diesel rabbit no start

Technical questions and answers concerning all models of VW diesel vehicles.

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slambomann
Glow Plug
Posts: 1
Joined: Fri Sep 21, 2018 6:12 am

diesel rabbit no start

Post by slambomann »

Hello all, this is my first post so please deal with me. this is also my thread from vw vortex, but maybe someone on here has some more helpful info..

I bought a 1980 diesel rabbit 1.5l about 2 months ago. When I got it was not running. Replaced a few small items at the beginning of troubleshooting. Swapped all 4 glow plugs and no luck (also replaced the solenoid on the injection pump). Finally realized the bus bar was making poor contact, got a new one and the car ran great for about 2 weeks. Then, the injection pump started leaking. Got one through someone on the forums with the fuel governor taken out. Took the car apart, made sure everything was at TDC, replaced the injection pump, timing belt, and v-belt . Filled the injection pump with fuel and turned it over. No fuel came through the fuel rails. Injection pump is getting good fuel in, and the return line is full of fuel also. So, I assumed it had to do with the solenoid on the injection pump. So I replaced the one on the new pump with the new one I previously bought. When I did that the wire (that was holding on by a thread of metal) and the eyelet came apart. So instead of replacing it the proper way, I pulled back some of the wire jacket, and screwed that back on to the solenoid I had on my old injection pump (probably not the best idea but it was only for troubleshooting) turned the car over, and the glow plug light lit up for about 2 seconds and instantly went out (usually it stays on for 7, and the flickers out) still no fuel coming out of the fuel lines. Also noticed a slight burning smell coming through the vents. After that I was pretty distraught after being at work all day and left it there.

Was wondering what my first step in trouble shooting should be? This is my first mk1 and I am not too familiar with the or diesel in general. I was told there is a fuse panel on the inside of the firewall where the ground from the injection pump solenoid goes. (hopefully that’s that burnt) if not I will check the relay under the dash?

Any help is appreciated!


UPDATE:
finally got fuel to all 4 injectors (with a whole lot of priming and a battery swap)
hard wired the injection pump solenoid to the battery so i can rule out the solenoid not working. Also tested and confirmed that solenoid gets a full 12.5 volts with multimeter.
Re-confirmed car is all timed correctly. (unable to time injection pump due to not having a dial.)
Replaced glow plug relay under dash.
Replaced hose from fuel pump (mounted in engine bay) to the injection pump with a clear hose. (no noticeable air bubbles in hose)
Replaced fuse in back of firewall (old one still looked good)

Now it seems if i leave the hard wired relay on the battery the whole time before i try to start it i will not get a GP light. if i kind of mess with it on the battery i can get the GP light to come on for about a max of 5 seconds. try starting the car right after still no start. I can hear the solenoid click when i connect it to the battery so i know its functional.

when i check the glow plug bus bar with a multimeter and turn the car over (not starting) i get about 11.8-11.9volts, for about 7-10 seconds, then i hear a click in the car (assuming a relay) and then the glow plugs drop voltage to 0.0 (not sure if this is supposed to happen)

seeing as i get fuel and spark, the only other thing i can think of is compression. haven't checked but the car ran before the injection pump started leaking, so i am assuming its still good.


Any help on the next step of trouble shooting would be great!


new note: i was also told the pump could be 180 out. i have everything spot on, including the mark on the inside of the pulley. could the mark on the pulley actually be 180 off, and instead be at the bottom and not the top?
bscutt
Turbo Charger
Posts: 1720
Joined: Mon Mar 10, 2003 4:49 pm
Location: Springfield, VA

Re: diesel rabbit no start

Post by bscutt »

Most of the 1.5s had the slow glow plugs. if even cool outside you may need 30 seconds of glow plug power. BTW the fuse on the firewall is for the glow plugs. If all else fails you can jumper straight from the positive post to the glowplug buss for 30-45 seconds and see if that helps. If that gets it starting you may want to get a voltmeter on the glow plug buss bar and make sure you are getting power there, at least for a short while. There are also to temperature sensors on the right side of the engine (facing engine from front), one for the glow plug relay, one for the temperature gauge. They are on the coolant flange and the wires going to them aren't very big, maybe 18 gauge. UNplugging the one to the glow plug relay (just unplug both, won't hurt anything) should force the glow plug relay to stay on. A word of warning the older rabbits (I had a 1980 first) had fuse box issues if water dripped on them and that can wreak havoc on the electrical circuits. The 79 I had I just ended up manually wiring in a pushbutton for the glow plugs I just had to hold for 30 seconds.

If your timing isn't way off, you have fuel to all 4 injectors, and glow plugs get hot enough it should start.
If all else fails recheck timing, making sure things are lined up properly etc.
Bob

'06 Jetta TDI
'82 Rabbit 1.6NA
Honda, 99 GMC Suburban, '41 Chevy Coupe
Fatmobile
Global Moderator
Posts: 7564
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: diesel rabbit no start

Post by Fatmobile »

Bad glow plugs.
How do I know? If they are all working you won't get 11.8 volts, they will draw it down farther with all those amps.
More like something below 11 volts.
An ammeter is often used to see how many are working. Something like one of those cheap dash mounted 60 amp meters.
Clamp it to the glow plugs and the battery. Mine has wires with an aligator clip on one end and a battery clamp on the other.

An upgrade to the glow plugs is to run a separate wire to each one so it will be easier to figure out which plugs aren't working.
Sooo while they are out learn how to solder and heat shrink lugs onto wires.

While you have the soldering iron out: the MK2s have a blade on the pump instead of the lug bolted to the solenoid.
I use a blade from the back of an old sealed-beam headlight. The hole is the right size, bend it straight and grind it skinny enough to fit in a flat connector. Bolt it to the pump. Solder and heat shrink a flat connector to the power wire. Now you to can just plug power into the pump.
Are you jumping the solenoid to the battery with the ignition wire still attached?

I agree with everything bscutt said about the early fuse boxes.
And add...
Your heater fan will melt a pin in the blue plug on the back of the box. So put a relay on heater fan high.
Pin #19??
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
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