Ok, I have read all the other posts, but no help...I have a 2004 EB 4.6 Expy with about 86,000 miles. All of a sudden I tried to start it one day and it didn't start the first try as it usually did, and it has been doing it for over 2 months...When I turn the key and crank for 2-3 seconds it dosen't start, I let off, then crank again for about 2 seconds and it starts (although it sometimes runs rough for about 2-3 seconds after it is started, then it smooths out and runs fine)...The first thing I did was change the fuel filter, didn't help...I checked the air filter (like new). I changed the spark plugs, didn't help. The battery checks good and cranks strong. It runs excellent even at full throttle and idles great(except where previously noted). It doesn't blow any smoke out the exhaust when it does finally start up. I tried turning the key to just before the starting position and let it set there for 3-5 seconds before cranking, but that does nothing to help. I have tried different brands and octanes of gas, and have ran fuel injection cleaner through it twice. I really do not want to take it to the dealer, so any help would be appreciated. Thanks...P.S. once in a while it will just start the first try, but probably only once in 35-45 starts.
Long Crank !!!!! Help !!!
- Thread starter Spicoli
- Start date
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green03
Full Access Members
replace the IAC..... This is a valve that regulates idle speed by varying airflow into the engine. I am 99 percent sure this is your issue.....
Matt R
Matt R
Sounds just like it to me... Its about 55-60 bucks to replace but a little of a pain to change since it sits right at the firewall. If i remember correctly there are 2 8mm bolts holding the IAC in. Basically what you are looking forward too is some free time, a few scraps here and there on your hands and patience.
One last thing... may want to use sockets that lock into the ratchet or those ratchet wrenches cause if this is the first time you will be doing it i can guarantee you that you will drop tools and then the fun really begins trying to find them and getting them out. Just a note of caution but nothing to be scared about.
One last thing... may want to use sockets that lock into the ratchet or those ratchet wrenches cause if this is the first time you will be doing it i can guarantee you that you will drop tools and then the fun really begins trying to find them and getting them out. Just a note of caution but nothing to be scared about.
replace the IAC..... This is a valve that regulates idle speed by varying airflow into the engine. I am 99 percent sure this is your issue.....
If the IAC was the problem, wouldn't it give a code...I went to Auto zone and they put the code scanner on my truck, all good, no issues..??
If the IAC was the problem, wouldn't it give a code...I went to Auto zone and they put the code scanner on my truck, all good, no issues..??
green03
Full Access Members
nope... there isn't a position sensor on the IAC.... The computer just tells it what to do and doesn't know if it is really doing it or not..... The computer can detect a shorted or open winding in the magnetic coil that drives the valve but that's it.
The symptoms are stalling when cold and all of the sudden when running rough it just "pops" back to a good idle.....
Matt R
The symptoms are stalling when cold and all of the sudden when running rough it just "pops" back to a good idle.....
Matt R
AvroAero
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If I have a slightly rough idle sometimes when the truck is in drive and stopped, could it be the IAC? Its more common with the AC on.
green03
Full Access Members
Yes this could be your issue..... also if your air filter gets pretty clogged up it can do this too.....
Matt R
green03
Full Access Members
Not if the truck is running.......
It maintains fuel pressure at all times with the engine running.
If the computer can't add enough idle speed via the IAC it will resort to adding timing to increase the idle speed which will give the engine the shakes. I have even resorted to changing some of the parameters on my custom tunes to allow the IAC to give more airflow that seems to smooth out the shaky idles that some trucks seem to have bone stock.
Matt
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