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Low power, low turbo boost 6lbs. ?????

6699 Views 20 Replies 3 Participants Last post by  ajnabi
Just got this 99 beetle, didn't have power when I bought it so I knew that it had some problems. I have put on a tb kit. Cleaned intake, replaced vacuum hoses, turbo vanes seem to function correctly by pushing on actuator while still hooked to turbo. I took the top hose loose n75 there was increasing boost pressure going to turbo. The power when driveing seems to stop at about 2000rpms and does no good to increase rpms above that. I don't know yet what max rpms should be but it only goes to about 3200 rpms. Also car is hard to start, has to crank over several times to start, seems to be worse when it's hot. I do have a scan gauge and the only code I've seen is 1550 ocassionally. I know 1550 has to do with boost. What's the problem????
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2000 rpm max!!! The engine should go to redline.

Some possibilities: bad MAF, clogged fuel filter. http://www.myturbodiesel.com/1000q/multi/low-power-fix-TDI.htm Here is the FAQ article on diagnosis for low power. See if you get stuck anywhere and post a follow up if it's fixed!
Sounds very likely but datalog the MAF sensor if you want to test it instead of buying a new one and hoping that it's the problem. Normally, such a severe power loss is maf, boost, or fuel.
The N75 just controls vac to vnt can, it's controlled by ecu. Does not directly control fueling. You could also increase the boost, will not directly increase fueling.

Fueling is controlled by ECU. If MAF fails in normal fashion the ecu thinks there is little air so why would it overfuel? There are other problems that could cause black smoke from overfueling but a MAF which reads low isn't one of them.
Disconnecting the MAF doesn't bring the car up to normal. It brings it up to a low limp mode power. If it's unchanged or the same, it's probably bad, although if there's a reason why the MAF isn't pulling air in like a clogged exhaust, it will mimic the symtoms of a bad MAF.
Most of the causes are in the FAQ. FYi, I don't know why you didn't get any codes...what code scanner are you using? You said earlier that you know hte cat isn't plugged, how do you know this? Did you disconnect the exhaust upstream of the cat to test for this?
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