Huge stutter under load...Help!

[Mel-D]

Also if you have a VTA BOV. Stalling and low idle can be a common occurance with vent to atmoshpere BOV's in cars running mass airflow meters this has been mentioned in my research on different forums. Just something I remembered reading.

 

[M0R81U5]

Cheers for the suggestions Mel
I've replaced the intercooler and all piping since I've had this problem and it hasn't had any effect on it. I've since re-checked all piping a few times to make triple sure there were no dodgy connections.

The car has no problems with idle or starting, everything is completely normal until I hit 5000 revs under a decent load. The only reason I still have the car is because I can just cruise around normally

I'm also running the standard BOV too.

 

[Mel-D]

Cheers for the suggestions Mel
I've replaced the intercooler and all piping since I've had this problem and it hasn't had any effect on it. I've since re-checked all piping a few times to make triple sure there were no dodgy connections.

The car has no problems with idle or starting, everything is completely normal until I hit 5000 revs under a decent load. The only reason I still have the car is because I can just cruise around normally

I'm also running the standard BOV too.

Could be a leak from the vacume canister. See Kats post For Pic http://ozvr4.com/forums/showthread.php?8140-Wierd-Issue&p=146875

 

[marc.r]

i think i have this problem too. not as severe though. hesitates and seems to cut out then keep going again at around 5k revs but then it picks up and keeps reving... few more stutters but will reach 7k. seems like it is hitting imaginary rev limits then continuing on.

 

[TME_Steve]

Marc yours sounds like our normal ignition problems with spark blow out

Micks car hits some form of an airflow limit, with a stock map we get to about 5k and it leans out instantly (like a fuel cut) and then we dropped in a tuned map and it runs to about 3500RPM and then severely hit the limit. My gues would be that this is the same airflow as we were running much more power with the tuned map so it seems to be a power/airflow limit of sort (no it's not a boost cut). So next we are thinking to try another ECU then it will be looking at the wiring from the MAF meter, it's like the analogue out signal gets to say 3V and then the signal degrades to zero.

I wasn't logging airflow but I would guarentee it's at excatly the same airflow point that it always occurs. And it leans out instantly from about 10.5:1 on a stock map to instantly 20-25:1 (meaning close to zero fuel)

 

[fieldy107]

This problem first happened to me straight after being flash tuned, so I think your probably on the money Steve. The problem would have already been there, but as soon as the car is tuned and running more power, the problem rears its head(probably hitting that power/airflow limit with the tune). Keep up the investigation, sure you will figure it out soon.

 

[TME_Steve]

We'll solve it but we keep having holidays and missing each other, Mick is away now then I go away when he gets back....

 

[TomTom]

Oh dear... sounds like I've the same issue!

Leads & plugs are less than 10k km installed, double & triple checked all piping... no leaks on the turbo, guess I try the MAF sensor first and I'll check the coil packs next week during my 5000km service.

My fuel consumption went from 12l/100km to 14l/100km!

Unlike Micks car, mine is not doing this constantly, some days it works... some days it could be me in this youtube video Mick posted! DAMN

 

[TomTom]

I think I fixed my problem! Looks like the snorkel was the reason that the car couldn't breath! Took the snorkel off this morning, booted it a couple of times today... no issues what so ever.

Tokyo Motorsports will check my MAF sensor anyway to make sure a faulty MAF sensor can be ruled out.

 

[godzilla]

Might have already mentioned it but is your filter clean, Tom?

Sounds odd that your airbox is not getting enough air through the snorkel.

 

[TomTom]

Might have already mentioned it but is your filter clean, Tom?

Sounds odd that your airbox is not getting enough air through the snorkel.

Thats due to aftermarket bonnet & bumper... I was always wondering where it is getting the air from hehe (the foam around it is squashed)

Ralliart filter is clean and only installed for about 2000-3000km.

Time for an ARC cold air intake ;-)

 

[M0R81U5]

Thats good news Tom
I haven't had a snorkel on my airbox for about 18 months now, so it's not that simple for me unfortunately.

Chris, my car had this problem when it was dead stock too, so it's not a power increase or reflash that's brought it about. Steve has been flashing the ECU to try and solve it adn so far, no flash has stopped it completely.

I'll put the call out there now, if anyone has a spare 7202 or a spare hour or so to swap ECUs with me to test, I'd greatly appreciate it. I'm around the inner west, but am more than happy to travel to solve this.

The only other thing I can think of if I can rule out the ECU is the fuel pump. I want to throw a fuel pressure gauge on and see what happens when it leans out.

 

[TME_Steve]

ECU then wiring from MAF are my bets, I'm almost certain it isnt a fuel pump but yeah get a gauge on there to rule it and any other fuel issue out. It's too instantaneous for me for a fuel pump Could be a blockage in the fuel line related to flow too

 

[Scottie]

What about the IFS Sensor? It is located on top of the front cam cover.

 

[M0R81U5]

I'm with you Steve, but for a little effort, I can rule it out. I've just had a generous offer from Dave (qball) to trial his spare ECU, so hopefully I'll have a definitive answer on the ECU by the end of the week.

IFS sensor hey, Scottie...tell me more...

 

[Scottie]

IFS = Ignition Fail Sensor.

As far as i can remember it is mostly to blame for the Tacho playing up. But i think i recall Athid having ignition issues before replacing this thing.

Worth a shot. Would only take 5 mins to try someone else's.

 

[AKKO]

Time for an ARC cold air intake ;-)

Going cheap cheap...
http://www.importmonster.com.au/vie...oroparts-thumb-1296799488501168.jpg&title=ARC

 

[jungle]

Off topic- Tomtom, is that your Leggy in your signature??

 

[Fully]

Off topic- Tomtom, is that your Leggy in your signature??

Yep
The Silver Arrow - its pretty sexy http://ozvr4.com/forums/showthread.php?4951-Tom-s-Silver-Arrow-Legnum-VR-4

Have you guys checked all your pipe work and clamps? Like no pin hole or pinching of the pipes to cause a small leak?

 

[M0R81U5]

Yeah, as I've said earlier in the thread, I've changed the I/C and all piping previously and it made no difference to this problem. It's also been on and off a few times for servicing etc so I make sure I double check it each time I put it back on.

Dave's spare ECU was a no-goer, so my plead is still out there for someone to help a brother out with an ECU swap......please?