FIXED: Help Please! Car won’t start after oil change.

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smudger28
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Re: Help Please! Car won’t start after oil change.

Post by smudger28 »

mark1gls wrote: Sun Mar 05, 2023 6:28 pm

I can measure the length of my earth lead if helpful then you can buy a genetic cable?
Yes please! I've been looking on ebay and they're quite pricey. I'm tempted to change the ignition coil pack along with the fuel filter too.

Hopefully now he can get some enjoyment out of it.

I think we would've been lost without you guys on here! 8-)


1986 MK2 Scirocco - GTX - 120k
smudger28
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Location: Falmouth, Cornwall

Re: Help Please! Car won’t start after oil change.

Post by smudger28 »

He’s just informed me the car is now idling at 2000 rpm after driving 20 mins. Will decrease the idle screw when he gets back, if he gets back 😂


1986 MK2 Scirocco - GTX - 120k
mark1gls
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Re: Help Please! Car won’t start after oil change.

Post by mark1gls »

Earth strap is 350mm long by 10mm.
Looking on eBay most seem to 300mm, They should be ok as there’s plenty hanging down on mine.

Picture of where it attaches to the top bolt of the coil bracket.

Image


Picture of idle screw on back of the throttle body if not sure where it is?

Image


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Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
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mark1gls
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Re: Help Please! Car won’t start after oil change.

Post by mark1gls »

I’m still using the original coil and it’s on my 1988 car with 317,000 miles so unless it’s not starting properly I would not worry about it.


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323
mark1gls
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Location: Somerset

Re: Help Please! Car won’t start after oil change.

Post by mark1gls »

The cars been in the family since 1994 and it was only 6 years old so I know what parts have been changed and whats still original. :-)


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323
smudger28
Posts: 124
Joined: Sat Jan 14, 2023 7:09 pm
fill in the right answer: 15
Location: Falmouth, Cornwall

Re: Help Please! Car won’t start after oil change.

Post by smudger28 »

Thanks for measuring the earth strap. I'll see if I can source one this week.

As for the idling screw I think I adjusted the wrong one. I adjusted the one that adjusts the fuel mix next to the fuel distribution head oops...

I will try adjusting the throttle screw instead lol...

Will leave the coil alone for a minute then. if it's not broke....


1986 MK2 Scirocco - GTX - 120k
smudger28
Posts: 124
Joined: Sat Jan 14, 2023 7:09 pm
fill in the right answer: 15
Location: Falmouth, Cornwall

Re: Help Please! Car won’t start after oil change.

Post by smudger28 »

Image
That’s the one I adjusted [emoji85]


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1986 MK2 Scirocco - GTX - 120k
mark1gls
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Location: Somerset

Re: Help Please! Car won’t start after oil change.

Post by mark1gls »

:-D You aren’t the 1st to do that hence the picture with my finger.
Clockwise to lower idle and counter clockwise to increase. Wait for the engine to get normal temperature as there’s an idle stability valve/anti stall valve which can affect things.


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323
mark1gls
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Location: Somerset

Re: Help Please! Car won’t start after oil change.

Post by mark1gls »

You need a 7mm spanner for the idle screw.


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323
smudger28
Posts: 124
Joined: Sat Jan 14, 2023 7:09 pm
fill in the right answer: 15
Location: Falmouth, Cornwall

Re: Help Please! Car won’t start after oil change.

Post by smudger28 »

mark1gls wrote: Sun Mar 05, 2023 10:07 pm :-D You aren’t the 1st to do that hence the picture with my finger.
Clockwise to lower idle and counter clockwise to increase. Wait for the engine to get normal temperature as there’s an idle stability valve/anti stall valve which can affect things.
And I won't be the last? :-D
Right that's a job for tomorrow. The boy is out in the car at the moment. I'll report back once it's done.

Thank you.


1986 MK2 Scirocco - GTX - 120k
mark1gls
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Joined: Thu Apr 02, 2009 9:28 pm
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Re: Help Please! Car won’t start after oil change.

Post by mark1gls »



Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323
smudger28
Posts: 124
Joined: Sat Jan 14, 2023 7:09 pm
fill in the right answer: 15
Location: Falmouth, Cornwall

Re: Help Please! Car won’t start after oil change.

Post by smudger28 »

Managed to get an earth lead from work. £15 not bad for genuine.

The idling issues look like a faulty hose, cabling and/or AAV. Found a chaffed pipe and two broken wires.

Image
I can fix the wires but not sure about sourcing the hose or AAV.

So fixed the plug and have 11.6v at the plug end. I ran this test that I got from this forum.

Detaching the electrical plug,running the engine (when cold) then pinch the air intact duct to aav hose, the idle speed should drop.

Then repeat the test when the engine is at normal operating temp, (replace the electrical plug),
pinch the hose, the idle speed should remain unaltered.

Both tests work as advertised.

So only problem remaining now is it idles around 900rpm when cold which is ok but once driven a while it fluctuates. See if I can post a video. It's hunting... Not sure what causes that.

https://youtube.com/shorts/bl76g1S00Uw?feature=share

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1986 MK2 Scirocco - GTX - 120k
mark1gls
Posts: 3957
Joined: Thu Apr 02, 2009 9:28 pm
fill in the right answer: 10
Location: Somerset

Re: Help Please! Car won’t start after oil change.

Post by mark1gls »

Looks like the idle stability valve is keeping the engine from stalling because the idle is set to low. If had the same thing when my idle screw would adjust it self over time.

Once the engine is warm increase the idle speed with the screw on the throttle body to at least 1200 rpm, blip the throttle a few times then lower the idle to 1000rpm.
If it’s still playing up it could be the rubber O ring on the idle screw has gone hard and not sealing.


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323
mark1gls
Posts: 3957
Joined: Thu Apr 02, 2009 9:28 pm
fill in the right answer: 10
Location: Somerset

Re: Help Please! Car won’t start after oil change.

Post by mark1gls »

Picture of what the idle screw O ring should look like.

I’m also on the Mk1 Golf forum..

https://vwgolfmk1.org.uk/forum/index.ph ... x-idle-low

I’ve got the measurements of the o ring if needed?


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323
mark1gls
Posts: 3957
Joined: Thu Apr 02, 2009 9:28 pm
fill in the right answer: 10
Location: Somerset

Re: Help Please! Car won’t start after oil change.

Post by mark1gls »

Check the idle screw 1st as AAV don’t usually go wrong, you can unscrew the two Allen key screws and remove the AAV, if you can see through it when cold and if powered up for a couple of minutes it should close.

https://www.youtube.com/watch?v=38DCMiGnaZw


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323