1994 Jetta III won't start

[INGUES]

Hello all,

I'm having an issue with my Jetta III that I would love to be able to fix myself if anyone can give me some opinions/advice on the problem.

The issue putting it simply is that the car will not start. When you turn the key the starter runs but the engine won't turn over. There's also not any smoke coming out of the exhaust while I'm turning the key.

I had been having some unrelated issues with the car previous to this happening that required me to change some parts. Those parts include:

MAS/MAF (Mass Airflow Sensor)
Breather Hose
Coil Box
Timing Belt
New muffler
Distributor Cap

Also, I recently had a tune up done which included:

New cables
New spark plugs
New air filter
Oil change with new oil filter
New fuel filter

I don't think any of these parts had anything to do with the car suddenly deciding not to start but I'm really not sure what else to check. Does anyone have any ideas? If there's anything I can check on and post to help narrow it down please let me know and I will do it.

Thanks,
David

[Franco2112]

Have you checked your fuses and or fuel pump relay switch?
Franco

[denisond3]

Or at least see if you can hear the fuel pump run (a very quiet -hummm- from the rear) for 1 or 2 seconds after you first turn the ignition key to the 'run' position. Mine is a 1990 MK-II, but I can always hear the pump run. Mine actually has two pumps, one in the tank, another under the rear seat on the passenger side.
I presume when you say the starter runs, that the engine is turning, the accessory belts moving; it just isnt firing and running on its own.
An engine runs if it has compression, a spark at the right time, and a burnable air-fuel mixture in the combustion chambers. You can hear if the compression is okay; its the up-down-up-down-up-down speed pulses when the engine is being cranked over by the starter. If you were to take all 4 plugs out and then crank the engine with the starter - you would hear an engine with zero compression. And a steady whirr instead of the pulsing.
If the engine ran at all since the work was done, then the spark would probably be at the right time - if there was spark. You can pull a plug wire off and put an old plug into it, let the metal of the plug lie against metal on the motor, and have someone crank the engine over a couple of times while you look for a nice spark across the plug electrodes. If no spark, have a good look at the rotor and how the cap is seated. The spark could happen at the wrong time, but if it had been running and now wont - its very unlikely the distributor would twist or its drive gear would slip - unless someone was working on the timing belt or distributor 'as of' the time it would no longer start.
The easiest way to see if the car would run if it were getting fuel, is to pull off that rubber inlet duct, and squirt starting fluid (ether) into the air intake.
The color of the spark plugs should be a very light brown, and almost white if the car had just been driven on the highway.
On mine, the MK-II, I have to cycle the ignition key a couple of times for the fuel pressure to come up to 40 psi, if its been sitting for more than a day. The end of the fuel rail on mine has a tiny bolt in it. With that bolt removed, I can put a 5/16th" hose over the end, and connect it to a fuel pressure gauge. I dont know if they kept that useful fitting on the MK-III jettas though. Its handy, but you have to be VERY careful, when working with gasoline under pressure in the presense of ignition wires. I think the highest fuel pressure is about 46 psi.

[INGUES]

Thank you all for your suggestions. I will check into this over the weekend and I'll let you know what I find out.

Thanks,
David

[Skyy211]

I have a 1994 Jetta GL and its cranking but not turning over, not getting any spark basically. Need to know what spot, if there is one, that the ignition relay goes into, basically which number spots all the relays go into. Lost the Relay/fuse guide for the fuse panel...if anyone has that that'd be helpful too, thank you!!