Noob: Timing or max load or ???

[joshh]

First, hi. I'm a noob to IDI VW diesels, but not gasser VW's. We picked up this '84 Jetta Diesel a little over a month ago and I've been working on it since.


Before:




After:







Anyway, on to my question. Since I'm new to these, I need a little guidance in figuring out an issue we're having. I have a slight hesitation/stutter/stumble just off idle. Also have an issue where coming from cruising to idle, it idles fine for a few seconds, then drops what feels/sounds like a couple hundred rpm, and it will occasionally, slowly, go up and down that couple hundred. I also get a LOT of black/dark-gray smoke at almost anything over 1/3 throttle. The first tank I just figured it was the old fuel. But now I'm on clean fuel.

Some info:
1.6 n/a 5 speed
new fuel
new fuel filter (changed 150 miles after filling tank with new fuel)
new oil and oil filter
new air filter
temps run right at the middle
lower crank case vent blocked (used to go to diaphragm pump, not have rotary style vacuum pump)
upper crank case vent is stock (into intake)
Mileage with old fuel - 40mpg
Mileage with new fuel - don't know yet, but it seems to be a LOT better. Went 150 miles and it's still touching the full line.
I have noticed very small foam-like bubbles in the line from the filter to the IP. Just figured this was normal

Symptoms:
Hard to start (long cranking and/or have to press accelerator)
lots of black/dark gray smoke above 1/3 throttle
somewhat erratic idle
hesitation when coming off idle, about 800 rpm above idle if I had to guess. Maybe lower. Runs fine otherwise.
very small foam-like bubbles in the line from the filter to the IP
Slow acceleration... wait, nevermind
If I think of more, I'll add it.


So, does this sound like I need to break down and buy the timing tools, or can should be checking elsewhere?

[MizpahPAH]

Sounds like you are sucking air into the fuel system

check underneith the car just below the back passenger side seat this is the water seperator
white yellow looking tank?

is it wet or moist?

mine was, I pulled it cleaned it out rigged up my radiator pressure tester dunked it in a bucket of
water and pressurized found a crack in a seam so I deleted it.

also I pulled the sump / fuel level assembly from the tank and found a bunch of Crud clogging the sump screen

before and after pictures look Great

[joshh]

check underneith the car just below the back passenger side seat this is the water seperator
white yellow looking tank?

Do what now?! Really? Had no clue that was there. Thought it just separated water in the fuel filter... hmm...


A quick note to add: I filled it up Wednesday night (10.1 gallons). About .5 mile later it started to run great until yesterday afternoon. Hesitation was gone, acceleration was better, etc... But it came back again yesterday afternoon (Thursday), although not as bad.

[MizpahPAH]

Not sure what year they started to put them in but my 86 has / had a water seperator
outside the car undernieth the rear seat passenger side. right in front of the rear tire.

a white / yellowish tank bolted up to the body might be black from undercoat or dirt.

is it moist or wet or if gone you may see a rubber fuel line attached wich means someone has removed it

but if you are seeing lots of air bubbles in the line coming from the fuel filter then you have a leak

[joshh]

Well, our '84 doesn't have a water/fuel separator. But, it does have an absent minded owner.

Got home today and couldn't even walk inside without stopping in the garage and messing with the '84. Took the fuel filter back off to fill it with ATF (a little more cleaning wouldn't hurt, plus I wanted to make sure the seal has seating well). Turns out the filter was only half full. AND, the previous filter's inner seal was stuck on the flange. AND... the bleed screw on top wasn't tightened down all the way.

Topped off the filter with ATF, removed the old seal, cleaned the mating surfaces with some 400 grit sandpaper, tightened the bleed screw, and no more bubbles. Went to crank it up, and it still wouldn't quite start right... until I remember to pull out the "cold start" handle. Cranked right up without any extra throttle! Awesome.

Test drive coming in a couple hours...

[smutts]

 ;)Good to hear.

[joshh]

Runs great. Much smoother, and less smoke than before.