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I am looking for some help in a problem I am having with a Ford Explorer 4.0L 2002. When starting it cranks but takes a while to start and other times it just starts right up. Fuel pressure is 67psi at idle and holds. check battery voltage and alternator-all good. Since it cranks I am assuming it is not starter. Once it is running it is fine. I am stumped as to where to look next. If anyone has any clues that would be great. Thanks.
Driveway Al
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You might be having an issue with the check valve in the fuel pump leaking especially if it happens mostly during the first start after the truck has been sitting. To verify this you could cycle the key to the ‘run’ position and count to 3, do this twice and then try and start the engine, if it starts up fine you may have an issue with this check valve. It doesn’t mean the fuel pump is bad but in order to ‘fix’ the problem you will need to replace the pump OR you could continue to start the engine cold as suggested and not replace the pump. Here is a video with some info that might give more insight to this problem.
It could be as simple as a severely clogged fuel filter.
There are a few things you can do without touching the fuel filter to confirm if you have a DSO.
You can simply see how many amps the fuel pump is drawing to start and then look for a lean condition at a wide open throttle through a 1 – 2 shift while monitoring the LTFT to confirm.
The LTFT should remain in the high digit positive and both up streams should stay +800 mv.
The fuel pump amp draw should be respective 6-9 amps or so. 10 amps and higher would raise concern and I would suspect the fuel filter.Or you could just crawl under it, remove it, and then try to blow through it to confirm.
I prefer hooking up a good DSO and scan tool to make a diagnostic decision then make some other grunt change it. Makes em real happy and wonder how the hell I did that without ever racking the vehicle or screwing a pressure gauge on itW;)
Does the vehicle run fine once started? Usually, if you have an issue with a plugged fuel filter, it would hesitate under WOT.
You may also have an issue with the FPR and im under the assumption you have a return-less fuel system, hence the FPR is apart of the fuel pump assembly.
You should see a drop in fuel pressure if you hook up a fuel pressure regulator if that check valve was bad.
There was no drop in fuel pressure, It was 67 psi and held there for at least 20min. after shutting engine off. Once the truck is running it is ok. There is no hesitation or stalling. It is ok under wot. 1 out of 4 starts on average it starts up just fine but the other times it cranks, turns over but will not start. One thing I did notice was there is some shaking with the harmonic balancer. The tensioner jumps quite a bit with the vibration. I know the crank sensor is mounted there. I am wondering if that could be a problem. Also aren’t these trucks known for having idle air control problems. Thanks.
Driveway AlQuoted From dreamer2355:
Does the vehicle run fine once started? Usually, if you have an issue with a plugged fuel filter, it would hesitate under WOT.
You may also have an issue with the FPR and im under the assumption you have a return-less fuel system, hence the FPR is apart of the fuel pump assembly.
You should see a drop in fuel pressure if you hook up a fuel pressure regulator if that check valve was bad.
You don’t always get a hesitation with a plugged fuel filter. I have seen them hide pretty darn good but cause and extended crank or multi prime.
Dude had this problem once and I chased it to he!! and back and never figured it out…… Fuel pumps – enjectors fuel rails – (Checked ERG to see if it was clogged) I mean I went threw this pup….. Bro I think its something this engine does when its just stopping and going all the time!!!
My old 2000 4.0l explorer did this when i first got it….
It had 80k on it….Some times it would start hard other times it would be fine went on for mouths….
I took it on a road trip (200miles) and it never did it again…
Wierd YEA!!! [url=http://www.youtube.com/watch?v=-Jd9imOs5jA:rvmpmmax]http://www.youtube.com/watch?v=-Jd9imOs5jA
M[/url]y self I think its a problem with enjects getting a little dirty!!!
Run it on a trip at around 80mph and see if it doesn’t stop!!!
Them 4.0s are the best v6s ever! Love them!!!
Let me guess you probably drive in town alote or go a few days with out driving it!!!
O BY THE WAY!!!!
Let say one day your driving down the road and all of a sudden your engine starts miss firing and and bucking -But you can get any codes out of it!!!
Spark plugs -Thats all it is!
These engines runs a platinum plug in them!!! Once there gone there gone _ _ _ _ You cant clean them and reuse them.
The only problem I had out of this dang thing In 5 years was – After driving on high way or in town for a long time – The engine would start cutting off like i was turning the key on and off!!!!
I got no codes!!!
I started with checking the tps -fuel filter – Fuel pump- Draining the tank- and sooo on….I basically had to set down and write a list of things that would not throw a code……. There wasn’t a alote of things but Finlay SPARK PLUGS!!!!!
Hope this helps you later one bro!!!Quoted From DrivewayAl:
There was no drop in fuel pressure, It was 67 psi and held there for at least 20min. after shutting engine off. Once the truck is running it is ok. There is no hesitation or stalling. It is ok under wot. 1 out of 4 starts on average it starts up just fine but the other times it cranks, turns over but will not start. One thing I did notice was there is some shaking with the harmonic balancer. The tensioner jumps quite a bit with the vibration. I know the crank sensor is mounted there. I am wondering if that could be a problem. Also aren’t these trucks known for having idle air control problems. Thanks.
Driveway AlI don’t know about Ford but the crank sensor getting chewed up was (is?) a problem on some Chevys. May be worth looking into – a dancing balancer is not a good thing.
check and adjust and clean the crank position sensor, visible from under the car behind the radiator fan blades on the balancer, loosten the 2 bolts and adjust the sensor to just tough the matal balancer.
this lets the electronics know where TDC is for the ignition timing. if it does not catch this puls – you have to go arround again and again till it fires. The car will run better too!Quoted From jbone:
check and adjust and clean the crank position sensor, visible from under the car behind the radiator fan blades on the balancer, loosten the 2 bolts and adjust the sensor to just tough the matal balancer.
this lets the electronics know where TDC is for the ignition timing. if it does not catch this puls – you have to go arround again and again till it fires. The car will run better too!Actually the best way to confirm a problem with the crank position sensor is by viewing it’s signal on a lab scope but I realize not everyone has access to one of those. Given that the CEL has not been set however I think it might be a bit early to start condemning sensors, in my experience with the absence of a CEL the problem is often something basic like a vacuum leak or tune up issue, the rule of KISS applies here in my opinion.
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