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Discussion Starter · #1 ·
Hi all, almost got this little bug sorted. Since I got it for her the CEL has been on and its throwing codes P0172 and P1128. The exhaust smells extremely rich, and I cleaned the MAF. Please point me in the right direction on this thing. I don't want to go slinging parts at it because there's a big list of whta it could be, from a leaking injector to a bad o2 sensor.
 

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Discussion Starter · #3 ·
Thanks man. I have no idea what is causing this. That's a huge list to just start throwing parts at the thing
 

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what sort of scan tool; do you have access to and can it read live data? If it does; what are the fuel trim levels?

Here are some links that should help:

trim levels:

https://www.google.com/search?q=ros...:en-US:official&client=firefox-a&channel=fflb

maf testing:

https://www.google.com/search?q=ros...vw+maf+testing&rls=org.mozilla:en-US:official

One test; I would want to get out of the way and rule out; is your fuel pressure, test it and see if it is in spec.

Please fill out your profile info (year, model, engine, trans, etc.); right hand side after "join date", that way we can help you intelligently in the future. thanks!
 

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Well, if you are going to keep the car and attempt repairs yourself, i recommend getting a vw compatible code reader/scan tool at the bare minimum (look on amazon.com for the Vgate VS450 for $50) or go all the way to a factory level scan tool like VCDS by Ross Tech.

As it is; you could rent/borrow some tools, like the fuel pressure test kit, from most auto parts stores and multimeters are cheap from places, like harbor freight ($10-$20 for a basic one), auto parts or home improvement store.

Many of the links; require advanced scan tools to diagnose things but many tests can be done with a multimeter or fuel pressure tester (both not expensive; possibly rent-able).

Diagnosing and troubleshooting; is a process of elimination, it helps to test things and keep going down the list, until you find the problem.... testing requires tools and they save you money in the long run (test, confirm with hard cold facts and proceed with repairs, based on those facts).
 

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Meanwhile, you could go rent a fuel pressure tester and rule that out and get a multimeter and start testing things like the 02 sensors and the maf. Go old school on the possible vacuum leaks and spray around the different hoses and see if it affects the engine rpm's and you might pinpoint some leaks. Needless, to say; access to VCDS or a basic vw code reader would be helpful but many testing, troubleshooting procedures can be done without them.
 

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Discussion Starter · #9 ·
Seriously appreciate all the help you've given me, if it's ok to bother you with just a couple more questions, if I may? What is the nominal fuel pressure I'm looking for, and will it be apparent if an injector is leaking? This one is turning out to be an ugly little demon. Like I know the P0411 in my Jetta is the AIR valve vac line pinched, and you know the single fault codes are easy. One thing that really bothers me is the possibility of camshaft timing. I assume that not only is the timing belt a JOB in these cars, but also that if I elected to have someone else deal with it for me its gonna cost me big. But, it doesn't seem to have a miss or act like it has slipped time. It's by no means sluggish, and as I said it runs on all 4. But I'm leaning toward mostly oxygen sensor or leaking injector because as I said the thing just smells rich while its running. It seems to be getting sorta poor gas mileage as well.
 

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Here are the fuel pressure specs and pressure testing procedures:

Fuel Pressure: Pressure, Vacuum and Temperature Specifications Specified Value: 3.5 to 5.0 bar: converted psi: 50 to 72 psi.

Volkswagen Workshop Manuals > Beetle L4-2.0L (AEG) (2000) > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pressure > System Information > Specifications > Pressure, Vacuum and Temperature Specifications

Walk through the steps/procedures and it will go through a process of elimination and test/verify; the fuel pressure regulator, the fuel injectors and the fuel pump. Note: make sure to test residual pressure; how long and if the pressure is maintained, when the engine is turned off.


As for the timing belt job; it is very doable as a diy at home in the driveway or garage type of job. How many miles are on the car and when was the last timing belt replacement done? Tell us about your mechanical skills and experience, if this is your first time... it would be a good idea to have a experienced buddy along for the ride, to look over your shoulder. The kits aren't tool expensive and you can save allot of money that way.

The "enhanced plus" blauparts timing belt kit; comes with everything you need, including the specific vw coolant (they even include a diy "manual" for the job).

free shipping and 10% off; for first time customers:

https://www.blauparts.com/proddetail.asp?prod=GH21100-1B
 

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Discussion Starter · #11 ·
I've never done a timing belt before, but I've been working on cars since I was about 15 or so. Kinda got burned out for a long time after dealing with nothing but the rotary from 16-23, and kept up with maintenance only. As for this timing belt its a 170k mile car, and I got no clue if it was ever changed. Surely it had to have been though right? The problem is none of my friends will work on cars. They just never had the resources to buy tools or whatever. Being a 2000 I would bet a dollar its an AEG, and that I believe is interference. So I definitely want to check it. 2.0 should live a 300k mile life as long as I keep up the maintenance on it from what I understand about the engine. I just changed the oil over to full syn and it hasn't leaked a drop, and doesn't burn any. Guess I can rule out overfilled oil on that list as well, because I know it has exactly the right amount.
 

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Discussion Starter · #13 ·
Hey Billymade seriously thank you so much for all your help with this. That timing belt kit is definitely the one I'll be ordering if upon inspection I see cracks or too much slack. lets just hope I dont find something shocking lol.
 

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Well, if you don't know the history of the car and with that many miles, I would recommend replacing it regardless (with a interference engine; it is a ticking time bomb!). Unless, you have documentation it has been done recently! For example; I just replaced the waterpump and timing belt on my car; the timing belt looked fine by my waterpump, was almost totally SIEZED! If I had waited much longer; the waterpump would have self destructed and I would have lost my 1.8iT head, with bent valves! The kit is dirt cheap; compared, to a whole head job! Do it ASAP! :)
 
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