based on which they "decide" how much to open or close the bypass air. Perhaps they are a bit tired and need a bit of push on the accelerator to make them establish the kind of "equilibrium" between the intake vacuum and opening of the bypass.
I was going to vote for the air bypass being clogged, but i'm not so sure. Image Unavailable, Please Login sjd
That's exactly what I was going to say, turn them out 1/4 - 1/2 turn max and do ecu reset and see if that helps. If it does rebalance the 2 sides with vacuum gauge.
Our discussion is very interesting, sept by step i’m Learning how the engine works. Could you explain how to rebalance the two sides with a vaccum gauge? Where to connect it and what vaccum gauge may i have to buy ? To should be nice to know that.
So if i understand well, the bypass is the N.2 part on the picture (one on both side). May I clean it (and all the pipes) with brake cleaner spray ? Image Unavailable, Please Login
Bypasses are shown in post #52. I imagine you would need vacuum gauges before you decided to disassamble these? Note the "do not touch unless you know what you are doing" yellow paint
If you decide to remove the bypass adjuster screws for inspection and cleaning, first screw each in until stop and record the number of turns from their original positions. After cleaning, you can then put them back where they were.
When i left my office This afternoon, i went to the garage where my car is. My idea was to clean the by-passes. I’ve checked the toolkit but the right wrench was not there, so it was not possible to do the job. It will be done tomorrow. I started the engine and....... very strange, it started correctely, without the gas pedal ! What is different from sunday ???? Just the air température (hot wheather today), from 25 to 31°C
problems like this often come and go and are not consistent making it difficult to resolve, change something and it works then problem comes back and the thing you changed did not affect it, it just seemed that way.
So, i've just removed the two throttle bodies for cleaning... Image Unavailable, Please Login Image Unavailable, Please Login
Here is one of the two air bypasses.... both are very dirty! on one side, when i put it back on the throttle body, i can screw 1/4 revolution more to close it ! Image Unavailable, Please Login
Post #52, you want to clean out that orifice, there is an o ring in there to replace if dry or damaged.
