HELP........ it won't start

Tried to fire up my GTI this morning, but just spun on starter. Engine would not catch at all. Last started it yesterday and it started on the nail

Can hear fuel pump working, checked pipe coming out of filter into metering head - fuel coming through. Plugs look wet after trying to turn it over - so  fuel supply seems OK.

Get a spark coming from King lead into dizzy, but spark looks weak from the HT leads - looks yellow rather than blue and small spark? Dizzy was replaced earlier this year and appears to be OK - tried new cap and rotor. All that leaves is the LT wires from dizzy to coil to igntion module… Going to check these tommorow with multimeter.

Would grateful for any advice on this one as getting to the point where my heads going to start banging on a nearby wall  :evil: . Has anyone had problems with LT wires?

Cheers

I'd be looking at the ignition module or the coil if you have a weak spark.  Check the coil voltage is 12v on the LT side also.

If you are getting a weak spark on the king lead my money is on the coil

Thanks Crazyquiff. Sorry didn't mention swapped the ignition module over today as well - made no difference. Have got a spare coil so'll try tommorow morning - mind you coil on car is only 6 mths old? Spark was OK on King lead - stronger than at HTs, but haven't looked at spark for long while so can't be sure if its good enough……..

Cheers

Markwon, the engine won't start if an air hose is leaking maybe one hose has come off somewhere around the inlet manifold. Also check the inlet manifold. Last resort could be to mess about with the mixture screw try turning the screw half a turn clock wise, you can always turn it back to its original position.

good idea looking for air leaks etc, but i would leave the mixture alone as said if it started fine the day before it will only confuse things if it doesn't go back to the exact position it was set at.

If you've got a strong spart at the king lead the only other options are rotor, cap and HT leads to the plugs (and of course plugs)

Coils can give spark and break down on load with the spark dropping away.  Wipe out the cap and cheak for moisture.  Check for burning on the rotor arm and the contacts in the cap - clean with fine paper if necc.  Also check the condition of the grahite plunger that is in the cap and goes onto the rotor arm

The cap and rotor look fine, but I have swapped them to be sure and makes no difference. Read the Haynes again and it refers to there being a strong blue spark at the end of the HTs - mine is weak and yellowish. Would this be enough to prevent it firing?

King lead spark is stronger, but doesn't look as good as should be. Is it possible the spark is weak and being disappated as it moves along the HTs? Got a spare coil to try tommorow - a friend said coils can get damaged if igntion accidentally left on? Was working on it yesterday, but don't recall leaving ignition on?

Does anyone know what to test when looking at the LT dizzy leads with a multimeter and what current/ampage should be present? Haynes Ignition section a bit brief and cobbled together from the all the various models. Mines a 1981 1600 with pointsless /electronic ignition.

Cheers

Correct fuel,timing and spark should produce combustion. A dropped valve or/and poor injectors will make difficult starting but should still start.

My money is that the mixture is weak due to air leakage, I've had this problem many times. Increasing the co mixture by turning the screw clockwise may make the engine fire up.

Cheers Lhasa, I'll have to check the pipes for air leaks. When you've had the problem has your car just spun on its starter or has it caught intermitently, but without starting?

My mk1 in the past has failed to start and has just kept turning over, always due to an air leak. The mess of badly thought out  air pipes from VW (imo) is an erRor from  VW. The air pipes and rubbers can easily detach or crack, the three way rubber onto the rocker cover is the common one to crack and leak. Don't be afraid of messing about with the co mixture. I tune my engine co mixture through the exhaust tone I don't bother going to garages they are all cowboys and rip off merchants.

In 6 years my mk1 has NEVER failed from the coil!

HT leads to the plugs (and of course plugs)

As crazyquiff said, check these. I have had two cars fail to start because of these. Especially in the damp.

Would add rotor arm, dizzy cap but you say you have already.

Was working on it yesterday

What were you doing? any clues there?

Peter.

Spark at the plug lead should be strong and blue - Mine actually makes a good crack sound as it sparks so you don't even need to see it!  Sounds like yours is weak.

Checked all pipes today - all looked fine. Checked and cleaned all contacts on alternator, ignition set-up, starter motor - no joy. Adjusted CO by half turn, then three quarter - still no joy. Plugs look wet and smell of petrol so obviously petrol getting into engine. When checking HT leads spark is yellow - has anyone else noticed this. Haynes and Crazyquiff say should be a blue spark?? Still haven't tested LT circuit.

Everything I have done has made no difference - car still just spins on starter  :cry: . Has anyone got any more ideas?

Cheers

Have you tried the earth that goes to the rocker cover right hand rear nut when looking under the bonnet

Cannot see any earth strap or sign of being one on rocker cover?

One earth strap attaches to the gearbox

There should be a small earth strap on the far right-hand bolt holding the rocker cover on. not sure this would make much difference tho. The electrical leads attached properly on the coil??
Billy

Earth Strap on g'box, but none rocker cover - Haynes says should be one on cylinderhead will have a look tommorow. Checked coil leads and cleaned them today, made no difference…..

markwon,

Have you swapped the coil for a good one yet?  If not this is a must in your trobleshooting

Thanks Crazyquiff, almost forgot to do that. Tried swapping coil - still no joy   .

So have now checked..

HT Leads
Rotor Arm
Dizzy Cap
Spark Plugs
Ignition Module
Ignition Coil
Fuel Filter
CO Adjustment
Air and Fuel Pipes
Alternator and Starter connections

Running fine Sunday - just spun on starter when tried to start on Monday Morning? Really can't get my head round this one… can't think what else to try? Missed several days of work trying to sort this  :evil:

Anyone got any other ideas - thanks…