Possibly large problem?

[MattL]

Ok here's the thing...

Car cold, not much driving... this doesn't happen... after being on for a while this happens.

Normal driving fine.
Planting the foot a little fine
Maintaining WOT... car sounds like it's hitting rev limiter at 5000rpm and shuddering like crazy.

Trying to figure what could be causing this. I'm stumped as where to even start...

Any help on this would be good, otherwise, I'm booking it into the mechanics!

 

[BMGTZ]

Ok here's the thing...

Car cold, not much driving... this doesn't happen... after being on for a while this happens.

Normal driving fine.
Planting the foot a little fine
Maintaining WOT... car sounds like it's hitting rev limiter at 5000rpm and shuddering like crazy.

Trying to figure what could be causing this. I'm stumped as where to even start...

Any help on this would be good, otherwise, I'm booking it into the mechanics!

my first guess would be plugs/leads or second guess boost leaks. next guess......throttle position sensor is dicky

 

[Rockabilly]

Maintaining WOT... car sounds like it's hitting rev limiter at 5000rpm and shuddering like crazy.

Matt if you mean sitting still & reving it, Miodrag put launch stutter on your chip I think.
Cheers !

 

[MattL]

BMGTZ - plugs were only just replaced 2000km ago
As for boost leaks, That was my thought too... but being that it was dark it made it hard to check.
As for TPS, that shouldn't be an issue.. but it's something I will need to check

Rockabilly - Nope, driving under full boost.


Funny thing is, I can be loaded up at 14PSI and not have a problem until I'm WOT

 

[mattrat]

id say ecu related maybe, your speedo still working?

 

[MattL]

Turns out my ECU tune has a stutterbox added into the tune and due to the speedo cable being snapped... the ECU reads speed/rolling from the Dash Cluster...

What that means is that the car is limiting at 4500rpm on the highway...and the reason I thought it was boost related was that when I go WOT the revs jump up enough..

Time to get a new cable!!

Thanks though guys!

 

[BMGTZ]

Turns out my ECU tune has a stutterbox added into the tune and due to the speedo cable being snapped... the ECU reads speed/rolling from the Dash Cluster...

What that means is that the car is limiting at 4500rpm on the highway...and the reason I thought it was boost related was that when I go WOT the revs jump up enough..

Time to get a new cable!!

Thanks though guys!

No way I would have thought of that....glad you found it

 

[MattL]

Yeah Rockabilly was on the money when he said it, I was just confused and didnt think it was Revs related at the time!

 

[Rockabilly]

A fault on other people's cars sometimes teaches us things we/I didn't know !
I knew if you are stopped, stutter box will work, but not that the speedo cluster is related to trigger the ecu.
Matt extra brake lights appearing at zero speed might be easier to trigger than I thought !
Cheers !

 

[MattL]

A fault on other people's cars sometimes teaches us things we/I didn't know !
I knew if you are stopped, stutter box will work, but not that the speedo cluster is related to trigger the ecu.
Matt extra brake lights appearing at zero speed might be easier to trigger than I thought !
Cheers !

Tapping into the Relay is one thing... but making it work when stopped might be another.
Time for you and Miodrag to get into doing it

 

[mattrat]

ahh just as i thought, the old speedo cable

 

[vr401]

Just drive with stock chip until you change the cable.

 

[MattL]

Just drive with stock chip until you change the cable.

Unlikely! I'll just drive manually. I don't really need to be over 4000rpm so it's not really too much of an issue!