Oh man this is getting annoying
Thread Starter
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New User
Joined: Nov 2003
Posts: 22
Likes: 0
From: Toronto
Oh man this is getting annoying
Ok boys here it is,
1991 e-350 351w efi. Idles rough, intermitent loss of power and occasionally dies right out. I can start it again right away but it will continue to run irregularly.
To deal with this problem I have replaced
ignition coil
tfi module
had tank cleaned
new fuel filters
new EGR
I would like to believe that it is a problem with fuel delivery but I just don't know enough about the pitfalls of the efi systems to check anything. From what I have read, I beginning to think of problems potentially with the
fuel pressure due to pump or fuel pressure regulator
fuel injectors or mix
Anyway, if any one could list some testing proceedures that I could do or could have done I would appreciate the guidance.
Many thanks
1991 e-350 351w efi. Idles rough, intermitent loss of power and occasionally dies right out. I can start it again right away but it will continue to run irregularly.
To deal with this problem I have replaced
ignition coil
tfi module
had tank cleaned
new fuel filters
new EGR
I would like to believe that it is a problem with fuel delivery but I just don't know enough about the pitfalls of the efi systems to check anything. From what I have read, I beginning to think of problems potentially with the
fuel pressure due to pump or fuel pressure regulator
fuel injectors or mix
Anyway, if any one could list some testing proceedures that I could do or could have done I would appreciate the guidance.
Many thanks
Lead Driver
Joined: Nov 2002
Posts: 9,557
Likes: 44
From: Concord, NC
Have you pulled the codes? That would be a good place to start from. Go here: http://fordfuelinjection.com/index.htm and go down on the left and click on "Getting Codes." EFI systems are pretty good about diagnosing themselves if there is something wrong electrically. I'd also clean the idle air control solonoid to make sure it is not stuck.
Postmaster
Joined: Jun 2003
Posts: 2,656
Likes: 5
From: shepherd
yeah the car doctor on the radio said it was carbon in the mass air flow sensor and related sensors. clean them and try. i had a truck like that. it was a 90 or 91 with maf 5.0 it had the dual intake mass air flow sensor on it. i just lived with it.
Thread Starter
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New User
Joined: Nov 2003
Posts: 22
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From: Toronto
I pulled the codes and got 33 and 41. Where is the mass air flow sensor.
I also read a possible problem from the van forum which led me to believe that it could be the temperature sensor. Cause the problem occurs only after a little driving.
I also read a possible problem from the van forum which led me to believe that it could be the temperature sensor. Cause the problem occurs only after a little driving.
Postmaster
Joined: Jun 2003
Posts: 2,656
Likes: 5
From: shepherd
code 41 on my 95 v6 mustang was an o2 sensor code. but i think they may be different. sorry i meant the throttle body instead of the maf sensor.my truck had the mass air efi on it i don't know much about the other efi or what years and vehicles it was on but if you engine has the 2 piece intake manifold it it a mass air efi. the throttle body is what the air filter intake hose connects to. clean it good but not with carb cleaner. you need something specifically for that
Lead Driver
Joined: Nov 2002
Posts: 9,557
Likes: 44
From: Concord, NC
if you engine has the 2 piece intake manifold it it a mass air efi
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Elder User
Joined: Jan 2004
Posts: 767
Likes: 1
From: Franklin, GA
Same situation, different truck. Mine turned out to be the O2 sensor itself and the associated wiring at the attaching point. All this was caused by an oil leak that had saturated the wiring. Worth a check.
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Postmaster
Joined: Jun 2003
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From: shepherd
yeah EPN told me that somebody may have done a mass air conversion before i got it. i thought the throttle body injection had an intake manifold that was simular to a carbed manifold and the throttle body looks simular to a carb. but anyway my 90 had one of those dual intake throttle bodies. the truck was bought new from fy great grampa then sold to my uncle and finally givien to me without knowing too much about it's history
Fleet Mechanic
Joined: Feb 2003
Posts: 1,314
Likes: 35
> Idles rough,
I had the same thing, could not idle, and it was Idle Air Control Motor. Very simple to replace. I wanted OEM part, but used something from Napa parts and it worked great.
I also thought it was TPS (sensor), but it wasn't.
I didn't have loss of power, which shows it something other than above.
IMO, O2 sensor would not cause either condition, just make it run rich, but not really loose that much power and it certainly would not make it die.
I had the same thing, could not idle, and it was Idle Air Control Motor. Very simple to replace. I wanted OEM part, but used something from Napa parts and it worked great.
I also thought it was TPS (sensor), but it wasn't.
I didn't have loss of power, which shows it something other than above.
IMO, O2 sensor would not cause either condition, just make it run rich, but not really loose that much power and it certainly would not make it die.
Junior User
Joined: Feb 2004
Posts: 60
Likes: 0
From: earth
i would try a fuel pressure gauge. it should crank up rather fast and hold for awhile. i think pressure should be around 38-42psi on those but could be mistaken. look in book. what is o2 sensor sayin is wrong lean/rich? if injectors are dirty it usally isnt intermident. if fuel pressure drops fast on gauge and dies its probally the pressure release in the pump. a lean condintion can also be caused by a vacume leak or bad map sensor. a bad iac valve could cause same thing try cleaning the pintle and port it may help but they usally require replacement.
let us know
let us know
Last edited by duff man; Feb 13, 2004 at 05:40 AM.
Senior User
Joined: Jun 2003
Posts: 400
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IAC stands for IDLE AIR CONTROL. IT'S LOCATED ON THE THROTTLE BODY AND REGULATES AIR BYPASS IN IDLE CIRCUIT. PICK UP A NEW GASKET, REMOVE VALVE AND CLEAN THE HECK OUT OF IT. LOOKING TO REMOVE ANY DIRT OR CARBON BUILD UP. INSTALL AND TEST. GOOD LUCK.
Postmaster
Joined: Jun 2003
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From: shepherd
running rich will make your motor run rough and lose power.
my 95 stang started running rich on 1 bank 1 month ago and that was because i had a bad bottom intake gasket. it started sucking unmetered air in which told the computer to richen the mixture up on that side. i have true duals so i had all kinds of black smoke puffing out one pipe. and it had bad acceleration until the plug got hot enough to even fire it off better. it smelled bad and i was getting fuel in my oil and bad gas mileage. smell your oil to see if it smells like gas. if it does then change it and that tells you that your engine is flooding.
my 95 stang started running rich on 1 bank 1 month ago and that was because i had a bad bottom intake gasket. it started sucking unmetered air in which told the computer to richen the mixture up on that side. i have true duals so i had all kinds of black smoke puffing out one pipe. and it had bad acceleration until the plug got hot enough to even fire it off better. it smelled bad and i was getting fuel in my oil and bad gas mileage. smell your oil to see if it smells like gas. if it does then change it and that tells you that your engine is flooding.