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Engine Specific Info and Questions => IDI Engine => Topic started by: Supersport654 on October 05, 2008, 12:46:07 am
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Hey guys! My name is Aaron, and I live in Washington State. I used to drive a really nice '81 Jetta diesel. I got bored with it and my buddy made me an offer I couldn't refuse, so off it went. I then "upgraded" to a '91 Jetta diesel. It was a REAL project. Nice car now, but it is giving me a strange problem...
About 1000 miles after changing the oil, I get the dreaded "low oil pressure" warning. The high side (2k RPM) one. Never at idle. But it does not seem to be the common problem with the actual warning system itself. Some doofus had put a gasser oil pressure sensor in the oil filter housing, but I changed that one out for the correct diesel sensor. I even changed out the main and rod bearings. My pressure IS actually LOW because my nice, thick Delo 400 is now the consistency of WD-40 when it is hot! And there is MORE OF IT THAN THERE SHOULD BE! :roll:
Clearly, I am getting about a quart of diesel into my oil every 1000 miles. The question I have for you guys is, "Where is it coming from?" At first I thought that I had an injector that was leaking down when the car was shut off, and that was what was dumping oil into my crankcase (down past the piston rings). So I sprung for a set of new injectors...same problem. I thought that maybe it was leaking from the LDA aneroid, going through the vacuum line, into the vacuum pump, and from there into the crankcase. The aneroid does leak a little, but that does not seem to be the problem. The pump is set just where it is supposed to be for a '91...at .90 mm. Pump seems strong. Car smokes a bit, but not much. Any thoughts? Thanks! -Aaron
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The LDA shouldn't hook to the vacuum pump.
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Can you take a picture of your engine bay? Where did you get your injectors?
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i had a similar problem... my oil level was rising and it didn't quite look like coolant, but i replaced the oil cooler anyway and the problem went away. i too thought that diesel was leaking from an injector after shut down because the oil level was rising... and when i drained the oil it was very difficult to tell if coolant was mixing with the oil. maybe if i drained it into a big pickle jar or something i would have been able to clearly tell.
i dont know if its because some guys like to really reef on the oil filter or what, but the oil coolers do go. VW recommends replacing them after any major engine work. not sure if bearings count, but worth checking out in your case :wink:
if i were you i would drain the oil into a glass jar and see if the oil separates. because like the others above, i dont see how diesel fuel can get into the oil other than leaking injectors, and that is assuming your injectors are not faulty.
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The LDA shouldn't hook to the vacuum pump.
The LDA is vacuum operated, right? The sticker on my core support shows the LDA connected to the vacuum pump. ---A
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The LDA shouldn't hook to the vacuum pump.
The LDA is vacuum operated, right? The sticker on my core support shows the LDA connected to the vacuum pump. ---A
The LDA is pressure operated, not vacuum operated. Think of the LDA as a mechanism that reduces the amount of fuel delivered when there is no boost. As boost builds, fuel in increased up to the max allowed by the max fuel screw. The LDA should be connected to the intake manifold and not the vacuum pump. With the way you have it connected it might be possible to suck fuel out of the IP and into the engine due to bad seals on the LDA and the vacuum pump.
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Can you take a picture of your engine bay? Where did you get your injectors?
The injectors are Bosch rebuilds, and were purchased through WorldPak. It did the same thing with the old injectors that it did with the new ones...that is why I replaced them. :cry: --A
http://i9.photobucket.com/albums/a59/cobrajet25/jettabay001.jpg
http://i9.photobucket.com/albums/a59/cobrajet25/jettabay002.jpg
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The LDA shouldn't hook to the vacuum pump.
The LDA is vacuum operated, right? The sticker on my core support shows the LDA connected to the vacuum pump. ---A
The LDA is pressure operated, not vacuum operated. Think of the LDA as a mechanism that reduces the amount of fuel delivered when there is no boost. As boost builds, fuel in increased up to the max allowed by the max fuel screw. The LDA should be connected to the intake manifold and not the vacuum pump. With the way you have it connected it might be possible to suck fuel out of the IP and into the engine due to bad seals on the LDA and the vacuum pump.
My car is a non-turbo...code ME. There is no boost to operate it. From what I understand, the turbo cars use boost pressure on the top of the aneroid pin diaphragm to push it down against the spring under load. The LDA on the normally aspirated motor uses vacuum on the BOTTOM of the diaphragm to pull it down against the spring under load. Correct? Do I have my terms wrong? I thought the aneroid on the turbos was called a "boost enrichment device" and on the non-turbos it was a "load detection aneroid"? Is this not right? Thanks for all your help so far guys! :P ---A
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If your engine is NA and not a TD, then you shouldn't have an LDA on it. Could it possibly be an altitude compensator? They look like the LDA. Can you post a pic of your IP?
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i had a similar problem... my oil level was rising and it didn't quite look like coolant, but i replaced the oil cooler anyway and the problem went away. i too thought that diesel was leaking from an injector after shut down because the oil level was rising... and when i drained the oil it was very difficult to tell if coolant was mixing with the oil. maybe if i drained it into a big pickle jar or something i would have been able to clearly tell.
i dont know if its because some guys like to really reef on the oil filter or what, but the oil coolers do go. VW recommends replacing them after any major engine work. not sure if bearings count, but worth checking out in your case :wink:
if i were you i would drain the oil into a glass jar and see if the oil separates. because like the others above, i dont see how diesel fuel can get into the oil other than leaking injectors, and that is assuming your injectors are not faulty.
Good idea...I will do it.
But engine oil + coolant + churning motor = chocolate milkshake lookin' mess, right?
The oil looks fine, at first glance anyway. Other than being really thin and reading a quart over on the dipstick. And I don't seem to be losing coolant. That's what made me think it was diesel in the oil. Can't be anything other than coolant or diesel, and since i didn't see a mess on the end of the dipstick, I assumed it was diesel. ---A
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If your engine is NA and not a TD, then you shouldn't have an LDA on it. Could it possibly be an altitude compensator? They look like the LDA. Can you post a pic of your IP?
I thought it was both? I know that when I turn the aneroid pin to different positions inside the pump it DOES affect how much power I have. It was my understanding that the altitude compensator was the part that was attached to the RH fenderwell. I thought it cut vacuum to the LDA at high altitudes, thus reducing the amount of fuel the engine gets when the air is thin...to prevent smoking. But the LDA on the pump is the same as the one on the turbos...it just works in reverse. Right? I think that is what Bentley says, anyway. :shock:
BTW pics are linked in a previous thread. Where in the Pac NW are you? I am in Olympia WA.
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that is the wrong pump for that motor. Not a big deal. The LDA should not be hooked up. You should cap off the barb fitting on the top and leave it alone.
I can't see how you have your injectors hooked up, but they should be hooked up in series with each other, capped off at one end and the other end going into the return fitting on the pump below the LDA. There should be no vacuum sources or pressure sources added into that circuit
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that is the wrong pump for that motor. Not a big deal. The LDA should not be hooked up. You should cap off the barb fitting on the top and leave it alone.
I can't see how you have your injectors hooked up, but they should be hooked up in series with each other, capped off at one end and the other end going into the return fitting on the pump below the LDA. There should be no vacuum sources or pressure sources added into that circuit
Wrong pump? It is the pump shown on the vacuum routing sticker on the radiator support. My car is a 1991 Jetta diesel, VIN WVW21RG1MW239XXX. Here is a pic of the sticker...
http://i9.photobucket.com/albums/a59/cobrajet25/vacuumsticker002.jpg
If you are talking about the fitting on the top of the diaphragm housing where the boost line from the turbo would come in when you say "barb fitting", then it has already been capped...from the factory. There is another fitting, above the fuel return fitting, where the line from the vacuum pump goes in. This fitting is ON the LDA, and apparently is supposed to be connected to vacuum. I have it hooked up the way the label on the car says to hook it up...hmmmm. Thanks!
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I'm on my Blackberry so I'm not going to try to load your pics.
NA engines CAN have a LDA on the IP.
AND they are hooked to the vac pump however, they are ran through an altitude compinsator (sp) first that regulates fuel delivery according to atmospheric pressure.
It sounds like yours is hooked up wrong from reading what others have posted. If your oil level is going up you either have a really bad injector because even if it was leaking down after shut off it only hold a table spoon of fuel yes I read you replaced them, so your oil cooler is the other item to address. HD or cracked head is all that's left.
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That was suppose to say HG not HD, I can't edit on the BB :(
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Now that i've seen the pics.
Is the alt compinsator mounted on hte passenger inner fender?
It's that other thing shown in your pic.
"Altitude Controll Aneroid"
Is the line ran as shown on the sticker?
(http://i9.photobucket.com/albums/a59/cobrajet25/vacuumsticker002.jpg)
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Take a pic of the back of the IP, like this pic but further to the right and facing the pump still. Make sense?
(http://i9.photobucket.com/albums/a59/cobrajet25/jettabay002.jpg)
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From the diagram, it looks as though if the "feeler pin o-ring" in the LDA is leaking you will indeed suck diesel fuel into your engine block.
Andrew
Only if the diaphragm is bad, the top of the diaphragm is sealed from the body of the pump.
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From the diagram, it looks as though if the "feeler pin o-ring" in the LDA is leaking you will indeed suck diesel fuel into your engine block.
Andrew
Only if the diaphragm is bad, the top of the diaphragm is sealed from the body of the pump.
The line from the vacuum pump attaches to the LDA below the diaphragm. I think. It is this suction that actuates the aneroid pin...and by extension the feeler pin below it. As I said I considered this a possibility before. There is a bit of fuel in the LDA below the diaphragm, so the feeler pin o-ring is leaking. But there does not seem to be enough to cause the problem I am seeing. And when I remove the line from the LDA to the vacuum pump, no fuel comes out of it. Not one bit. It's really strange...
I honestly think that this engine runs far too well for the problem to be a head gasket. It lights right up with a flick of the key, and runs steady, strong, and smooth. As I said before, the oil looks fine...other than being thin and there being too much of it. Here is the requested pic of the back of the pump... Thanks guys!
http://i9.photobucket.com/albums/a59/cobrajet25/backofpump.jpg
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Perhaps it's sucking the fuel out past the feeler pin o-ring, but when vacuum is not applied it doesn't leak.
I can't see how a leaking headgasket would leak fuel into the sump, coolant maybe, but not fuel.
Andrew
Just for the sake of future reference, I think I have this problem figured out. In order to check for diesel being sucked through the aneroid vacuum line, I changed the oil and disconnected the vacuum line from the LDA on the injection pump. I replaced the t-fitting with a straight fitting so I could keep vacuum to operate brakes, climate control, etc. I capped the barb fitting on the pump. I had planned to drive the car for 1500-2000 miles, keeping tabs on the oil level along the way.
After 300-400 miles, I noticed that diesel was leaking out of the aneroid PAST THE RUBBER CAP on the barb fitting. When I removed the cap to see how much diesel leaked out, diesel fuel SQUIRTED OUT UNDER PRESSURE! This happened with the engine OFF.
I think it's obvious this is how diesel was getting into my oil. It was leaking past the aneroid feeler pin o-ring, into the aneroid, being sucked up through the vacuum line, into the vacuum pump, and from there was draining into the crankcase. Now to replace the o-ring in the aneroid...which looks like a pain in the ass. Any tips? Thanks for your help guys! ---Aaron