ton van der sluijs

Hello everybody
As you noticed in several topics which i've opened, that I've bought a truck in July with several misfuntions. At this moment she runs and rides great and I'm also a bit proud of all the effort which I'd put in . There's only one thing left to disolve: idle is going up and down ( between 900 and dips to 500 and back) I've think a bad IAC valve, but I've also read that the right opening of the butterflyvalve is very important... Can anyone tell me how to adjust this?

greetings Ton

Good old Bill

Hi Ton, hows it going? The IAC or as I miscall it ISC is disconnected electrically, (unplugged) then the base idle is set to around 450-500 RPM's. The engine will barely run. What is being done is to prevent any sticking of the throttle plate to the bore of the throttle body. As a machinist, I'm sure you understand this function. After that is done, the ISC, excuse me the IAC is controlled by the PCM to maintain engine idle and also to serve as a faster idle during engine start ups.

Double check for any vacuum leaks, the older models the IAC could be cleaned and also we found if you would use a bottle brush from the wifes kitchen to swab out the throttle plate and bore itself, helped alot. On my 02 this procedure is placaarded against performing. Why, I don't know?

ton van der sluijs

Hi Bill Yes I'm fine thanks or as they say "we mustn't grumble" grinn.
I've adjusted idle the way you said, but there's no difference. I've connected my OBD1 codereader and it says 173 what means Hego always to rich... further invertigation says O2 sensor not switching... What is the meaning of this? Do I have to swap the Lambdasensor? Or is there an other cause what doesn't switch the O2?.

best regards to you Ton

Good old Bill

I'm not sure of the true engineering fuction of the heated O2 sensor. In my laymans mind the "not switching" means the heater function of the sensor is not truning off, thereby possibly giving a false reading.

ton van der sluijs

Hey Bill You were right about the throttle adjustment. I drove the truck until it was on the right temperature, and the idle wasn't bad at all! Okay, some hiccups remained, but The LPG injection equip has to be finetuned.
About the 173 code.... I did the test with a nearly cold engine! Stupid fool I was! Every cold engine is to rich. I still have to run the test with a hot engine, but..... later First I'm gonna remove the tires from the wheels... The painter sprays my wheels next week and.... new tires are waiting at the tireshop next door. My truck is sprayed ( or is it painted?....my English let me down) three months ago and with new tires, sprayed wheels she looks brand new ( and a refurbished engine).

best regards Ton

FordsForLife

An o2 not switching means its either running too rich or too lean could be any false air readings, fuel pressure alot of stuff all's the heater in it does is bring it up to temp faster on cold starts because a cold o2 wont switch. When you hear switch their talking about the Milli volts of the sensor going from rich to lean and so forth and so on. Not the heater going on and off