Mk 1 GTI missfire

[strawbs]

My mates Mk1 golf GTi misfires when reved and he had it checked out by a specialist and they said that the ignition system is ok but said it could be the injectors also after a long run on the motorway when he comes off at a junction and takes his foot of the accelorator it concks out, the specialist said try to change the coil that will sort it out.

Any help would be helpful :D

[deltafox]

Check the plugs first, then the leads, then the distributor cap, then the rotor arm.

Leads should show around 1K ohm of resistance each.
The rotor arm also should carry around a Kilohm of resistance.
Also check to see that the rpm cutout isnt broken on the rotor arm; if the springs weak or missing itll play havoc with your ignition.

Coils of the type fitted to the gti mark 1 hardly ever play up so its unlikely to be that, although connections to it may be iffy.

Problem may not even be ignition at all.

Basics first. hth.

[M3 Mitch]

Could be the ignition switch itself, which is behind the box, did the oil pressure, etc. lamps come on when the engine died? If the lamps are on, probably the switch is OK.

My Scirocco refused to start a couple weeks ago and the culprit was the pin/socket connection on the back of the fuse box. On Scirocco it's connection G2 IIRC. This is the black wire coming down from the ignition switch. On my car there are 2 black wires, one goes to the gauge cluster and the other goes to the fuse block, the coil is fed from there. Sometimes just wiggling these blocks, just pushing the wires back and forth a little will effect a temporary cure.

Another situation on these is that the ignition module may be bad, or maybe just the connection to it (this is just under the cowl, on my car it's on the drivers side ie left side of the car (I'm a Yank)

[M3 Mitch]

Also see what I wrote about these MkI/MkII cars in EmmaP's thread.

[DarrenW]

The misfiring could be fuel-related... It's common for the metal pipe that goes from the filler cap to the tank to rust, leaving loads of flakes in the bottom of the tank. Let the fuel run low, and it all gets sucked up into the system, blocking injectors and causing all kinds of chaos.

My 16valve Mk1 was just like that - it'd suddenly decide not to rev over 3000rpm, or wouldn't idle but would pick up OK. Loads of injector cleaner in the tank sorted it for me, and I had the injectors cleaned in an ultrasonic bath which made a big difference. I also replaced the filler neck (replacements from German and Swedish) and tied a magnet to a stick and fished around in the tank to get most of it out. Ideally I need new injectors, must get round to that sometime...