Our 2001 Project DII
#23
03-14-2016, 06:15 AM
OK. I am surprised you did not also have a P0307 code for a misfire on cylinder 7.
DIIs have something called a wasted spark ignition system. I'm not going to go into all of the details here (you can research it separately if you like) but a disconnected cable on 2 caused the misfire on 5 because those two cylinders are paired on the coil. Number 6 is paired with number 7, so the wire disconnected on 6 should have caused there to be no spark on 7 also.
All of this assumes that I have come to understand how the system works but I think it is correct. If only Savannah Buzz were still active on this forum I know he would know for sure.
And as I said previously, having plug wires disconnected may have caused the O2 sensor code. As others have said, get the codes cleared and see if any come back.
Now, what brand of ignition cables are on the truck? Can you read the writing printed on them? What color are they?
DIIs have something called a wasted spark ignition system. I'm not going to go into all of the details here (you can research it separately if you like) but a disconnected cable on 2 caused the misfire on 5 because those two cylinders are paired on the coil. Number 6 is paired with number 7, so the wire disconnected on 6 should have caused there to be no spark on 7 also.
All of this assumes that I have come to understand how the system works but I think it is correct. If only Savannah Buzz were still active on this forum I know he would know for sure.
And as I said previously, having plug wires disconnected may have caused the O2 sensor code. As others have said, get the codes cleared and see if any come back.
Now, what brand of ignition cables are on the truck? Can you read the writing printed on them? What color are they?
#24
03-14-2016, 06:23 AM
And as I said previously, having plug wires disconnected may have caused the O2 sensor code. As others have said, get the codes cleared and see if any come back.
Now, what brand of ignition cables are on the truck? Can you read the writing printed on them? What color are they?
I did have the codes cleared and the light came back on. Going to have the codes pulled this afternoon.
Last edited by DiscoBuckeye; 03-14-2016 at 06:34 AM.
#26
03-14-2016, 01:01 PM
I had the codes read at lunch as follows.
I'm a bit ticked at myself cause he said I only had 4 codes but it looks like I had 8. I'll get them re read later.
I am disappointed because she in running a bit rougher than last night right after I put the new plugs in.
#27
03-14-2016, 01:26 PM
#29
03-14-2016, 03:19 PM
I got a little lost on this thread but I've had every kind of mishap and misfire a person can have, I HOPE, and the cases all fit into these categories:
Bad spark plug. Swap plugs from known good cylinders to known bad ones until you find the culprit--the misfire will follow the bad plug.
Bad wires or wires touching and arcing. You can actually see this sometimes, in the dark.
Head gasket failure with coolant loss or milkshake on the dipstick. Bad one.
Bad MAF (hard to diagnose but easy to check... Swap one in from a good running Rover or get a cheapie). This is hard to diagnose and doesn't always throw a helpful code. But if you exhaust everything else unplug the MAF and if the situation doesn't get any worse, it could be the culprit. I've just borrowed my buddy's.
Coils miswired. Codes will just be misfires.
Dying or dead coil. Just shows misfire codes. You can check spark by putting an old spark plug on the end of a spark plug wire and safely (with rubber on your hands) holding it near the block. You should see lightning. Do it with help. Helper can turn engine on and off if you can't convince them to hold the wires of death.
Something unplugged (idle air control valve or or purge valve, knock sensor, crank position sensor); almost always accompanied by a code pointing you to the right place.
Bad injector (waters down oil. You would smell gas in the oil strongly... It can do much worse and did on mine) just shows up as a misfire.
And my personal favorite and guess here: vacuum leaks at a hoses or the upper intake plenum gasket. This has been hard for me to find but if you look for smoke test or cigar test you MIGHT find a small vacuum leaks. Bigger ones are easy to spot... Spray brake cleaner on the hoses and under the upper intake. If the engine changes when you do that, the brake cleaner is being sucked in and you have a leak for sure. Use good common sense doing this though. No sparks or flames in the area. Also, it helps if you remove the fan and run for a short period of time because the fan will blow it all over, including your face. Ask me how I know.
I have also had another vehicle misfire, badly, when a catalytic converter was ruined by a bad spark plug dumping gas in it. My rover cats were ruined by a head gasket leak once and misfires badly... The cat was restricting the exhaust. Easy way to check is unbolt the exhaust before the cats and turn it on. It will be shockingly loud and you wouldn't want to run it that way for long, or drive it at all. But of the engine evens out then that's a good hint that the cats are obstructed.
Your SRS code may be as simple as a dirty connector on an airbag. But you need a good code reader to check and reset it. I use an icarsoft930--amazon cheapie.
I'm sure there are other possible causes for misfires like bad gas or low fuel pressure or a cracked block, but the ones listed above have always been the ones for me. If you think the gas is bad you can put some stabilizer in it (I ran 5 year old gas once in my rover with stabilizer in it...but that was before ethanol and I added about 5 gallons of new gas), but be sure it is safe for a fuel injected vehicle.
Bad spark plug. Swap plugs from known good cylinders to known bad ones until you find the culprit--the misfire will follow the bad plug.
Bad wires or wires touching and arcing. You can actually see this sometimes, in the dark.
Head gasket failure with coolant loss or milkshake on the dipstick. Bad one.
Bad MAF (hard to diagnose but easy to check... Swap one in from a good running Rover or get a cheapie). This is hard to diagnose and doesn't always throw a helpful code. But if you exhaust everything else unplug the MAF and if the situation doesn't get any worse, it could be the culprit. I've just borrowed my buddy's.
Coils miswired. Codes will just be misfires.
Dying or dead coil. Just shows misfire codes. You can check spark by putting an old spark plug on the end of a spark plug wire and safely (with rubber on your hands) holding it near the block. You should see lightning. Do it with help. Helper can turn engine on and off if you can't convince them to hold the wires of death.
Something unplugged (idle air control valve or or purge valve, knock sensor, crank position sensor); almost always accompanied by a code pointing you to the right place.
Bad injector (waters down oil. You would smell gas in the oil strongly... It can do much worse and did on mine) just shows up as a misfire.
And my personal favorite and guess here: vacuum leaks at a hoses or the upper intake plenum gasket. This has been hard for me to find but if you look for smoke test or cigar test you MIGHT find a small vacuum leaks. Bigger ones are easy to spot... Spray brake cleaner on the hoses and under the upper intake. If the engine changes when you do that, the brake cleaner is being sucked in and you have a leak for sure. Use good common sense doing this though. No sparks or flames in the area. Also, it helps if you remove the fan and run for a short period of time because the fan will blow it all over, including your face. Ask me how I know.
I have also had another vehicle misfire, badly, when a catalytic converter was ruined by a bad spark plug dumping gas in it. My rover cats were ruined by a head gasket leak once and misfires badly... The cat was restricting the exhaust. Easy way to check is unbolt the exhaust before the cats and turn it on. It will be shockingly loud and you wouldn't want to run it that way for long, or drive it at all. But of the engine evens out then that's a good hint that the cats are obstructed.
Your SRS code may be as simple as a dirty connector on an airbag. But you need a good code reader to check and reset it. I use an icarsoft930--amazon cheapie.
I'm sure there are other possible causes for misfires like bad gas or low fuel pressure or a cracked block, but the ones listed above have always been the ones for me. If you think the gas is bad you can put some stabilizer in it (I ran 5 year old gas once in my rover with stabilizer in it...but that was before ethanol and I added about 5 gallons of new gas), but be sure it is safe for a fuel injected vehicle.
Last edited by Charlie_V; 03-14-2016 at 03:22 PM.
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DiscoBuckeye (03-14-2016)
#30
03-14-2016, 03:26 PM
I got a little lost on this thread but I've had every kind of mishap and misfire a person can have, I HOPE, and the cases all fit into these categories:
Bad spark plug. Swap plugs from known good cylinders to known bad ones until you find the culprit--the misfire will follow the bad plug.
Bad wires or wires touching and arcing. You can actually see this sometimes, in the dark.
Head gasket failure with coolant loss or milkshake on the dipstick. Bad one.
Bad MAF (hard to diagnose but easy to check... Swap one in from a good running Rover or get a cheapie). This is hard to diagnose and doesn't always throw a helpful code. But if you exhaust everything else unplug the MAF and if the situation doesn't get any worse, it could be the culprit. I've just borrowed my buddy's.
Coils miswired. Codes will just be misfires.
Dying or dead coil. Just shows misfire codes. You can check spark by putting an old spark plug on the end of a spark plug wire and safely (with rubber on your hands) holding it near the block. You should see lightning. Do it with help. Helper can turn engine on and off if you can't convince them to hold the wires of death.
Something unplugged (idle air control valve or or purge valve, knock sensor, crank position sensor); almost always accompanied by a code pointing you to the right place.
Bad injector (waters down oil. You would smell gas in the oil strongly... It can do much worse and did on mine) just shows up as a misfire.
And my personal favorite and guess here: vacuum leaks at a hoses or the upper intake plenum gasket. This has been hard for me to find but if you look for smoke test or cigar test you MIGHT find a small vacuum leaks. Bigger ones are easy to spot... Spray brake cleaner on the hoses and under the upper intake. If the engine changes when you do that, the brake cleaner is being sucked in and you have a leak for sure. Use good common sense doing this though. No sparks or flames in the area. Also, it helps if you remove the fan and run for a short period of time because the fan will blow it all over, including your face. Ask me how I know.
I have also had another vehicle misfire, badly, when a catalytic converter was ruined by a bad spark plug dumping gas in it. My rover cats were ruined by a head gasket leak once and misfires badly... The cat was restricting the exhaust. Easy way to check is unbolt the exhaust before the cats and turn it on. It will be shockingly loud and you wouldn't want to run it that way for long, or drive it at all. But of the engine evens out then that's a good hint that the cats are obstructed.
Your SRS code may be as simple as a dirty connector on an airbag. But you need a good code reader to check and reset it. I use an icarsoft930--amazon cheapie.
I'm sure there are other possible causes for misfires like bad gas or low fuel pressure or a cracked block, but the ones listed above have always been the ones for me. If you think the gas is bad you can put some stabilizer in it (I ran 5 year old gas once in my rover with stabilizer in it...but that was before ethanol and I added about 5 gallons of new gas), but be sure it is safe for a fuel injected vehicle.
Bad spark plug. Swap plugs from known good cylinders to known bad ones until you find the culprit--the misfire will follow the bad plug.
Bad wires or wires touching and arcing. You can actually see this sometimes, in the dark.
Head gasket failure with coolant loss or milkshake on the dipstick. Bad one.
Bad MAF (hard to diagnose but easy to check... Swap one in from a good running Rover or get a cheapie). This is hard to diagnose and doesn't always throw a helpful code. But if you exhaust everything else unplug the MAF and if the situation doesn't get any worse, it could be the culprit. I've just borrowed my buddy's.
Coils miswired. Codes will just be misfires.
Dying or dead coil. Just shows misfire codes. You can check spark by putting an old spark plug on the end of a spark plug wire and safely (with rubber on your hands) holding it near the block. You should see lightning. Do it with help. Helper can turn engine on and off if you can't convince them to hold the wires of death.
Something unplugged (idle air control valve or or purge valve, knock sensor, crank position sensor); almost always accompanied by a code pointing you to the right place.
Bad injector (waters down oil. You would smell gas in the oil strongly... It can do much worse and did on mine) just shows up as a misfire.
And my personal favorite and guess here: vacuum leaks at a hoses or the upper intake plenum gasket. This has been hard for me to find but if you look for smoke test or cigar test you MIGHT find a small vacuum leaks. Bigger ones are easy to spot... Spray brake cleaner on the hoses and under the upper intake. If the engine changes when you do that, the brake cleaner is being sucked in and you have a leak for sure. Use good common sense doing this though. No sparks or flames in the area. Also, it helps if you remove the fan and run for a short period of time because the fan will blow it all over, including your face. Ask me how I know.
I have also had another vehicle misfire, badly, when a catalytic converter was ruined by a bad spark plug dumping gas in it. My rover cats were ruined by a head gasket leak once and misfires badly... The cat was restricting the exhaust. Easy way to check is unbolt the exhaust before the cats and turn it on. It will be shockingly loud and you wouldn't want to run it that way for long, or drive it at all. But of the engine evens out then that's a good hint that the cats are obstructed.
Your SRS code may be as simple as a dirty connector on an airbag. But you need a good code reader to check and reset it. I use an icarsoft930--amazon cheapie.
I'm sure there are other possible causes for misfires like bad gas or low fuel pressure or a cracked block, but the ones listed above have always been the ones for me. If you think the gas is bad you can put some stabilizer in it (I ran 5 year old gas once in my rover with stabilizer in it...but that was before ethanol and I added about 5 gallons of new gas), but be sure it is safe for a fuel injected vehicle.
by gosh, I might just call this a sticky. nice one.