Why does my VW Scirocco sometimes crank and not start, or run rough when cold?

Short answer: If your Scirocco sometimes cranks and cranks but won't start, then starts fine later, check the relay panel under the dash above the driver's left foot. A leaky windshield can corrode it. Also make sure the in-tank fuel pump recall work was done. If it runs rough when cold, have a shop test the CIS fuel injection (VW's mechanical system) pressures, cold start injector and timing.

Symptom: Most days it starts right away, but once in a while it cranks and won't fire, though it roll-starts. Or on cold mornings it runs very rough, and the idle slowly climbs while you hold the pedal steady.

What to check first

1. Check the floor and relay panel under the dash for water or corrosion.
2. Listen for the fuel pump when it won't start.
3. Run your VIN for the 1985–1987 in-tank fuel pump recalls.
4. Have the CIS fuel pressures tested with the right gauge.
5. Check ignition timing and replace old injector seals if they leak.

Likely causes

1. Corroded relay panel under the dash. A member said Sciroccos had trouble with the relay panel above the driver's left foot. A leaking windshield can corrode it, and relays then act up.
2. Flooded engine. Too much fuel in the cylinders. A member suggested holding the gas pedal to the floor while cranking.
3. In-tank fuel pump. Two VW recalls covered in-tank pumps on 1985–1987 cars that could fail or seize in hot weather.
4. CIS fuel injection pressure or cold start parts. CIS is VW's mechanical fuel injection. Members said the first step is a CIS fuel pressure test, and to check the cold start injector and warm-up regulator.
5. Ignition timing set too far advanced. On the 1985 car, members said to put the timing back to spec first.

What it usually costs

No owner posted prices in these threads.

Is it safe to keep driving?

A car that randomly won't start can strand you. A rough-running engine is usually drivable gently, but if you smell gas, stop and get it checked. Verify with a mechanic.

DIY or shop?

Mixed. Relay panel cleaning and injector seals are DIY. CIS testing needs a special gauge and know-how.

Recalls, bulletins and complaints in plain words

• Related recalls: NHTSA lists these recalls touching this area of the Volkswagen Scirocco: 85V090000 (1985 model year, in-tank fuel pump); 87V053000 (1985-1987 model years, in-tank fuel pump); 91V201000 (1987-1988 model years, fuel tank). Check your VIN at nhtsa.gov/recalls. If your car is part of this recall, the dealer fixes it for free.
• Plain words: Recalls 85V090000 and 87V053000 covered in-tank fuel pumps that could fail or seize in hot weather, which can stall the car or stop it from starting. Recall 91V201000 covered a fuel tank that could crack near a seam weld and leak. If your car is part of these recalls, the fix is free, though these are old campaigns. If you smell gas, don't drive it. Verify with a mechanic.
• NHTSA complaints: 12 keyword-matched complaints for Volkswagen Scirocco 1982–1988 (of 14 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-28; keywords: start, crank, stall, rough, idle, cold, fuel, relay) (NHTSA returned no data for 2 model-year queries). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In '86(7?) Scirocco 16v starting problems on Car Talk, an owner who kept a 1986 or 1987 Scirocco 16V for about 200,000 miles said that once in a while, at random, it would crank as long as he liked and not start, though it roll-started fine. One member asked whether he held the gas open, since a flooded engine can do this. Another said Sciroccos had problems with the relay panel under the dash above the driver's left foot, where a leaking windshield could corrode the connections and make relays act up.
• In 85 Scirocco Engine Problems on Car Talk, a 140,000-mile 1985 Scirocco owned since new started running very rough on cold starts, and the idle crept up slowly while the owner held the gas steady. Members said to put the ignition timing back to spec, check the cold start injector and warm-up regulator, check compression and valve adjustment, and above all connect a CIS fuel pressure gauge and follow VW's CIS test steps. Some suggested new injector seals, since old ones leak air.

Quick tip

Pull up the driver's floor mat. If it's damp, you may have found both your leak and your no-start.

Vehicle focus: 1982–1988 Volkswagen Scirocco (second generation, CIS fuel injection, US).

Safety / mechanic note

CIS systems hold fuel under pressure. Relieve pressure and work away from sparks. Verify with a mechanic.