5.4 Issue!

[Konasan]

Hey guys I need a bit of help here. This morning going to work I started my 99 EB up, its turning over but the engine won't fire up. I try started it 3x then eventually the 3rd time it fired up by pressing the gas pedal. Later today during my lunch break I tried to start up again and did the same thing. When I got off work it works fine now. Anyway I know it works fine right know but I just don't trust it and tomorrow I'm sure it will do that again. Is it the fuel system, ECM (God I hope not) etc. I hope someone can help me figure this out. Thanks! (^_^)

 

[FordandPolaris]

Well no one has responded to you yet so I will take a crack at it. Do you have a check engine light? You probably would have said so if you did, but just to check. Without a code though its hard to try and pinpoint the problem. It could be that the fuel pump is going bad, but I don't think that it would allow the truck to start after giving it some gas on the pedal. Does it sound like the engine is cranking with full force when it isn't starting?

 

[Konasan]

Well no one has responded to you yet so I will take a crack at it. Do you have a check engine light? You probably would have said so if you did, but just to check. Without a code though its hard to try and pinpoint the problem. It could be that the fuel pump is going bad, but I don't think that it would allow the truck to start after giving it some gas on the pedal. Does it sound like the engine is cranking with full force when it isn't starting?

Hi FordandPolaris! The check engine light is not on and yes the engine is cranking full force when it didn't start. This happened to me twice today although with a couple tries, the engine starts up.

 

[2k3Expy]

I would check the fuel pressure first and maybe check the fuel filter.

 

[mpsjr]

It sounds like a fuel related issue, and my guess would be the fuel filter and/or fuel pump. How old is the filter? They should be changed every 35,000 miles or so anyway. You really need to check the fuel pressure on your fuel rail to see if there's pressure while trying to start it. If the pressure is low, then I'd start by replacing the filter, and then see about taking it to a shop to check the pump. If there is enough pressure on your fuel rail, then it could be a bad, or dirty injector(s).

 

[toms89]

I assume you are just giving a bit of throttle. If you go wide open throttle it goes into clear flood mode and does not inject any more fuel while cranking. If your w.o.t. when it starts its flooding for whatever reason.

As said it may be fuel related. Because of the individual coil on plugs, ignition related issues would be more likely to create a miss than a no start situation.

Its possible your IAC valve is faulty or in need of cleaning but this can also create idle issues. The IAC opens a predetermined amount for start up. (If the IAC is completely closed or blocked the engine would stall and or not start with out some throttle)

If it is running well otherwise you can rule out the mass air sensor as it is not used during start up.

 

[superexpy]

I vote a sticky IAC. try taking it apart and cleaning it.

 

[Thermo]

Konasan, I want you to try something. when you start having issues, rotate the ignition key to the RUN position (do not take it to the START position). Wait there about 5 seconds and then attempt to start the truck. If it fires off like it normally does, then you have a bad fuel pump. If it is still having issues, then I would go after the IAC valve, especially if you notice that your idle varies by about 200 RPM or so when the motor is cold. If you need assistance in cleaning the IAC valve, let us know. It is easy to do.

 

[CARO'S98EB]

Check it like Thermo said and also watch for the theft light flashing. when you crank it does it spit and sputter a little but not really start or does it just crank over?

 

[Konasan]

Hi guys sorry for the late reply. I was busy couple weeks ago. Thank you so much for your replies guys. Right now it's working fine but when it's less 1/4 full tank of gas(or 25 miles before empty on the FC/compass display) left that's when the ISSUE comes up. And I have another question too. Do I need to depressurized the fuel lines in order to replace the fuel filter and do I really need a special disconnecting tool for it? I just read it on the Chilton Manual.

 

[Exia]

If its only doing it with less fuel sounds like to me its the fuel pump getting weak, pumps dont work as hard when its full, once you start getting near the bottom of the tank the pump works harder to pressurize the tank to get fuel flowing again. Thats why if you listen closely you hear the *hiss* coming from the tank when you shut it off, it releases all the pressure. Take your filter off than have someone turn the key to ON not start.. if it blasts out of the line with some good force pump is fine but if not. There would be your issue.

Either that or the readouts are off and you have less fuel in the tank than it says..

 

[JUST4FUN]

If its only doing it with less fuel sounds like to me its the fuel pump getting weak, pumps dont work as hard when its full, once you start getting near the bottom of the tank the pump works harder to pressurize the tank to get fuel flowing again. Thats why if you listen closely you hear the *hiss* coming from the tank when you shut it off, it releases all the pressure. Take your filter off than have someone turn the key to ON not start.. if it blasts out of the line with some good force pump is fine but if not. There would be your issue.

Either that or the readouts are off and you have less fuel in the tank than it says..

the fuel pump puts pressure in the tank??? really? to get fuel flowing?

 

[Exia]

the fuel pump puts pressure in the tank??? really? to get fuel flowing?

You have never noticed on any vehicle, ?? You're tank becomes pressurized, when the pump engages. Remember pumps dont lay at the bottom they are at least 1/2 in from touching the tank...

Take a siphon house same principle except the pump keeps a constant feed, ( Not gravity ) which is why they have a pressure regulator, keeps the flow at that psi.. I thought everyone knew that. Unless they changed this in the last 25 yrs, Sorry but I am old school 60 -70S these new ones tick me off

Electric pumps are "PUSHERS" they are like the siphon hose they push fuel through the lines with "pressure" which is the *hiss* from near you're tank its a relief system

Mechanical pumps are opposite they "PULL" fuel through the lines under vacuum

 

[JUST4FUN]

yes fuel pumps push fuel through the lines, but pull fuel from the tank. They do not put pressure into the tank to help pump fuel if this was the case there would be 40 to 50 psi in the tank. this would be a safty hazard and a fire hazard
pressure regulators are vaccume controled at idle the pump sends more fuel than the engine can use so it sends it back to the tank (on older cars and trucks).as you give it more gas the vaccume is lost and the regulator closes suppling more gas to the engine. at max or 100% vaccume is gone and max fuel and pressure is going to the engine. my Expedition has never had the hiss come out of the tank that is suppost to be taken up by the EVAP contaner and stored till the next start. if working rite. we are smog tested here every two years if its not working rite you cant get your plate stickers

 

[JUST4FUN]

which is the *hiss* from near you're tank its a relief system

auto fuel systems are not to be vented to atmosphere in any state.

 

[stamp11127]

Modern day fuel pumps do not directly pressurize the tanks, they pressurize the fuel lines. Some older fuel systems have return lines that dump heated fuel back into the tank. This will in time increase pressure in the tank - expanding liquid in a confined area will increase pressure.

Exia things have changed, Go Ol' Ford has "variable speed" fuel pumps - cycling the pump on and off quickly due to demand. My two Escorts don't have a fuel return line or fuel regulator. Instead they have a fuel pressure sensor that reads the pressure in the line which the pcm uses to signal the fuel pump module.

The last two fuel pumps I put in, the strainer/pickup was slightly off the bottom of the tank in a recessed depression. Not 1/2 inch from the bottom.

Exia, the old days are long gone for us old school guys. But I haven't found anybody still wishing they had a set of points under the hood or oil bath air cleaners.

 

[Konasan]

Thanks for your reply guys! (^_^) Exia and stamp11127 thanks guys for sharing your knowledge about fuel systems. I don't even know how these PRESSURIZED thingy works on the fuel lines and to/from the fuel tank . Anyway i'll bring it tomorrow to the mechanic to check fuel lines and the fuel pump. I'll keep you guys posted.

 

[hovocop]

hi gang, my 98 eb does a similar thing with not cranking up right away .......... I do the "wait 5 seconds rule" and it usually starts up on first or second time....... but if it was the fuel pump, wouldnt it just not start at all? Also, my problem does not vary with amount of fuel in the tank

 

[stamp11127]

hovocop, in your case the pressure/fuel in the fuel line drops down over time when not running. When you turn the ignition to "on" the fuel pump pressurizes the fuel line. Sometimes you may need to cycle the ignition to "on" more than once to pressurize/refill it enough to start. Classic sign of needing a pump.

 

[JUST4FUN]

hovocop, in your case the pressure/fuel in the fuel line drops down over time when not running. When you turn the ignition to "on" the fuel pump pressurizes the fuel line. Sometimes you may need to cycle the ignition to "on" more than once to pressurize/refill it enough to start. Classic sign of needing a pump.

BUT if its running ok most likely the pump is ok,but the check valve is bad or going bad. if you can live with turning the key on and off to "prime" the pump should be fine.