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Discussion Starter · #1 ·
2002 1.8 T... I filled the fuel tank with regular ( I see that it should be premium now) but it has burned a 1/4 tank in 15 miles? Something majorly wrong. Going to check out air filter tomorrow but thinking an O2 sensor? Any thoughts?
 

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Discussion Starter · #5 ·
Did you fill you tank completely? Is this a new car for you? Once the needle starts to move it can float around quite a bit.

Is your check engine light on?
Yes, filled it completely. Yes, new car to us. I have thought about the needle floating a bit like my Toyota. But any way the car is positioned, it reads the same. I've only driven it to the auto parts store twice and the needle doesn't float when driving but 1/4 tank gone? Am going to check many things tomorrow but thinking I'll replace the air cleaner, MAF sensor and O
2 sensor to make sure all is good. The guy who had it before me didn't change the oil, I did that yesterday and replaced the broken dipstick tube and dipstick. Had to add brake fluid. It was really low and the brake light was on. But it's a pain to get to so he probably just shrugged it off like a bonehead. The coolant was really low as well. But at least the turbo has been replaced, the timing belt was done and the alternator too. But I suspect the battery is going to need replacing as it slowly cranks to start but after running, it cranks up fine. Or there is a constant draw somewhere. Fun..... NOT..
 

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Here’s my story on fixing my daughters beetle, some catchup maintenance and clutch replacement after she’d had it about a year.

 

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I would check for trouble codes and a quick way to confirm the fuel delievery “tune” status is the fuel trims, + or ~ 10% being considered in the “normal range”, outside of that you have a out of spec rich or lean condition, requiring diagnosis, to find out why. This can point in the direction of vacuum leaks or a defective maf sensor;, etc the maf functionality, can-be tested using live data at idle and wot in 2nd gear. This would require a scan tool; a vw specific scanner is preferred (vcds, obdeleven, vag, etc) but even a cheap ELM 327 obd II , plugin, wireless scanner/dongle,off of Amazon and a app like obdfusion or dash command on a phone or tablet can work as well, give you the live data you need to see (like fuel trim, maf readings).



Parts like mafs, fuel pumps, 02 sensors and other parts can get expensive fast, rather then throw parts at the problem, confirm they are bad before replacing them.

The fact that a new turbocharger has been replaced and timing belt/water-pump has been done; is really great! Both of those jobs, cost thousands of dollars to do, in parts/labor; both are common repairs at this point, in the the life of the 1.8T.

If crucial parts are in need of replacement; stick with quality oem parts:

Maf and 02 sensors: genuine Bosch only.
Spark plugs: NGK
Fuel pumps: Bosch or VDO
FCPeuro is a great online supplier of high quality oem parts and offers a lifetime warranty; on everything they sell, if you can wait for shipping.

1.8T’s can be a bit finicky and after 15-20 years of neglect; a wide range of parts can be in need of replacement (fuel delievery, ignition, etc) and boost control systems, boost leaks, are common issues, degrading performance, fuel economy (n75, diverter valve, vacuum pump, pcv, hoses, etc). We see many parts that are “tired” or in “soft” failure mode; e.g. working but not to their needed top condition, that make the engine run at its normal tune levels and responsiveness, fuel economy, etc.

The state of tune, tends to degrade over time and the computer; can compensate for this but things can end up, where the 1.8T is not running as well as it should (no fun).

Don’t get too discouraged if the 1.8T doesn’t seem to be running well at this stage; keep in mind, it may take a number of diagnostic cycles, attempts and bad parts replacements; testing, re-checking, after new parts installs and confirmations, then repeating these diagnostic sessions, until things finally start performing well. At that point; driving your 1.8T New Beetle; will really be more enjoyable, addicting! :)

It can be surprised how well these 1.8T engines run; when they are tuned up and functioning correctly, in particular the boost systems are usually not right, making the 1.8T seems sluggish, not as responsive as they should be. It is very satisfying; taking a sluggishly running 1.8T and getting it tuned up, running in top form! :)

My 1.8T gas mileage, performance improvements; in my quest in getting things running well were tired or worn parts like: fuel pump, filter, fuel pressure regulator, leaking fuel injector seals/cups, spark plugs, maf sensor, 02 sensor, coolant temp sensor, n75, boost hoses/leaks, etc. All these parts contribute to fuel trims and the over all efficiency,, performance of the engine.

Owning, maintaining and fixing. a turbo charged vw engine, like the 1.8T; is definitely a learning process, curve and if you diy things, you tend to become your own “expert” in keeping them running in top condition.

When running right; they can be lots of fun to drive and have room for performance improvements. Get it running right first and go from there.
 

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Discussion Starter · #9 ·
I would check for trouble codes and a quick way to confirm the fuel delievery “tune” status is the fuel trims, + or ~ 10% being considered in the “normal range”, outside of that you have a out of spec rich or lean condition, requiring diagnosis, to find out why. This can point in the direction of vacuum leaks or a defective maf sensor;, etc the maf functionality, can-be tested using live data at idle and wot in 2nd gear. This would require a scan tool; a vw specific scanner is preferred (vcds, obdeleven, vag, etc) but even a cheap ELM 327 obd II , plugin, wireless scanner/dongle,off of Amazon and a app like obdfusion or dash command on a phone or tablet can work as well, give you the live data you need to see (like fuel trim, maf readings).



Parts like mafs, fuel pumps, 02 sensors and other parts can get expensive fast, rather then throw parts at the problem, confirm they are bad before replacing them.

The fact that a new turbocharger has been replaced and timing belt/water-pump has been done; is really great! Both of those jobs, cost thousands of dollars to do, in parts/labor; both are common repairs at this point, in the the life of the 1.8T.

If crucial parts are in need of replacement; stick with quality oem parts:

Maf and 02 sensors: genuine Bosch only.
Spark plugs: NGK
Fuel pumps: Bosch or VDO
FCPeuro is a great online supplier of high quality oem parts and offers a lifetime warranty; on everything they sell, if you can wait for shipping.

1.8T’s can be a bit finicky and after 15-20 years of neglect; a wide range of parts can be in need of replacement (fuel delievery, ignition, etc) and boost control systems, boost leaks, are common issues, degrading performance, fuel economy (n75, diverter valve, vacuum pump, pcv, hoses, etc). We see many parts that are “tired” or in “soft” failure mode; e.g. working but not to their needed top condition, that make the engine run at its normal tune levels and responsiveness, fuel economy, etc.

The state of tune, tends to degrade over time and the computer; can compensate for this but things can end up, where the 1.8T is not running as well as it should (no fun).

Don’t get too discouraged if the 1.8T doesn’t seem to be running well at this stage; keep in mind, it may take a number of diagnostic cycles, attempts and bad parts replacements; testing, re-checking, after new parts installs and confirmations, then repeating these diagnostic sessions, until things finally start performing well. At that point; driving your 1.8T New Beetle; will really be more enjoyable, addicting! :)

It can be surprised how well these 1.8T engines run; when they are tuned up and functioning correctly, in particular the boost systems are usually not right, making the 1.8T seems sluggish, not as responsive as they should be. It is very satisfying; taking a sluggishly running 1.8T and getting it tuned up, running in top form! :)

My 1.8T gas mileage, performance improvements; in my quest in getting things running well were tired or worn parts like: fuel pump, filter, fuel pressure regulator, leaking fuel injector seals/cups, spark plugs, maf sensor, 02 sensor, coolant temp sensor, n75, boost hoses/leaks, etc. All these parts contribute to fuel trims and the over all efficiency,, performance of the engine.

Owning, maintaining and fixing. a turbo charged vw engine, like the 1.8T; is definitely a learning process, curve and if you diy things, you tend to become your own “expert” in keeping them running in top condition.

When running right; they can be lots of fun to drive and have room for performance improvements. Get it running right first and go from there.
Thank You for all of this info! Much appreciated! This forum has some great, knowledgeable people. I learn more every day. Cheers.
 

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Any particular brands that are better than others? I see a couple that run about 150 bucks. Launch CRP123 on sale for 150 on sale. Usually 175 on Amazon
Launch and these other brands will not do what VCDS does. I have a Launch 129 and I wouldn't even think of hooking it to my VW's and trying to get any useful information from it.

 

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Generic OB2 is better than nothing and beats having to go to an Autostore. Mine was a Bosch for $25 or so. Beyond these, just get the real deal. Kid you not, this AM I fixed our bug by clearing a set of codes that put the car in limp mode. 3rd or 4th time it paid for itself. Not a shill or other BS just happy camper.
 

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If you want a interim solution a elm 327 and a obd II app, is handy to keep in the car, be able to view data pids, live data, read basic codes on your smart phone or tablet..

I have genuine Ross tech vcds cable and a Wi-Fi ELM 327 dongle, paired with apps like dash command, obdfusion, running on my iPhone, both have their place.

 

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Yes, filled it completely. Yes, new car to us. I have thought about the needle floating a bit like my Toyota. But any way the car is positioned, it reads the same. I've only driven it to the auto parts store twice and the needle doesn't float when driving but 1/4 tank gone? Am going to check many things tomorrow but thinking I'll replace the air cleaner, MAF sensor and O
2 sensor to make sure all is good. The guy who had it before me didn't change the oil, I did that yesterday and replaced the broken dipstick tube and dipstick. Had to add brake fluid. It was really low and the brake light was on. But it's a pain to get to so he probably just shrugged it off like a bonehead. The coolant was really low as well. But at least the turbo has been replaced, the timing belt was done and the alternator too. But I suspect the battery is going to need replacing as it slowly cranks to start but after running, it cranks up fine. Or there is a constant draw somewhere. Fun..... NOT..
 
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