Issues when accelerating hard.

[lemoncurd 0 1 Vehicles]

Hi all,

The last couple of runs I have been having issues with the car under hard acceleration (3rd,4th,5th heavy throttle) - an example situation would be overtaking. The boost kicks in, however at around 3500-4000 revs, the car seems to lose power and judder, almost as if the engine is getting flooded... This is accompanied with a number of backfires from the exhaust... It is literally as if it is coughing! If I back off, I the "coughing" stops. The power loss is enough to prevent making a maneuveur as you seem to lose most of the acceleration.

I have attached a freescan log that I took on my private test track/airfield. Previous forum topics describing symptoms like this mention fuel starvation as a possible cause. On the logs, I notice that around this time there is a BLM cell with a stupidly high value (~140) being used ... would this correspond to that problem?

If so, can anyone suggest what I should be looking at to try and solve this issue... I am an absolute newbie at these things so "Dummies guide" descriptions would be much appreciated!

Thanks,

Ben

freescan.zip

[Dermot 0]

Ben,

Can you email me the file. The server can't deliver downloads.

Dermot

[email protected]

[lemoncurd 0 1 Vehicles]

Ben,

Can you email me the file.  The server can't deliver downloads.

Dermot

[email protected]

<{POST_SNAPBACK}>

You have mail.

Cheers,

Ben

[Jonathan 13]

Oooo would have had a look for you Ben as well but I cannot make head or tale of that file - try and grab it as a CSV if you can, makes viewing a lot easier with MS excel.

There's a multitude of things you can check - have you got the LEW freescan manual....if you're freescanning you need it so you can do your own sensor checks and find out what they mean.

Can you get past the stumble or does it bottle out ?

Does it do the same stuff in neutral or only on load ?

All gears or just high gears (3rd-5th)

Certainly be interesting to see the freescan.

[lemoncurd 0 1 Vehicles]

Oooo would have had a look for you Ben as well but I cannot make head or tale of that file - try and grab it as a CSV if you can, makes viewing a lot easier with MS excel.

There's a multitude of things you can check - have you got the LEW freescan manual....if you're freescanning you need it so you can do your own sensor checks and find out what they mean.

Can you get past the stumble or does it bottle out ?

Does it do the same stuff in neutral or only on load ?

All gears or just high gears (3rd-5th)

Certainly be interesting to see the freescan.

<{POST_SNAPBACK}>

'tis a csv file, but I was having problems getting the forum to accept the file so zipped it up. I think windows should extract the file(warm_080706.txt)... renaming it to .csv will let Excel automatically open it.. otherwise let me know and I will mail you a copy.

Yeah, I have the manual... It was that that made me think the BLM values were out, but I am still getting the hang of things so I am pretty much limited to looking for numbers outside the ranges shown in the manual! B)

Ben

[dodgy 26 1 Vehicles]

just extracted the txt file from the zip and then renamed it .csv , that worked.

that is alot of data to go through!!!! blm seems to double at around 3k when accelerating then drop back when backing off.

been toying with the idea of selling my s3t and buying a se/s4/gt3.

[Dermot 0]

Guys,

Ben sent me the log file directly and I have just had a look over it and sent him a long email. He is welcome to post my reply if he wants.

Dermot

Edited July 9, 2006 by Dermot

[Jonathan 13]

aye - would be helpful incase anyone else has this problem up and coming.

[Pete_Inno 0]

Indeed, would be helpful just to gain knowledge of freescan interpretation.

[JeffYoung 0]

I had the same problem. Turned out to be a slowly dying fuel pump.

[TurboSE-SLO 2]

Hi,

check a fuel pressure. Check also a hose which is going from fuel regulator valve to crankcase breather valve connection.

rgds, B

Hi all,

The last couple of runs I have been having issues with the car under hard acceleration (3rd,4th,5th heavy throttle) - an example situation would be overtaking. The boost kicks in, however at around 3500-4000 revs, the car seems to lose power and judder, almost as if the engine is getting flooded... This is accompanied with a number of backfires from the exhaust... It is literally as if it is coughing! If I back off, I the "coughing" stops. The power loss is enough to prevent making a maneuveur as you seem to lose most of the acceleration.

I have attached a freescan log that I took on my private test track/airfield. Previous forum topics describing symptoms like this mention fuel starvation as a possible cause.  On the logs, I notice that around this time there is a BLM cell with a stupidly high value (~140) being used    ... would this correspond to that problem?

If so, can anyone suggest what I should be looking at to try and solve this issue... I am an absolute newbie at these things so "Dummies guide" descriptions would be much appreciated! 

Thanks,

Ben

<{POST_SNAPBACK}>