Updated: 11-Jul-2023
Starters
Everything you should know about VW starters and solenoids*:
The above link includes:
- How it's made
- Upgrading
- Replaceable parts
- Troubleshooting
- Lots of starter issues are wiring related
- Sometimes it starts, others not
- Starter stays on even when driving or after the car is shut off
- It grinds like a mofo!
- OK, the starter is out, how do I know if it's good?
- Slowwwww cranking
- The starter spins, but doesn't engage the flywheel
- Replacing the starter
* Diesel starter is shown/used in that link. Diesel starters contain reduction gear sets and are larger and heavier than gasoline starters.
Intermittent Starting
Causes and remedies:
- Ignition switch is faulty. Replace ignition switch.
- Starter is faulty. Replace starter.
- Faulty battery cables and/or electrical connections. Replace battery cables and/or clean/repair electrical connections. Be sure the ground connections are good. Note: Replacing the battery cables is a wise idea whether or not your car is suffering from starting issues.
- 1990+: Coolant temp sensor (CTS) is faulty. Replace blue CTS.
- Cabriolets with automatic transmissions:
- Not starting when hot: Starter is suffering from heat-soak. Install a hot-start relay and be sure the heat shield is in place.
- Intermittent starting: Starter-interlock system is faulty (1990+). Replace or bypass the interlock relay.
- Fuel pumps are overheating. Replace fuel pumps.
- Fuel pump relay is faulty. Replace relay.
No Start
Common causes:
- No spark
- Faulty/wet distributor cap, rotor, and/or spark plug wires
- Weak coil
- Faulty ignition switch
- Defective Hall sender and/or wiring
- Incorrect ignition timing
- Broken timing belt
- Faulty fuel system
- Engine mechanical failure
- Faulty hot-start relay, if installed
"Engine will not turn over." Turn over, in the car world, means to crank. When describing a no start issue, "will not turn over" is an indication to experts that the engine is not cranking. Because specifics are better, it's wiser to say that "the engine will crank, but not start".
Is it a starting issue, or a running issue? If the car starts and runs, albeit poorly, it does not have a starting problem; the car has a running issue. For troubleshooting, visit the engine and/or fuel system pages.
For complete diagnostic procedures for all of the above, please refer to your Bentley Service Manual (or other repair manual).
No Restart When Hot
Is it an automatic? Automatic Cabriolets are notorious for this problem due to the poorly-located starter (next to the exhaust manifold). The best solution for this problem is to install a hot-start relay. Also, be sure that the heat-shield is in place.
Installing a hot-start relay: 
Spark Plugs
Spark plug guide:
Bosch is still making decent wires, so they are still recommended. However, NGK is now making a set of plug wires for these cars, which are also recommended (#VWC013, or NGK57283).
Firing order: 1-3-4-2
Distributor Components
Ignition distributor component guide:
| Component | Part Numbers | Years | Engines |
|---|---|---|---|
| Distributor Cap | 113-905-207C Bosch 03010 |
1981 - Oct. 1984 | JH, EN |
| Distributor Cap | 027-905-207 Bosch 03212 |
Nov. 1984 - Sep. 1986 | JH |
| Distributor Cap | Bosch 03214 | Oct. 1986 - 1989 | JH |
| Distributor Cap | 050-905-207 Bosch 03368 |
1990 - 1993 | 2H |
| Rotor | Bosch 04038 | 1981 - 1989 | JH, EN 14mm distributor shaft |
| Rotor | Bosch 04170 |
1990 - 1993 | 2H 10mm distributor shaft |
| Distributor | 026-905-205L1 | up to Oct. 1984 | JH to engine #140000 |
| Distributor | 026-905-206B2 | Oct. 1984 - Oct. 1987 | JH engine #140000 to 280000 |
| Distributor | 026-905-205AH2 | Oct. 1987 - Apr. 1993 | JH from engine #280001 |
| Distributor | 026-905-2053 | VIN: up to L-12000 |
2H |
| Distributor | 026-905-205F3 | VIN: L-12001 to M-21000 |
2H |
| Distributor | 026-905-205K3 | VIN: from M-21001 |
2H |
| Hall Sender | 035-998-065 | 1980 - 1983 | EJ, EN |
| Hall Sender | 035-998-065A 034-998-065 |
1984 - 1993 | JH, 2H |
|
1 Replacement distributor is 026-905-205L 2 Replacement distributor is 026-905-237X 3 Replacement distributor is 037-905-237X |
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Ignition Coils
Ignition coils guide:
Ignition Control Unit Pin-outs
| Pin | K-Jetronic Function | Digifant Function | Wire Color |
|---|---|---|---|
| 1 | Terminal 1 on coil | Terminal 1 on coil | K-Jetronic: Green Digifant: Red/Black |
| 2 | Ground | Ground | K-Jetronic: Brown Digifant: Brown/White |
| 3 | Terminal 1 on Hall generator - |
n/a | Brown/White |
| 4 | Terminal 15 on coil | Terminal 15 on coil | Black |
| 5 | Terminal 3 on Hall generator + |
n/a | Red/Black |
| 6 | Terminal 2 on Hall generator | Terminal 25 on Digifant ECU | K-Jetronic: Green/White Digifant: Green/Black |
Load Reduction Circuit
Also known as the "X" circuit, the load reduction circuit is exactly that: It is the circuit that reduces the load on the ignition system during cranking by cutting power to high-load accessories. These accessories include the headlights, the HVAC system, windshield wipers, and rear window defroster.
More thorough explanation and troubleshooting can be found at this link.
Battery
North American Cabriolets were originally equipped with Group 41 lead acid batteries. These are now becoming harder to find in some regions, but there are other options available; refer to the guide below.