Gas...Or no Gas?

[Nasanieru]

Hey guys,

Got another question!

I purchased a K&N Filter for my 99 expedition 5.4, AWD. Hoping it would help performance and it did for just a little while. I noticed that the truck was starting to take longer and longer to start. It never didn't start...just took a bit. I also had a hole in my manifold...Thinking it was the manifold, I ended up changing it. To my surprise the problem stayed the same. So I heard that K&N filters can leak onto the MAF sensor, so I cleaned It and It got worse. But my performance got better. The truck now drives and runs beautifully! but, still hard to get it started. My next fix will be the fuel filter but, it has been only a year since I changed it last so I would think it's still good. Could be wrong...

Any help would be awesome...Oh yeah, I checked the battery and the alternator and both of them are good too. There is no check engine light on either.

Thanks Guys!

 

[Yudaman]

Did you clean the filter or the MAF?
I have read a lot about oiled filters sending oil downstream and gumming up the MAF. But to my knowledge, if the MAF is gummy, performance goes down across the board...
I am not totally up to speed on the use of aftermarket filters and their downsides. I am sure there are a few forumites that can help more than I can.

 

[stamp11127]

As a test remove the air filter and try starting it. If it improves then you have filter problem.
Next I would check fuel pressure at KOEO and running before throwing parts at a problem that you don't know the cause of.

 

[BIGRED03]

Hey guys,

Got another question!

I purchased a K&N Filter for my 99 expedition 5.4, AWD. Hoping it would help performance and it did for just a little while. I noticed that the truck was starting to take longer and longer to start. It never didn't start...just took a bit. I also had a hole in my manifold...Thinking it was the manifold, I ended up changing it. To my surprise the problem stayed the same. So I heard that K&N filters can leak onto the MAF sensor, so I cleaned It and It got worse. But my performance got better. The truck now drives and runs beautifully! but, still hard to get it started. My next fix will be the fuel filter but, it has been only a year since I changed it last so I would think it's still good. Could be wrong...

Any help would be awesome...Oh yeah, I checked the battery and the alternator and both of them are good too. There is no check engine light on either.

Thanks Guys!

Are you talking cold or hot starts? What fuel rating and blend do you use? Weaker summer blends will be over soon so back to a little more punch in a gallon of fuel maybe this will help also.

 

[tonydiv]

Although I've always been a K&N fan, I use dry type filters on new computer controlled vehicles.

 

[toms89]

The mass air sensor is not utilized during cranking. It basically targets specific airflow and injector pulse width based on engine temps. I would not consider the mass air sensor or air filter to be a problem if it runs and drives great otherwise.

My first guess would be fuel pressure related issues. I would do as Stamp mentioned and check your fuel pressure both with key on, engine off and with it running. A significant vacuum leak will allow more air in than desired leaning out crank fuel.


Is it worse when its hot or cold start?

Once you start it can you shut it off will it crank and start immediately after?

 

[Nasanieru]

Answer to Questions

I know that if I turn it off and then turn it on its good. If it sits for any period of time it starts hard, cold and hot. I tried turning the ignition on but not start the truck, basically prime the line and that helped a little. It made it quicker but not like I am hoping for. What are the thoughts on the plugged fuel filter?

Thanks guys, please keep up the help!!!

 

[toms89]

I would change the fuel filter as it is a tune up item anyways. If the problem still exist it may be a failing fuel pump. Checking the fuel pressure would confirm.

If priming the pump several times improves starting, it is a good indication it is fuel related.

 

[Nasanieru]

If I pump the pedal it doesn't improve the starting kind of makes it worse...lol, only turning the key to the on position has help. And I only tried it once...Well, I will start eliminating fuel systems unless we are certian its the pump? I thank you so much for this help...

Sincerely!!

 

[toms89]

If I pump the pedal it doesn't improve the starting kind of makes it worse...lol, only turning the key to the on position has help. And I only tried it once...Well, I will start eliminating fuel systems unless we are certian its the pump? I thank you so much for this help...

Sincerely!!

Pumping the pedal is kind of pointless while cranking with fuel injection. If anything it will lean it out due to the extra airflow. With the older carburetor cars you had an accelerator pump that would pump additional fuel each time this was done.

My guess would be the fuel pump but this can be easily confirmed by checking fuel pressure.