2000 Explorer won't crank after motor is hot

[Sparkles254]

I have a 2000 4.0. Here is my scenario. I'm a mail carrier and drive approximately 85 miles on the route. 14 mikes each way to and from work. After I drive to work. The vehicle sits around two hours until I'm ready to head out on the route. No problem cranking then. My problem comes after I've driven the 84 miles and get back to the office. Cut the vehicle off and come back approximately 10 minutes later and if I can actually get it to crank then it idles very rough. Sometime I can rev the motor and if I can get the revs high enough it will start idling like normal and can actually drive it. Otherwise it dies out and there is no hope of actually getting it to crank for a good 20 more minutes. I can then drive about 10 miles towards home and stop and get gas which only lasts a few minutes and the vehicle cranks right back up. As long as I don't ever cut the vechile off during the 85 mile route it never has a problem with the idle or running properly. Could this be a fuel pump issue or something else all together? Thanks for any help!

 

[MrQ]

TLDR: Possibly fuel pressure regulator in tank, probably fuel pump.

Easiest way to check if its the fuel pump is when it's hard to start, turn the key on and off (don't start the motor) two or three times to prime the fuel rail and try and start it. If that happens, I bet you have a bad regulator in the tank since it runs fine normally. You have a non return fuel system which means there is a pressure regulator (pretty much a glorified check valve) that keeps pressure in the fuel rails. If fuel is by-passing it very slowly the pressure will drop over time taking it longer to start. This could be further complicated by a weak fuel pump (there is a check valve in the fuel pump as well). Since you have to drop the tank anyway to get to either of these items, I would replace both at the same time.

 

[Mbrooks420]

If it always starts cold, and will restart after a few minutes, but not longer while still warmed up, I’d bet on the coolant temp sensor.

 

[MrQ]

If it always starts cold, and will restart after a few minutes, but not longer while still warmed up, I’d bet on the coolant temp sensor.

Could possibly be that, however if the CTS was bad only at a certain temperature range, then the engine would die as he was driving and warming it up into that range, not just when he was letting it cool down.

Do you have any codes? A bad CTS sensor will usually throw an out of range code. Another possibility is an intake gasket leak, in which case you might get lean codes.

 

[Mbrooks420]

Could possibly be that, however if the CTS was bad only at a certain temperature range, then the engine would die as he was driving and warming it up into that range, not just when he was letting it cool down.

Do you have any codes? A bad CTS sensor will usually throw an out of range code. Another possibility is an intake gasket leak, in which case you might get lean codes.

Naw, that’s not the case. This is classic coolant temperature sensor failure. It won’t cause the truck to die, it just has trouble starting on the wrong mixture. I dealt with this for over 6 months (burned it up apparently by welding on the frame). It never once stalled. Was just hard to start after a period of time until cool. If I ran the starter for several seconds three times it would start on the fourth try.

I don’t believe mine threw a CEL during this time except for Evap Emissions Leak due to bad hoses on my charcoal canister.

 

[MrQ]

Naw, that’s not the case. This is classic coolant temperature sensor failure. It won’t cause the truck to die, it just has trouble starting on the wrong mixture. I dealt with this for over 6 months (burned it up apparently by welding on the frame). It never once stalled. Was just hard to start after a period of time until cool. If I ran the starter for several seconds three times it would start on the fourth try.

I don’t believe mine threw a CEL during this time except for Evap Emissions Leak due to bad hoses on my charcoal canister.

Huh, learn something new everyday.

 

[Mbrooks420]

Huh, learn something new everyday.

I don’t know if it could cause a lean/rich condition, though. It’d think the o2 feedback would keep it in check, but maybe not.

 

[donalds]

If it always starts cold, and will restart after a few minutes, but not longer while still warmed up, I’d bet on the coolant temp sensor.

My guess to
When it is cold starts up good every time when it's hot no start or barley starts then dies
Coolant temp sensor would be my guess

 

[Sparkles254]

It cold starts perfectly. If I turn the engine off and restart within just a couple minutes it starts perfect. After about 10 minutes it will barely start. Then idles incredibly bad and dies unless I can pat the gas enough until I can actually rev it really high. Then once again it idles perfect and I can drive it. I've tried to prime the pump/fuel rail by turning the switch to on and back off 4 or 4 times and that doesnt seem to have any positive effect on trying to get it to start and idle.