1998 SOHC 4.0 Won’t Start

[dave_1998]

1998 SOHC 4.0 Explorer XLT 4WD intermittently won’t start, seems to occur only when cold. I have about 40psi on the fuel rail. When it starts you can turn it off and it will start right back up. After it starts it runs great. The THEFT light is on solid when I crank it over then turns off after about 3 seconds of cranking. What to check next.

 

[Blee1099]

Try a few things, try turning the key to on for 2 seconds and then back to off then try starting it. This gives the fuel pump more time to prime which could be the reason why your having a hard time starting.

 

[dave_1998]

I have been waiting the 2 seconds for the last week and the truck has been starting first try. Thanks for the tip.

Any idea what is causing this to happen. The truck has 66k on it. I never changed the fuel filter but I would think if the turck can go 80mph the filter is OK. I tested the fuel pressure over time and the pressure holds. After a few hours I still
have 30psi. at the rail.

 

[aldive]

The problem is most likely the fuel pump.

Good luck ........

 

[dave_1998]

I had the pump replaced under waranty when the truck had 10k miles because it would not turn on when it was hot.

So is failure mode now the pump takes longer to turn on and generate pressure, but once it's running it's OK or is it going to fail on me when I am driving.

 

[aldive]

Ifit is indeed the fuel pump, you need to replace it asap.

Good luck ......

 

[Billy177]

if it had 40psi at the fuel rail when it would not start it is not the fuel pump. my guess would be the crankshaft position sensor

 

[dave_1998]

Update: 1998 SOHC 4.0 Won't Start

Update on my no start problem. 23,000 miles ago my rear timing chain failed and took out the passenger side head. The dealer replaced the head, both timing chains and installed new spark plugs. The plugs they put in were not platinum. After 23,000 miles the gap was 0.76 in. When I was having the no start problem I suspected the plugs and changed the drivers side because it was easy. The passengers side has more of a pain I was ready for at the time. I figured that 3 new ones would be better than 6 old ones. Wrong. I forgot that the coil fires two spark plugs every time. The cylinder that is in compression gets most of the spark but with one plug at .054 in and the other at .076 in I think that made things even worse. I changed the passenger side and what a difference. Before the car would typically crank for a few seconds before it would start. Now the truck starts almost instantly just like when it was new. Thanks for the help.