2003 f225 idle issues

[wayneo99]

2003 f225 serial # 69jx1002517

idles at 750- 800 out of the water, has a slight hesitation about 900-1000ish, intermittant intake back fire at 900-1100 but not always seems better when warm but not sure.

TPS at idle 691 Mv
idles is 7-8 according to yami digital gauge
VST filter just cleaned, looked ok
injectors just cleaned, 2 were in need of cleaning due to leaking and 1 had low flow also new injector screens.
entire fuel system lines were cleaned and blown out
new inline racor and yami filter replaced.
new plugs
gas is new

went through the TPS and throttle synchrinization 2 times to make sure I did it right and had the correct TPS voltage.

I do not have vaccum gauges for each intake setting.

read almost all the posts here via the search about the EFI systems, TPS, injectors, VST etc.

any suggestions? cant afford to fry a piston or something.

 

[wayneo99]

Re: 2003 f225 txrb

Re: 2003 f225 txrb

just found rod bolts old post about a sticking ISC/IAC

on every key off I hear the chatter, when the motor is running the IAC is warm not hot.

when I take the 3/4 gray hose off of the plastic fitting on the top of the motor towards the back nothing changes.
If I close off the hose with my finger the motor runs terrible.

also will be doing a shock treatment with ring free and 6 gal of gas, dont know if it has ever been done on this engine.

any thoughts?


wayne

 

[rodbolt]

Re: 2003 f225 idle issues

your on the right track anyway.
with only those symptoms I would not sweat frying anything just an aggrevation.
but the only way to properly adjust the throttle plates is with a manometer . no other way.

 

[wayneo99]

Re: 2003 f225 idle issues

thanks rodlolt,
I have a friend who is a HVAC tech, he has a manometer for me to use.

any suggestions on the pressure for each plate or average port to starbord?

Wayne

 

[rodbolt]

Re: 2003 f225 idle issues

its in the manual.
I know thats not what you wanted to see but the procedure is about 4 pages long and is fairly complex.

 

[wayneo99]

Re: 2003 f225 idle issues

I totally understand,
Can it be done with a simple manometer doing 1 throttle plate or intake
port at a time or do i need a 3 bank unit.

 

[rodbolt]

Re: 2003 f225 idle issues

a 3 bank unit and the correct tamper proof torx bit.
and the service manual

 

[wayneo99]

Re: 2003 f225 idle issues

Revisiting the rough idle again, seemed fine all summer long until a few days ago.

Confirmed that the ISC/IAC was operating at shut down with audible chatter at key off. motor only running a few minutes.
ran to my fishing spot to drift fish. on almost evey restart the idle started at 1200 then came domwn to 700 in about 10-15 sec. when put in gear it stumbles to about 400.
give it a bump to 800 or more and its fine. WOT 6k no issues at any other speed.

cleaned the ISC with some carb cleaner at the dock and it was working.

ran it tonite and did the same thing and now no audilbe at key off.

I have to shoot it with a temp gun next time out and see if the ISC works when the motor is cold.

is there a another way to test the IAC

 

[wayneo99]

Re: 2003 f225 idle issues

Ttt