Injector pump problem

[David]

I have a 91 jetta 1.6. I commute about 40 mi to work with it and it has run great. It had been loosing a little power. I drove it to work no problem and when I went to go home it started then quit right away. It never started again. I thought it was a timing issue so I checked the belt. It was loose but intact. I got it hauled home and checked the timing. The valve timing was on but the pump lock hole and the marks on the ip gear to the back plate didn't. I changed the belt and the water pump, timed it all up and attempted to start it. No luck. Searched the internet and found your forum. I have tried several tips like using a hand vacuum pump on the return to pull fuel into the pump I got fuel through the return, but not a lot. Nothing comes out the return or the injector lines while cranking. The stop solenoid clicks when it is activated. I haven't removed it yet as it appears to be a 23 mm and I only have 22 and a 24. It looks like a trip to the store. I haven't tried a feed pump yet either but I do have one purchased while troubleshooting a John Deer backhoe fuel problem. I didn't disassemble the pump other than to remove it from the engine to replace the water pump. There is no smoke coming from the exhaust when cranking.
I am an experienced mechanic but not specifically diesel. I have re-timed many Rabbits after they suffered from too much snow in the engine compartment. I worked on several projects at Lockheed with a mechanical nature. The Dragon Wagon was a 8 wheel drive truck with articulated steering now used by the military and a pump that pumped dry powered coal for gasification a process that takes waste coal and uses it to create a gas that can replace natural gas.
I would appreciate any input on this issue. Is a tooth or 2 on the pump timing enough to cause it to quit that suddenly?

[TylerDurden]

Sounds like a plugged filter or tank screen.

I'd put clear tygon lines in and out of the IP, then I"d "bottle feed" it from a clean container to see if the fuel lines/filter are the issue, & check for bubbles & fuel flow.

If the timing or compression is marginal, a tooth off on the IP sprocket can make an engine run poorly or not at all.

[David]

"I'd put clear tygon lines in and out of the IP, then I"d "bottle feed" it from a clean container to see if the fuel lines/filter are the issue, & check for bubbles & fuel flow."
How much flow should come out of the return while cranking?
"If the timing or compression is marginal, a tooth off on the IP sprocket can make an engine run poorly or not at all."
That is what I thought. It doesn't seem like the timing was off enough to make it not want to start or at least put out some smoke. The car was running well but I have noticed for a couple of months when climbing the long grade on the way back from work it isn't carrying as much speed when I top out.
This is my first major issue with the engine and my trouble shooting is hampered by my lack of experience on diesel engines. There are very few of these cars in my area, but I did find a good source for parts. I know the 2 previous owners of the car. They are relatives The first of them had the pump rebuilt or at least worked on 4+ years ago.

[TylerDurden]

How much flow should come out of the return while cranking?

Good question. I've never tried disconnecting the cutoff to get a quantity when the engine is not running. I'll let you know later. WAG- 8oz. @30sec.

When running, they put out a lot of fuel - the excess fuel circulation cools and lubricates the pump.

[bscutt]

One easy test for fuel is to open each of the injector lines at the injectors (17mm wrench) maybe a half turn or so. Put the pedal to the floor and crank for 15-20 seconds. Look for fuel at each injector union. If no fuel then I would work backwards and make sure fuel is getting into the pump. You will find several references to having at least the pump incoming fuel line being clear so you can see fuel and possible bubbles.

This sounds to me like you're not getting fuel especially since this came on fairly suddenly. Possibly clogged fuel filter, leaking line allowing air in the input lines, problem at the water separator etc.

Of course these are just some guesses but are some simple things to do right off the bat. NO fuel to the injectors obviously will keep it from running. If timing is only off half a tooth or less it may not be that. It's always good to run through the whole crank to cam to pump timing check just to eliminate that as a possibility.

[David]

Here is an update
I have had one of the injector returns come off while cruising down the freeway and it put out quite a lot of fuel. Tonight I installed a plastic filter in place of the factory one and it pumped it full pretty quickly. It didn't start so I removed the stop solenoid plunger and cracked a injector line to see if anything came out. There was quite a bit of fuel that came out of the stop solenoid hole. After re-installing the stop solenoid I ran the starter some fuel came out the injector line and it fired a couple of times, but the battery ran down. Don't have a very big charger so it takes a while to charge. Time take a break.
Thanks for all the useful suggestions and I think I am on the right track. Still not getting much out of the return. Probably because he pump isn't full yet. I might try the boost pump to prime it faster and not so many battery charges. There may still be a fuel supply restriction too. Is there any issues with blowing air back into the tank to clear the line? I haven't tried holding the throttle open while cranking to see if more fuel comes through.

[30dodgeboy]

Once the injection pump is full of fuel, there should only be a small amount of air bubbles in the return line to the tank (mostly fuel being returned). Too much air bubbles in the return line indicates a suction leak on the fuel system, which may cause an engine to quit and not restart. Air in the pump or injector lines is compressible, diesel fuel is not. High pressures are needed to pop the fuel injectors, but the cushioning effect of air in the system prevents those high pressures from being reached.

no smoke during cranking usually means a lack of fuel to the cylinders.

be careful with compressed air, you could cause damage to the tank or the water separator housing.

One can access the fuel tank sending unit through an access hole in the trunk floor.

[Fatmobile]

You can use a 15/16" wrench on the stop solenoid.
Do you have clear fuel lines?
If you do; what does the fuel look like going into and out-of the pump?