1992 F350 C&C 4x4, 460 idle speed.

[BigRigTech]

I bought this truck a month or so ago, I finally got around to tinkering with it this week. I bought a used 10ft steel work deck for it. I drove it a little this week and noticed the engine runs good but it idles too high....Around 1000-1100rpm...It has some vacuum leaks to be fixed, there is a pile of crap in the engine bay that needs to come out because the truck was a field mechanic rig on a pipeline in it's former life and most of the gear has been removed. The air pump has been deleted and there are no CAT's on the truck. My emissions label is gone from the engine bay - I need to know what the base timing should be set at and what the idle speed should be....A little tuning can't hurt, it's a "thirsty" beast...

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[Diesel_brad]

the emissions sticker is on the hood. I dont know if thats where you were looking?

 

[BigRigTech]

The emissions sticker is long gone - that's my problem. This truck has oxygen sensors but no cat's, might have been emission excempt for light commercial work????

 

[Diesel_brad]

was just looking on my 96 today. There is a second emision sticker on the drivers valve cover. And by the 92's there was no such thing as emision free for the "heavy duty". Dam tree huggers

 

[BigRigTech]

No tags on mine anywhere. It has oxygen sensors but no cat's....The IAC works but I think the problem is with the coolant temp sensor. I noticed my gauge hardly moves and I feel the PCM could be thinking the engine is cold and therefore keeping the rpm's up. If I disconnect the IAC when the engines warm it still idles at 1000rpm...Now if I shut it off hot and restart it right away without touching the fuel pedal it idles at 750rpm until the first time you give it fuel

 

[Goofyexponent]

do those 460's have the same kind of high idle control as our IDI's? I would imagine it is all computer controlled on that engine.

 

[BigRigTech]

Nah, just your typical gas guzzler EFI system....The thing needs to be working right as it's a pig on fuel in it's current state.....Passes everything but a gas pump.......Once I get this high idle issue solved and do a full tune up I might eek out another 1-3mpg........Otherwise it's getting an IDI transplant now that I had to sell my Cummins.

 

[Goofyexponent]

thats right too! you got that IDI in the garage just begging to be installed in a truck. I think i may have found a spare motor for my truck for $400...it's in a truck running and I can have it for $400 if i pull it.....might have to take the tractor to lift it out of the frame rails. Know anyone looking for an almost new set of 87-91 fenders and a brand new gas rad support?

 

[BigRigTech]

What are you doing with the dually? I might be interested in the rad support. I can make it fit my diesel.

 

[Goofyexponent]

i am putting the newer style front end on it....i should have thought about before i stripped it down and sold the good fender i had. The rad support i have is for a gasser, but if you cut it and dropped the bottom of the cradle down you could make it work. I have a brand new 4 core aluminum rad for the same year gasser, but I am going to try and put it in the 1992-1996 rad support. the two fenders I have for the 87-91 are damn near mint, if not brand new painted yellow

 

[tknomaj]

10 degrees btdc and idle 650 +or- 150 disconnect spout connector before setting timing as for coolant temp sensor it has two one for ecm and one for guage and a bad coolant and air temp can make it run rich very very rich it will set adapt limit codes because it can no longer control pulse width with program

 

[BigRigTech]

Where is the temp sensor for the ECM? I would like to see it idling at 700rpm. I have an old school blink code reader for it so I might see what is stored in the ecm.

 

[tknomaj]

to the left side of dist or in coolant passage it will have two wires temp sensor for gauge only has one wire

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[BigRigTech]

I checked the coolant temp sensor, the readings were in line with the temps according to my book. I might try another TPS for the hell of it.

 

[tknomaj]

Your truck runs a vehicle speed air density program for engine fuel managment check you air temp sensor, map , and baro sensor if coolant temp sensor reading going to ecm are correct the problem will be in those listed