Hard Start

[kylecolb]

So I have been having this problem for some time now. It doesn't matter the temperature or how long my 02 Explorer is sitting, but it seems to happen more when sitting for a few hours.

I get in the truck, turn the key, and it tries to turn over for 3-4 seconds before it finally does, them it seems to be a hard start and the idle drops, then it goes up to normal idle. (this is only turning the key and trying once, it always starts the first time, but every once in a while there is a hard start like this). It has done it at -20 degrees and at +70 degrees out and all in between. Then sometimes when this happens, if I try to shift right away, the truck will die. No dashboard lights come on. It just turns off, then when I try the second time it will start how it should.

This one is confusing me. I have taken it to the dealer before cause it was doing this and they ran a test and came back with a code and reprogrammed the computer. Before they did this, it was that I would turn the key and it would try to turn over but it wouldn't on the first try, and would turn over on the second time. Now it only takes 1 long try to get it to turn over.

Anything battery related? Starter related? What could this be? I haven't tried anything really yet for it since I have been in school full time and working full time. Finally just got new brakes on today and got the rotors turned. So getting this one figured out is my next mission.

 

[matt0248]

HAve you fuel pressure checked. You will probably find that after the pump shuts off the pressure is bleeding down to 0. The extra cranking time is needed for the pump to build sufficient pressure

 

[kylecolb]

HAve you fuel pressure checked. You will probably find that after the pump shuts off the pressure is bleeding down to 0. The extra cranking time is needed for the pump to build sufficient pressure

About what would this cost to get fixed? Or how would this get fixed?

 

[matt0248]

About what would this cost to get fixed? Or how would this get fixed?

It depends on what is wrong and which engine. The worst case would be fuel pump module replacement I would guess parts and labor would be well over $500.00. If it is a v8 that has a fuel pressure regulator and the regulator is bad, it could be maybe $150.00 with labor.

 

[Pontisteve]

The Explorers should have a mechanical returnless regulator in-tank. Not sure if it is part of the fuel pump module or not. Fuel pressure should remain a consistent pressure. Try cycling the key several times before attempting to actually start it. If it starts up much easier because of this, suspect the pump is losing it's prime due to a problem with a one-way check valve in the fuel line near or in the tank. This one-way check valve ensures the pump won't lose it's prime for a minute or so after the key is cycled and the pump runs for a couple seconds.

 

[matt0248]

The Explorers should have a mechanical returnless regulator in-tank. Not sure if it is part of the fuel pump module or not. Fuel pressure should remain a consistent pressure. Try cycling the key several times before attempting to actually start it. If it starts up much easier because of this, suspect the pump is losing it's prime due to a problem with a one-way check valve in the fuel line near or in the tank. This one-way check valve ensures the pump won't lose it's prime for a minute or so after the key is cycled and the pump runs for a couple seconds.

The v8's have a return line and a rail mounted regulator.

 

[Pontisteve]

Are you sure about that? I think there's a fuel pressure damper on these, but not a regulator.

 

[fsumotorhead]

i had a similar issue with a friends ex that had good fuel press.

It turned out to be a bad cylinder head temp sensor, if i remember right.

 

[Pontisteve]

Head temp sensors replaced coolant temp sensors. Either way, their primary job is to let the PCM know when the engine is cold, so it can enrich the mixture (like putting it in choke mode). A bad one of these, and you can count on lousy performance, hard starts, bad mileage, etc. Easy to figure this out out with a scan tool that reads live data. Just look at the data from cold to warm, and make sure it makes sense.

By the way, I looked up my 03 Explorer V8 on the Ford CD. It has a returnless fuel system in it. It has a single line to the front, and a mechanical regulator in the tank.

 

[matt0248]

Head temp sensors replaced coolant temp sensors. Either way, their primary job is to let the PCM know when the engine is cold, so it can enrich the mixture (like putting it in choke mode). A bad one of these, and you can count on lousy performance, hard starts, bad mileage, etc. Easy to figure this out out with a scan tool that reads live data. Just look at the data from cold to warm, and make sure it makes sense.

By the way, I looked up my 03 Explorer V8 on the Ford CD. It has a returnless fuel system in it. It has a single line to the front, and a mechanical regulator in the tank.

I think the 02 is different. I will have to look at mine when I get some free time.

 

[Pontisteve]

Weird, I looked up the O2 fuel system on my Ford CD, and it did say it had a regulator, but didn't give squat for details. Then again, it showed a picture of a 95-01 type Explorer, so I dunno. Not very accurate sometimes, this CD.