Starting issues

[jojo22]

1998 GT, when the engine gets warm and the car has less than 1/4 tank it drives fine, but if you shut it off (like at the store) it will not start until it has cooled down. Not an issue when the tank is full. Changed fuel filter, still happens.

Any ideas??

 

[MustangChris]

so:
gas - 1/4 full ~ engine - cold - no start (how did you start it the ery first time? to get it to the store?)
gas - 1/4 full ~ engine - hot - re-starts fine
gas - 100% full ~ engine - cold - ????
gas - 100% full ~ engine - hot - ????

why do you think it is a fuel problem? and not a faulty starter, starter seloniod, bad ground wire? bad power wire?

what does it do when you try to start it, and it doesnt start?

 

[jojo22]

Okay

1/4 tank cold = start

1/4 tank or less warm = no start (well it did start once at the store but while going from reverse to first died when I tried to hit the gas) but normally will not even idle long enough to get in gear.

anything more than 1/4 tank it will start every time.

It cranks and tries to start, but appears to not be able to idle or keep running. I concluded fuel filter because I knew it was original and the dealer told me it's a good place to start for an issue like this, but they also said it could be fuel pump, and with it running normal at anything over a 1/4 tank that seems odd. But dad had the filter in the garage already so I swapped it out, needed done anyways.

Also with this being my first "issue" post thank you for the quick response I'd love to fix this for dad tomorrow, he is terminally ill and I would really like him to get as much use out of this car as he can while he can drive.

 

[MustangChris]

im sorry to hear about your dad.

it sounds like maybe something is going on inside your tank. ive never opened a mustang gas tank up, so im more useless than tits on a nun at this point.

but some one else will chime in, no worries.

 

[jojo22]

Thanks, and thanks for taking a crack at the problem. I was kind of hoping it was just some type of censor or something needing cleaned.

 

[MidniteGT]

Well instead of just tackling the fuel system. Test your fuel pressure. Do it with 1/4 tank full cold and see where your psi is. Do it hot with less than 1/4and engine hot see where you psi is at. You can start ruling out the fuel system that way.

Also when you do try to start it warm and it doesn't startwhat is the engine actually doing. Also what chris said might not even be your fuel system.


Sorry about your father btw.

 

[joekd]

anything more than 1/4 tank it will start every time.

Not to sound cold and unfeeling but if his time is limited isn't a good fix to just keep well over 1/4 tank for now instead of tearing the car apart to fix a car with such a simple workaround?

 

[MustangChris]

anything more than 1/4 tank it will start every time.

Not to sound cold and unfeeling but if his time is limited isn't a good fix to just keep well over 1/4 tank for now instead of tearing the car apart to fix a car with such a simple workaround?

you should always try to keep more than 1/4 tank of gas because our pumps are fuel cooled, thus more fuel will maintain an overall lower temperature. Also, an easy "work around" is technically neglecting the main problem. neglect may cause larger issues later on.

Well instead of just tackling the fuel system. Test your fuel pressure. Do it with 1/4 tank full cold and see where your psi is. Do it hot with less than 1/4and engine hot see where you psi is at. You can start ruling out the fuel system that way.

Also when you do try to start it warm and it doesn't startwhat is the engine actually doing. Also what chris said might not even be your fuel system.


Sorry about your father btw.

good advice,

jojo, do you know how to test your fuel pressure? if not, i can write it up, but i dont want to insult you with information you already know.

 

[MidniteGT]

Also, lower than a quarter and a warm pump(thatsw weak) it could have problems getting the fuel.

 

[MidniteGT]

+1 to chris about neglecting the problem. Wouldn't be good if his father had a bad fuel pump or something and then his car breaks down when he is driving somewhere. But ya reply to the fuel pressure.

 

[jojo22]

Okay, thanks for all the help.

No I have no idea how to test the fuel pressure.

When I try to start the car during the issue it is like it is trying to start but "can't" no knocks, pings, or odd noises, it turns over, sounds from the exhaust like it is getting good compression, and the air filter is clean, so of the major things a car needs (fuel, air, compression, and ignition) I have most. I can look at them one at a time. Fuel, the issue seems to run around the amount in the tank and engine temp, Air, clean filter and car runs fine when it is moving so I therefor assume it is getting air, Compression, when turning over the exhaust is throaty as normal leading me to believe this is not the issue, Spark, no issue when cold, and the motor starts to turn over but will not idle, without spark it would not try. I think it is getting some fuel, just not enough, almost like when a filter is dirty (had that issue on an old car of mine and it seems identical)

No simply ignoring the problem is not an option. If something is wrong it NEEDS FIXED!! This car will be passed to me as his only son, so even if it's not fixed now (which I am hoping to do so he doesn't have to worry about it while still owning it, I will be fixing the issue in order to keep the car in the condition he would have liked to see it. So either way, the tread is needed. Also with everything else on his mind watching for the quarter tank mark is not top on his list I am sure (though I try to keep all fuel injected cars above that mark). And yes to imply doing such is somewhat cold, just because he has limited time does not mean he no longer cares about his things or should let them go, he is still a person with pride, at least leave him that.

 

[MustangChris]

to test the fuel, you need the proper gauge and fitting. the local parts store can assist you with that. just say you need a fuel pressure test gauge that will work on a 1998 4.6L V8 SOHC fuel rail.

on the top of the motor, you will see two chrome "shafts" running across the top of the motor. these are Fuel Rails. They supply fuel to the injectors. on the driver's side rail, you will see a small black nipple on the front portion. this is where you place the gauge. BUT FIRST:

open the trunk, behind the drivers side trunk pannel (youll have to pull the pannel outwards to see it) there is a large red button. make sure it is depressed. then de-connect the plug from the bottom of the button. This is the fuel cut-off switch.

Next, start the car. keep starting the car until it wont start any longer. remove the key.

Put on a work apron (if you have one, not mandatory) safety goggles, and gloves, a mask too if you have one handy.
remove the black nipple. be careful as it may spray fuel on you (i leanred this the hard way. hense i suggest all the safety equipment.)

plug your newly purchased/rented fuel pressure gauge onto that fitting.

return to your trunk. plug the button back in.

turn your key to "on" (the final position before it trys to turn over- listen for your fuel pump to engage and "buzz")
turn your key to "off"
(do this a total of 3 times.)
this primes your fuel system and attempts to re-pressurize the system to avoid a dry-start.

after the third time start the car. let it idle for 10-15 seconds.
turn the car off.

go read the gauge. it should maintain pressure for quite a while.



anyone else have anything to add?

 

[jojo22]

Okay and what range am I looking for, and if it is low, seeing as the filter was replaced does this tell me that it is the fuel pump?

 

[jojo22]

BTW: Thanks again for all the help.

 

[MustangChris]

here is a picture of my 1996. as you can see, above the valve cover on the drier side is my permanant fuel pressure gauge. thats where you test the pressure.

<img src="http://carphotos.cardomain.com/ride_images/2/4359/1841/23395920188_large.jpg">

 

[MidniteGT]

Make sure you wipe of any gas that may get anywhere. I test mine a little different but chris's way works just fine. Around 38 or so. Mine stays around 40 now. Also before taking the tester of to bleed the tester

 

[MustangChris]

how do you do it midnite? just curious. always like learning new things.

 

[jojo22]

Thanks guys. I sare the info with dad and see what he says tomorrow.

 

[MidniteGT]

One more thing at one point when your doing the testing to just put key to on and see what the psi is(when it starts having the problem do this).

Note: bleeding your tester gauge will drop the gauge back to 0 psi

 

[MidniteGT]

how do you do it midnite? just curious. always like learning new things.

Do what? I'm a f15e crew chief so learning cars and picking up maintenance is preety simple. Compared to the millions of jobs I do on a jet a car is simple

Edit: BTW iwish my motor was that clean.