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General Information => Troubleshooting => Topic started by: rabbitman on November 28, 2011, 10:57:46 pm
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So I got the '92 golf running ok and then I was gonna mess with IP pressure when I found a huge fuel leak out of the back of the pump. I pulled it and found I'd used the wrong O-ring on the cold start advance shaft so I threw the right one on, put it back on the car and after cranking for maybe 20 seconds it fired right up. Here's where it gets weird.
It would only "rev" to a low idle and pushing the go pedal wouldn't change a thing, I did this for a while and noticed through my clear fuel lines that there was no fuel going to the pump.......no bubbles, nothing. It quit shortly after so I rigged a bottle of fuel and got it to start and run just fine off that. So I hook the lines back to the filter and fire it up and all is good for a short time and then the IP runs out and it won't start again.
I blew through the return and feed line and both are clear, I also bypassed the filter with the feed line but it still won't suck fuel AT ALL.
Any clues?
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id guess air leak on line.. yea it will suck from a can.. but not from the tank.. id check over all you connections...
else the internal pump failed and now requires a pump to push fuel to it..
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id guess air leak on line.. yea it will suck from a can.. but not from the tank.. id check over all you connections...
else the internal pump failed and now requires a pump to push fuel to it..
The weird thing is it worked just fine until I pulled the pump and replaced the cold start o-ring, it does suck from a fuel bottle too.
Is there some kind of valve in the feed line that coulda shut?
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Did you forget to tighten the lines on the filter, or washers on the inlet? Maybe the new O ring is still too small or not sealing there. Sounds like a basic air leak to me. Go back to what you touched last and source it out. Cover plate not tight or on crooked?
Gotta be something very simple.
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thats why i say check all the connections you touched.. any one of them seeping air will do that... it will suck from a can close to front of car/pump.. but not pull from fuel system... since pump was OFF all your connections need double checked along with the timming plug as it will suck air too.. if you set pump timming...
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since pump was OFF all your connections need double checked along with the timming plug as it will suck air too.. if you set pump timming...
Which i hope was done if he removed the pump lol :). Definitely sounds like an air leak.
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Well I hooked up a clear hose to the feed line so wouldn't drink any diesel and sucked on it with my mouth, very easy to get fuel up there :(......
The IN/OUT lines have copper washers and are tight on the pump.
The only thing left is I have the pressure regulator set for ZERO internal pressure so I could get the static timing right without internal pressure throwing things off (yes it's trial and error), and I'm pretty sure the little vane pump draws a lot less fuel at that setting so maybe it just ain't enough to get it up to the pump. It's weird that it worked yesterday with the wrong o-ring though.
I gotta wait 'til evening when I'm the only one here to run it since it's rather smoky so I'll get back then.........
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Internal pump pressure set to zero for what reason? Tap that sucker down about a 1/4 inch or better yet get a gauge on it and set it for 40 lbs at idle. No where have I read or heard do you need to do that. So stop doing it. Then try it.
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Internal pump pressure set to zero for what reason? Tap that sucker down about a 1/4 inch or better yet get a gauge on it and set it for 40 lbs at idle. No where have I read or heard do you need to do that. So stop doing it. Then try it.
My thinking is that if I get it so it starts good with zero internal pressure then the static timing is good. I don't want it to start up and then clack more and more as the pressure rises and the timing advances at idle.
Also this is the pump that wouldn't get above 35psi at 1000rpm.
But yeah maybe I'm straying from the tried and tested methods.
I do have a gauge setup so that won't be a problem.
So far nothing has explained why it worked fine until after I changed the o-ring.
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You have had the pump apart and know that pin that goes into the ring that holds the 4 roller bearings is connected below the pump to WHAT? To the advance mechanism and cold start lever. And on the other side of the pump is a cover plate that keeps some shims and a BIG honking spring from falling out.
That spring need to be compressed with internal pump pressure before advance occurs. Granted some advance happens early but at idle no advance is supposed to be happening at 40 lbs of pressure. That is why the advance of the cold start level is all mechanical, lever twists on cam that pushes piston and mechanism over to develop about 2 degrees advance.
Now why do you have an air leak? O rings not of proper diameter and thickness? Top screwed down tight? That is a big gasket and mine needed several rounds of back and forth half turns on all screws to get it down tight.
Did you pinch and O ring and take a piece out of it? Done that a time or two on o rings.
Nut on top the throttle tight as it can go? It pulls up on the shaft and seats the o ring in the underside of the cap up tight.
You can see I am grasping here to figure out where all the mystery air leaks seem to come from. That is all I can think up right now.
Keep looking.
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So I tapped the regulator down a little bit (less than 1/8th inch) and fired it up, now it sucks fuel........why now and not before? I guess higher internal pressure makes it have to flow more.
Now it rattles waaaay too much, I should've swapped the gov shaft sleeve for one without the bleed hole since I think it's messing up the 43psi @1000 idea. So I need to know the proper internal pressure for this pump.
This pump: 068 190 081N
Rabbits pump: 068 130 107AG
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Pressure inside the IP would still be the same, 43 lbs@ idle. Having the hole in the sleeve is for lubrication in my mind. It all floats inside the same housing and look where you are measuring the pressure. Just below the out bolt? With a second banjo bolt? or did you super it up so you have a gauge drilled and threaded in the side of the pump in that nice 1/4 inch sunken flat spot?
Most pumps I deal with have to have a positive output in order to sphion up additional water or fluid to charge the pump.
You said the vanes on this pump were not stuck so can you tap on that pin again and up the pressure past 35# now?
If not there must be air in the system or wear in the main chamber someplace.
Let us know.
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Here's a picture on the second page (not my pic) of a sleeve like my '92 has. In the pic you can see the hole is like a slot. What you can't see is the "vent" holes under the guy's thumb.
http://www.vwdiesel.net/forum/index.php?topic=30187.1
My rabbit does not have the slotted hole, just the vent holes. I'm pretty sure the vent holes are just so the sleeve can slide on the gov shaft without getting any pressure or vacuum inside the sleeve.
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The shaft and the sleeve are immersed in the diesel fuel that is pressurized to what ever amount the regulator is set to. I believe the vents are for lubrication purposes. There may be a slight build of pressure or vacuum on the two parts as the sleeve slides up the shaft as RPM's increase but the counterweights pull it back as they collapse as the RPMs drop. The sleeve locks into the base of the four pieces. Or am I whacked on that?
So I don't think the vent holes have a thing to do with the pressure inside the pump. It is a mechanically driven operation that works in a fluid filled environment. Does this make sense?
Part 115 just slides on part 108. The little triangles, 805 make it move.
(http://i1087.photobucket.com/albums/j475/Orcoaster/DieselFuelInjectionPump.jpg)
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Hey thanks for the picture, no your not quite wacked haha.
I did forget to say that #108 is drilled up the middle and has a hole near where the o-ring sits on the shaft and another one near the end of the shaft. The sleeve slides and either covers or uncovers the hole near the end thus blocking or unblocking a passage.
The hole near the o-ring has a matching hole in the IP housing so fuel can travel from, I believe, the regulator, up the middle of the shaft and then the sliding sleeve lets it travel out into the housing or not and raises or lowers the internal pressure depending on whether the hole is covered or uncovered.
It's a load/rpm sensing method of changing the timing to help with emissions but it's been a while since I read about it. It was either on this forum or the vwdieselparts forum.
Hope that makes more sense ;).
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What would happen if you plugged up the hole in the middle of the shaft # 108? I zoned out that this is not a 109 pump. Sorry on that. My thought on plugging is that then it will not be a source of any problems. It would disable the emissions part and perhaps act like a 109 pump and then it would run correctly.
Did you replace the O rings on this shaft? Use lube on install to keep them from breaking or cracking?
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I believe it's job is to provide extra advance under hard acceleration by increasing the pressure supplied to the timing piston when the hole is covered up - if it is plugged then you would have extra advance at all times. Not sure if that is what you want or not, but that's what you'd get. It would make for a noisier engine at cruising speed at the very least.
I'm not sure I understand what the goal is though?
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I believe it's job is to provide extra advance under hard acceleration by increasing the pressure supplied to the timing piston when the hole is covered up - if it is plugged then you would have extra advance at all times. Not sure if that is what you want or not, but that's what you'd get. It would make for a noisier engine at cruising speed at the very least.
I'm not sure I understand what the goal is though?
I just don't know what to set the internal pressure at with that hole messing things up. If I disabled that feature I would just time it like a normal pump. Maybe that's why this engine is supposed to have 54hp instead of 52 like my rabbit ;D.
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I would be looking at setting the pump at 40 lbs first. If you can even get it there. If at 40 lbs at idle it still has some running issues then try for 43 at idle. Those are the only numbers I have seen other than those of us that finally throw a gauge on the pump and find that we are all running at 20 because of wear and maybe PO's dinking with it previously.
If the mechanism seems to function as a secondary method for the pressure to get to the other side of the timing advance it is only going to be working when you are under a higher RPM than the idle. Hence I say set it up and try it out. If you can't get the pressure past 35 #s then I would still be looking for a problem internally. Or thowing about 4 ounces of wax into a gallon of diesel, letting it warm up and disolve, or heat it to make that happen and then run it off the isolated gallon and see with the wax addition what the pressure might be. If it goes up than you know you have a worn out pump because the thicker fuel is taking up some of the wear factor. I would pull as much fuel out of the pump and inject waxed fuel into it so that dilution is minimal.
If thicker fuel is what you need all the time then adding oil to the diesel is the only out where it is getting cold right now. You don't need gelled fuel in the filter, lines or tank ever. If you can get your hands on that 60W oil aircraft use that is the ticket.
Good luck
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I believe it's job is to provide extra advance under hard acceleration by increasing the pressure supplied to the timing piston when the hole is covered up - if it is plugged then you would have extra advance at all times. Not sure if that is what you want or not, but that's what you'd get. It would make for a noisier engine at cruising speed at the very least.
I'm not sure I understand what the goal is though?
I just don't know what to set the internal pressure at with that hole messing things up. If I disabled that feature I would just time it like a normal pump. Maybe that's why this engine is supposed to have 54hp instead of 52 like my rabbit ;D.
The hole is supposed to be there though? Why would it mess up your internal pressure setting? Am I missing something and you're trying to use a particularly unusual pump?
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The hole is supposed to be there though? Why would it mess up your internal pressure setting? Am I missing something and you're trying to use a particularly unusual pump?
Yeah this pump is different than what us North Americans got(afaik).
The hole leaks pressure from inside the pump body back to the vane/lift pump so instead of forcing the fuel through the OUT bolt it just recirculates it and so doesn't build any higher pressure until the hole is plugged, I don't know at what pressure or throttle position the hole would be plugged or unplugged by the sleeve so it's a guessing game so far.
I did get it to run perfect though so I'll leave it alone for now. I've driven it around and (other than the horrible misalignment and resulting wandering) it is a pleasure to drive, fast response to the go pedal, super tight shifter and VERY FEW RATTLES.
Another major problem is it starts hard. This morning it was 22F out and it would hardly fire, I plugged it in and tried throughout thre day with no success so I bought a new battery and it cranked waaaaay faster but still wouldn't start until probably 4 hours after being plugged in then it fired up and ran perfect.
The heater blows HOT air too, it will be a welcome change from the rabbits heater............
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Sounds like you have the pump problem solved and now you need to source out the glow plug functions. Do they work, how long and do they shut off like they should. Be plenty of discussions here on those topics so start searching.
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See I was pretty sure our pumps had that feature too - I don't think it bleeds ALL pressure, just some. The specific point that it kicks in can be changed by adjusting the governor shaft (behind the pump sprocket).
Either way, glad you have it running now!! :) Glowplugs next most likely...
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The hole is supposed to be there though? Why would it mess up your internal pressure setting? Am I missing something and you're trying to use a particularly unusual pump?
Yeah this pump is different than what us North Americans got(afaik).
It's actually a feature on all the "newer" pumps (pre-TDI of course). I can't say exactly when it started but I think it was around the time of the fast idle, which I think was 87ish.
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It's actually a feature on all the "newer" pumps (pre-TDI of course). I can't say exactly when it started but I think it was around the time of the fast idle, which I think was 87ish.
Thanks Tyler, that makes sense.
As for the GP's, they were new duraterms when I put the engine together maybe 5 miles and lots of failed starts ago.
Tried starting it today at 23F (plenty warm for my rabbit fire up), I glowed the plugs until I heard the relay shut off then glowed 'em again until the light went out then I cranked away. It almost started, it cranked faster and faster like it was trying and then it just gave up, I think these diesels can flood if they don't start quick enough.
One cylinder definitely fires harder than the rest. I'll make sure the GP's are good.
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GP's are good, they're wired Vince style so I can touch 'em one at a time to the battery and get a big spark. Also checked to make sure they're getting power so I see no reason for it to not start...........other than low compression which I've not checked.
Just tried again and it almost started, blows black smoke and sounds like it's gonna and then just stops firing.
When I fired the GP's this last time I heard a dull thud in the exhaust system, and while I'm cranking I hear it every now and then. So I think it's pushing lots of fuel right through the engine.
The cold start doesn't really make a difference pulled or not.
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I wouldn't call it flooding but rather cold fuel cooling the combustion chamber.
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Got it to start finally, plugged it in for two hours and did a pre-glow and it fired up like nothin' was wrong.......runs perfect too.
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I wonder if it was an air-in-fuel issue
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You mean in the lines just before the injectors? Some injectors getting the fuel they needed but not all? Hope it continues to start once it cools down over a cold night. Keep us posted.
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You mean in the lines just before the injectors? Some injectors getting the fuel they needed but not all? Hope it continues to start once it cools down over a cold night. Keep us posted.
Yes, or even air in the pump only allowing some of the injectors to get some fuel some times.
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I agree. Sometimes these pumps are harder to burp than a baby. Like they store pockets of air for later or something. We need clear plastic pumps.
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We need clear plastic pumps.
haha that would be cool.
So today at 15F I tried to start it. I did a complete pre-glow til the relay clicked off and then glowed til the light went off. It cranked real fast, firing on all four and almost fast enough to pass the starter so I stopped to reglow it and then it would just do the "fire on one cylinder" thing and wouldn't even think of starting so I plugged it in...............I'll go try now..............
Fail, it was plugged in for 6 hours so I thought I'd glow 10 seconds (longer than the light calls for), leave the CS knob in and not push the go pedal. It started and quit so I glowed a bit more and pulled the cold start and push the go pedal but by then it was done.
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OK, disregard most of that last post, the block heater cord is a poor connection to the block heater itself so the oil pan heater was the only thing working ::).......... it has been intermittant so just now I wriggled the plug and heard coolant start to sizzle. grrrrr
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So a half hour of actually having a block heater going and the hoses and VC warm to the touch failed to start it, very little firing even.......a total joke........
I'll get my hands on a dial indicator and see what that's at. I don't see how it could be the problem since it runs soooo good but right now I'm out of ideas.
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The only time mine acts like that is when there is air in the pump or lines. Can you see air anywhere when you are cranking it. Return line might show it best.
A real catch 22 here in that you need the air out to get it to start and the air is preventing that from happening. Only solution I could recommend it a pump on the inlet or a squeeze bulb but that would be a royal pain in you cold weather.
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The only time mine acts like that is when there is air in the pump or lines. Can you see air anywhere when you are cranking it. Return line might show it best.
A real catch 22 here in that you need the air out to get it to start and the air is preventing that from happening. Only solution I could recommend it a pump on the inlet or a squeeze bulb but that would be a royal pain in you cold weather.
I have one on my rabbit and haven't had an issue with it in the cold........granted, I rarely use it either though.
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>:(
So today I plugged it in until the top rad hose was really warm to the touch and it still didn't want to start. Finally after cranking forever the rpm got high enough and it fired up and ran PERFECT. This thing runs like a dream........
Pulled it in the shop and checked compression, the results are depressing.
Checked almost up to full temp.
#1: 330psi
#2 250
#3 265
#4 160
Its gotta be the rings since I just redid the valves. The cylinder walls looked nice, crosshatch were still visible.
Any chance dumping kerosene in the cylinders and soaking it will fix anything? I really don't feel like doing rings right now.
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Do you think the rings are in there tight and not expanding? Hence the solvent in hopes of breaking them free? Kind of a two edged sword here. They may come free but then they may really be loose and your compression would get worse.
Being where you are kind of rules out thicker oil now doesn't it. Could you get the pistons down in the cylinders and try some ATF? That stuff has a lot of detergent in it. Are you close to an oil change. Someone on here mentioned that they run a quart of ATF for the last few hundred miles in there oil before changing it. Perhaps that might help from the lower end. But in all reality the tops are where the coke is at most times.
If you already have the head off then aren't you half way home on doing the repair? Or are you stating the cross hatching in the cylinders from your memory when you did the valves?
Bummer, but a kerosene soak and ATF in oil combo might get some results. Do let us know.
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Yup, the crosshatch is from memory. IIRC the PO also posted about the crosshatch of this engine too.
Yeah I read (maybe on this forum) about soaking rings in kerosene to free 'em up but it's been a while.
One reason I'm thinkin' they're stuck is 160 psi means a ring either broke or has something else wrong with it.
I'll try a leak down if I can find the fittings and see if it's rings or valves........
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I'm gonna start another post about my low compression since the topic has changed
http://www.vwdiesel.net/forum/index.php?topic=30534.msg273732#new