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'01 F-150 won't start

 
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old.rancher old.rancher
User | Posts: 102 | Joined: 03/11
Posted: 02/26/13
04:37 PM

Hi again people -

I'm baaack - and just had two cars go out on me at the same time as I was headed to the ranch to pull a windmill for the second time.  I've got a handle on one of them, water pump on the wife's Jeep, but my daughter just limped into the driveway and said her F-150 (V8, 4.8?L) took three crankings to start.  Went out and put the Actron Auto Scanner on it and not one danged error code comes up. Nuttin'. Nada. Nope. Everything's just fine according to it.  Tried to turn the truck on and it almost catches but never quite gets there.  It rumbles through a few revs and then quits. No idiot lights, nothing.  
There IS gas in the tank, about 3/8ths of a tank.  I think I hear the pump working when I turn the key on.  The daughter did say she thought she saw some smoke coming from under the hood when she shut it down in the car port and that it ran pretty rough on the way home.

I hate to think about it but at 114K miles could it be needing new plugs?  Wouldn't a misfire have registered for this?

When it rains it dumps here in Texas - but no wet stuff in the right places!

Any thoughts are appreciated.  

waynep71222 waynep71222
Guru | Posts: 825 | Joined: 03/12
Posted: 02/26/13
08:03 PM

get out her owners manual or i can direct you to a download probably..

there is a fuse and relay section.. the second section is for the under hood relays..

figure out the relays for the PCM and for the Fuel pump..

there may be a third for power windows that is the same size...

mark them to where they came from and then SWAP..

i worked on a 2000 explorer yesterday that needed the relay contacts cleaned..

the full size relays are a PAIN to extract from the cover.. but you can gently slip the movable contact plate sideways to allow cleaning the silver contact faces with a tiny flat file..

if you break the sides of the relay cover.. the relay box is rain tight anyway..

and you will probably want to replace them.. but toss them into a blank area in the relay box for backup..

Thats what i would start with..

you might also look at your scan tool in live data mode if it has it.. and look at the cranking rpms..  while cranking..


you might also have to open the throttle slightly while cranking... to get it to start..

if the throttle body and the idle air control valve are dirty...  

waynep71222 waynep71222
Guru | Posts: 825 | Joined: 03/12
Posted: 02/26/13
08:06 PM

does the fuel pump stay on during cranking/??  

old.rancher old.rancher
User | Posts: 102 | Joined: 03/11
Posted: 02/27/13
04:43 AM

Thanks Wayne.  I'll check this out this morning and let you know.  The two valves you mentioned are on the air intake line aren't they?  

old.rancher old.rancher
User | Posts: 102 | Joined: 03/11
Posted: 02/27/13
09:16 AM

Well, what we have here is, apparently, a temperature related problem.  I checked the fuse for the fuel pump and it's OK.  Cranked the engine and after a rev or two it started up and ran fairly well.  A little roughness now and then but it tended to smooth out as the engine warmed up.  Put the code checker on the test port and, again, nothing shows up in the error codes.  Checkd the air filter to make sure a cat didn't crawl up in there and also looked at the sensor in the interior of the air intake line - is that the MAF sensor?  The two small filaments in there seem to be intact.
One thing did happen when I switched the code scanner over to view the real time data while the engine was running.  The scanner seemed to freeze up, which it's never done before.  Disconnected it and re-attached it and it went back to normal.
Don't know on this one.  Guess I'll try and drive it around until it gets good and warmed up to see if it starts to run rough again - or worse.  

waynep71222 waynep71222
Guru | Posts: 825 | Joined: 03/12
Posted: 02/27/13
01:47 PM

did i ever give you the link to motorcraftservice  dot com??   and have you download the obd2






this is the idle air control valve... it gets clogged with carbon... take it off.. hold it electric end upwards and blast it out with some brake cleaner...  then shake it out..



you will also want to remove the air inlet duct into the throttle body...

have somebody hold the throttle wide open.. ENGINE OFF of course...  spray some brake cleaner on a rag and wipe the carbon from the bore where the blade closes..

try NOT to fill the motor with any spray.. its really easy to damage it..

once you do this.. you may have to hold the pedal part way open to start the engine and get it running.. once its running.. hold the speed steady for 20 or 30 seconds.. then very slowly.. take about a minute to reduce the engine speed to idle... this will let the engine learn the amount of bypass air...

you may still need to change the idle air control valve.. they are about 50 bucks in some stores..  and they do wear out electricaly.  

old.rancher old.rancher
User | Posts: 102 | Joined: 03/11
Posted: 02/27/13
02:08 PM

motorcraftservice.com?  No, don't think I ever got that link but I'll certainly check it out.

I guess the idle air control valve is on top of the intake manifold, maybe on the throttle body?

I just ran the truck down to the gas station and put some unleaded plus in it with a dose of the STP injector cleaner, the black bottle, in it.  It did feel as if it had some roughness in the idle on the way back to the house.  We've been known to have bad gas around here but I don't know where it was that my daughter filled up last.  I've never put much stock in the injector cleaner products but now and then I don't think it will hurt.

I'll pull the IACV off and look at it for sure.

Thanks!  

waynep71222 waynep71222
Guru | Posts: 825 | Joined: 03/12
Posted: 02/27/13
02:10 PM

how the idle air control motor works is the computer controls the voltage into this..

this is a LINEAR electric motor...

when the engine is cold.. the computer commands the valve open fairly far to allow more bypass air for fast idle and starting...

as it warms up.. the computer starts closing the valve to slow the engine to a normal idle..

if there is carbon build up.. it might not be able to command it open far enough to start the engine..


carbon build up around the throttle blade also reduces the amount of KNOWN bypass air... this forces the computer to attempt to open the idle air control valve farther each time...

but it can ONLY open so far...

if it hangs up... you won't have enough air to start the motor...

once its running.. and i am taking there is a plastic shield over the top of the intake.. look and listen for vacuum leaks.. some fords have vacuum elbow hoses that collapse in hard to see areas... this is unmeasured air.. and will cause rough running as the computer does not know its coming in so it won't add that much extra fuel for it...  

waynep71222 waynep71222
Guru | Posts: 825 | Joined: 03/12
Posted: 02/27/13
02:21 PM

at motorcraftservice dot com..

look for this in the left frame.. click the proper link to download a PDF file..


OBDII Theory & Operation

The general descriptions (below) provide an overview of the OBD system used on Ford, Lincoln and Mercury vehicles since 1996.


OBD System Operation Summary - Model Year 2001 (296KB)

you don't need all of the info. but it is nice to know how some of it works..  

old.rancher old.rancher
User | Posts: 102 | Joined: 03/11
Posted: 02/27/13
05:04 PM

Ok, found the IACV on the top of the intake manifold and cleaned it.  It probably needed it.  The valve seat really doesn't open that much but it seems to be moving more freely now.  Didn't have time to clean the inside of the manifold but will as soon as I have time.  The truck seems to be running much better so time will tell on how well this fix worked.  Now if I can only talk my daughter in to driving it again.

There is one vacuum hose coming off the back of the intake manifold that needs to be replaces as it's got a significant amount of dry rot on it but it hasn't collapsed yet.  I haven't found any others that are leaking, however.

I know I downloaded the OBD system information in the past but I think it's on the other computer.  I'll get it again so it'll be on both.

Thanks.  

old.rancher old.rancher
User | Posts: 102 | Joined: 03/11
Posted: 02/27/13
05:12 PM

Ok, so if all the gas engines Ford puts out each year has the same OBD system is each engine's performance personality derived from the program on the computer's chip moreso now rather than it with the cam shaft and compression ratios like it used to be?  

waynep71222 waynep71222
Guru | Posts: 825 | Joined: 03/12
Posted: 02/27/13
10:03 PM

the OBD2 system monitors and adjusts the fuel trims to get the CLEANEST air out the tail pipe..

it also allows easier and standardized diagnostic tools to be plugged into any car..

so a mechanic does not have to relearn everything every time he opens a different hood...


it was forced by several groups that wanted to allow free access to out of warrantee repairs.   manufacturers were attempting to keep all the car repair business to them selves..

i have an older scan tool... it was 1800 bucks.. with a domestic cartridge.. the import cartridge and cables were 900 bucks more..

with OBD2... i just needed to buy a new cartridge every year or two... and perhaps a chip for the smart cable..   but now.. there have been so many advances... one needs to spend well over 5 grand on a scan tool...  to keep up...


i have given up trying to keep up with the other techs.. so i just pitter around with older stuff they don't want to fix any more..  older stuff now a days in beginning to become 2004 models..  

my advantage is i got in on the early electronic systems in 1980.. gm actually had electronic fuel injection in 1976 in sevilles and probably 1975 in eldorados..  i am really good at those also..  there were feed back carbs in 1978 here in california..  but VW and bosch had electronic fuel injection back in the late 60s..  or very early 70s...  chrysler had them beat by a decade.. 58 chrysler had electronic fuel injection.. but there were issues with the vacuum tubes lasting as the car was driven.


but i have gotten off thread..


cams.. port design.. adjustable cam phasing.. fuel injector design...  piston shape.. combustion chamber shape..  variable displacement.. where the valves are deactivated by controlling the hydraulic lifters..  switching them off and then back on without you even feeling anything.. other than the fuel burn decreases..

i just cannot wait for those hydraulic lifters to start failing.. talk about a hard to find misfire..  

old.rancher old.rancher
User | Posts: 102 | Joined: 03/11
Posted: 03/01/13
07:38 PM

You've basically described why I got out of networking in the schools.  Everything changes constantly.  When the last iteration of whatever OS you work with did just fine and certification in each little aspect of everything from basic TCP/IP to the latest version of MS Server cost $$$ and was obsolte by the time you got your certificate you simply did nothing more than chase your tail.

One of my favorite websites is written by a guy who's mantra is "everything is a business model".  It's all designed to extract buck$ out of you every time you turn around.  

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