Yet Another No Run Thread

[8v-of-fury]

And from an frequent member even!

Now, I consider myself to be above average on the knowledge of how and what these diesels need to run.. And I'm pretty sure my IP is on its way out..

Go outside today to do a final torque on my head bolts.. so i was gonna drive it around as they call for a warm torque. Get inside, fires up as normal, immediately begins to run rough (like 400rpm). does this for a couple seconds.. dies. hit the gp's again and attempt another try crank crank crank crank crank starts to run, then rough again but not for a couple seconds this time, immediately dies. crank crank crank crank with the peddle down, starts and revs up like normal for the first rev on the way down the rev it stalls out. Lots of smoke while this is happening also!

So I pop the hood, and look around. rig up some wiring to control the pump solenoid, starter, and glowplugs from the engine bay so i can diagnose.

solenoid is clicking fine
the glowplugs are fine

I pulled the lines off the filter and blew and sucked on both, and there doesn't seem to be any restrictions in either.. At this point I figure I have a plugged up fuel filter or something right, even though i haven't noticed any performance issues. pull it out, and while im at it i run the car off a jerry can of older diesel.. couple of weeks old (stuff in my tank is Friday, and I've already put 300km on it so thats not the problem), and what do you know.. it draws from the jerry can and takes off no problem. Starts up runs rough as it works the air out, and then perfectly normal.. revs up and everything.. So i figure HMM! Musta been the fuel filter since i could blow each line with no issues.. I just happen to have a spare full of diesel sitting in the garage. Put it in, starts up on the fuel still in the pump from jerry can, and then runs the exact same way as before.. #@$%.

I have had this problem before.. on an older pump that sat for years.. the shaft bushing went bad and it wouldn't pull from the tank, ran rough and had no idle. YET it would still rev up if you gave it peddle and held it. it had a pretty bad leak on the bushing yet still ran.. it was so bad it was flinging off the belt while running and it even had a hole in the clear fuel line from the filter to the pump! This engine has tight fittings everywhere.. and no visible leaks belt side of the pump.. yet wont run for more than a second..

This is quite the bummer! it was running perfectly fine up until now.. what a time for this to happen i'm set to drive to New Brunswick (4000km total trip) in this car next Tuesday...

[8v-of-fury]

Another thing, on the start where i can get it to rev up i can physically see it trying to pull fuel up to the filter from the hard lines. Turning the starter over doesnt seem to pull fuel up from the tank though...

I have clear lines from hard line to filter, filter to pump, pump back to filter, and filter back to hard line. I see all!

ANY IDEAS!?

[macka]

fuel starvation could be caused by bad fuel lines, a cracked water separator, bad connection to the fuel tank, messed up sending unit. I'm guessing here, but I'd look at the fuel lines and water separator, then the sending unit. You can also test the vacuum on the pump by running an intake line into a jerry can, which if you weren't so frustrated would have done already. Double check your timing if you are getting fuel but no combustion. Take a deep breath and relax you'll fix it quickly.

[8v-of-fury]

The breathe has been taken.

No water separator, fuel lines seem fine in the engine bay, they are metal hard lines back to near the tank where small rubber ones go on to the tank. The one from tank to feed line is new, installed that when i swapped this car to diesel in Jan. Its an mk1 btw . what could go wrong on the sending unit? telling me i gots fuel when i really don't? Hmm it says 1/4 tank ive got about 275 out of the $20 i put in at $1.20/L all highway.. so assuming I pumped in 24L, and it wasn't empty I should have somewhere around 11-12L or 1/4 tank like the guage says.. Me thinks it checks out, for a rough test.

ALSO I did the "run it from a jerry can" test, fired right up and ran perfectly fine. Combustion and timing are spot on, It ran flawlessly (as if there were no problems) off the jerry can.

Injection Pump Is D.O.A isn't it

[jasonsansfleece]

Another thing, on the start where i can get it to rev up i can physically see it trying to pull fuel up to the filter from the hard lines. Turning the starter over doesnt seem to pull fuel up from the tank though...

I have clear lines from hard line to filter, filter to pump, pump back to filter, and filter back to hard line. I see all!

ANY IDEAS!?

Can the pump draw fuel from a jerry can thats on the floor? Pull fuel up the same head as from the tank?
If it can/can't then that should say something about the condition of the pump and your fuel lines?

[macka]

if you are running an IDI and it fires from the jerry can, it means everything from the pump to the tank should be suspect. The pump works if it pulls fuel from the can. The filter could be crap, the fuel lines could be compromised with air leaks, the sending unit could be partially plugged with floating debris. Like I said, start cheap, replace the filter, then the soft lines, then the sending unit to check for debris floating in the fuel. I've seen guys put a kim towel in company trucks fuel tanks to cause "ghost" problems.

[Dakotakid]

If this is a Mk. I fuel filter set-up, change the copper washers at the top where the fuel line enters/exits.
Also the washers on the pump banjo. Better yet, buy some of the Zexel brand rubberized washers and employ those instead.
I was so happy the day I sold my last mk. I....never looked back.

[8v-of-fury]

Yes she be a 91 ME N/A hydro motor in a 84. I currently have a mk3 filter setup with the fuel running to and from the filter on each trip. No leaks there.

I guess I gotta pull the backseat and look down in the tank...

[745 turbogreasel]

put a lift pump  in upstream, and wait for a leak to show.

[R.O.R-2.0]

check your fuel lines and filters for pine needles, they have a way of causing headaches on VWs..

[Mark(The Miser)UK]

Could you have an issue back at the fuel filler cap area? EG blocked cap vent, blocked crudded up fuel vent etc.... All would disappear from a Jerry can

[mtrans]

Perhaps than use Jerry can try only one original line and another one to jerry

[8v-of-fury]

Because this car was gasoline not to long ago it doesn't have a venting gas cap, it has a third line that follows the hardlines back to the tank that I have snipped off in the engine bay. Pine needles? How does one get pine needles in on ones gas tank? Lol kev I think you had vandles! Ill pull the back seat and check the sender and look in the tank.. Can you physically see the fuel in the tank by looking through the tanks top on an mk1 jetta?

Also what I was thinking is a small helper pump with a low psi of 3-5 inline would work great.. So like any fuel pump for a carb application should work out fine for me eh? If it is ok to pump gas.. Can it pump diesel too??

[macka]

Can you physically see the fuel in the tank by looking through the tanks top on an mk1 jetta?

Also what I was thinking is a small helper pump with a low psi of 3-5 inline would work great.. So like any fuel pump for a carb application should work out fine for me eh? If it is ok to pump gas.. Can it pump diesel too??

1. yes you can see if there is crud in the tank, all you need is a light

2. not all fuel pumps will work. some will disolve internals with diesel. Make sure it is disel compatible.

[Quantum TD]

The tank has a screen inside it. Pull the sending unit and you'll be able to see it. It's probably gummed up with rust. If it is, I would pull the screen, clean it out, and then force out all of the gas through the OUT line, with the rubber hose disconnected. You may have a tank full of scaling rust (it was a gasser after all: they tend to rust the worst). Use the exhaust of a vacuum cleaner, or an air hose with the return hose and vent hose pinched. Put it into the filler neck with a rag wrapped around it. It will force out that fuel in a hurry.

If it's NOT clogged, then my guess would be a clogged return line or vent hose which is causing cavitation in the tank.