Page last Modified:

Wednesday, February 15, 2006 12:41:37 PM - Views Technotes :: Ignition Troubleshooting Guide

QuickLaunch [System Overview] [Hall Sender Overview] [Replacing the Ignition Coil]
Ignition System Overview

CIS 8v (probably applies to CIS-E and Digifant I and II to some extent)

Problems starting the car? cranks but no spark? Ignition. Here's a page of help to fix common ignition problems.

To start off... do you have spark? to check, take a wire off of a spark plug, and hold it about 1/4" away from the block. Have someone crank the engine. *be careful not to have your hands close to the end of the wire, or you might be shocked*

Spark? if yes, then you probably have problems else ware, like in the fuel system (pump, filter, injectors, etc)

If you have no spark then continue here.

Take the center plug out of the distributor and hold it close to the block. Same thing, have someone crank, see if there's sparks.

If you get sparks here but not from the spark plug wires, you probably have a bad rotor and/or cap. Replace them, they're really cheap at the local parts store.

If you get no sparks, then this gets a bit more evil. Now we check the resistance of the spark plug wires. Get a multi-meter, and set it to measure K Ohms. Spark plug wires should be in between 4.6K and 7.4K. the coil wire should be 1.2K to 2.8K. If your wires are out of spec, replace them. 8v wires are like 21.00 for some pretty good wires at checker or whatever. 16v wires are ungodly expensive and I think you can only get them at dealers.

If your wires are good, check the ignition coil.

Check between the + and - of the coil with the meter set for ohms. Should be small resistance, like .52-.76 ohms. next, check between the + and the center tower of the coil. Resistance should be 2.4 K - 3.5 K ohms. anything far out of that, and your coil's probably the culprit.

Still can't find the problem? Hall sender. Check the wires that go to it. it's the square plug on the side of the distributor body. check that wire for any breaks. Take the cap off of the distributor, take the rotor and dust cap off, and check the hall sender itself. (it's a small black plastic thing that is a magnetic pickup. If it's there, then so far so good. That's as far is I got, mine was shattered. Test the hall sender like this:
-This is from Dr Don Madbug's Dad on VWVortex
Here's how to check out the hall sender using a test light: Disconnect the connector from the hall sender, turn the key on, with the test light connected to the battery ground cable, "tap" the center wire on the hall connector with a quick on and off motion and you should get a spark each time. If yes, you have a bad hall sender (dist), if no, the problem is the coil or ignition module.

The ignition module sits in between the hall sender and the ignition coil. This is mostly just trial and error if one of these goes. Get one from an A1 car at a-pick-part.

Hall Sender and Coil Overview

Replacing the Ignition Coil

Yet another Easy Fix on the car, but can make a huge difference on your ignition system namely how powerful your spark is at the plugs.. I felt that after 15 years of service and yet still functional, I replaced it because I am trying to find a "sluggishness" in pick up on the car.

This picture is showing the location of the Ignition Coil (Behind the Throttle body bolted to the firewall on a 1985 8v Rocco that is. I already removed the rubber seal and cover plate at this point.
Looking into the drip tray you will find 2 bolts, remove the first bolt.
Remove the wiring. Then remove the other bolt. It can be easier if you pivot the coil to get to it.
Here we have the original Coil of the car and the new one, Externally aside from the old one being dirty and the new one is cleaned, without testing the coil per say, there are no mechanical parts in a coil, and life expectancy of a ignition coil can vary.
Reinstalling the coil is in the reverse order, lower bolt on first, reconnect the wires and upper bolt back on. Don't forget your ground strap or cable - that is important!

Comment on this Techtip

[Back to Top] [Index] [VWC Forums] [Contact/Donate]