Power issues continue after new MAF

[CoriBug]

I discussed this in another thread.

For the past 10 days - 2 weeks, Daisy has been having power issues. She was having trouble exiting the underground garage I park in (going from a dead stop up a steep hill), accelerating at all speeds, etc. I suspected the MAF since it had never been replaced. My mechanic thought the same so I bought one at the dealer and he replaced it for me Monday. Since then the power has improved and she can exit the garage better but still has problems accelerating as I go through the gears. She actually maxed out at 60mph in 4th gear on the highway!!!

Stuff I know needs looked at/replaced:
1. Battery is 5 1/2 years old and was barely passing the test 6 months ago so I can imagine it's ready to go
2. Glow plugs on cylinders 3 and 4 - since those darn things tend to be weird I'm thinking maybe they are bad plugs or maybe it's the relay or harness? They are almost brand new since they were replaced recently because of the recall.

Thoughts please! I want my turbo power back!

[just4fun]

hey I am having the same problem I hope some one has some idea I have read on here that you may have to reflash the computer to get it to reconize the maf not sure that is reliable since no one had replied to that post

[CoriBug]

I can't imagine that my mechanic would forget that detail since he usually remembers important stuff like that. He is rather anal when it comes to anything car related. I can call him Monday morning though.

[DZLBUG]

Battery and glow plugs will not cause any low power symptoms. Glow plugs are a cold weather starting aid only and do not affect engine performance.

When was the fuel filter changed last? Any hard or long starts? I suspect this is a fuel related issue, either dirty fuel filter or a bad lift pump. The stock lift pumps do tend to fail after awhile.

Other ideas:
Air filter?
Snow screen?

If none of these things are the problem, I would have your mechanic run some logs with VCDS to see if there are any boost issues going on. MAF requested/actual and MAP requested/actual should all be logged and charted.

[CoriBug]

Fuel filter has about 12,000 miles on it and I run very good quality B20 all the time. She's been starting GREAT - even in below freezing temps after not running for 6+ hours. Great mileage too.

Pump - maybe.
Air filter - my mechanic cleaned it off when he replaced the coolant sensor. It actually looked pretty good before he used the compressed air on it.
Snow screen - maybe

He did hook it up to the computer and it said "low boost". He didn't run any actual numbers though.

Thanks! I will call him Monday...again. I should have his number on speed dial.

[CoriBug]

Just checking...the lift pump is the same as the fuel pump? That was replaced around 5000 miles because of a recall.

[DZLBUG]

Air filter - when the airbox gets opened the filter element should ALWAYS be replaced. The seals on them are only designed to seal once and they will leak if the filter doesnt get replaced. Not your problem now but it should be changed.

Snow screen - clean it.

Fuel filter - wouldn't hurt to change it.

Lift pump - it is the low pressure fuel pump in the tank, it supplies fuel through the fuel filter to the tandem pump which is the high pressure pump that feeds the injectors. I believe that the tandem pump was the recalled item.

Was it a boost deviation negative code? I would check all the boost piping connections, particularly at the turbo outlet and at the intake manifold connection. You may need a "doggie collar." There are other causes of low boost, but I am unfamiliar with the causes on these engines since they have a different actuator system.

[CoriBug]

Air filter - will check on that
Snow screen - ditto
fuel filter - I don't think that's my problem because the 1st one lasted over 45k miles before I realized it had never been replaced (Doh!) B20 has been my main fuel and I even use the same pump every time.
lift pump - yes you are correct, it was the tandem pump that was recalled. so that could definitely be a possibility.

I hate it when my car acts up. Just like the kid I nanny for!

[CoriBug]

NOT a random question....is it true that part numbers get an "X" at the end if the part is remanufactured? Yes this is related to this thread.

I will also check on that boost code.

[Growler]

yes, remanufactured parts have an X designation after the normal part number.

the boost system in the PDs works very similiar to the ALH, it onlyhas an electric sensor fro feedback.

some good boost logs and MAF logs would def help in diagnosing the issue.

If you can get access to VCDS and get some logging done, I would be happy to take a look at the logs for you.

you want a good 3rd or 4th gear pull from 1800rpm to 4500 rpm all in one shot do not hold the rpms in any range, just accelerate.

log group 3 and group 11 at the same time.

def check the boost pipe connection, especially at the intake manifold as these are problematic like DZLBUG mentioned.

the Doggie collar mod is available from JasonTDi in Wisconsin, and for more money from the kermatdi website. pick one

Aaron

[CoriBug]

Hi Aaron. Thanks for your help. Jeff I forgot to thank you too I really appreciate it.

I left the garage a couple hours ago and my poor car couldn't make it up the ramp! I had to back up and get a running start!

I believe that the dealer sold me a remanufactured MAF sensor. Even if the new one is working properly, I'm a little upset that I didn't get a new one.

Since it's Saturday, I can't do anything about the situation until Monday so hopefully I'll know more then.

[The Cheat]

i am leaning towards the lift pump. low boost alone wouldn't cause it to not exceed 60mph. case in point: dad's tdi had a failing turbo and clogged cat (could be that too, disconnecting the dp off the turbo allowed it to boost again), it could still hit 85mph easily even with the clogged cat and 4psi.

is there a way to check the duty cycle of the injectors like in a gas car? never had to in my 05...

maybe the ecu is dialing back the boost to compensate for low fuel.

[CoriBug]

So the lift pump can have problems intermittently? I have acceleration problems at all speeds and gears but then she'll be okay for awhile. No problems with idle and the cold weather doesn't seem to make it worse.

[just4fun]

try unpluging the maf i did this today and what a diffence it made I have my power back.

I had it to the dealer today to reset the radio ( i didnt have the code) and they asked why the maf was unhooked so I told them I had one on the way.

I ordered the one from Marquette Automotive for $ 105 cant wait for it to arrive.
you got nothing to lose by unhooking. at least you'll know if its the maf or not. if you look at the maf? post there is a link to it

[The Cheat]

cori has already replaced her maf sensor, i HIGHLY doubt that is the core issue.

however, a while back, we had another member who described the same symptoms (albeit worse), and her lift pump went bad.

[CoriBug]

Since the MAF is not a new one I thought maybe there is something wrong with it. If it is functioning properly, the lift pump sounds like it's the problem.

[CoriBug]

Problem solved. The solenoid valve was kaput. That was one of the possibilities from TDI Club. Mechanic replaced it and now she's much better. No CEL but the computer was saying a negative deviation.

[Growler]

this was the N75? white topped vacuum solenoid?

good catch.. that thing is hard to diagnose.

[CoriBug]

yes that was the problem. He drove her 3 times on the highway and had no issues and my mom drove her home and all was normal so I think she is back to her old self.

[CoriBug]

I am thrilled that my baby is healthy again! The real test was going up the ramp to leave my garage. After work, I entered the garage then turned around and left again. NO PROBLEM! Yay! I love my mechanic!