1991 Jetta, TD, newbie

[ringram]

I'm new to Jetta's and diesels. What does that lever to the left of the steering wheel do? The one with the handle that you pull out? It pulls on a cable that is attached to the pump (injection system). Does it advance the timing for cold starts? Enrich the fuel mixture? Or ?

I've been running this for about a week. It was staring and running well. Now, when cold, it puts out a lot of white smoke. (unburnt fuel?), and runs rough. But, after a couple of minutes, it warms up a bit and runs smooth and no smoke. I suspect a problem with the glow plug(s).

Any thoughts/suggestions would be appreciated. thanks.

[82vdub]

Welcome to the forum and welcome to the world of VW diesels.

The lever to the left of the steering colum is called the cold start cable. It changes the timing in the injector pump (IP) that advances the timing allowing for easier and better cold starts. You'll know a difference when it gets cold out in the fall.

With the white smoke, this is likely unburned diesel fuel. This could be a result of the IP timing or glow plugs as you suspect. If you pull the cold start cable, it should run better when this happens and may minimize the smoke. For a lot of people, the slight cloud when started cold is somewhat normal, depending on a lot of factors, but somewhat normal.

if you're going to service the car yourself, save yourself a lot of headaches and money and buy an official Bentley repair manual for your car. It's the bible of books for VW repairs and is full of everything you need.

Put your physical location in your profile. Cold staring in Florida is different that cold starting in upper Maine.

[ringram]

OK, updated the location.

So, it's a cold start cable? And, all it does is advance the injector timing?

For the first week in driving this vehicle, the initial smoke was minimal. Now, it's much more, and lasts longer. But, goes away after warming up for a couple of minutes. I'll check the glow plugs and hope it's something simple.

Is there any checks that I can do to the injectors? IP pressure? turbo checks?

[82vdub]

And, all it does is advance the injector timing?

yes

For the first week in driving this vehicle, the initial smoke was minimal. Now, it's much more, and lasts longer. But, goes away after warming up for a couple of minutes. I'll check the glow plugs and hope it's something simple.

Were the temps the first week warmer than they are lately?

Is there any checks that I can do to the injectors? IP pressure? turbo checks?

You can pop test the injectors, but you'd need to buy or build a pop tester. You can replace the nozzles in the injectors and pretty much have a new injector. Do you hear your turbo spool up and feel any boost? That's one way to test if it's working.

Since the car is new to you, I'd recommend a couple things.

- Change the fuel filter. Even if the previous owner just changed it, change it for yourself because then you know for a fact it was changed.

- Check the condition of the timing belt. This is an interferrence engine. If the timing belt goes, your valves hit the pistons and ends up wiping out the head or just the valves. This is a crucial point to always remember with these engines.

- If there isn't clear fuel lines going from the fuel filter to the IP and from the IP back to the fuel filter (return lines), then I'd install clear lines. This will save lots of time troubleshooting starting/running issues if you ever have any.

- Check to see if your IP is dripping from the high pressure end of the IP (the end closest to the hard injector lines). Look at the bypass hose running alongside the engine block for any streaks where diesel leaked on that hose or a swelled hose in that area. Diesel eats hoses (and timing belts). So if this hose bursts, you may toast the engine before you discover the issue.

- Read hagars 163 page thread - every word and every page. In a week, you'll probably know more about these diesels than you wanted to.

[Fatmobile]

Ohhh a '91.
It probably has the levers to raise the idle too,
when the cold start lever is pulled half-way out.

[vixentd]

1, Be careful removing speedo cable at tranny that you do not knock off the plastic gear.

2. The fastest method for big hands or small is to remove the
a. dr side dash vent. Use a smalll screwdriver flat and pry out the plastic vent
b. Behind that is one philips screw. Remove
c. Slide the plastic hose no down and reach your hand through the vent hole to undo the speedo cable.
d. Hook up the cable the same way.

Prying the cluster out and reaching in your hand is easy to break the plastic fitting on cable.

[Quantum-man]

I'm new to Jetta's and diesels. What does that lever to the left of the steering wheel do? The one with the handle that you pull out? It pulls on a cable that is attached to the pump (injection system). Does it advance the timing for cold starts? Enrich the fuel mixture? Or ?

I've been running this for about a week. It was staring and running well. Now, when cold, it puts out a lot of white smoke. (unburnt fuel?), and runs rough. But, after a couple of minutes, it warms up a bit and runs smooth and no smoke. I suspect a problem with the glow plug(s).

Any thoughts/suggestions would be appreciated. thanks.

To check the injectors when kit is scarce; remove fuel lines, remove injectors.
Number the injectors with marker pen, then replace fuel line upside down, and reattach injectors in order.

Undo glowplug power at bus bar.

Cover engine bay with an old sheet. Get someone to crank engine from cold a few times and observe injector clouds. Look for non uniform behaviour. Repeat with engine hot if you like...

[mattbondy]

If you test your injectors per the last post just be aware that diesel injectors operate at extremely high pressures. These pressures are high enough to inject poisonous diesel rather deep in living tissue. Quick stat off the web: if the pressure is over 2000 psi amputation rate for fingers is greater than 50%.

[Quantum-man]

Yep, don't put your fingers over the injector outlets. Perfectly safe at any distance, when correctly atomized, but you only want to be standing at such a distance to be able to observe all 4 jets together in any event, as you are looking for consolidated streams of fuel, that will have more energy, or general differences in spray pattern..

[ringram]

Wow. Lot's of great information. Thanks for the replies.

I'm on page 26 of Hagar's thread. Lots to read.

The engine was rebuilt about 30,000km ago. A new timing belt was installed at this time. The transmission was also inspected. New struts all around as well. There doesn't appear to be fuel leaking from the high pressure side of the IP. But, a couple of the injectors look like there is some oil on them. Hard to determine if this is from a leaking fitting, or just old oil. I would have to clean the engine and run it for a fews days/weeks and monitor.

The fuel lines from the filter to the pump (and back) are clear (yellowed). What would I be looking for in those lines? Air bubbles? I will purchase a new filter.

I just changed the oil/filter and installed a new air filter last week. Is there special oil to be using, or is a good quality 10w30 or 10w40 sufficient?

I'll pull the injectors and test as described in a couple of weeks. I need to attend to the glow plugs first. I've picked up the materials to remove the buss on the glow plugs and install a separate wire from a fuse distribution block and relay. I need to determine if the glow plug timing relay on the cars fuse panel is defective or not. Appears to be an intermittent connection in the fuse panel itself. Lots of current running through this relay. I notice the wires get warm. I plan on using the stock relay to energize my new relay under the hood to power the glow plugs.

In Hagar's thread, he talks about testing the IP pressure by pulling on the cold start cable. I'll assume this is from inside the car, and not with the scale attached under the hood. I feel little resistance at all when I pull on it either with engine stopped or running. I'm not sure I know what I should be noticing.

I'll try the wax once I've worked out a few bugs. But for the first tank of fuel, I drove 816Km on 50.6l of fuel. That works out to 6.2 l/100km or 45mpg (imperial). Not bad for starters. I will be interesting to see what I can do once I've done my "Hillbilly tune-up".

Roger

[82vdub]

Good start on the reading. Any oil you use should have a diesel service rating on the oil, not just standard automotive oil. The cold start lever should be hooked up to the arm on the back of the IP inbetween the head and IP. If it's not hooked up, it will have the same resistance (and not much at that) when running or not. But, if hooked up, you'd likely notice a difference. Don't forget new heat shields to install under the injectors when you pull them. The key with the clear fuel lines is that you can see bubbles in the line. Diesel turns to foam under a high vacuum situation (blocked tank, fuel line, or filter) and the car will loose throttle response and die. But, it will likely just start back up just fine, leading to a scratching of the head scenario. So, this is an aide in troubleshooting or general routine maintenance.

[ringram]

The cable is connected to the lever on the back of the IP. I've read that the resistance on pulling the cable is heavier when the engine is off, cold. And is much less when running, hot. I'll try that again. But, so far, I notice very little resistance.

When I ran the fuel down to about 1/8 of a tank, I did notice some air bubbles in the fuel line next to the fuel filter. I didn't see any after filling the tank. I'll be changing the fuel filter this weekend. We'll see if that makes a difference. After that, I have to fix the soft brakes. Not sure what's up, but I'll be installing new shoes/pads/rotors/drums and see what it's like after that.

Roger

[Mr. Natural]

It is prudent to use a diesel fuel additive to try and improve the lubricity of the fuel. Our IP's were designed to run on a fuel formulation with sulfur in the fuel, and the fuel is the sole source of lubrication for the IP... So, most of us use a fuel additive from Stanadyne or Power Service (Walmart carries this brand). An alternative in warm weather would be to use from 5% up to 20% biodiesel... but Bio is a solvent and will free up all of the varnish and junk in your fuel system, so don't be in a hurry to go this route.

Either of these fuel additives will in my experience reduce smoke from the tailpipe, quiet down the engine and the IP; and make happy diesel sounds. They also raise the cetane level, which should improve mileage marginally.

You could run Seafoam (Walmart also sells this) through your engine to try and clean up the injectors and such. I understand that Mercedes Diesel owners use Seafoam routinely. I have never used it myself.

Oil? I have always run Delo400. Some run the Walmart branded Diesel motor oil. Both of these are mineral oils (petroleum based, not synthetic). Synthetics should improve mileage, but they are more expensive, and if you have leaks or blow by that added cost might annoy you; and if your engine consumes oil... well synthetics don't work as a fuel. The critical thing is to change the oil on schedule (3K miles or 6 months (which ever comes first) for the TD), and to use good quality filters (Mann or Mahle). I don't necessarily change the oil filter with every oil change. I sometimes leave the filter in place through a second oil change interval.

Fresh oil is more critical for the TD than for the NA, as the oil serves to lubricate and cool the turbo... Dirty or degraded oil will shorten the life of your turbo. Turbo chargers are expensive, and when they blow up they can destroy your engine... So, check the freeplay on your turbo impeller shaft and feed it clean oil on schedule.

Some blow by is common in these engines. This means that diesel fuel mixes with the engine oil and reduces it's viscosity. This is another compelling reason to change the oil on schedule. Watered down (thinned with fuel) motor oil won't do what it needs to do for the Turbo.