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My '83 GTI doesn't respond to tuning..?

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Any ideas? 


My 83 GTi has been off the road for just under 5 years - we've finally got it back on the road and running however it doesn't seem to enjoy running properly. 


After setting up the little screw on the metering head, idle control valve and timing we thought we had it spot on so took it for a spin. All was fine! 


When I got home and turned it off and back on the car then wouldn't start. 


So basically the timing and fuel needs to be way out for the car to start(around 2000rpm idle) but then it's too high when actually running. 


Thanks in advance! 



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Have you got fresh petrol in it? I had a VW Beetle that I spent ages twiddling with settings, replacing plugs etc etc with no joy. Eventually needed to fill it up and it ran fab after that.....

1983 Mars Red 1.8 Golf GTI
1987 Alpine White 1.8 Clipper Cabriolet

The trouble with doing nothing is that you never know when you are finished.

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Early-1800 said

Have you got fresh petrol in it? I had a VW Beetle that I spent ages twiddling with settings, replacing plugs etc etc with no joy. Eventually needed to fill it up and it ran fab after that…..



Thank you for your reply. It's had new petrol in so I don't think it's that! 

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I would look for:
Vacuum leaks including the Idle by-pass screw that is on the back of the throttle body, if it turns easily with your fingers then the o-ring is bad and needs replacing.
Count the Turns to remove it, write that number down, then go to a good hardware store and get a new 0-ring.
Going back wrap the threads and threads only with PTFE tape (teflon).  Return it to the Count.

I would also check the grounds on the car, bad grounds causes a myriad of things to read incorrectly.

Then Set the static time.

I would also check the duty cycle as you can be way off.
Which would effect your timing.

Replace the plugs with NGK, you can see www.cabby-info.com for the type needed for your car, as I know mine got a second life when I changed them.


What do Divorces, Great Coffee, and Car Electrics all have in common?

They all start with GOOD Grounds.

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Injectors or injector seals? Inlet maniold leak?

Metering head itself may be gummed up after so many years idle along with the WUR on the front of the block

All cause issues

My 90 cab has been the same, i have just managed to get it running the same every time i start it although it still messes about on a few occasions   :lol:Needs some further tinkering beyond my capabilities and tech so it's going to a mate who began his apprenticeship at VW way back when the Mk1 was new  :lol: 

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Seems more like a starting issue than a running issue.

I'd be looking at vacuum advance on the dizzy and fuel accumulator.

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Is it holding pressure in the fuel system after switch off? nearly all Kjet hot start issues are due to bad non return valves letting the fuel pressure drop too quickly which leads to the hot fuel boiling in the injection lines which then plays havoc with the injectors

Also when its hot I'd un clip the wire to the 5th injector in case the thermo time switch is faulty.  You could be flooding it when its hot.

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Thank you for all your replies everyone. Got lots to look at now!

Yomp said

Is it holding pressure in the fuel system after switch off? nearly all Kjet hot start issues are due to bad non return valves letting the fuel pressure drop too quickly which leads to the hot fuel boiling in the injection lines which then plays havoc with the injectors

Also when its hot I'd un clip the wire to the 5th injector in case the thermo time switch is faulty.  You could be flooding it when its hot.





I've actually  got a new non return valve on the way so I'm hoping that could be the main issue. Thank you!  


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