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'81 golf GTI start problems after restore.

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Ignition or Fuel System?

Hi everybody,
I’m Sandro from Italy and I’m restoring my ’81 Golf GTI, but I’m not a mechanics..
I’ve problems to run well the car: sometimes starts immediatly (cold engine), sometimes starts but stops after 20-30 seconds. and it does not start anymore.
I have disconnetted one spark plug and when engine try to starts I don’t see fire on spark, only sometimes there is a fire and the engine try to start but then failed.
This is my question: it’s a problem on ignition (coil or something else) or a fuel system problem?
I ask this because when I try to start the engine (and doesn't starts) there isn’t fuel smell from the exhaust, so my hypothesis is that are two problems in the same time: no current on spark and no fuel in injectors (maybe the fuel return directly to the tank?)
Are the 2 problems correlated? So, when there is not fuel in the injector it’s corrent to have not fuel on the sparks?

I've renew:
-fuel tank
-fuel pump
-fuel filter
-spark plugs
-rotor and cap
-engine belts

Sometimes the engine run but if I go for a trip after 2-3 km there is a failure, the engine fail but then restart in autonomy after 2-3 seconds (the car is is movement).
On the sparks there is a black depot (mixture too rich?), before the car restore the sparks were perfect, brown!
thanks in advance for your suggestions and sorry if this is could be stupids questions..
Have a nice day
Sandro

 

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Its not possible to say from your description. You need some way of properly checking for spark, and/or fuel

                                

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I agree with what paul_c says about your description. The coil sends a pulse to the fuel pump relay which then powers the fuel pump. It is possible the two are the symptom of one problem. At a guess from your description, I would start with the ignition system first.

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Thanks paul_c and Saulty. I'll try with the coil and the icm.  
I'll update you

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If your spark plugs are black you will not get a good spark and it's quite hard to clean them properly, check the warm up regulator has got power, if not that would cause a rich mixture

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I replaced the coil and the ICM module. The machine immediately started working perfectly for 30 seconds, but then it stopped. And it's not started anymore…
The next work I will watch the WUR.
A question: it's normal that the file pump run also without the switch relay?
Thanks

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It sounds like you need to start from scratch on this one otherwise you are going to spend a lot of money chasing shadows around.
The fuel pump should run for a second when you switch on the ignition to purge the system, not all cars do this. It should then running when the engine is cranking and when running.
You need to check that your ignition system is healthy and valve timing is correct before moving on to the fuel system. Here's a link to my thread when I was getting my car going, you will need to be methodical and patient but these cars are basic and I doubt you'll have any problems getting it running. There are plenty of other posts on the forum as well which will help.

https://vwgolfmk1.org.uk/forum/index.php?page=topicview&id=technical%2Ffuel-systems-and_3%2Finjector-testing-and-k

Don't be afraid to ask questions but you will need to provide info on tests you've carried out etc.

Good luck.

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Hi everybody,has anyone available the Bentley wiring diagram like the one attached? can you send it to tescarobis@libero.it?
Thanks a lot 
Sandro 45E6B520-B723-4757-B427-B4B2BF78D2C9.jpeg

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Well, I would suggest that you can buy one off of ebay the haynes and get all of them for probably 20 dollars USD shipped.

I don't know of too many folks that will tear out pages of a book and send them to you.  PDF's of a scanned page would be ok I suppose.

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