5.2l mpi not running right, lots of fuel smoke
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01-27-2010, 02:50 AM
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5.2l mpi not running right, lots of fuel smoke
i need idea's about my.. dare i say it jeep...
it has a 5.2l mpi mopar engine and the guys on the jeep forums dont really seem willing to help so far.
im sorry if im in the wrong area, but the durango is the closes thing to a grand cherokee you have.
near the end of a 200 or so mile trip recently, while pulling into a parking spot. the engine stumbled itself to death with no restart.
we tested for compression, fuel pressure and spark. all three seemed good and in time with one another.
we were baffled how it wasn't running. we let the local dealer have a look see.
what they came back to us with was that the cap and roter were bad, and therefore were replaced.
were not really sure that thats what the issue was, but whatever they did they got it running again, long enough to get it home anyways.
about the time we got back to town it started missing on more than 3 cylinders and trying to die. made it to the driveway and there it died again, except this time it restarted.
as of now it holds a correct idle speed, a little bit shakey but correct speed.
it starts and dare i call it "runs"
with a nice puffy fuel smoke at all times and lots of it.
by process of elimination, by unpluggin injector wires wile it is idleing.
we find that all of the cylinders are firing and any combination of 2 injectors unplugged will nearly kill the engine(singles are almost unnoticeable because of the shaky running)
we cheked all the the injectors and had them pop tested. fuel pressure still holds at 40-45 psi
we found info about the dielectric grease in the pcm going bad and gelling leading to poor connection, so we pulled the connection and thouroughly cleaned it with no change.
it still revs all the way though the rpm band and idles at the right speed but there is an enourmous amount of unburned fuel smoke.
my only though right now is that the injectors open when it starts and never turn back off?
anyone have experiance with this? the jeep is one of our favorite rigs and we'd really like to have it back to healthynesstivity.
any idea helps sorry for the long long long post and thanks in advance
it has a 5.2l mpi mopar engine and the guys on the jeep forums dont really seem willing to help so far.
im sorry if im in the wrong area, but the durango is the closes thing to a grand cherokee you have.
near the end of a 200 or so mile trip recently, while pulling into a parking spot. the engine stumbled itself to death with no restart.
we tested for compression, fuel pressure and spark. all three seemed good and in time with one another.
we were baffled how it wasn't running. we let the local dealer have a look see.
what they came back to us with was that the cap and roter were bad, and therefore were replaced.
were not really sure that thats what the issue was, but whatever they did they got it running again, long enough to get it home anyways.
about the time we got back to town it started missing on more than 3 cylinders and trying to die. made it to the driveway and there it died again, except this time it restarted.
as of now it holds a correct idle speed, a little bit shakey but correct speed.
it starts and dare i call it "runs"
with a nice puffy fuel smoke at all times and lots of it.
by process of elimination, by unpluggin injector wires wile it is idleing.
we find that all of the cylinders are firing and any combination of 2 injectors unplugged will nearly kill the engine(singles are almost unnoticeable because of the shaky running)
we cheked all the the injectors and had them pop tested. fuel pressure still holds at 40-45 psi
we found info about the dielectric grease in the pcm going bad and gelling leading to poor connection, so we pulled the connection and thouroughly cleaned it with no change.
it still revs all the way though the rpm band and idles at the right speed but there is an enourmous amount of unburned fuel smoke.
my only though right now is that the injectors open when it starts and never turn back off?
anyone have experiance with this? the jeep is one of our favorite rigs and we'd really like to have it back to healthynesstivity.
any idea helps sorry for the long long long post and thanks in advance
#2
01-27-2010, 07:48 AM
#3
01-27-2010, 03:49 PM
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its a 95
there doesnt seem to be any fuel in the oil or any oil in the fuel, its allways seemed to burn a lot of oil compared to all the other rigs we have but not so much as to be alarming.
it also comes up with two trouble codes involving something in the injector system, but the book is so unspecific that its hard to figure out that it means injection system
there doesnt seem to be any fuel in the oil or any oil in the fuel, its allways seemed to burn a lot of oil compared to all the other rigs we have but not so much as to be alarming.
it also comes up with two trouble codes involving something in the injector system, but the book is so unspecific that its hard to figure out that it means injection system
#4
01-27-2010, 07:41 PM
#5
01-27-2010, 09:14 PM
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crazymike
Since you have 1995 5.2L, There could be many things that can be wrong with it. You wrote the cap and rotor were replaced, What about the spark plugs? What you did with injectors, and try to find which cylinder is firing. That is find, but you can do the same thing removing the plug wires one at a time. Here some things to look for, Look down the throttle with engine off. See if there lots of oil inside the manifold-laying on the pleunm plate. That means you maybe sucking oil up into the manifold and mixs with gas and goes out the tail pipe. Or the valve seats are leaking and going out the exhaust. I need three sets of compression test from you. 1st = dry, thats taking the plugs out and turn the engine 125 to 150 is good, 2nd=wet test leave the plugs out and add small amount of oil, one at a time and see if there is any change. If the compression goes up, the most likey cause would be rings.3rd=runing compression. This where you put all but one spark plug back, start the engine and record each cylinder. specs 1/2 of what your dry compression should be. So if your dry is 150, then running should be 75 psi. This lets me know if the valves are the problem. And don't worry if you post on the wrong section.Also by all means,if you think someone on the forum can help you do ask.
Since you have 1995 5.2L, There could be many things that can be wrong with it. You wrote the cap and rotor were replaced, What about the spark plugs? What you did with injectors, and try to find which cylinder is firing. That is find, but you can do the same thing removing the plug wires one at a time. Here some things to look for, Look down the throttle with engine off. See if there lots of oil inside the manifold-laying on the pleunm plate. That means you maybe sucking oil up into the manifold and mixs with gas and goes out the tail pipe. Or the valve seats are leaking and going out the exhaust. I need three sets of compression test from you. 1st = dry, thats taking the plugs out and turn the engine 125 to 150 is good, 2nd=wet test leave the plugs out and add small amount of oil, one at a time and see if there is any change. If the compression goes up, the most likey cause would be rings.3rd=runing compression. This where you put all but one spark plug back, start the engine and record each cylinder. specs 1/2 of what your dry compression should be. So if your dry is 150, then running should be 75 psi. This lets me know if the valves are the problem. And don't worry if you post on the wrong section.Also by all means,if you think someone on the forum can help you do ask.
Last edited by master tech; 01-27-2010 at 10:16 PM. Reason: spelling
#6
02-03-2010, 06:16 PM
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sorry it took me so long it's been raining no stop out here and i dont have a covered place to do this.
and just finnaly had a chance to do the test without the rain drowning me.
compression dry is good as before, with adding a small amount of oil it went up just a bit but not much, 2 3 psi maybe, and when runningalso a litle more than half as per a few psi.
is the electronic connection to controll the injectors all fed to its own injection controll unit or is it done by the pcm? my book isnt clear on this spot, but then again haynes manuals never really got on my good side since the camaro, (in the troubleshooting section it mentions your back windows rolling down... and references it a few times.)
and just finnaly had a chance to do the test without the rain drowning me.
compression dry is good as before, with adding a small amount of oil it went up just a bit but not much, 2 3 psi maybe, and when runningalso a litle more than half as per a few psi.
is the electronic connection to controll the injectors all fed to its own injection controll unit or is it done by the pcm? my book isnt clear on this spot, but then again haynes manuals never really got on my good side since the camaro, (in the troubleshooting section it mentions your back windows rolling down... and references it a few times.)