1.8 gti not starting - no spark

Hi all,

I'm helping a mate sort his tintop mk1 gti at the moment and we just can't seem to get it to fire up… it turn over though, The car was in storage for around 6 years before my mate brought it so we haven't ever heard it run.

Things we have checked:

1) Starter motor - Tested outside the car, the Solenoid works and starter turns when connected directly to a battery so I know its good and was removed from a running car.

2) Switch wire to starter motor, I am getting power and even tested by running a live from the battery to the switch on plug on the starter…no joy

3) connected a earth jump lead from battery to body of starter motor …no joy

4) connected a live jump lead from battery to live terminal on starter….no joy

5) replaced ignition module from working car…no joy

6) when turning on the ignition I hear the fuel pump prime and can confirm the plugs are soaked in fuel…so i definitely have fuel

7) earth strap removed and cleaned.

8)battery replaced…again removed from working car


The car is cranking slowly, even though the starter turned over a lot faster in the car it was removed from and I have ran both live and negative from the battery to the starter to remove the possibility of being a bad connection…. any idea's what we can check next?


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Just checked the wires to the ignition coil with the ignition on (while the fuel pump is priming)

and I got the following results

Green/Black  =  live
Red/Black  = live

x2 black wires = live

Is this normal when the ignition is on?

How old is the fuel, petrol goes off after 9 months ish, have you looked in the fuel tank and drained out the old fuel?

mark1gls said

How old is the fuel, petrol goes off after 9 months ish, have you looked in the fuel tank and drained out the old fuel?

Before i did anything I confirmed the tank was almost empty so put in around 10 quid of fresh fuel….when pulling out the plugs they are soaked in fuel so the pump and injectors are definitely working, however I see no soot on the plugs and no spark when trying to arch them on the engine block.

abit of an update:

I swapped out the ignition coil from a running car then removed one of the HT leads and connected a  spark plug…it now appears I have spark.. Although it looked quite weak if I'm honest…and yes i did manage to shock myself on the second attempt

The car is still turning over slowly even though the starter motor,ignition coil and battery all fired up in the parts car before i swapped them over.

My concern is when the ignition is on the black wires going to the coil are coming up as live when I connect a tester to them…is this meant to be the case?

After digging around the engine bay near the coil I found 2 plugs there didn't seem to be connected to anything… Can anyone confirm what these are for and if they would stop the car from starting?






Pic one is a small connector with x2 wires.. one is Brown/red and the other is White/red

The second connector is larger with 3 wires coming from it,however only 2 go into a loom and the 3rd (black) is broken off.

One wire is solid brown and the other is white/green.

anyone got any ideas?

I carried out a voltage drop test following a guide on you tube and the multi meter shows 0v loss across the negative from the battery to the starter while cranking, however I saw 0.3V on loss while cranking when testing from the positive terminal on the battery to the positive on the starter.

Also, when I carried out the test on the wire from the ignition switch (live when cranking) while cranking I saw a 0.3v loss… would this explain why I'm unable to start the car?

When checking the voltage across  the battery with everything off I see 12.6V, during cranking this drops to 6.5V and the positive from the battery to stater gets really warm

How easily does the engine crank by hand? It sounds like the starters struggling because something seized. Will it crank with plugs out.

Sounds like your battery is old and may need replacing.
Have it tested at least.

Replace your Battery to frame and Frame to engine Grounds.
Probably wouldn't hurt to replace the main power cable to the starter with a new cable as well.
 

2 pin is vacuum switch for upshift light, big plug is for early gearbox with multi pin plug for up shift and mpg gauge. both are only used on early clocks with the mpg gauge up top and for 100% working you need early box. neither will cause your running issue.

coil black wires are ignition live from fusebox and power for spark module, that is all good.

the red/black is rev counter feed to fusebox and green is pulsed trigger from spark module. you will see 12v if you measure here as the module/rev counter will be earthign thru your multimeter.

to rule out bad battery cabling run a jump lead from battery negative to one of the bolts holding the starter on, if it cranks over fast then theres the issue. if not as above but from battery live to the fat stud on starter.

the mk1 negative for engine is in a poor location, top of gearbox bracket. corrosion builds up between the box and bracket. late mk2 and mk3 moved this to a stud on the end of one of the gearbox -> engine bolts, much better.

so since my last update I have replaced the copper bush in the bell housing for the starter and since then the starter is definitely spinning up faster/normal… however the car still isn't starting.

I have ran a earth direct from the battery to the start casing…no joy ( did the same with the live…also no joy)

Just to confirm the x2 black wires which are live..which pins should these connect to on the ignition coil?… I ask  as the original connector has been replaced with spade connectors so there is nothing stopping them being connected incorrectly…. I read somewhere the black wires should go to the + (15)…is this correct?

yes black to +/15, green and/or red/black to -/1