Engine Tuning Problem

Tiny
SENELA
  • MEMBER
  • 1999 VOLKSWAGEN JETTA
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 145,000 MILES
I have a 1999 VW Jetta MK4 2.0, I recently replaced the spark plugs and wire set. Now the injectors are making a strange noise when I run the engine. They are louder than usual and I suspect I can smell raw gas coming from their vicinity. I am not sure if the noise is from all of them or some. I had to unplug the injectors to access the plugs. I am sure I reseated them properly. Could this be faulty wires/plugs? I am afraid to keep the engine running for long because of the gas smell. The noise sounds as though the injectors are firing but the gas is not being ignited.
Wednesday, July 13th, 2011 AT 3:42 PM

10 Replies

Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
The injectors should have been ok, I would start with re checking plugs (correct plug and gap) and leads fitted correctly, you will see any fuel leaking around the injector, just make sure that all injectors are connected correctly, I feel it will be something simple with what you have already touched.
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Wednesday, July 13th, 2011 AT 10:59 PM
Tiny
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  • 5 POSTS
Sorry it took long to reply, I found the problem was a stripped thread on one of the spark plug holes. Is there any chance that I can repair this without pulling the cylinder head? I have read online that there are certain kits available that can do this, how effective are they? It is stripped pretty bad, a chunk of it actually came out with the spark plug.
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Sunday, July 17th, 2011 AT 12:24 AM
Tiny
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  • MECHANIC
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There is a kit called a thread re coil, you do have to drill out the old thread and insert the re coil, problem is metal entering the engine, you really should pull the head to fix this, otherwise you may introduce sizable metal into the combustion chamber and this can damage the piston.
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Sunday, July 17th, 2011 AT 12:58 AM
Tiny
RIVERMIKERAT
  • MECHANIC
  • 6,110 POSTS
Helicoil.
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Tuesday, July 19th, 2011 AT 3:31 AM
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Was not sure if you called them that over there as well, I am in Australia so I got to be a bit careful with term I use, but we also call them Helicoils as well.
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Tuesday, July 19th, 2011 AT 7:25 AM
Tiny
RIVERMIKERAT
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Trade name.
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Tuesday, July 19th, 2011 AT 7:46 AM
Tiny
SENELA
  • MEMBER
  • 5 POSTS
Yes, I have seen some of these 'Helicoils' advertised on the internet, I understand the risks involved in drilling and have metal particles fall in the combustion chamber, is there any trick by which this can be minimized? If possible, I really want to avoid pulling the head.
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Wednesday, July 20th, 2011 AT 10:12 PM
Tiny
RIVERMIKERAT
  • MECHANIC
  • 6,110 POSTS
You might try using compressed air to clean the cylinder out after installing the Heli-Coil, but there really isn't a trick to keep the shavings from entering the combustion chamber short of removing the head.
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Wednesday, July 20th, 2011 AT 10:30 PM
Tiny
MEBRBRI
  • MEMBER
  • 2 POSTS
Back in the day you could use a magnet but if the head is aluminum that wont work. In addition to using compressed air you could crank the engine with the spark plug out which in theory might push any reamining particles out the spark plug opening. Theres really no way to know if you've goten all of them removed though so I would agree the safe bet is to remove the head.
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Wednesday, July 20th, 2011 AT 11:49 PM
Tiny
RIVERMIKERAT
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Yeah, but a magnet wouldn't always get everything. I always pulled the head. It sucks, but it should be done.
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Thursday, July 21st, 2011 AT 6:53 PM

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