VadGTI

The car is a '93 100CS Q. My girlfriend drove it about 50 miles today and it was running perfect. She came home, parked it, and I got in the car 15 minutes later. Tried to start it, and it started but had a very erratic idle. I tried to accelerate, but the pedal had no effect on the engine, as it continued to sputter in the low rpm range, then died. From then on, it would turn over and sputter for a couple of seconds, then die. I let it sit for about an hour, tried to start it, and again it started with an erratic idle, I attempted to accelerate and it continued to sputter for a couple of seconds, then died.

So, what could it be? It's been raining heavily in SoCal the last week, but she said she didn't drive over any deep puddles. She did add several gallons of gas during her trip. I'm leaning towards clogged fuel filter or dead fuel pump.

Where's the fuel filter located? Is the pump in-tank or out of tank? Is there more than one pump?

Bmthorn

Pull the codes.

austinado16

Fuel filter is that round cannister laying on it's side right there on the passenger side of the engine compartment. It's up top, above the air filter housing against the strut tower. Doubtful that's the problem.

Fuel pump is in the tank. To confirm it's working, simply loosen a fitting at the fuel filter, crank the engine over and watch it spray fuel everywhere.

Pop the air filter housing top off......4 bails and it lifts right up, and inspect the air filter for being clogged, and wet. Replace as needed, but only with a real German one, not some POS from Kragen or Autozone.

There's a thing called an "Output Stage" on the passenger firewall in with a row of connectors and stuff mounted on a long bracket. It's tan and has a metal face. This powers the coil pack. When they fail, you wind up with an engine that may run, but won't take throttle because the coil is firing so weak. So that's one possibility.

There's a camp position sensor at the back of the left rear cylinder head. It's looking to see what the cam is doing and compares that to the flywheel teeth being counted by the crank sensor. If the cam position sensor is failing, or if the t-belt timing is way out of wack, you could get the results you have, but typically you just get an engine that won't even fire.

You could also have a bad MAF (Mass Airflow Sensor) It's in the silver round thing bolted to the top of the air filter box. If the hot wire in that goes bad, or gets covered in crud, you could have the problem you're having.

You're going to have to get the codes read because there are just too many variables, and you don't want to waste time and money throwing parts at it.

If you had a good wrecking yard in the area, you could go grab an output stage on the cheap and see if that changed anything.

DaveInSaltLake

3rd on pulling the codes. You can do that with a paperclip on a 1993, at least for the ECM. TCM and other modules will require VAGCOM or VWTOOL.

VadGTI

Do I need a VAGCOM to pull the codes or will a regular OBD2 scanner do? Also, the Check Engine light hasn't gone on... Does that mean no codes lit up or can there still be codes?

VadGTI

So, I just went outside to try and start the car. Now it cranks but won't start at all. I'm guessing the fuel flow has completely stopped, since I can't hear the fuel pump when the key is in the on position. Where is the fuel pump relay located? I looked in the relay box by the windshield, but didn't find it. All there is is a Fuel Pump fuse in the dash box, but that one's fine.

Also, just realized, the car is not OBD2... So, the only way to scan is with a VAGCOM?

VadGTI

I think I've figured out where it is (the general location), under the steering wheel. How do I go about jumping the relay to test it? Which terminals need to be connected and what do I use to connect them together?

austinado16

2 second job as opposed to locating and jumping fuel pump relays.

VadGTI

I missed it and just went back and read it, thanks! I just want to have backup to be able to figure out what's not working if there is no fuel delivery (which I'm pretty sure there won't be, due to no pump noise, clicking relay, and the fact that the car is no longer running, but simply cranking endlessly).

austinado16

The relay doesn't make noise, nor do the pumps. That's normal.