85 Jetta no spark or fuel pump

Any ideas?

I had a fuel pump relay fail in my 1984. New relay and all was good.

yep it might be the fuel pump relay and possibly also the ign switch. There could be 2 problems! 8^) The fuel pump relay usually supplies a couple of seconds of power to the fuel pumps when the ign switch is ON. The engine may lose power while cranking (No Spark) due to a faulty ign switch also.

Check out the idiot lights to see if they go out at all when the ign switch is ON or in the Crank Position.

You can also try starting the engine with that jumper wire in place of the fuel pump relay. ;-)

Sooooo many people check this and that and then they realize that the timing belt is bad. Please check that too!

Thanks to everyone for their tips

Tried a good fuel pump relay, but it was of no help. The relay from the 85 Jetta was put into an 86 GTI and the 86 GTI fired up and ran.

The ignition side of the coil is getting battery current, but when a test light is placed on the distributor side of the coil it glows, but doesn't blink. A different distributor was also tried.

Where is the fuel system control unit? Per the Bentley manual, it is the next item to check.

Wayne Faas

You can take a spare distributor and plug it in and then spin the bottom of it. Make sure you have the center wire from the ign coil going close to ground to see a spark as you spin the distributor shaft. DON'T HOLD THAT WIRE while doing this test!!! Now if it sparks look to see if the distributor rotor on the installed distributor turns when you crank over the engine.

The ECM is in the engine compartment under the windshield on the vehicle's left side along with the ign module.

OK back to trying to get the 85 Jetta GLI (CIS-E) running after taking time off to fix my sons' 87 Golf and 86 GTI.

As previously mentioned, there is battery voltage at terminal 15 on the coil. When checking for battery voltage between the tow outer terminals on the unplugged Hall sensor connector, there is only 3 volts. One terminal measures 11 volts and the other measures 8 volts. Per Bentley, the measurement should be 12V.

Have tried a different coil, ignition module, fuel pump relay, knock sensor control unit and the module under the ignition module with no success.

Any ideas?

Wayne Faas

Jim,

I am using the Bentley A2 manual. Finally made a copy of the ignition section and crossed out everything that was not pertaining to TCI-h with knock sensor. The ignition section covers the TCI-h, TCI-h with knock sensor, CIS-E Motronic and Digifant, all inter-mixed.

Previously, when checking the voltage at the coil when switching on the ignition (VOM between terminals 1 & 15), no voltage was measured. Installed a know to be good ignition module, the VOM jumped up to 4 volts for the required 2 seconds. Also, when grounding out terminal 12 on the knock sensor cable, I was able to get the VOM to jump to 4 volts for a couple of seconds.

I was also able to get the coil to fire a spark plug connected to the coil wire, by grounding the same terminal 12 on the knock sensor cable..

However, the distributor would not produce any spark.

My son came home from college about that time (86 GTI 16V (transplanted)), so tried both ignition modules on his car and both worked just fine,

When measuring the voltage between the outer two terminals on the Hall sensor cable, one measures 11 volts and the other measures 8. However, when rotating the distributor, no voltage is measured at the center terminal (and no spark). A couple of non mounted different distributors were also tried.

Per Wikipedia, a Hall sensor requires a voltage supply, a ground and the third wire for the output. Therefore, why do the outer two terminals both have voltage, with a difference of 3 volts?

Perplexed, Wayne

Found the culprit, thanks to Thomas Fink at the Bentley Publisher's Tech Forums. Thomas advised me to look for a bad ground from the knock control sensor, in particular one of the wires bolted to the drivers side of the intake manifold. A broken wire was found and when the broken wire was grounded, the fuel pump ran and the engine started.

Wayne Faas