THE STARTER CRANKS ON THE JETTA 4 NO WSPARK - Jetta Volkswagen Cars & Trucks

i wood check that the belt from the stareter moter is not sliping

no cranks all end in no start.
low battery
bad battery cable corrosion at 4 ends.
bad starter.
dead battery can be bad charge system. or left lights on,.
hot wire the starter solenoid and see if it cranks now.
yes, then the park lock out is failing to send key start to starter
no?, then starter is bad, if hot wire fails.

Check, clean and tight correctly the battery leads. If the problem still occurs remove the electrical starter motor out from the engine, repair it (change carbon brushes, bearings, ...) and install it back in place. Then test the engine. It should cranking & start immediately.
Good Luck!

are you sure that there is not a small piece of the wire from the battery cable to the starter crossing over to the solenoid? that was a booby trap that I was taught by the military and it takes a VERY small piece of wire to do that.

Your starter relay may be cracked or not making contact with in the relay. Follow the + cable from the battery, it should lead to a small box looking relay. It should have another + cable leading from it to the starter. This relay that the two + cables connect to, is most likely the bad source.

check fuel rail pressure with a gage from renting from auto shop shold hold 30 PSI for 60 seconds if not replace fuel pump.

Can be a Junk Relay, access is limited, but giving the Starter a "crack" with a mallet, often cures the problem temporarily. But check the Battery terminals, and Cable to the Starter solenoid ,first for tightness and security.
Regards,DT

I have an 87 Jetta also. The problem is basically that the electrical wiring throughout the car is getting brittle and the wires rub against metal and other items on the frames (sometimes sharp edges are involved. Once moisture gets under the wire insulation, the braided wiring begins to corrode and resistance to current flow increases over time. This has effected everything from the radio to the headlights in my car. Starting the car with the ignition switch got more and more difficult.
Then, I simply got a starter button from autozone (about 15 bucks), wired it with new 10 gauge wire directly to the starter and the battery and mounted the switch on the left side of the steering wheel on the dash (eerily there is a perfect mounting place for it). For the last 4 or 5 years, I just turn the key to the on position and push the starter button and it cranks reliably every time. Some day when I get time, I will run a new hot wire from the battery to the main fuse block under the dashboard. In the meantime, the car starts and runs great.

could be a loose wire on the starter , check your connections

If when scranking the engine, the engine do'se not turn. The possible cause's are; the flywheel teeth are worn down or the start motor bendix is not moving into the engaged possition. You need to investigate these solution to rule them out.