Ok, I THINK its the fuel pump, i was gonna replace the filter first just for ****s since its cheap, but.


When i start it up, some times it fires right up but most of the time i have to crank for a few seconds, stop, then crank again and it fires right up..


or some mornings (been happening a lot lately) and tonight too. When i start it, it sputters a little and doesn't want to really run, then after a few seconds it comes around to idle right. THEN i go to drive and the FIRST start off it chokes and doesn't want to run, then it catches up and runs just fine.


My buddy suggested fuel pump, which almost makes sense. I'm gonna test the fuel pressure when I get around to it, but it seems to run fine after the initial start up


I just want some insight of what may have happened to someone else before I spend w/e the discounted price of one is.


99 4.0




Mmmkkk, i had searched like 5 pages when i made this, then started finding good stuff around page 6. It looks like this is my issue, I'll throw a pressure gauge on it Monday at work to confirm.

 

Turn the key on and wait 15 seconds.

What do you get?


Is this a hot start issue or a cold start issue?

 

both. well the sputtering when i start off is a cold start issue, not wanting to start right away is hot and cold


oh yea, and if i leave it in the on position for a while then it has to crank for a while. then if i turn it off and back on it turns right on

 

I have the same problem but for some reason my truck only has a problem when it is real moist outside.

 

good point, i don't think it was too humid in Wyoming, and it didn't happen too much. if i remember correctly?

now in texas its humid as hell lol

 

I'd check your MAF sensor maybe. Also check wiring for fuel pump and for MAF sensor. Throw some dielectric grease in the plugs.

 

I belive the best way to tell is with a pressure gauge. If it is not the FP, I'd look at the filter, TPS, MAF, plugs, etc, just start with the basics

 

as you mentioned it sounds like a fuel delivery problem. Maybe it is not keeping the fuel pressure up after your turn the engine off.

 

plugs and wires were done in august/september

 

Was browsing and came across your thread. Don't know if you've solved your problem yet.

Had a similar problem and it ended up being the fuel pump relay - a lot easier to replace than a fuel pump. Also a common problem on earlier Explorers.

I know it is a problem in the 4.0 liter SOHC engines - don't know about the earlier 4.0s, which I believe yours is.

Maybe worth looking at.

Keep us posted on how it turns out.

 

one of the guys at work said they sell aftermarket in-line check valves/*****... w/e


so once i get around to putting a fuel pressure gauge on it and seeing whats going on i may do that instead of buying a new pump..