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2002 4.0 no start

rrlund

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March 20, 2017
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Year, Model & Trim Level
2002 Explorer XLS
I just got a 2002 Explorer XLS with a 4.0. It's not a Sport Trac,but I can't find a forum on here to post on this specific model. This should be close enough. It's been sitting for about two years. It died on the road for the previous owner. He was told by somebody who was just guessing,that the timing chain broke. The same thing happened to our 2002 Sport Trac a few years ago. I told him I'd take it and put a junkyard motor in it like I did the Sport Trac. When I got it home,I put a battery in it,cranked on it and it fired and died. I stuck a screwdriver in the oil fill hole on one side and a sensor hole on the other side and everything is moving like it should.
It will fire for just about a second then die. After that,I have to wait 30-45 minutes before it will fire again. It cranks over,just won't fire. It won't even fire on starting fluid being shot straight in the intake with the air cleaner tube off. I put a new crank sensor on it today and there was no change. I have my doubts about it being the idle air control. There were no prior symptoms as far as I know. When I let it sit,then try it with the accelerator to the floor,it backfires instead of firing smooth for a second. Don't mistake what I'm saying,it doesn't run for a few seconds,pretty much literally just for about one second.
I had the coil pack here off the old engine from the Sport Trac and I put that on it. No change. I can hear the fuel pump running for two or three seconds when I turn the key on. I really have to believe its an electrical problem. Any ideas?
 



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Is there a cam sensor on the engine. I had several go out on other engine causing a no start. Dave P
 


















driver valve cover toward the front.
OK,got one small bolt,maybe 8mm wrench,holdng it in? That might be the one I took out to stick a screwdriver in to see if the cam was turning.
 












I haven't thrown any more money at it,but I tried something today. I laid a spark plug on the negative terminal,plugged it in to a spark plug wire and had the wife crank on it. I told her to hold the key right through it starting and keep it cranking until I told her to stop. It still had spark even after it died. I've eliminated that now. Would that sensor stop it from having spark? If it would,no sense spending money on one. If not,it could still be the problem.
 












Quick compression test will tell you if the timing went. Easy to do.
Is there such a thing as a quick compression test on one of those? You need a little helper monkey to get in there to get the plugs out.
 












Sounds a little like the knock sensor... 12mm bolt secures it to the top of the block about halfway back, under the intake manifold. The wiring on mine was cracked and shorting to the block, and it was acting like this ... I also had a blown head gasket, so take that for what you will.

Engine won't start with a false positive from the knock sensor.
 






Sounds a little like the knock sensor... 12mm bolt secures it to the top of the block about halfway back, under the intake manifold. The wiring on mine was cracked and shorting to the block, and it was acting like this ... I also had a blown head gasket, so take that for what you will.

Engine won't start with a false positive from the knock sensor.
Now I've got to wondering. I was out there early this morning getting chores done before the rain starts. I saw the reflection of a red light blinking in the lower center of the windshield. Do you think there could be an anti theft device that's gone bad and causing this? How would you disarm it if it has?
 






Now I've got to wondering. I was out there early this morning getting chores done before the rain starts. I saw the reflection of a red light blinking in the lower center of the windshield. Do you think there could be an anti theft device that's gone bad and causing this? How would you disarm it if it has?
possible, but not as likely as the camshaft or knock sensor failures. Also, you'd have a flashing THEFT light.

The knock sensor in particular won't throw codes at startup due to the OBD2 programming basically ignores trouble codes, but still will allow input to hang the start by tricking a misfire.
 






Have you done the compression test? That will tell you absolutely everything. To be honest you only really have to do one or two plugs on each side and you'll know if you have those valves closed. Trust me, it's definitely worth the time because that will tell you everything. If you can't get it to fire with the ignition spray but you know you're getting spark then its compression. That's almost the only other answer. If not then it's computer related and if that's so I'll find out where all the sensors are for ya.
 






possible, but not as likely as the camshaft or knock sensor failures. Also, you'd have a flashing THEFT light.

The knock sensor in particular won't throw codes at startup due to the OBD2 programming basically ignores trouble codes, but still will allow input to hang the start by tricking a misfire.
I changed the cam sensor yesterday. No change. We used the scanner on it this afternoon,no codes.
 






Have you done the compression test? That will tell you absolutely everything. To be honest you only really have to do one or two plugs on each side and you'll know if you have those valves closed. Trust me, it's definitely worth the time because that will tell you everything. If you can't get it to fire with the ignition spray but you know you're getting spark then its compression. That's almost the only other answer. If not then it's computer related and if that's so I'll find out where all the sensors are for ya.
Haven't done a compression test. If you could hear it start,you'd have to believe everything must be normal. It doesn't even miss. That's the next step I suppose,but it's getting old checking things and finding nothing wrong.
 






Haven't done a compression test. If you could hear it start,you'd have to believe everything must be normal. It doesn't even miss. That's the next step I suppose,but it's getting old checking things and finding nothing wrong.
I totally understand.We had a 2001 Sport Trac that was rolled over and when we got it back upright it simply wouldn't start. It didn't try or anything. Just cranked forever but it simply didn't start. There was absolutely nothing wrong as far as my spark and fuel pressure but I did the compression test and found I didn't have any compression. So I thought head gasket and once I got it opened up it was the timing chain guides completely shattered and in the oil pan. Trust me. The compression test will tell you everything.
 






Spray starting fluid into the throttle body while someone cranks it. If it acts like it wants to start or run then dies that would tell me the fuel pump is dead.

The compression test is great advice. A fuel pressure test would also help rule out a couple of things like a dead fuel pump or a totally clogged fuel filter or fuel line.
 






Spray starting fluid into the throttle body while someone cranks it. If it acts like it wants to start or run then dies that would tell me the fuel pump is dead.

The compression test is great advice. A fuel pressure test would also help rule out a couple of things like a dead fuel pump or a totally clogged fuel filter or fuel line.

I believe he said he already tried starting fluid spray, but definitely check the fuel system. I'm willing to bet its a timing system. The rear timing chain tensioner on those can be kind of crappy and will shatter. Same with the balance shaft one so definitely do a compression test and check your fuel systems.
 



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