laybradley6

So I have a 2000 Audi A4 Quattro 1.8T and here is the problem i'm having.

The car starts fine, the injectors are fine, (no MISFIRES) I tightened all the hoses down, clamps, etc. I have not used a compressor to do a boost leak test (tho i'm going to soon), I spray'd the hoses with a mixture of windex around the intake/turbo hoses to see if the car would bog at all maybe there was a leak, tho as i stated before still haven't done the compressor test. Anyways the car runs like it is gutless when I start it up, and it runs a little better threw out the day, but the main problem i'm having with the car is when it goes to boost it dumps it, I mean it will boost for literatly like 1000 rpm's while accelerating from 1500 to 2200 and then it's gone and I gradually get up to what ever speed i'm trying to get to, extremely slowly after that. Then sometimes out of know where it would boost like it should but only in first gear as soon as i shift out it goes back to the gutless thing again. I know my expectations aren't high because I have felt the true power and want it. I was going to do a boost leak test with compressor, replace the MAF sensor, and see if the waste gate was getting stuck open because it's internal on this car and I hear that the internal waste gates that were made for this year of car was very poorly made. Any input from you guys? Let me know please, and i'll tell you what happens as well.

gsjohal

Hi, a couple of things you could try. First try unplugging the air mass meter connector and see if this makes a difference. Drive the car with it unplugged. The ecu will revert to a default air mass quantity so if it drives ok then the air mass meter was calculating incorrectly. These are quite common.
Secondly check all the vacuum hoses onto the turbo and solenoid valve for splits and wear. These can only be done properly from underneath. Hope thus helps.

laybradley6

So i did that and the car drives the same either way. My guess is its bad, already got it with maf sensor cleaner. Should i get a new website unplug the negative cable on battery, install ire etc? Orrrrr

Prospeeder

Sounds alot like overboost. What happens is the ECU will see overboost and then go into a limp mode and no boost. If you turn the engine off and back on it will try to boost again untill it sees overboost then bam it stops boosting and is in limp mode.

Bad solenoid, bad wastegate diaphragm or stuck wastegate.

gsjohal

Another possibility is the boost pressure sensor, miscalculating the charge pressure being generated. Check the connector/pins and may be try cleaning/replacing the sensor.

laybradley6

Thanks for the reply's. Where is this solenoid located on the car? Sorry but i'm just not sure where you are referring to on the car. Also if I unplug my MAF and it runs the same as it did with the MAF plugged in i'm guessing that's not good either lol. I've put so much time into getting this car running right i'm not going to stop now I am 100% open to opinions on what route to take first etc.

1. How do I test the waste gate (my plan is to remove it and hook an air compressor up to it and also check the inside of the manifold to see if maybe there is a break of some sort), by this I mean what kind of signs to look for when testing it? Also I hear that the internal waste gate on this year/model of audi is known for it breaking on the inside of the manifold.

2. Would love to know where the solenoid is located because the only solenoid I personally know of is on the starter but i'm sure there is more on the car and I know that this one probably has to do with the intake system on the car, are you maybe referring to a solenoid that controls my waste gate orrrrrr?

Honestly I'm pretty savvy when it comes to working on the car, but this is the first turboed car i've owned. Thanks for the reply again I REALLY appreciate it.

gsjohal

You could connect a hand held vac gun onto the vacuum unit on the turbo and check for a full and smooth movement of the waste gate linkage. The vac unit should also hold pressure and not drop off, if it does drop off, it's leaking internally.
If you follow the vac pipe from the turbo back, it will lead you to the solenoid valve.