Weirdest thing that makes no sense to me

A6 All/ S6 All
#1

Hey guys I have an Audi s6 2007 as you saw in my other topics I was having problems with the electrical and changed high pressure fuel pumps. So today a bizarre thing happened like a miracle I was driving around randomly the car started driving perfectly and smooth with no shake at all for 10 mins and it was amazing I went like what the hell and then after it started to slowly come back but when it did it wasn’t shaking as bad as before. The engine light never came back yet I didn’t start the car engine to check yet.

The engine light codes were p3299 p1087 p1083 until they disappeared
Does anyone have any insight on this?

#2

There has always been an urban legend that audis can just fix themselves! Though some problems on a few of my audis over the years have in fact fixed themselves (noises mostly), it is 1% / 99% and rarely happens

Your issues sounds like an electrical problem with a loose wire or ground. You could try running ground resistance tests on your engine harness and see if you can locate a bad ground somewhere. My .02

#3

I changed the entire harness lmao and every o2 sensor I’m thinking it has to do with the fuel pump the thing is whining way to loud I can hear it outside the car

#4

I’ll check all the grounds again but I’m thinking it’s the fuel pump it was the longest running theory and I have one to swap it out with. I’m going to change it and hopefully that works if not I’m just eliminating it from my list

#5

With battery disconnected, run ground resistance on the chassis ground in the engine bay all the way back to the ground on the battery to get an average baseline. Then run test from chassis ground to a few locations on the harness in the engine bay, at the fust box inside the car, and might as well check resistance at the fuel pump if your going to be pulling up the bench anyway.

I’m guessing you put that large 4 gauge ground strap back on the block on the passenger side or I doubt it would run well ever

Iirc this car has two fuel pumps right? How did you plan to test them?

1 Like
#6

I changed that damn fuel pump and it made the car run way better it was smooth during the day but as it got colder it started a little shake but nothing bad as before and the fuel pump is way quieter before the shit was loud

#7

I’ll try to mess with checking the resistance tomorrow since my automotive class made me buy a $500 fluke so I might as well put it to good use

#8

Fluke is the only way to go. You’ll have it forever. Sounds like your in my industry…

Congrats on the fuel pump. Did it change any warmup lumpy idle stuff?

#9

Yeah it really did the car starts faster and way louder and the idle is way smoother and I have so much more power when I’m driving

#10

I’m thinking of changing the jet suction pump or whatever that thing is called that isn’t the main fuel pump in the tank

#11

Hmm

Do you have the before and after of the fuel pump psi etc?

Is there a way for us to tell if we have weak pumps?

Maybe after 130k is time for new pumps but dont like to pay and replace un necessarily

#12

I never checked the pressure after but before I remember it staying at 35 and jumping down to 32 and when I was accelerating it was dropping to 27 before it kicks back in and goes up to 45 and so on after but slowly after it started staying at 27 idle which it got lower from 35 and I also kept getting these rich codes.

I don’t know how the pressure is supposed to be but that’s what it kept doing it was just dropping when I was accelerating to a certain point before the pressure went up and high. I think the idle changing from 35 to 27 made it more obvious

The most obvious factor was how loud the fuel pump was whining and I heard it outside the car all the time just normally running which isn’t normal at all from what I was told and now with this one the pump is silent with faster and smoother starts I can easily accelerate so much faster

#13

By the way my car is about to hit 80k and it seems like a Murphy law with how early the pump went

#14

Oh yea if your hearing it then hands down its gotta go. Glad to hear you improved it. Should be enjoyable to hoon now

#15

I’m still getting bank 3 too rich and idle shakes at random when it wants to. Bank 4 hasn’t came back. What do you think?

#16

What is this jet pump you soeak of? I just ordered a new pump for my S6 c6. Also did you use oem pump?