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

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

Post by smudger28 »

Hi guys

So the boy changed the oil, rocket cover gasket and sump gasket. Put the correct oil in. Car started fine and he drive to football. After football he went to start the car and it just whirs and doesn’t fire.

Could this be spark plugs or Dizzy cap problem and just a coincidence that he changed the oil?

Cheers guys
Last edited by smudger28 on Tue Mar 07, 2023 5:50 pm, edited 1 time in total.


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

Post by GT_II »

Looking at under-bonnet pictures of the DX engine in Mk2 Sciroccos/Mk1 Golfs on the web, it looks like there is a set of fuel system vacuum hoses that need to be moved to access the rocker cover, and possibly other stuff, so could something have got dislodged/damaged in the process of changing the rocker cover gasket? Otherwise, I guess it could be random fault with either the ignition system or the fuel system.


1992 VW Scirocco GT II 1.8 90PS Brilliant Black 30k
smudger28
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Re: Help Please! Car won’t start after oil change.

Post by smudger28 »

Hi GT

Thanks for getting back. We’ve left the car at the college for now. I never took part in the process but I’ve no idea what they’ve disturbed. His friend is a self taught mechanic and they followed the guide on how to do it.

We’re going to recover the car tomorrow on a trailer and have a good look in the light.

I know they took the breather valve tube off but that all looks fine from what I saw.

They had to take the HT leads off but they must’ve put them on correctly as he started the car twice and drove it to football. It’s been sat for an hour during football and now fails to start.


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

Post by mark1gls »

Nightmare… go over everything they have done and unpluged, check nothing fell out/off.

Try and start the car before putting it on the trailer as it may be a warm start problem?

If still not starting check if it’s got a spark or fuel getting to the cylinders, you should be able to see/smell fuel on the spark plugs after cranking the engine over.


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smudger28
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Location: Falmouth, Cornwall

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

Post by smudger28 »

Hi Mark

I will have a look over the car tonight when I get home. I’m sure they’ve not touched anything. I’ll check all the hoses are secure that they might’ve disconnected.

Forgive my ignorance but what’s warm start? I can guess what it is I think?

My steps tonight will be Spark plugs, Dizzy cap and coil.


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

Post by mark1gls »

Warm start problems is usually down to a faulty accumulator, it’s a big cylinder near the fuel pump which holds the fuel pressure when you switch off the car, to test it there’s a little screw on the back of it and if you remove the screw and petrol leaks out it’s shot.
You can’t repair it as inside is a big spring with a metal disc with a rubber seal to hold the fuel pressure.
Other cause is faulty none return valve on the main fuel pump.

I’ve just fixed my warm start problem and my accumulator leaked fuel out of the screw.
Car would start fine from cold and drive ok, once the engine was hot you could stop for petrol or quick shop and it would start not problem but sometimes a little bit more cranking and run lumpy.
A couple of times if I did a big shop or stopped for about an hour or so the car would just keep cranking over and not start, I removed the spark plugs and they were dry and no smell of fuel.
If I then let the car cool down the car would start no problem as the 5th injector would work and the WUR would increase fuel.

I’ll try and post up some pictures later.


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 »

Great video to explain the accumulator etc.
About 3 mins in is the fuel pump return valve and just after that is the accumulator.

https://www.youtube.com/watch?v=a4fJAfXYxWk


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
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smudger28
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Re: Help Please! Car won’t start after oil change.

Post by smudger28 »

Haven’t watched the video yet Mark.

Done some checks.

1. Nice spark from plug.
2. Dizzy cap clean and arm rotates freely.
3. Fuel to the engine filter.

However no fuel coming out of the fuel distribution unit when engine cranked over. Haynes manual mentions a plunger inside that could be stuck. So no fuel going into engine.

Will watch video now.


1986 MK2 Scirocco - GTX - 120k
smudger28
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Re: Help Please! Car won’t start after oil change.

Post by smudger28 »

Ok, so we've removed the fuel distribution unit carefully and the plunger is free to move up and down. How far should that plunger come out? It doesn't come out very far. It looks fairly clean inside the unit too.

So I'm ready to tow it to our local garage who services all our cars to see if they can get it going.

Just thinking I've not swapped out the Fuel pump relay for stamps. It would make sense that the engine is being starved of fuel. I'm sure I can hear the pump run though?
Last edited by smudger28 on Wed Mar 01, 2023 9:33 pm, edited 1 time in total.


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

Post by mark1gls »

My accumulator leaked when removing the screw.

Image

View from under the car to show where it is.

Image

I had to seal the screw with some builders silicon to stop it leaking as I needed to use the car for work until I could change the accumulator.

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 »

Yes possibly a stuck plunger, remove the rubber boot above it and when lifting the plate you should feel a little resistance.
If not some carb cleaner may free it up but it’s not easy getting underneath the metering head with all the stuff in way and the fuel filter attached..


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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 »

The plunger does move up and down albiet not to far but it is free.

https://flic.kr/p/2ojFRJp
https://flic.kr/p/2ojJ2qi


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 »

Not checked the Accumulator as yet but would like to try a new relay just to rule that out. My only thinking regarding the relay is because the old fuse board blew up directly below the fuel pump relay. I wonder if it damaged it somehow. Unfortunately we don't have a spare Fuel Pump relay.


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 »

So tried relay 53 in place of the fuel pump relay which means it's always live when you turn the ignition on and you can hear the fuel pump running. That's ruled that out at least. I'll check the accumulator tomorrow. Still looking like a trip to the garage!


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

Post by mark1gls »

Try spraying it with brake cleaner or carb cleaner to see if it will free up.


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