Hello everyone! I bought my first Audi, a 98 A4 1.8TM with FWD this fall, and I've been reading this forum since then. I love my A4 and have really been enjoying it.

I have one problem with it though. The previous owner installed an ARP Chip with two programs (stock and 92 octane), a 710N DV, and a boost gauge. I replaced the 710N with an aluminum DV that I bought off ebay. Anyways, the problem is that the car is not making as much boost as it did when I bought it. Switching programs yields no difference in how the car acts or performs.

When I got the car it could make upwards of 16-18 PSI and felt very strong. Now it makes less than 5psi. The other day I got outrun by a GMC Yukon while pushing the car to it's limit. This, my friends, simply will not do.

I have checked and replaced the DV, I checked the resistance of the N75 valve and it was in spec. I have looked over all of the boost hoses for cracks and poor connections and found nothing wrong. I found some worn out vac lines coming off the intake manifold and replaced these, but still no change. Also no check engine light, but I know that some codes don't activate the CEL, so I'm hoping to get a Vag-com cable soon.

Any ideas? advice on what to check next?

My apologies for the long essay, but I wanted to demonstrate that I do have some knowledge and am not someone who is saying "uhh..my car's broke, whut happen?"

Pics.

 

i love that color. do you have a check engine light on? i give you props for actually having a boost gauge, most people ask similar questions with no idea how much boost they are actually making. if something happens that your car doesnt like, to protect itself, it will go into 'limp mode' which limits boost to 5 psi and holds back timing and so forth to prevent more damage. i would go to autozone and check for any codes that might be stored in there. if there are none, then you probably have a leak somewhere. type in 'leak test' or 'tennis ball method' in search.

 

Thanks for the reply! Limp mode is what I'm afraid of, but the autozone scanner came up with no codes. (hence me wanting a Vag-com cable) Would Vag come up with more info that the autozone scanner missed?

I'll look up that tennis ball method, thanks.

 

check around the suction pump. after getting my car chipped i blew a hose right off that suction pump.... its right above the intake manifold.


in this picture is the object with the big #4 on it.

 

Disconnect the battery from the car and let it sit for 10 min. THen hook it back up and turn the ignition to ON but do not start it. Let it sit there for another 5 min (throttle body alignment) then start the car, let it warm up and then see if it's better. If your in limp mode doing this will get you out. If it's still doing it then there is something else going on.

Josh

 

I've tried resetting the ECU multiple times like that, never makes a difference. So it's probably not in limp mode. I'm going to try a leak test this weekend. I'm worried, if I dont find any leaks, does that mean my turbo is bad?

 

Check to see if the ECU fuse is blown. Mine went into limp mode and a scanner didn't come up with anything and even the local Audi dealer didn't know what was wrong, turned out that it was just a fuse.

 

We should get pictures of our Michigan Tech plates together when it's not so crappy looking outside. You staying up here for the summer? I like how you took pictures in the Hardee's parking lot, right?

Furthermore, we should try out my cable again because I have a little different software now that might do the trick. Worst case, in about a week I'll have a copy of AllData (google that, my friend), so at the very least we'll have a better means of getting your car back to normal.

 

Why are your wipers so high up?

Anyway, you should probably do the tennis ball method to find any leaks on the car. What color is the smoke that comes out of the exhaust?

 

what kind of dv did you put in and did the problem occur right after that? Have you gone over all the charge piping to make sure there are no cracks/holes? Definitly do the leak test too and see what you get.