Optikalillushun
Registered User
where did ur F-450 go?
1992 F350 C&C 4x4, 460 idle speed.
- Thread starter BigRigTech
- Start date
ameristar1
The One Blue Thing
How's the EGR system? Ya know carbon buildup makes life bad for these engines.
BigRigTech
Diesel junky
Very little to no egr on it. The air pump is deleted, there is a new EGR valve on it though. The ports for the IAC are clear, the TB doesn't look bad but I'm going to remove it for a cleaning any how....Next up is plugs and wires. I need to spend a day, verifing all the sensors for resistance cold and hot to see if eveything is ok and in spec. So far everything checks out.
ameristar1
The One Blue Thing
I wonder if there would be any advantage, once all the sensors have been checked, of advancing the timing a little to compensate for that bad combustion chamber the 460 has. Maybe it'll help with the mpg, I know the smaller bore 5.0 and 5.8 motors like a little more initial timing with the stock heads.
BigRigTech
Diesel junky
I always jam the timing ahead until I hear pinging and then back it down a little...More power and it runs smooth....I just haven't got to that yet on the 460.
BigRigTech
Diesel junky
I sold my F450 as is was useless in the winter, I wanted a 1-ton 4x4 so this was available cheap and it drives good.
tknomaj
Registered User
well does it run right yet or still a gas hog?
BigRigTech
Diesel junky
Still a pig, I haven't done much. I cleaned and verified that the IAC works. The coolant temp and IAT both were showing the correct resistance when they were 70F. I'm on vacation in a week so I plan to work at it then thoroughly to see what I can find.
MUDKICKR
Full Access Member
the throttle body has a coating on it and you can tear up the coating by spraying it with the wrong stuff. what you are talking about almost sounds like a vaccum leak. could be a glitch in the o2s but i would ck the vaccum first. also if the ck engine light is on then that has it in cold start mode, could be what your feeling. if it has o2 sensors, then it came with cat. converters. also the air pump pums air into the exhaust, without it there your o2 sensor will never read correctly. but you can take a spark plug fouler, drill out the center and install it between the o2 sensor and the exhaust bung, if one doesnt help use 2
BigRigTech
Diesel junky
The vacuum system on this thing is a mess....I haven't put a gauge on it yet to see what it's pulling for vacuum. I'll also spray some ether around it while it's running to find any leaks - if any. No check engine light and only one code in the ECM to do with the EGR valve. It doesn't smell rich or smoke. I'll post my findings once I spend a day on it.
BigRigTech
Diesel junky
I played with it today and noticed 2 things. If I unplug the MAP sensor wiring it drops about 200rpm and the IAC supply hose has vacuum in it wether the IAC is plugged in or not - what gives?
tknomaj
Registered User
how are you disconnecting vacuum line to idle air control it does not have one . here is the picture of throttle body and idle air control valve. what are you disconnecting ? please post pic
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BigRigTech
Diesel junky
Mine does not look like that, mine is on the intake manifold directly under the TB. If you take the IAC off, there is 2 holes, about 1/2" each in size. One is plumbed to a 3/4" nipple pointing towards the front of the truck and this has a hose from the nipple to the fresh air supply to the TB....It's a mix of factory setup and not seeing as my belt drive system is custommized because it used to have an air compressor.
