Bosch VE pump; won't idle after rebuild

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Flynn
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Location: England

Bosch VE pump; won't idle after rebuild

Post by Flynn »

Howdy guys, this is my first post around here so don't be too nasty :wink: I pulled my Bosch VE pump to reseal it and put it back on, it runs and revs fine but after a minute or two it goes into this weird "mode" where it hunts in the revs (i.e., revs up and down) and the idle goes really low and eventually it cuts out. I know it's not a fuel delivery problem because I have run it from a bottle of fuel. I have had to replace the levers as well as a governor weight that fell out.

This is what I have tried so far:

Adjusting throttle arm position
Adjusting max fuel screw
Rebuilt pump several times
adjusting governor shaft (the one with the jam nut)
bleeding the fuel system
running the stop valve without the spring so it is always open
Adjusted idle screw
Checked timing
Tried pump at full advance and full retard
Washed all internals in diesel before reassembly
Pulled injection ports, cleaned and replaced

I really am stumped for ideas. Here's a video showing the problem:
Image
The pump is also real hard to start:
Image

I've got this feeling it is to do with the governor flywheel and weights myself. Looks kinda quiet around here, so I'm not gonna get my hopes up for anyone to reply really :|
Fatmobile
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Location: north central Iowa

Re: Bosch VE pump; won't idle after rebuild

Post by Fatmobile »

I don't see any clear fuel; lines.
and I'm going to move this to the general fora,.. not really a performance enhancement.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
Flynn
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Joined: Sun May 27, 2012 1:23 pm
Location: England

Re: Bosch VE pump; won't idle after rebuild

Post by Flynn »

Alright thanks bud. No I don't have clear fuel lines but I know that there is no air in the system because I have ran it from a bottle of fuel and it still has the same symptoms. Not really expecting anyone to be able to diagnose it really, just wanted to see if it had happened to anyone else :?
damac
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Joined: Sat Jul 17, 2010 11:29 am
Location: bay area

Re: Bosch VE pump; won't idle after rebuild

Post by damac »

I posted on another problem with a similar problem. For me it happened at the craziest time. One day the car had been running for months with no issues.

Then one day I decided I wanted to mess with my pump top settings to deal with how the smoke came on with boost. At that moment I had found diesel in the lower chamber which I guess shouldn't have been there. So I messed with those settings and decided to do a diesel purge and that is when my problems started.

I would start the car, which was labored and then after just a couple minutes i could see the idle slowly drop until it got bad enough it would die after stabbing the throttle and letting off.

thinking i needed to clear it out i drove the car hard a couple times and got stuck on the side of the road less than a mile away each time. at that point the car wouldn't restart until it rested a bit and i busted all the lines open.

it was so bad i rigged new lines through the firewall into a container under the front seat which didn't help.

i was so baffled and stuck in the moment that i decided to break down my pump completely.

only thing i found was a spec of something in that aneroid seal which i think led to that leak. everything else was indexed right and i saw no bluing of parts or debris.

where it got wierd is i put it all back together and was able to get it started with extra pedal, it acted like it would die otherwise and not start.

i said screw it and played with my fuel screw a bit and got it to idle and then redialed things in. no leaks of fuel since. and i have had the car on the road for months but there has been one issue that has persisted.

that is the idle speed. i have set it when warm and working good to just under 1000, and there have been random times when letting off the pedal that it drops a tad. i know the sound of the engine so believe it coincides with the dash tach readout. luckily it hasn't once dropped low enough to die. but i have noticed with the cold engine you might notice that slight drop in idle as being that much less smooth while warming up. my screws are all tight, no obstructions and the linkage is correct and lubed so i assume its something internal.

that is all i can add. im actually trying to bring back another pump now that works good with an electrical pump forcing fuel through, but doesn't want to pull on its own. its scared me ever since the incident that i will be left on the side of the road one day.
1985 jetta turbo diesel, 5 speed manual
Flynn
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Re: Bosch VE pump; won't idle after rebuild

Post by Flynn »

Thanks bud, useful information there. To me it sounds like something got out of calibration when we rebuild our pumps. My one is also hard to start after it has cut out as well. I have had the fuel screw 2/3rds of the way in and it still has problems, I am gonna try it all the way in this time and see if I can atleast get it idling just to get back on the road! Which seal is the aneroid seal by the way?
libbybapa
Turbo Charger
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Re: Bosch VE pump; won't idle after rebuild

Post by libbybapa »

Running from a jug has not eliminated air as a possibility. Air could be entering the pump at the fuel inlet, main shaft seal, internal pressure regulator or the non-pressurized side of the dynamic advance piston even if running from a jug. Using clear lines for the supply and return is the first step with any pump diagnosis.
damac
Diesel Freak
Posts: 165
Joined: Sat Jul 17, 2010 11:29 am
Location: bay area

Re: Bosch VE pump; won't idle after rebuild

Post by damac »

lol, i am now having the same issue with an unknown pump to me that i got off a junkyard engine. fuel seemed to be primed still when i got to it and it had paint swabs all over the place that looked untouched, so i assumed rebuild.

this pump started working if i used a electric pump because it wouldn't pull fuel but was getting it from a jug of diesel from the return side?

i just broke the whole thing down yesterday and resealed it and put the settings back to what i assume were stock. now it pulls fuel but is doing things like yours. it will not start or idle without throttle. and as the car warmed up a couple times i got it to do wierd things and then the car would die and not act the same on next start.

i even experimented with the residual fuel adjustment and max fuel and nothing was working right. on this pump it has the seesaw thing for high idle/advance and i noticed before coming in that no matter what position, rocking that each way never produced a change in revs. nor did adjusting the arm to each extreme. so on that front i can't imagine what i put together wrong since its just the governor and that spring under there but i will have to recheck since i think idle is adjusted with the seesaw, not the stopper like other pumps with just advance.

now this was driving me crazy a bit to since my car has been on the road and i just disabled it to put on a supposedly rebuit pump. my only goal was to have an untouched pump settings wise to see if it would help with my cars on boost smoking. i just can't seem to adjust it away with my current pump.

and i slapped my other pump on and it runs just like before to cancel out other variables.
1985 jetta turbo diesel, 5 speed manual
Fatmobile
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Location: north central Iowa

Re: Bosch VE pump; won't idle after rebuild

Post by Fatmobile »

Flynn wrote:Alright thanks bud. No I don't have clear fuel lines but I know that there is no air in the system because I have ran it from a bottle of fuel and it still has the same symptoms. Not really expecting anyone to be able to diagnose it really, just wanted to see if it had happened to anyone else :?
Yeah, clear fuel lines.
Into and out of the pump.
Otherwise you are just guessing about air in the lines.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
Flynn
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Posts: 30
Joined: Sun May 27, 2012 1:23 pm
Location: England

Re: Bosch VE pump; won't idle after rebuild

Post by Flynn »

Okay, tried a replacement fuel pump (unopened by anyone), same problem. So the problem is not the fuel pump. Also tried spare injectors, same problem. Checked timing, checked woodruff key slot (sometimes they get chewed up for some reason), checked fuel inlet and outlet banjos, checked almost everything. I am honestly lost. if it idles the idle goes up and down like if you were pressing the throttle slightly. The only thing on the fuel side of things I haven't changed is the injector lines. Gonna pull the belt, change the pump pulley and put the belt back on checking everything as I go, but I don't think it will help any. I can't see it being the injector lines TBH, sometimes it runs okayish and then starts to go really clattery again, if the injector lines were blocked it would be like this all the time.
the man 53
Turbo Charger
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Re: Bosch VE pump; won't idle after rebuild

Post by the man 53 »

Fatmobile wrote:
Flynn wrote:Alright thanks bud. No I don't have clear fuel lines but I know that there is no air in the system because I have ran it from a bottle of fuel and it still has the same symptoms. Not really expecting anyone to be able to diagnose it really, just wanted to see if it had happened to anyone else :?
Yeah, clear fuel lines.
Into and out of the pump.
Otherwise you are just guessing about air in the lines.
^ x2 on what he said. If you do more work without doing this I would consider you unintelligent.
Flynn
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Joined: Sun May 27, 2012 1:23 pm
Location: England

Re: Bosch VE pump; won't idle after rebuild

Post by Flynn »

Where would the air be coming from though? If you've run it from a bottle for about a minute that should have cleared all the air right out. I don't really get why it would be sucking fuel in now, the only areas of the fuel system that need disturbing for the pump change are the fuel inlet and outlet from the pump.
82vdub
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Re: Bosch VE pump; won't idle after rebuild

Post by 82vdub »

Air can get in the fuel lines at any connection point in the whole line, or at a fuel line that has cracks in it. If you have a blockage in the line and the fuel goes under a vacuum situation, too much vacuum will lead to the air coming out of solution and condensing in the fuel line. I've personally seen this happen. Car runs just fine, then it quits. Won't start right up, but after 20-30 seconds or so, it starts and runs fine, till the problem happens again some minutes later or something. I was troubleshooting under the hood and watched as the entire clear supply fuel line went to foam, and the car died. This was over a decade ago so I don't recollect how long, but it was like 10-15 seconds and the air went back into solution and the fuel line was full of fuel. It also took a few seconds when the fuel line went "white" till the car died. It happened really fast. If I didn't see it happen, I would have never ever diagnosed my fuel problem. It happened so fast and the evidence was gone fast enough so that you wouldn't get the hood open in time to ever find it. The car had a pusher pump on it in the fuel line that apparently was going bad. The IP couldn't pull fuel through the pump, so there was a blockage and the high vacuum situation. Removed the inline pusher pump and everything was fine.
Everybody else lists their cars here - but not me.

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Fatmobile
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Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: Bosch VE pump; won't idle after rebuild

Post by Fatmobile »

You want us to make a list of every reason you might have air in the lines,
instead of just using clear lines.

Doesn't seem like asking you to try clear lines was such a big deal,..
what'd ya do? buy expensive viton lines and really have to use them now, ha.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
Flynn
Cetane Booster
Posts: 30
Joined: Sun May 27, 2012 1:23 pm
Location: England

Re: Bosch VE pump; won't idle after rebuild

Post by Flynn »

Okay guys I will try some clear lines and see how it goes.
Rolson
Glow Plug
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Location: Ironton, MI

Re: Bosch VE pump; won't idle after rebuild

Post by Rolson »

Here are a couple of thoughts from my experience with my 2 Jettas.

Mine would lope like that a few months ago, and I changed the fuel filter. Took care of it.

Second time happened a few months later. Started loping again. My dad had recently purchased a 4x4 Case IH tractor from a used equipment dealer and had similar problem. He found algae in the tank. Plugged many filters, treated and washed out the tank etc before finally getting it to run right. So, this being an old California car, I thought it might be algae in my tank. Bought a new filter, added algae killer and still did it. Even opened up the tank and looked inside. Clean as a whistle.

Finally, while having the hood open one day, I noticed some air bubbles in the clear line from the filter. Hooked it up to my bottle and it ran fine. I hooked up an inline clear filter between the tank and the filter and saw bubbles in the clear filter.

I replaced the line from the tank direct to the filter. Cured it.

Been driving for a few months now with no issues, until this week. Unrelated problem though.

Rick
1985 Jetta 1.6L, NA
1991 Jetta 1.6L, NA (sold)
1990 Ford N Benz, (Ranger 2WD, extended cab, with a transplanted OM617 Turbo diesel)
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