96 passat crank but no start

I may have a chance to check out a tdi passat this week. The only details on the car I know of is that they (husband and wife) were driving on the highway and the car suddenly died. The engine will crank over but it will not start. They said their VW mechanic said its "an electrical problem". Any insight on to what this could be. Ive done some reading on here for the past few days and saw suggestions on it being the fuel shut off valve or 109 relay etc...

I used to own an alh but ended up selling it and Im trying to get back into tdis again.

Any suggestions of things to look at or what it could be would be very helpful

The car has 144K on it.

thank you

Starting from simple to harder: (1) relay 109 (2) crank sensor (3) out of fuel (4) broken wire (5) timing system problem (belt broke, tensioner or bearing broke, crank bolt broke..... How much do they want? The fix could be from $20-$3000.

I agree with rdkern, could be simple, could be difficult.

Start with the basics and work from there. Personally, I start with looking for chafed wires around the fuel pump since it's a common problem with the B4's.

Try the key, you should be able to hear (and feel) the N109 relay on the fuse panel (new relays will say 601 since the 109 relay is printed upside down). Also check that the N109 valve is clicking when you do this. If it's not:

Jumper the + side of the battery to the N109 valve on top of the injection pump (it's the single black/white wire connected with an 8mm nut to the top of a 24mm bolt) and see if it clicks. If it does not it's probably your N109 valve (not the relay) since this bypasses the relay. The car should start.

If it does, I would look at the two threads below for any breaks in the wiring to the fuel pump.

Look here for the thread, specifically at post #23.

And here, post #13.

Then I would crack an injector and crank it over, seeing if fuel came out. If it does, it's probably a timing issue and not a fuel issue and I would verify mechanical timing. If no fuel comes out, the pump has lost prime and will need to be primed. Just remove the flexible fuel hose at the #4 injector (all the way on the driver's side) and pull a vacuum with a Mity-Vac or something similar until you see fuel, then try again.

Good places to start anyway.

personal experience

I would look at timing belt, pulleys, rolls ect.... if there a belt there and its loose or the belts gone pull the vavle cover off and check the cam

Thank you very much for the quick responses, I will take this info with me and hopefully the car is not sold (someone was supposed to look at it today) It has brand new michelins on it and they were asking 2K

One thing I would do regardless is pull the valve cover and look at the cam and lifters. If there is wear like this on there, pass on it.

Crank sensor??

Older thread but wanted some insight on crank sensor? I have 96 Passat tdi. Going thru checklist replaced relay 109 still starting issue cranks and cranks. Does the car have a fuel pump in tank? Seems like fuel issue. It’ll eventually crank over but it takes some time. I’d like to just fix the issue instead of making things worse.

there is no in tank pump from the factory. just the sending unit.

if a seal has failed, the injection pump can be loosing its prime and take a while to finally get fuel to the injectors. there is also check valves in the fuel lines that may have failed...

if it will eventually fire after several seconds of cranking, i would tend to agree on a fuel issue. considering your location in florida, literally anything with the glow plug system is irrelevant, as it should start fine down to 10-15* degrees with them completely disconnected...

look at the clear(ish) fuel line going to the pump, there shouldnt be a bunch of air in it. if there is, you found your issue.

Bad injector pump??

Thank you for your quick response ketchupshirt88, well I check this morning before work and it looks as if there is no fuel in that clearish line. So what’s next? Replacement of seals in IP? Is it possible the sending unit from the tank went kaput?

basically any air intrusion along the fuel supply side can cause this. the common ones are injection pump seals and the fuel filter fittings.

check the "T" fitting and hoses on the fuel pump, it can crack or have a bad seal.

look under your injection pump, specifically at the rubber hoses that will swell up if exposed to diesel... if there's leakage going on there, reseal the pump (or send it out to have it done)

there isnt really anything in the sending unit to fail... the pickup screen can get clogged i guess... but that doesnt fit your symptoms. theres a hatch in the trunk if you wanna spend 15min and check it out for peace of mind...

theres a pair of check valves near the sending unit as well that can restrict flow, or allow fuel to bleed backwards as well. but fuel wont bleed backwards if the seals ahead of it are in good shape...

Fixed!

Sure enough she started right up after replacing the fuel filter and tee along with replacing an old cracked looking hose. I did the liquid moly diesel purge too just to give it a good cleaning. Bought a mityvac from harbor freight what a great little tool that thing is. Thankful I didn’t have to take apart injector pump. Did it yesterday and fired right up this morning. Hopefully no issues from here on out. Thanks ketchupshirt88 for the advice.