Engine cutting out
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Engine cutting out
Hi guys, I just got a 02 Merc mountaineer premier 4.6 awd for my wife. 64k miles and runs great, well until tonight. Ran about 10 miles and the engine cut out. Didn't have any tools with me so I checked what I could, swapped fuses/relays, listened for the fuel pump and it wouldn't start. Got a ride home and brought in my diesel and trailer, figured I'll give it a shot.... fired right up 
Dad drove it home and I followed, 2 miles from the house it cut out again...wouldn't start... still didn't have any tools with me.. LOL Came back 30 mins later and it fired right up. At this point I'm leaning toward either the coil cutting out or fuel pump getting weak when hot.
One other thing I did notice is every now and then their is a muffled noise coming from the intake at idle, then it goes away. I held it at 3k for about 30sec, let fall back to idle, it muffled and shut off. But fired right back up. Could the EGR valve be sticking open? Going to hook up the auto enginuity tomorrow after work and see if I can find anything. Any ideas? Thanks!
Dad drove it home and I followed, 2 miles from the house it cut out again...wouldn't start... still didn't have any tools with me.. LOL Came back 30 mins later and it fired right up. At this point I'm leaning toward either the coil cutting out or fuel pump getting weak when hot.
One other thing I did notice is every now and then their is a muffled noise coming from the intake at idle, then it goes away. I held it at 3k for about 30sec, let fall back to idle, it muffled and shut off. But fired right back up. Could the EGR valve be sticking open? Going to hook up the auto enginuity tomorrow after work and see if I can find anything. Any ideas? Thanks!
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Joined: Jun 2009
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From: Cedar Rapids, IA
When it won't restart, does the engine crank over fine, just not start, or you don't even get the starter motor? I'm guessing, since you suggest a fuel pump, that it cranks fine.
When started and idling, does it idle smoothly? Do you have a fuel pressure gauge to check the fuel pressure? Have you tried opening the throttle slightly when it won't start to see if that makes a difference?
-Rod
When started and idling, does it idle smoothly? Do you have a fuel pressure gauge to check the fuel pressure? Have you tried opening the throttle slightly when it won't start to see if that makes a difference?
-Rod
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The engine spins over fine, just no fire. I haven't had a chance to put any gauges on it yet (getting ready to). I tried with partial pedal, half pedal, and full pedal when starting but that didn't seem to make any difference.
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Update:
Ok I checked a few things out this afternoon, fuel pressure at idle was 64psi. Couldn't find my extension hose so I don't know what pressure is going down the road. Alt is running hot but still putting out 14.1v According to the AE the egr valve is opening and closing. I can minmick the gurgle thru the intake by going from P-R, R-N, N-D or still from revving and going to idle.
Biggest change from last night to today is I couldn't get the engine to shut off...idle will drop to 500 or so while gurgling but go back up to 7-800. During the test drive it came to a point where all I could muster was 35mph, EGR showed 0%. Couldn't find anything out of the ordanary. Sat for 20 mins and it ran great again
If the cats were plugging up would they be free flowing again after a short cool down???
Ok I checked a few things out this afternoon, fuel pressure at idle was 64psi. Couldn't find my extension hose so I don't know what pressure is going down the road. Alt is running hot but still putting out 14.1v According to the AE the egr valve is opening and closing. I can minmick the gurgle thru the intake by going from P-R, R-N, N-D or still from revving and going to idle.
Biggest change from last night to today is I couldn't get the engine to shut off...idle will drop to 500 or so while gurgling but go back up to 7-800. During the test drive it came to a point where all I could muster was 35mph, EGR showed 0%. Couldn't find anything out of the ordanary. Sat for 20 mins and it ran great again
If the cats were plugging up would they be free flowing again after a short cool down???
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From: Cedar Rapids, IA
I think if the cats were plugging you would smell it in the exhaust and the CEL would be flashing, you'd have codes for catalyst efficiency issues, and you would see goofy numbers for the oxygen sensors.
What does the AE show for short and long term fuel trims around the times that it is acting up?
-Rod
What does the AE show for short and long term fuel trims around the times that it is acting up?
-Rod
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I just got back from a 20 min ride and I couldn't get it to shut off or hold back on acc. I did however get it to do the muffle thru the intake when I got back. The short term, both banks bounce between -2.5 and 5, showing a different value for both. The long term stays pretty consistant around -5.08 bank one and -7.43 bank 2.
Tried changing the EGR valve so maybe that was causing the stall???
Tried changing the EGR valve so maybe that was causing the stall???
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Almost forgot, I am getting a P1000 OBD2 systems readiness test not complete code now. It comes back everytime I delete it.
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Logistics Pro
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From: Cedar Rapids, IA
The negative value for the fuel trims would indicate that the oxygen sensors are determining a rich condition rather than a lean (vacuum leak) condition. Sounds like maybe your fuel pressure sensor is not working properly or an injector or two is sticking. You could also have a spark misfire causing a rich condition if
-Rod
-Rod
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That makes sense, I took it out to the garage to get looked at. So far they haven't found anything as far as it cutting out (since it won't......) I'll run some injector cleaner thru it and double check the vac lines with some TB cleaner when I get it back. I know the PO ran the tank next to empty almost all the time so dirt wouldn't be a surprise.
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From: Cedar Rapids, IA
Oh, and I forgot to mention in my last post that when you clear the diagnostic codes, it will also reset the drive cycle, hence the P1000 code each time you attempt to clear that code. You need to drive the vehicle enough to complete the drive cycle to get the P1000 to go away. Or, you can read up on what it requires to complete the drive cycle and go for a specific drive to complete the cycle. It require a sequence of accelerations, cruising, and decelerations.
-Rod
-Rod
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