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| Wet oil at the base of a glow plug..... http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=36515 |
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| Author: | jmoomaw [ Mon Oct 06, 2008 7:14 am ] |
| Post subject: | Wet oil at the base of a glow plug..... |
Besides the obvious....what am I looking at... There is wet oil at the base of the most forward glow plug. I cleaned the grim away from components around the area to see how long it takes to replenish the grim. I assume it will need replacing for full effectiveness. Do I replace all and what have people paid. It is one of those ongoing maintenance issues that happen to everyone? I love this Jeep and wish I had purchased it locally or from a more reputable dealer.... |
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| Author: | retmil46 [ Mon Oct 06, 2008 9:48 am ] |
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Any evidence of an oil leak, such that oil has simply ran down the top of the engine and collected at the glow plug? Depending on how long it's been, could be someone just got sloppy on the last oil change and slopped oil down the side of the engine, and didn't bother wiping in and around the glow plug. If a glow plug does decide to go south on you, it'll throw a CEL on the dash, and you'll experience problems with starting it up cold and noticeably decreased fuel mileage. For the time being, I'd just clean around the glow plug as best you can and keep an eye on it, to see if the oil/grime collects again. A side question - you sig says you have an HHO/Brown's Gas unit installed on yours. Where in the devil did you find room to mount one, and any results/details you could share on it? |
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| Author: | bugnout [ Mon Oct 06, 2008 10:04 am ] |
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Just out of curiosity, Why would you see a noticeable decrease in fuel mileage. I thought the glow plugs were only active during the starting sequence. not needed after the tractor is warmed up? |
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| Author: | retmil46 [ Mon Oct 06, 2008 10:42 am ] |
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bugnout wrote: Just out of curiosity, Why would you see a noticeable decrease in fuel mileage. I thought the glow plugs were only active during the starting sequence. not needed after the tractor is warmed up?
Depending on conditions, the ECM will cycle the glow plugs after the engine is running as it determines is needed to maintain proper cylinder/combustion temps. That's why many people that had an EGR go south on them ended up having to have the glow plugs replaced as well (myself included) - the ECM basically burned out the glow plugs keeping them on full time in an attempt to maintain proper conditions to compensate for a malfunctioning EGR. If the glow plugs weren't on for some amount of time after starting, until the engine is up to proper temps, and especially in cold winter weather, there would be times that engine would be kicking and bucking like a Missouri mule until it got warmed up. Even on my old '87 MB, there's a factory mod you can do to add afterglow capability to the glow plug circuit - such that the glow plugs will be on for a certain amount of time based on engine coolant temp after starting, to aid in cold weather starting. I found out the hard way a couple months ago the previous owner of my MB had done the infamous "purple wire" mod - he'd cut the wire from the ignition switch that shut off the GP relay after starting, such that the preglow (pre-starting) timing circuit kicked in again and kept the glow plugs on for upwards of a minute after starting. I had thought until then he'd simply done the afterglow mod. While down in Texas back in July, one day the timing circuit didn't shut off, and I drove for 30 miles before discovering the glow plugs were stuck on. I had to disconnect the GP harness itself to shut them off, and next day disassembling the relay to check it out discovered where the PO had cut the purple control wire. I reconnected the wire, such that the GP's now shut off once the engine is running. But a couple weeks later, two of the GP's went south - burned out by the abuse they'd seen because of that shade-tree mod. I had to replace all the GP's over Labor Day weekend, and just like our CRD's, you had to remove the intake manifold to get access to all of them. I expended quite a bit of profanity that day concerning the previous owner. |
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| Author: | bugnout [ Mon Oct 06, 2008 11:48 am ] |
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Very interesting. Sounds like implementing the ORM or SEGR increase the likelihood that the ECM will cycle the Glow plugs on since it takes longer to warm up to operating temperatures. So during normal operations if the EGR mechanically fails, it induces some sort of race condition where the ECM may command glow plugs to stay on too long when not required and burn them out. I would think that, with the ORM, your failing the EGR electrically, right at the get go and the ECM takes into account the EGR is disabled and adjusts accordingly. The SEGR, on the other hand, fools the ECM into thinking the EGR is working and might run into the same race condition that a mechanical failure induced. Sound reasonable or am I overthinking this? |
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| Author: | retmil46 [ Mon Oct 06, 2008 12:23 pm ] |
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If I remember correctly, glow plug failure along with a failed EGR was most common when the EGR failed open. EGR is implemented to recycle exhaust gases into the intake, replacing air with essentially noncombustible gases, to reduce combustion temps in the cylinder and prevent NOX formation. Too much flow or at the wrong times from the EGR (ie, stuck open), it would reduce combustion temps too much and the ECM tries to compensate by using the glow plugs. From what I remember of those that had the EGR fail shut, fuel mileage actually improved noticeably. In my case, it failed open - fuel mileage went into the tank, ran like a broke-legged dog, and blew black smoke like a freight train. A couple weeks after the EGR was replaced, the glow plugs started going out. When the second one went, I had the dealer replace it and the remaining two as well - no problems since, even with ORM/SEGR. |
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| Author: | jmoomaw [ Mon Oct 06, 2008 3:52 pm ] |
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retmil46 wrote: A side question - you sig says you have an HHO/Brown's Gas unit installed on yours. Where in the devil did you find room to mount one, and any results/details you could share on it? I have a running post under alternative fuels that I update weekly. So far no mileage increase. I do believe the engine runs smoother with much less soot at the tail pipe. We will be adjusting the amount of HHO output this week or next once the engine is a bit cleaner. If there is too much HHO the engine typically doesn't get better mileage.....we shall see... |
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