4.9L Idle
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Joined: Apr 2003
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From: Venezuela
4.9L Idle
Hi there, the idle of my f150, 1995 was acting funny but the engine was having too much blow by so I was guessing the problem could be my old engine.
Recnetly I did installed a totally rebuilt engine and the idle still same so I have to ask:
1° What is the normal idle? hot engine, No A/C tranny neutral?
2° With A/C turned on??
3° With tranny in "D" gear??
My truck does so:
Hot engine, no A/C, neutral gear: 650 RPM
Hot engine, A/C on, neutral gear: 850 RPM
Hot engine, A/C on, "D" gear: 750 RPM
As far as I know the idle should be 600 - 650, can some one confirm this?
I also notice each throtle plate has a orifice, a friend told me there is supposed to be a couple of plugs installed, is that right? what kind of plugs??
Any comments will be appreciated. Regards;
Recnetly I did installed a totally rebuilt engine and the idle still same so I have to ask:
1° What is the normal idle? hot engine, No A/C tranny neutral?
2° With A/C turned on??
3° With tranny in "D" gear??
My truck does so:
Hot engine, no A/C, neutral gear: 650 RPM
Hot engine, A/C on, neutral gear: 850 RPM
Hot engine, A/C on, "D" gear: 750 RPM
As far as I know the idle should be 600 - 650, can some one confirm this?
I also notice each throtle plate has a orifice, a friend told me there is supposed to be a couple of plugs installed, is that right? what kind of plugs??
Any comments will be appreciated. Regards;
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Joined: Feb 2002
Posts: 504
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From: Saddle Brook United State
Those figures look fine to me. "I also notice each throttle plate has a orifice" why would ford drill holes in the throttle plates and then plug them----they are most likely idle air bleeds or would be if it were a carburetor.
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From: Venezuela
Guys thanks for the comments.
Yes it is EFI and I want know if all trucks with similar configuration show same behaviour. My personal opinion the idle some times is too high and tranny kick a bit when "D" is applied.
Some small Ford EFI engines have drilled orifice at throtle plate, those are use to install calibrated plugs used to help the IAC to control Idle characteristic. I have never seen a specific procedure to calibrate the throtle plates for the 4.9L I asume this is not requiered since this is a big engine, compared to engines used for compact cars.
Any more comments?
Yes it is EFI and I want know if all trucks with similar configuration show same behaviour. My personal opinion the idle some times is too high and tranny kick a bit when "D" is applied.
Some small Ford EFI engines have drilled orifice at throtle plate, those are use to install calibrated plugs used to help the IAC to control Idle characteristic. I have never seen a specific procedure to calibrate the throtle plates for the 4.9L I asume this is not requiered since this is a big engine, compared to engines used for compact cars.
Any more comments?
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Posting Guru
Joined: Apr 2003
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From: Venezuela
Mistake here are the correct readings...
Hot engine, A/C off, neutral gear: 950 RPM
Hot engine, A/C on, neutral gear: 850 RPM
Hot engine, A/C on, "D" gear: 750 RPM
Hot engine, A/C off, "D" gear: 650 RPM
Hot engine, A/C off, neutral gear: 950 RPM
Hot engine, A/C on, neutral gear: 850 RPM
Hot engine, A/C on, "D" gear: 750 RPM
Hot engine, A/C off, "D" gear: 650 RPM
Postmaster
Joined: Dec 2006
Posts: 3,603
Likes: 10
From: Spokane, WA
That would certainly be a bit steep for my carbed application. I'm not familiar with the EFI idle characteristics.
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From: Venezuela
Good point!!!
Well for testing, I did disconnect vacum lines going to vacum reservoir so all emission solenoid where out of the "equation" but idle remaind same. MAP sensor and fuel pressure regulator lines where verified also.
New PCV valve was installed just to be sure it was working right. The idle is noticeable reduced if the PCV valve is totally pluged.
Tomorrow I'll take off the booster line to see what happend.
Any More Ideas guys?
Well for testing, I did disconnect vacum lines going to vacum reservoir so all emission solenoid where out of the "equation" but idle remaind same. MAP sensor and fuel pressure regulator lines where verified also.
New PCV valve was installed just to be sure it was working right. The idle is noticeable reduced if the PCV valve is totally pluged.
Tomorrow I'll take off the booster line to see what happend.
Any More Ideas guys?
Postmaster
Joined: Mar 2002
Posts: 3,545
Likes: 4
From: Coal Region
usually with the A/C on the engine will up the RPM to compensate for the load. urs are opposite. have u checked out the IAC and cleaned it?