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General Information => Troubleshooting => Topic started by: vegfuel on March 26, 2007, 12:49:03 pm
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My 1981 VW Rabbit diesel runs and drives but it has a problem with lots of smoke and high reving at hard acceleration. Like when you rev the engine up to let the clutch out it will "run away" on me. It only does this when you rev the engine up high, other wise it idles fine and drives at low speeds ok. I'm thinking that I have excess blowby, it's buring oil because it is like 50 degrees out and it's still puffing blue smoke. I checked the vent on the valve cover and there is no smoke and almost no oil coming out, just nice warm air. I havn't tried it at higher speeds though. I'm thinking that I might have to do a minor overhaul and replace the piston rings. Has anyone on here done this? My question is, is it only one or two piston rings that are worn or all four? Can anyone give any input? Would it maybe just be the air intake clogged?
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Search for "runaway". There is a plastic oil deflector that goes under the valve cover to reduce the possibility of oil vapors going into the intake and cause the runaway. If you don't have one, get one. If you do have one and your getting the runaway problem, the show is over. Ring time.
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you might as well do all 4 piston rings while you're in there... why do one or two cyls, just to find out that a couple of months later you've got more blowby in the ones you didn't do???
rings can be done by simply removing the pan correct????
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you might as well do all 4 piston rings while you're in there... why do one or two cyls, just to find out that a couple of months later you've got more blowby in the ones you didn't do???
rings can be done by simply removing the pan correct????
Only if you drop the crank first. Even then, you really should hone the cylinders, and it's better to do that with the head off. If there are any ridges, they need to be removed also, which HAS to be done with the head off. Plus all that stuff has to be cleaned really well.
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Hey guys, I think I may have found something that will stop my over revving. The Rabbit never takes off on me it just over revs when I let out on first!
To quote a VW manual on Diesel Fuel Injection: " The maximum engine speed adjustment prevents the engine from over-revving and self destructing.
So these would be the maximum and idle speed adjusters on the IP.
Also the guy I bought from, evidently screwed with the IP.
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If you turn up the fuel screw, and don't adjust the residual fuel screw (idle stop screw) the rpm will drop very slowly after winding it out in gear.
If the "lots of smoke" you are seeing is black, it sounds like your previous owner turned in the fuel screw and didn't adjust the residual fuel screw.
Try backing out the fuel screw 1/8 turn at a time and see if you "overrevving" goes away.
Or you could putz with the residual fuel screw (idle screw) and that should also reduce your "overrevving" but won't reduce your "lots of smoke"
Did you try running it with the breather hose disconnected and see if your "overrevving" went away.
The things that need to be clarified are: "lots of smoke", is it black or white? Is your "overrevving" a very slow reduction in RPM after accelerating, or is it a runaway, uncomanded acceration, when you take the engine to high rpm?
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Would it be better to hook a tachometer up (Rabbit does not have a tach) to check rmp before fiddling with the screws?
The Rabbit can drive. I can shift out of the high rev when gaining speed. It just leaves a bunch of blue smoke when it does over rev.
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"I can shift out of the high rev when gaining speed."
What happins when you take your foot off the accelerator and leave it in gear when its doing the high revving?
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yeah, it does stay up there when I let off of the peddle....
but it doesn't take off on me.
What I like to do to test the problem is just pop the hood while it's on idle and press on the IP lever and see how far I can get the rpms before it starts to take off, and then I have to turn it off with the key because it won't rev down.
But it's funny because it doesn't take off on me and it will still drive in most of the gears.
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Black smoke, too much fuel.
Blue smoke, rpm staying high when the accelerator is relaxed, its looking like a runaway.
Disconect the breather hose from the air cleaner and see if it solves the problem.
Revving the greegree out of the poor thing in nuetral will not help the matter.
Isolate the cause, attack the cause, enjoy the bennifit.
There is an outside chance that the throttle shaft is sticking in the injection pump. The 1.5 pump used to do that. Hose it down with WD40 and work it back and forth(engine off) and see if it frees up.
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Thanks saurkraut I will try that,
I bought this Rabbit for 400 bucks. I needed a car to run my biodiesel for my senior project. The rings are most likely worn for some reason. One thing I found was that the oil pan had really bad leak and the oil level was always extremely low with me having to fill it up all the time.
I think maybe the rings got worn because of the lack of lubrication, I don't know.
But do you think it would be safe to use it for my biodiesel project until I graduate? And then I can worry about a minor overhaul. It does have a little of 200,000 miles on it.
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Find the oil baffle that goes under the valve cover. It completely covers the cam shaft and has successfully worked for others with far worse symptoms. I have them in all my diesels. i tried to find a picture of one, but couldn't find one. You can post a WTB for one in the for sale section of this web page. Or Email [email protected] and he can send you one.
The oil baffle may solve you problem for now.
Why rings wear out. There are two causal factors.
Driving too conservatively. Carbon deposits form in the ring lands, behind the rings. Eventually, the carbon becomes so thick it pushes the rings out and they wear faster. Some times they even stick in the ring grooves and the compression goes by by. This can occur at 80,000 miles or less, if someone drives like a real sausage.
Solution: drive it like you stoll it.
Causal factor 2, long hard life 300,000+ miles. The bores in the block become egg shaped, the rings have to do a lot more booging in the ring grooves. Piston clearance becomes excessive. Death rattle sets in, and if its pushed to its limmits, skirts break off the pistons and the show is over.
Oh, and one more. never changing oil, and / or running S rated oil instead of C rated oil. Soot particles build up in the oil, the oil either doesn't have the ability to break down the soot particles, our it lost the abilty to do so. The soot particles actually machine the inside of the motor: bearings, bushings pistons, ring and bores. Eventually the compression is so low, it won't start any more. once again, show over.
how bad is your moter? hard to say. One the pluse side, it still starts. On the negative side, you have enough blow by to get the overreving thing, but apearently not enough to get the full blast runnaway, complete with overheated breaks and a really wild ride.
so, it may live for a while, maybe a long while.
Find the oil baffle and give it a try. Don't baby it too much, but don't thrash the living beejeepers out of it either. Run a C rated oil and keep your finger crossed.
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Hey thanks
Are you a mechanic? Not to question your validity in knowledge, you just seem to some good stuff. This has gives me some hope. I don't want to screw around with the IP with first checking the rpms. I havn't really done a good "checkup" on this little Rabbit. I will research the oil deflector or what ever it is and that might get me by for my project. After that I'm thinking about doing an overhaul and re ringing it.
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How would I go about seeing if I have a oil deflector, just by taking the valve cover off? What does it look like? Is it ok to take the valve cover off and then on again?
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How would I go about seeing if I have a oil deflector, just by taking the valve cover off? What does it look like? Is it ok to take the valve cover off and then on again?
if you take the oil cap off and you can see metal, then you don't have the oil deflector...
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The oil baffle:
http://www.rsjparts.com/catalog/product_info.php?cPath=21&products_id=139&osCsid=6be9216fb14d89bc70fe2f2631712647
One piece reusable valve cover gasket
http://www.germanautoparts.com/Volkswagen/Golf/Engine/102/1
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Like jtanguay said, just open the oil cap and look down. If you see the cam, then you don't have the baffle. If you see black plastic, you do have it.
The good advice has already been given:
-Change the oil, because you really don't know what's in there or how long it's been in there
-Put the baffle in
-If the baffle doesn't help, you may have to divert the crankcase vent
If left unchecked, the problem can get bad enough that you won't be able to shut the engine off with the key. It will run off the engine oil, and you'll have to stall it to stop it. I've had that happen before; you want to avoid it.
Furthermore, you'll want to address this before you move onto biodiesel or SVO. You don't want to be troubleshooting car problems and fuel problems at the same time. Ask me how I know ;)
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Here is what I did to vent the crankcase blow-by. This helped the engine make it another 3,000 miles before it developed a huge oil leak. I would recommend venting the air to the back of the car with a long hose.
Since you are using this car as your senior project using B100, I would imagine that you want this car to promote clean air. You will probably show this car off every chance you get. With this in mind, venting the blow-by out into the air is NOT what you want to do then. The smoke from the blow-by is white, foggy, and stinks. It would not help your project to have one exhaust smell like french fries and this other exhaust to be smokey and stink. There is a reason why the blow-by is fed back into the engine to be burned and that is to reduce emissions.
(http://webpages.charter.net/sidneyt/Pictures/EngineTopss.JPG)
(http://webpages.charter.net/sidneyt/Pictures/VentHosess.JPG)
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"Ask me how I know " from addautomotive
I dying to know
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So tonight I took everyones advice and went out to see if I had an oil baffle and low and behold, I do. So then I took her for a spin up and down our long drive way with the breather hose disconnected from the valve cover. She still wants to go when you rev to high.
I can't do a rebuild now because I am to busy and not enough money. I'm thinking it will be ok for my biodiesel.
Anyone here think different?
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I can't do a rebuild now because I am to busy and not enough money. I'm thinking it will be ok for my biodiesel.
Anyone here think different?
Yeah, personally I think you're in for a world of pain. But heck, sometimes the hard lessons are the best lessons.
Here is what I've learned (very slowly):
If you can't afford to do it right, you REALLY can't afford to do it wrong.
Find a way to bypass the crankcase vent. You may even be able to jerry rig a catch bottle that will collect the liquid oil, but still burn off the fumes.
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Turn this screw in 1/4 turn and see what happens
You need to loosen the 13mm lock nut
(http://img.photobucket.com/albums/v603/burnyourmoney/screw.jpg)
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if you can't afford doing a proper rebuild, then go to the store and buy wynn's oil stop leak and throw it in. it sucks for cold weather though, just to forewarn you!
it did stop nearly all oil burning in my '86 TD which had new rings but not honed.
i think it's less than $10. thick and gooey! that will get you going for now. most people say not to use that stuff, but then again, its not most people who really want to spend hundreds of dollars to fix an old car.
wait it might be called stop smoke now... not too sure! just make sure you get the stuff that says stops oil burning!!!
(http://www.halfords.com/wcsstore/HalfordsConsumerDirect/images/catalog/400-176610.jpg)
that is what it should look like.
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What the heck, I'll try it. I've tried to loosen the fuel screw to see if it would calm down but that didn't work. I don't even know what rpms the engine is set at.
My mentor for my project has a Mercedes TD. Maybe I should hold off on using the Rabbit for bio just yet and see if someone else would test it for me. I don't even have bioD compadible hoses or seals yet!
So, burn_your_money, what is the 13mm lock nut?
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It's been a while since I messed with that screw. You need to loosen a 13mm nut and then you can adjust the screw. You should probably start by making 1/8 turn adjustments at a time and see what happens. Expect a power loss by doing this
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So then I took her for a spin up and down our long drive way with the breather hose disconnected from the valve cover. She still wants to go when you rev to high.
It doesn't sound like it's reving too high, sounds like it just doesn't drop back down after you let off the fuel.
If you disconnected the crankcase vent from the intake and it still does it, it wasn't burning oil.
If you backed off the max fuel screw and it still does it (not overfueling), I'd say the injectors are spraying funny and leaving some fuel in the cylinder after the burn... so it burns the next time around.
I haven't read the whole thread in awhile but if the throttle isn't sticking (first thing to check),
... I'd pull the injectors and test them.
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what if the rings were so bad that the oil was shooting past them??? worst case scenario of course...
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So then I took her for a spin up and down our long drive way with the breather hose disconnected from the valve cover. She still wants to go when you rev to high.
It doesn't sound like it's reving too high, sounds like it just doesn't drop back down after you let off the fuel.
If you disconnected the crankcase vent from the intake and it still does it, it wasn't burning oil.
If you backed off the max fuel screw and it still does it (not overfueling), I'd say the injectors are spraying funny and leaving some fuel in the cylinder after the burn... so it burns the next time around.
I haven't read the whole thread in awhile but if the throttle isn't sticking (first thing to check),
... I'd pull the injectors and test them.
How about the residual fuel screw also? After my IP mod, I had to unscrew it a little because after blipping the throttle, the engine speed would stay up there and not come down to idle.
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It is a funny situation. She always starts right up. Even in the cold weather of northeastern Washington. So the compression is good. I was thinking about contacting the owner before the previous owner to see if he knows what's wrong. Also another thing: the Rabbit came without a fuel cap and there is not a little metal sealer like on gasoline cars, just a straight hole, so I imagine moisture was allowed in the fuel. Thanks alot from everyone for all the input. I'm learning more each day.
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burn_your_money,
How in the world do you loosen that 13mm nut? It's on there pretty good like someone has stuck some LocTite on the threads.
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burn_your_money,
How in the world do you loosen that 13mm nut? It's on there pretty good like someone has stuck some LocTite on the threads.
you need to break the collar first, then you can spin the screw... i think some people chisel it off or something like that. just be sure to not hit it super hard... aluminum pump!
if all else fails don't forget my suggestion about that oil... i'd recommend it as a cheap fix. just remember to let the engine warm up (30 seconds idle even when hot outside and half gauge before driving it hard!) and in winter, you MUST change the oil or she won't start (ask me how i know... :lol: )
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Jimfoo wrote:
How about the residual fuel screw also?
Which screw is that? Same as the max fuel screw I mentioned? Same as burn_your_money's "This screw"?
what if the rings were so bad that the oil was shooting past them??? worst case scenario of course...
While the gasses are exploding and pushing the pistons down? Hard to imagine oil staying on the walls while all the gasses are pushing past the rings (on a car with low compression due to rings,... of course because excessive oil doesn't get past good rings).
I suppose some oil could coat the cylinder walls on the next stroke, when the piston comes up to push exhaust out, then goes back down... but I picture it being blown back into the crankcase next time the pistons come down,... preceded by a big explosion and gasses rushing past the rings again.
I think it's the gasses being pushed into the crankcase, forcing oil vapors out the valve cover and into the intake that causes the engine to run on oil.
veg fuel wrote:
I've tried to loosen the fuel screw to see if it would calm down but that didn't work.
....How in the world do you loosen that 13mm nut?
Oh, it didn't work because you couldn't loosen the lock nut? I thought you tried it and it didn't keep it from reving.
That should fix it, if not check the injectors.
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Jimfoo wrote:How about the residual fuel screw also?
Which screw is that? Same as the max fuel screw I mentioned? Same as burn_your_money's "This screw"?
It is the long horizontal one on the back side of the IP, behind the max fuel screw. It pushes against the throttle linkage. I have a good picture I printed out of all the screws descriptions, but I have no clue where I found it.
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I don't know if we don't have a sticking throttle shaft yet. On page one of this thread I covered: lubricating the throttle shaft, fuel screw, residual fuel screw, disconnecting the breather hose, oil baffle and more.
So far we have pulled the breather hose and we still have the phenom.
The phenom, from what I can discern is a high RPM hang up. There is white smoke in the exhaust, but we don't have a full blown run away. The full blast, E ticket at Disneyland run away may be on the horizon, but we haven't had it yet.
If this is a 1.5, their pumps are notorious sticking throttle shafts.
It would be helpful if we knew the throttle shaft was not sticking.
This can be verified by moving the throttle lever on top of the pump (ENGINE OFF) and see if it snaps smartly back to the Idle stop(residual fuel screw).
If is dosen't, apply liberal amounts of WD40 to the base of the throttle shaft and working it back and forth untill it moves freely.
If the throttle shaft is not sticking, the max fuel screw, or the residual fuel screw (idle stop) should be backed off.
To undo the Jam nut on the max fuel screw, use a 13mm box end wrench on the nut, while holding the screw with a long screw driver. When the jam nut is loose, move the max fuel screw OUT 1/8 turn at a time. Seat the jam nut and test the results.
Or, reduce the idle stop screw (residual fuel screw). Pritty much the same procedure as the max fuel screw, except you can do it with the engine running: undo the jam nut, move it out. The normal idle setting is pritty low.
If you move the idle stop screw (residual fuel screw) out too much, the engine may quit on decelaeration.
If you watch what your doing, and keep track of where you moving stuff, you can't really screw this up. You can always put it back to where you were if you don't get the results you want.
If this does not fix it, the only other thing I can think of is an increadably dirty are filter, and shot intake valve seals. If the air cleaner is dreanched in oil and plugged with dust and other crap, we may have high enough maniflod vacuum to pull some oil down very loose valve guides with shot seals.
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+1
What he said!
Move on to checking for a sticky throttle.
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Ok, Update on the Rabbit
With the engine off I pressed the throttle up to full speed and let it go. There is no resistance whatsoever. The accelerator cable is not even tight. I also noticed that the "residual screw" the one behind the max screw is turned out really far. What would happen if I turned it in? Would I have to adjust the max fuel screw then?
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Try lowering the idle with the residual fuel screw.
If you have a really smooth idle now, its probably up there because the prev. owner tuned up the max fuel screw. A little more fuel won't hurt anything. And from what i can tell from your description, you not blowing big black clouds of soot.
Normal idle isn't really rough, but there is a little more clatter, or "nailing".
Back it down to where you think its a little low, snug the jam nut and take it for a test drive.
Oh, by the way, what is your oil consumption like?
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When you were testing the throttle shaft for sticking you did it from in the engine compartment and manually moving the lever right?
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burn_your_money: Yes that is correct. I just pressed the lever on the IP.
saurkraut:
Everytime I start it up it will heavely smoke for about five minutes. This smoke is never nice black soot, but always a greyish blue. It goes away after you let the engine warm up but I when you press on the throttle it puffs little clouds whether it's cold out or not.
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Are the little clouds white as well?
That could be coolant in the combustion chamer or incorrect timing, I forget if it's advanced or retarded though...
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Sounds like your timing is retarded. My Jetta's timing was retarded and it would do the exact same thing. The retarded timing might contribute to your high reving problem. I say it might becuase I noticed that with the timing retarded, the the engine took more time to idle down after reving up.
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Everytime I start it up it will heavely smoke for about five minutes. This smoke is never nice black soot, but always a greyish blue. It goes away after you let the engine warm up but I when you press on the throttle it puffs little clouds whether it's cold out or not.
In my experience with gas engines, blue smoke after sitting for a while is always valve seals
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Here's the idle smoke
http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=96856952&albumID=883033&imageID=5395076
And here is the smoke when the engine won't rev down or "runs away"
http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=96856952&albumID=883033&imageID=5395499
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apparently I need to sign up to view your pictures. You should try www.photobucket.com
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Yeah I was afraid of that,
here's the idle smoke:
[/url]http://i152.photobucket.com/albums/s191/vegfuel/NatesPlace284.jpghttp://here's the "run away" smoke, not easy taking this pic with my foot on the pedal. http://i152.photobucket.com/albums/s191/vegfuel/NatesPlace295.jpghttp://here's more idle smoke:http://i152.photobucket.com/albums/s191/vegfuel/NatesPlace287.jpghttp://
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that looks like just a worn injector... my car used to do that until hot... but then i got smog injectors and now all i see is black smoke, with a hint of blue-ish grey due to a possibly dying motor... oh well!
mess around with the timing though. try 0.95mm and 1.05mm it can't hurt.
(http://i152.photobucket.com/albums/s191/vegfuel/NatesPlace284.jpg)
here's the "run away" smoke, not easy taking this pic with my foot on the pedal.
(http://i152.photobucket.com/albums/s191/vegfuel/NatesPlace295.jpg)
here's more idle smoke:
(http://i152.photobucket.com/albums/s191/vegfuel/NatesPlace287.jpg)
there i fixed that up for you!
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How many km/miles have you got on the motor?
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She's got 220,065 miles! Yeah she's a little worn out, but I was hoping to get another 80,000 if I did a rebuild. I guess I got suckered in to this car, for $400 you can't expect a much. I was just needed a vehicle for my high school biodiesel project.
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I have 235,000 on my Rabbit engine and it still runs good. Engine is practically untouch except for one head gasket and the fuel pump. You should still have some pretty good life life in that engine if it was reasonably taken care of. I would think you should be able to get atleast 80,000 before a rebuild. Looking at the smoke, I still think your problem is with your timing. That is the same smoke I had when my timing was retarded. Read up on hill billy timing to advance your time. Rotate the IP towards the head about 1/16 of an inch, and it should stop smoking. Or do it the professional way like jtanguay said.
$400 is not too bad of a price. Does not look like it has much rust on it. It seems like whenever I get a car, it needs atleast a couple hundred dollars put in it.
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Yeah, they outside is pretty nice. It's the inside that kinda bad. But who cares!
So you are saying to advance the timing? I could try that.
As for the "over revving" problem, I have found out something else, I know this is getting to be ridiculous but this could mean something:
What is the lever right under the throttle lever on the IP? When pressing on the throttle, THIS lever is not coming back!! It has to be pressed back and it feels like it's gummed up.
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well Dr. Diesel just acquired a new, very cool toy! damn! if you could time your motor with that, i have no doubt that the smoke would go away.
because i do honestly believe that you have worn injector(s). now if you have one really bad one, and 3 decent ones, that one injector will need to be changed.
come to think about it... that device could actually detect when an injector fires, and allow you to detect an injector that is firing at improper intervals. SICK! but then again... if you put a brand new one, you throw the rest out of sync. If all of your injectors are worn evenly (rarely happens) then you can just increase timing to compensate. the downside to this, is that if you have a leaky injector, you will be in for some severe damage (my pistons started melting at the edges... mind you i didnt really know much about egt at the time, and would be smoking everyone out :lol: engine still runs half decent though!)
IMO, get your injectors done, time it properly, and be happy. if you run veg, i think people recommend increasing the timing, as the increased viscosity of the fuel will slow down injection time, so you compensate by increasing the start of injection. there is even a place that sells special veg injectors (bigger nozzle to compensate for higher viscosity)
now if the car was spewing out black smoke (at idle) then you have compression issues. we don't see that, so this car should easily do another 80'000 with you keeping the oil topped up. I have personally seen a toyota truck with around 30-50 psi one one cyl, 100 on the next.. 140 on the next, and the last one had 300 or so. the engine REALLY wanted to start! nice big puffs of black smoke out the tailpipe. eventually it did run, at around 1500-1800 rpm. bucked really bad. but at that point, the motor is pretty much useless. turns out that the po ran it too hard, and the exhaust manifold runs from front to back, and so the rear cyl got the heat from all 4 cyls and got cooked real nice. :lol:
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vegfuel - It just occured to me that your throttle might be sticking with the springs hanging it up. I got my rebuilt pump put on and a few says later, it would not idle down very well. I then realized that the actual throttle lever on the pump took a second to get to the idle position. The new paint on the springs were hanging it up.
Solution - hose down the throttle springs with WD-40. It solved the problem and has not happened since.
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dieselsnowmobile,
I have already tried oiling the springs on the throttle lever, there is vertually no resistance. I'm just wondering if it might be the governor spring inside the pump connected to the throttle shaft.
Another thing, you said you have a Rabbit diesel engine like mine, is there a lever located right beneath the throttle lever? I have this lever and it is connected to a spring as well but it is as sticky ever.
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dieselsnowmobile,
I have already tried oiling the springs on the throttle lever, there is vertually no resistance. I'm just wondering if it might be the governor spring inside the pump connected to the throttle shaft.
Another thing, you said you have a Rabbit diesel engine like mine, is there a lever located right beneath the throttle lever? I have this lever and it is connected to a spring as well but it is as sticky ever.
just try and spray some wd-40 on it. just make sure to wipe up the excess when it's done. can't hurt. and maybe it will fix the problem.
maybe it is the accelerator cable itself??? i've had a golf gasser that had a really stiff one... it wouldn't hang though...
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Here is a picture of my newly rebuilt Rabbit pump. I think that the lever you are talking about is the lever underneath the throttle lever that is against the high RPM limitor block but below the high RPM limitor bolt in this picture. Unfortunately, I have no idea what that lever does nor if it suppose to be sticky. The problem I had was when they rebuilt the pump, they hosed everything down with paint which added friction to the spring and eventually made the throttle hang up. I also remember that on my old Rabbit, the throttle would sometimes take awhile to idle and I did the same thing there too. Sorry I am not much help as to what that lever does, I am sure someone might know or you could read Bosch Training Manual (http://members.shaw.ca/vwdiesel/diesel_training/diesel_training.html) on the pump and figure it out.
(http://webpages.charter.net/sidneyt/Pictures/Pumpss.JPG)
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is there a lever located right beneath the throttle lever? I have this lever and it is connected to a spring as well but it is as sticky ever.
Yes, that there lever is called the cold start lever (if I'm correct). It increases fuel to the injectors for easier starting. I don't really know if that can cause reving or not. But, when I pull it on my Jetta, it seems that it just fires harder :roll: .
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Geeze, some times this forum is a font, over flowing with miss information.
The cold start lever is on the back of the pump.
It is nowhere near the throttle lever.
It has no effect on the throttle lever.
Its is hooked up to a solid wire cable that is attached to the cold start nob in the dash board.
When you pull out the knob, its advances the timing at idle rpm (I don't remember the RPM, but it pritty low).
It does not add fuel.
Above idle, it is disabled.
There is no detriment to driving around with the cold start activated. It may screw up the idle emissions of a fully warmed up engine. Ive never taken the time to hunt that one down.
Now, back to the smoking rabbit. It appears we have two problems: (1) A sticky throttle lever. (2) marginal (shot) injectors.
First the throttle lever. Get a can of WD 40. A big can of it. ENGINE OFF. Disconnect the trottle cable from the pump. Work the trottle lever back and forth while spraying the the shaft with WD40. This may take alot of cycles. The continous spray of WD40 will help wash out the crud that is binding the small lever. Keep going untill the little arm snaps back with no resistence. Continue to spay and cycle the arm a couple three dozen times more. Put everything back togather and report back here.
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well actually the cold start lever increases timing up till 1800 rpm. his model might have the idle speed boost as well, which in fact does give more fuel? :wink:
i almost think that maybe the pump internals are shot, or in need of cleansing... get some lubromoly diesel purge.
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Its an '81. Idle booste didn't exist then. As a mater of fact, i haven't seen any idle boost on any US mechanical pumps.
The advance below 1800 may change the RPM slightly, like a phemto RPM, but i can't detect it on any of my stuff. i can hear a slight increase in "nailing" when I pull my cold start when the engine is warmed up. no noticable increase in RPM though. So, no, its not getting any more fuel.
What he is describing, the little lever below the big lever hanging up, is classic old corroded pump behavior. It is really common on the 1.5 pumps. Working it back and forth, while spraying WD40 on it has worked for me. Befor we toss the pump, lets try somthing simple and proven.
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Ya, when I finish rebuilding my Jetta motor, I might need to do a little adjusting on my pump. I noticed when I was running it, before its reduild, it was running sort of crappy like reving when I even touched the throttle. That's why I was so confused about the fuel adjustment screw. But after I get my new rings, bearings, and seals in i'm sure that nothing underneath would go wrong (I might need a new pump), no more worries. So, the problem with vegfuel's rabbit is probably that either the pump or injectors are bad. Sorry about the comment on the cold start, I didn't even know that it advances the timing :oops: . Well at least I learned something too.