Really need help! Starting problem

[greg s]

97 Explorer 4.0 SOHC 240,000 miles

Recently my x had been hard to start usually in the morning. I had to crank several times before it would finally try to start and then it would take several seconds before the engine really got running. After it got started it runs great. So one time when it was hard to start I checked for fuel at the schrader valve and did not get much fuel with the key on, so I figured with the age and miles it needed a new fuel pump.

So I replaced the fuel pump last week and everything seemed good until today. Its acting the same way as before. When I check for fuel at the schrader valve with the key on I dont get a burst of fuel but more like air and fuel mixed together. But when I check it with the truck running it a big steady fuel flow out the valve.

I swapped the fuel pump relay with the WOT a/c relay and that did not change anything.

I am going on a 400-600 mile family trip the end of next week and dont want to get stranded, so I have a week to figure it out and get it fixed. I need all the help I can get!

 

[corkey]

fuel filter changed too ?

 

[greg s]

I had changed it about 1000 miles earlier for normal maintenance. The inside of the tank was super clean.

And the tank is about 3/4 full. It runs great after it gets started, I towed a trailer with a 1200# mower on it yesterday and it performed great.

 

[greg s]

So I went out this morning to test start it and see what happens. After 1-2 seconds of cranking it started fine and idled ok. So I shut it off and tried it several times and it acted the same. Whenever I turn the key on I can hear the fuel pump run for a few seconds.

So then I went to check for fuel at the schrader valve. With the engine off and cycling the key on there is no fuel coming out of the valve. With the engine running its a full flow of fuel coming out of the valve. After I shut the engine off and check for fuel at the valve there is none. So it seems like the fuel pressure is bleeding off very quickly and it takes the extra cranking to build pressure back up.

Any ideas on what the problem could be?

Could it be a injector sticking open or not sealing shut and allowing the fuel pressure to bleed off?

 

[greg s]

Does anyone know how the fuel pressure regulator works on this year? Does the FPR act like a check valve? Is there a check valve in the system any where? Help!

 

[2000StreetRod]

Ford Explorer Ranger Fuel pressure test procedure

Ford Explorer Ranger Fuel pressure test procedure

The FPR should maintain pressure in the fuel rail for several minutes after the pump shuts off.

 

[greg s]

I finally got a fuel pressure tester and have it connected to the truck. I have not been able to get the truck to fault again fully as I havent driven it long enough in the middle of the day (work). I did notice once that when it was hot that the pressure did drop to about 15psi after it sat for about 30 minutes and when I tried to restart it there was a slight hesitation. Later I tried it again and could cycle the key 3 or 4 times to get it back up to 40psi. I am thinking it may be the injectors leaking after a hot soak.

 

[dennis h]

Sounds like injector bleed off.

 

[greg s]

So after more testing I figured out that the IAC was not functioning correctly. I tried to clean it, but it did not help. I could slide the piece inside and it would stay stuck in whatever position I left it. So I replaced it and it solved about 90% of the starting problems. Still working on the other 10%.

 

[dennis h]

starting problems

I just got my ranger started yesterday. Too stubborn to check the timing as it was a new belt, crank sensor EGR, both O2, TPS. I took all connections apart, cleaned and greased them. Never considered a stuck cam from 2 years of dry bearings. Well, I ate a lot of crow this week and decided to check. Sure enough, jumped about 4 notches on cam and one on jack shaft. The sensor on jack shaft must cause spark because I was getting fuel, no spark condition.

OK, so engine started badly, ran worse and died repeatedly, all the while giving the distinct smell of running rich. Ran the codes. Codes read out were both coil circuit failures and O2 sensor. Reset them and it ran a bit better, misses and rich condition remain. Trouble with idle, no power (which got a little better) still a rich running condition. I'm hearing a vacuum leak around fuel rail vicinity but can't isolate it by covering the pot or vacuum lines. So I went for the EGR and air bypass solenoids. Air bypass connection wiggle caused increase disruption of idle. Caused a miss increase.

One thing strongly on my mind in the older models is the EVAP system. This caused me much grief 4 years ago. 160 dollar part as it must be purchased from Ford as complete unit. I stood o my head looking for the problem until I actually found the wire pinched under the battery. So today I'll put the fan blade back on, run it til warm and pull the neg cable for system reset. Yippee, two car family again.