Sick '94 Jetta IDI - Doctors Required!!!

[EdmontonTD]

Hi fellow auto Doctors - I need your help!

My 1994 Jetta TDI was running like a top, until recently. I went on a bit of a road trip (200kms round trip) twice in 2 days, lots of highway time, and upon arrival at my destination, I noticed a slight hiccup now and again at idle. That was in October, and it was a bit warmer. That hiccup has gotten worse. About 2 weeks ago I ran it almost completely out of fuel, and things have gotten worse.

Symptoms: During a cold start with choke out (as per usual), sometimes it takes 2 tries to start. It used to always start first try. Once started, it stumbles and puffs (blue smoke), and has a nasty hesitation for the first few minutes until there's heat in the cylinders. I don't think its the glow plugs because I replaced them all last year, and the problem still exists even when I park it in the garage (+5 celsius at least, possibly warmer).

Once started and run for a few KMs, it runs OK, but not terrific. Once fully warmed, if I push in the choke I'll smoke out the cars behind me (literally) - lots of blue smoke, especially at idle at a light. And when I mean warm, this is after driving 20 kms or more. I have to keep the choke out for it to run anywhere near smooth.

I was reading the Haynes manual, and it indicated I would experience similar symptoms if I had a bad injector - makes sense - the injector would be drizzling diesel into the cylinder, not spraying it. Pulling the choke (advancing the diesel pump timing) would give more time for the fuel to burn. The Haynes indicated diagnosing this by:
1) warm the car up
2) shut it down, disconnect the steel line to one injector, wrap it with a cloth
3) start the car (choke pushed in), see if the smoking at idle goes away.

I tried this tonight with each injector, but the symptom didn't change much (just a suckier idle). This test is supposed to effectively eliminate one cylinder (and one bad injector). Could it be more than one bad injector?

I also ran a bottle of "gunk" diesel fuel system cleaner/treatment in this tank of fuel - no noticeable improvement so far (1/4 tank gone). I have another brand of diesel fuel additive/cleaner to try as well - its good stuff I've used in the past, but ran out (thus, the "gunk" brand).  I also replaced the fuel filter about 6 weeks ago, no issues there after the replacement.

I purchased on injector and the heat-shield seat from local parts place ($85cdn + $1.50 for the seat), and am ready to replace one injector if necessary, but can't figure out which one.  I would rather not replace all 4 injectors, then realize that its not the injectors. Called a local diesel service place and they can test the injectors for $25 per. Is this a good idea?

I initially thought this problem might be a vacume leak, however I've sort of dismissed that thought with what the Haynes had to say. Once warmed up with the choke pulled out, it runs not too bad, but certainly not what it was before. Always started, no problem, no hesitation, stellar mileage, lots of power, no smoke...  After a bit of reading here, I'm leaning towards a stretched timing belt, resulting in late fuel delivery timing (and pulling the choke/fuel timing advance seems to counter that - it makes sense).  I've also been reading about the wobble on crank pulleys and the (sometimes) wrecked key between the crank and the timing sprocket.  Could this be starting to wobble on me, stretch the belt a bit and throw the timing off?  Its time for my timing belt anyways, so what parts do I need to do this operation (cam lock, pump lock, valve cover gasket, tensioner, timing belt) - what else?  

So, doctors, what do you suggest I test next?  Please help!

[Smokey Eddy]

Glow plugs are always an easy check - do it.

Put a screw drive to each injector with the butt of the driver in your ear. Listen for abnormalities between the cylinders. Ie. one sounding much knock-ier than the others. that will tell you if you have a sticking injector.

You may have two sticking so listen to see if two sound much louder than the others.
If they are working properly, for 1 stage injectors anyways, they shouldn't be too noisy. they should sounds what you would expect to be normal. a real bad knock from a sticking/clogged injector will literally make a loud knocking sound with your ear on the driver.

is your car a TDI or IDI your subject and car description conflict (TDI im guessing)

if you can, check the injection pump timing. Too advanced or retarded may give similar to described problems.

You're right that it's fuel delivery though for sure (at least thats my reckoning)

so check each GP first, then listen to the injectors, still no dice check the IP timing. That's MY advice.


If it's none of that maybe a lifter is sticking? but it sounds like injector/pump fuel delivery


changing a timing belt is a pretty easy job. You dont need any special tools if you don't want to spend lots of money.
An injection pump timing dial and mount is a very good to have though.
You can clamp the gears at "TDC". (Use the timing marks) The cam has a cut out on the tranny side of it. the cam locking plate goes into that flush with the flat surface of the head so just make sure you're not 180 degrees out when you line up the fly wheel.

I just clamp the cam gear and injection pump gear in place once i have the belt around everything and im ready to use the tensioner to get the belt tight. Check the fly wheel double! and put the belt on! you can pull on the tensioner hard enough with a friend putting the nut on it if you want to avoid buying the tensioner wrench. You can also pull too hard and turn the crank by accident so always double check the cam-flywheel timing before you start the car. Get someone to watch the hole through the bell housing while you turn it with a wrench, it's very sensitive.

A new tensioner is always a good idea with a new timing belt. I've never heard of timing belts stretching exactly, just breaking. But im young and haven't heard much :roll: .

(my methods are the cheap way of doing it. it's much easier with the right tools im sure. It would be the "right" thing to do.  just so long as your not trying to fight with gears and not just guessing the timing without the right tools. It's gotta be right. a couple teeth out can cause valve contact on the pistons. 1 tooth isn't a big deal but it is scary that you missed a tooth and it won't run right and you'll know as soon you start it. I have an IDI, i don't know how much different it is for a TDI.)

[EdmontonTD]

Ya, its a '94 (IDI).  I've been exchanging e-mail with Vince (on this forum, and others) - he's given the same kind of advice.  Last night I took a flash light and started my car for a bit - the crank pulley has a little wobble to it, so it looks like that has to come off and get some attention when I do the timing belt too.  I've got the belt, tensioner.  Vince indicated the valve cover gasket can be reused if its not leaking.  Cheap replacement tho.  I'll be sure to also get the big crank bolt as well (single-use item).  Is it technically a stretch-bolt like a head stud/bolt?

I'll update you with how it goes (or if it blows up before I get to do the work).

EdmontonTD

[VW_Commuter]

Yes, the crankshaft timing gear bolt is a single use item but since they are <$4.00 at the dealer it's not a wallet breaker.

[Vincent Waldon]

Al at Basco just off Whyte Ave will have 'em, and anything else VW you need.

Tell him Vince sent you, and he'll tell you what a geek I was in Jr. High.

Jr. High, mind you.  Certainly not now.  :wink:

[jtanguay]

crappy running is a telltale sign of the 1.9 crank problem.  as you must have been told already, it has to be fixed, and fixed right.  fixing it at this point won't cost you too much, but later down the road it will.

i would say that you might as well just replace all 4 injectors as the nozzles are good till about 150,000km anyways-although some people like to push that to its limits  :lol:

get a friend to start the car in the morning (after you let the car sit overnight) and check the clear fuel lines.  if you see lots of bubbles, then you know that you have a leak somewhere in the system.  the heated fuel return line that plugs into the fuel filter is a good culprit to start with.  the next is the fuel lines themselves.  they have a tendency to crack on the inside, so you won't know until you pull them off (which is a pain in the cold weather)

[dieselweasel]

Yup, definitely classic symptoms of retarded timing, very likely due to a worn crank sprocket keyway.  

First thing, I'd highly recommend buying a Bentley manual...much more and better information than a haynes.  Using a haynes is like ogling over the lingere models in the sears catalogue when you could be looking at a playboy.  

You're going to want to remove the crank sprocket sooner than later, as there will be major engine damage if the sprocket lets go.  If the crank nose is badly worn, you'll have no choice but to have it repaired...the popular fix is to get it welded/machined to accept a TDI crank sprocket.  If the keyway isn't bad and you end up leaving the setup as is, there are a couple things you can do to prevent the crank sprocket issue.  I've taken preventative measures and put over 150,000 kms on my AAZs without any problems. Search around here and read all you can on the subject, there's lots of info.  

I wouldn't spend the money on rebuilt injectors without getting the old ones tested first.  I spoke to Giles at Performance Diesel Injection who is nothing short of a god in the Bosch fuel injection world.  He said Bosch doesn't even sell nozzles for the 1.9 IDI anymore, and he said they rarely wear out anyway.  Any "rebuilt" injectors are using aftermarket nozzles, which may be of questionable quality.  

If you need any further assistance, feel free to PM me...us '94s gotta stick together.