I purchased my 99.5 a4 b5 wrecked. It was hit in the driver side. So far I have spent quite a bit of money on a "mechanically sound" car.

Yes this car starts up every time, drives smooth, and gets me to and from work 60 mile round trip every day. But this car is not right. In fact it is far from right.

I drove several bone stock a4 18t's prior to purchasing this one. They all were fairly peepy. Nice acceleration, smooth shifting etc.

Long story short, what sold me on this car was the extensive service history prior to the accident. The trans has been rebuilt or replaced by Audi dealership, ABS pump replaced. New tires, new alternator etc.. The car started and ran great when I purchased it and drove it home.

I took it out to my body shop and it was there from April this year till this month. It was a long expensive ordeal but I finally have my A4 B5. But I get in it to drive it home and... CEL on, no power and while running the AC the car will hardly get out of its own way.

I immediately took the car to my mechanic, who knows apparently everything about GM 3100 and 3400's but nothing about Audis. He checked it out and said the turbo is spooling but it is weak.

After extensive research on here and other forums and while still sourcing misc. parts like fog lights, lower grills etc. I decided that I may not be able to repair this car. I have read so many Limp mode posts that don’t ever seem to get resolved. Cars only making 5psi boost etc. I am DISHEARTENED to say the least.

Here is what I know. The a4 b5 Quattro 1.8t (auto tiptronic) has a CEL, it is a MAF code, clearing the code and it immediately comes back on. The maf is new and has been tested. The turbo has no shaft play, and the car does not smoke. Sometimes the car feels like its coming to life and then it just drops off. Also sometimes it has what seems to be a hard time shifting out of 3rd and 4th gear. It acts like its holding them out too long, but is still drivable.

I don’t know what a DV is or an n75 or other terms used on here. I haven’t tested the waste gate, that I have read is an extremely common failure. I know the battery has died on this car several times while setting at the body shop and not having doors. Don’t know if the TB was ever re aligned.

I have sank SOO much money in this car repairing the body, I don’t want to get rid of it but I can’t afford to open a can of worms with this engine that I don’t understand. I have almost pulled the trigger at replacing the turbo, but my gut tells me that a clean turbo, with no shaft play and the car not smoking, the turbo is possibly fine, that the computer is not allowing the psi made to make it to the engine.

There is also a long tube running off the top of the intake box down by the heat shield that is not connected to anything. I am not sure what this is or if it should be connected so I will take a pucture of it.

Someone please help me... I can take all kinds of pictures and have mechanically ability, just no Audi knowledge.

 

Good move not replacing the turbo right away. You always want to start with the cheap stuff and work your way up to the big stuff so you don't waste money on **** you don't need.

Since you mentioned big GM diesels and your waste gate I'll assume you're familiar with turbos. The N75 is a solenoid controlled by your ECU that acts as an electronic boost controller. It controls when the waste gate opens to regulate the flow of exhaust gas over the turbine wheel thus controlling the amount of boost you make.

DV stands for diverter valve, which you can think of kind of like a vacuum operated waste gate for intake air. When you take your foot off the throttle, the turbo is still spinning it's little *** off creating boost. But since you took your foot off the gas, the throttle body is all or partly closed, trapping the excess boost in your intake plumbing. When the throttle body closes and creates a vacuum in the intake manifold, the DV opens allowing the excess boost to escape--either back into the turbo inlet, or out into the atmosphere depending on your set up.

Anyway, on to your car. Is the shifting behavior you're seeing worse when the car is warm or cold? I don't know much about automatic transmissions but it doesn't sound like a mechanical problem to me, especially because the trans is relatively new.

As for that tube that isn't connected to anything, can you take a picture of it and post it up? Everything connected to the air box should be connected to something else.

 

Thanks for the reply. I am planning on taking pictures this afternoon when I get off work.

Somthing I found this morning. I cleared the Maf code before I left for work and the car ran fantastic.

At lunch I went out and started it and the CEL came back. Same MAF code and it had no power. Cleared the code and back to a almost normal car. It runs much better (as long as the code is cleared and the scanner is hooked up) but It seems to be throwing the code on start, without the scanner. Generic OBD2 scanner....

Also, I understand this car is AWD and a 4cyl. So I dont expect to stomp the peddle and it throw you back in your seat.

 

I know you said that the MAF is new and was tested, but everything you keep saying points to a bad MAF. Try unplugging it and going for a ride. You'll still have a CEL from it being unplugged, but if it's bad the car will run better without it.

 

Thanks again for the reply. I actually think that you figured it out.

Check these out...









So I think the Maf was unplugged. But I still dont know where the pipe / hose goes...

Thanks

 

Yeah that hose in your hand is part of the evap system. That is DEFINITELY not OEM. That system of check valves and tubes helps burn gasoline vapor vented from your fuel tank. The bit in your hand is supposed to be routed back into the turbo inlet. Mine is more or less set up properly right now if you'd like me to take some pics for ya.

 

Thank you CCA4! I think I found the spot that evap tube goes into. There is a hole directly in front of the turbo inlet on the intake rubber.

This car drives quite nice again. I am still going to pull the battery cables and re learn the TB. But as of right now no limp mode and no cel.

I think next is a new set of head lamps a chipped ecu and try to find the fogs and front valance still missing.

Any suggestions were to try to find these. Audi wants a small fortune for these bits.

 

Where are you located? The best way to clear CEL's and do TB alignments is with Vag-Com or a VAG-specifc scanner, I've got both.

As for headlights, I would recommend these. The projectors will allow you to run HID lights for WAY better light output. The front valence and fogs are going to be expensive no matter where you get them, so your best bet there would be a part out or junk yard.

 

Im near Dayton Ohio. I will definitely go with a 1 piece headlight with projector and HID bulbs / ballast, as that is what the car has stock (w/amber corners).

But I really like the look of the newer audi with the LED eyebrows... There are several pictures of B5's on ebay that show these headlamp housings, but the listings are for bodykits not headlamps lol.....

I am going to go scrapping sometime soon and try to find the lower valaince and at least the driver fog, and lower grills.

 

and.... CCA4 I sent you a pm.. can you check that out?