Rs4 won't rev.

B6/7 S4/RS4
#1

OK guys I need some input here. As I’m sure most of you know I’ve been having an issue with my car not going to redline. I have no idea what could be causing this issue. I have replaced every sensor that could potentially limit rpm. I re Flashed the car last night and no change.

The car shuts down at 7500 rpm and not the same way as when u hit the Rev limiter. There is no bounce it just shuts the fuel right off. Other than this issue the car runs amazing and pulls like a freight train. Shifting at 7500 I still ran 11s with wicked trap speeds so the car is performing.

My thoughts are now to the ecus themselves but before I go buy those expensive fucks I was wondering if anyone has ever heard of any car doing this. Or does anyone have an idea I haven’t thought of or something I should try?

#2

I can’t remember what thread exactly I was reading, but a guy was having the same problem and it ended up being a relay located underneath the ECU.

#3

can you remember anything about the thread that I could maybe search? if you could help me find it I would be ever so greatful.

unless of course u were reading my build thread and saw that I had replaced the component supply relay under the ecu and my mechanic had thought he fixed it. he swore up and down that the car was reving to 8500 however when I got in it it did not.

#4

I haven’t read all your posts but how old are the fuel pumps and fuel filter?

#5

Fuel pumps show perfect flow on vcds. My fuel filter I changed when I bought it. Could maybe use a change.

#6

Just throwing my $.02 in here, but I have a hard time wrapping my head around it being ECUs… I mean, both of them going “bad” after a high RPM?? Could someone walk me through the logic of why an ECU (from a hardware perspective) would properly run a motor up to a given RPM, then fall off…

Just spit-balling:

Re-flash the ECUs
Crank position sensor
Fuel pump relay

Emphasis on the last one.

#7

I did a reflash and no change. And I believe it is something fuel related. When the car hits 7500 the fuel just shuts off and u almost eat the windshield. It’s hard to diagnose without a code and no one ever having the issue before. But most definitely fuel is being cut for some reason.

#8

Any rev limit is going to be cutting the fuel. For some reason the car seems like its turning on one of the protection lower revlimits. have you logged the car to get the exact rev limit cut off

#9

Does the car rev past 7500 when in neutral? Or does it still cut power then or is only when driving.

Is it 7500 in every gear?

#10

If he answers or tests it to answer I will be stunned.

#11

LOL you dont think he will test it. Those are some good points to test. That will be good information to know

#12

I don’t know the history, but it seems that you are correct.

#13

indeed. Too easy.

#14

Any logs yet or did you get this fixed. I keep checking in because Im really interested to hear what it is.

#15

see post 9

#16

lol

#17

Did you ever figure out and resolved this issue Badtoyz?

#18

Im sure he will jump and explain more. I heard he fixed the issue. I was seeing if he posted more about it