#10 fuse is blowing 2002 1.8T GLI

[OhioBuckeyeBeetle]

Background:
Nov. 24, '08 #1 coil needs replaced. Done on Nov. 25,'08
Dec. 1, '08 #3 coil needs replaced. Replaced #3,#4 & #2 coils and plugs on Dec. 3, '08.

Dec. 28, '08 drive 70 miles on a dry day to a friends, go to leave and bug cranks but won't start. Tow to local VW dealer. Next day dealers says mis-fire code on #1 & #4 and blown #10 fuse, they want to replace all the coils and fuse. Also, found water (not coolent) in a spark plug hole. I call mechanic who installed coils and he doesn't buy that the coils are bad or that after a 70 mile trip on a dry day there is any water in the spark plug hole. He wants to see the car ASAP. Call dealer back and they replaced the #10 fuse and car runs fine but they really want those coils replaced. Get the car back to mechanic and he says nothing is wrong witht he coils but after 2 test drives the #10 fuse blew again. He could not fine the reason the fuse blew and replaces the #10 15 Amp fuse with a 20 Amp fuse. Says some time on older VW those mini fuse will blow and one size up will take care of problem but if the 20 Amp fuse goes bring it back.

My mechanic is a long time friend and one of the best foreign car guys in the business in this area but I'm not thrilled with the upsizing of a fuse.

Go to my Bently Publication VW Beetle book. But there I find another problem. My 2002 1.8T GLI with a AWV engine (this has been verified by the owners manual and looking at the stampling on the engine) and the Bentley book do not agree. No where in the engine control wire diagrams (for the AWV) is the #10 fuse shown but on another 1.8T engine wire diagram there is a #10 fuse. Where the #10 fuse is located in the other engine wire diagram the AWV wire diagram indicates fuse #37 but further on in the Bentley book fuse #37 also fuses the Monsoon radio. Also find the the #10 & #37 mini fuses should be 10 Amp fuses.

Problem:
I'm not happy with a 20 Amp fuse in 10 Amp fuse location. Still don't know why the fuse is blowing in the first place. And the wiring diagrams in Bentley are no help.

Clearly the #10 fuse is in the control wiring for the Coils and fuel injectors.

Sorry so long winded but I wanted to provide as much of the picture as possible.

Questions:
Has anyone had a similar issue with the AWV engine & #10 fuse and what was the solution?
Are the Bentley Publication wire diagrams wrong?

[NBTurboFreak]

Originally Posted by OhioBuckeyeBeetle

Problem:
I'm not happy with a 20 Amp fuse in 10 Amp fuse location. Still don't know why the fuse is blowing in the first place. And the wiring diagrams in Bentley are no help.

Clearly the #10 fuse is in the control wiring for the Coils and fuel injectors.

Sorry so long winded but I wanted to provide as much of the picture as possible.

Questions:
Has anyone had a similar issue with the AWV engine & #10 fuse and what was the solution?
Are the Bentley Publication wire diagrams wrong?

I would not be happy with a 15A fuse in a 10A spot. You have to remember that wire is expensive so the manf will go with the smallest suitable wire they can. So if the circuit is constantly running higher than 10A then there is a chance something in line later will overheat or melt, something has a short to cause the higher amp draw.

My AWV has not had this issue. If you can get a hold of a VAG-COM and monitor the voltage blocks for the coilpacks and see if any are have large differences in the values compared to the others. (sorry, don't remember the block number off hand) If any are way higher or lower in value then the rest I would recommend replacing just those. As far as the water in the holes, not sure but it is never good.

So far I have not found my Bentley manual to be wrong on the wiring.

Hope it helps or gives you some ideas.

[OhioBuckeyeBeetle]

Typo on title, "GLX" not GLI.

Agree, putting a bigger fuse then design is a bad solution that does not address the issue, hence the reason for the posting. My mechanic have never steared me wrong in 15 years of taking various cars to him and his personnal vehicals have alway been VW's. I trust this guy, he worked on this bug for 3 hours to find and solve this fuse issue but didn't charge me a dime because he didn't find anything. This guy though is a mechanic and business man (he owns his repair busness) he is honest to a fault. Yes, hard to believe but it's true and that why if I can't fix a car problem I go to him but in this case I'm willing to hear more thoughts.

Really also want to know about the Bentley Publishers wire diagrams for the AWV engine not illustrating the #10 fuse but indicating that fuse #37 is shown in the engine control schematic and the Monsoon schematic.