2- During acceleration at half throttle the car will over accelerate and it will decelerate again (it feels like almost full throttle and then back to half throttle again).

3- During acceleration from a Stop, the car feels lazy and it jerks and requires more throttle to accelerate.

I have the EVOMS GT640 installed and just installed new MAF and I did the EVOMS Mode that require the installation of the OEM screen before the MAF to avoid frying my 3rd MAF. Many people told me that it is a bad throttle body. But, are these symptoms are the result of the bad throttle only?

Please help

 

First thing you should do is have evoms convert the giac file to evomsit.

 

Thanks for the advice but not very helpfull.

Anyone

 

Give us the information requested in this link

then we can help you.

 

actually its more helpful then you think , he wouldnt have said it if it was not.

 

There is no conversion from EVOMS GT640 to EVOMSit.

There is however an upgrade to EVOMSit GT660.

It's not inexpensive to perform this upgrade as there are other items to swap/install besides the flash...

 

i have an issue with my car and it is not running normal. and you are telling me to upgrade my ECU. are u guys stating that the Gaiac Software is causing the problem. i guss not. i had it for a long time and never had this problem before. something is wrong with the car i just have to confirm it.

 

1. MY 2003

2. Model 996TT

3. Mods: EVOMS GT640

4. Maintenance history
Serviced every 7K Miles

5. Codes
None

6. Current mileage
40K Miles

7. Driving style (street/track)
Every Day Car.

 

So no codes... using what code reader? (you have a backfire and no codes....hmmmm. If you have no codes and you are getting those issues, the first place I would look is at the ECU. Can you re-flash it? When you say serviced every 7000 miles, you mean what exactly? When was the last time you changed the plugs? After that its leaks, MAF, etc. all of which would throw codes.

 

Hey Wross, I know you have heard me say this before BUT the MAF can be bad without throwing a code, No codes on the Durametrics of Porsche Factory tool AND the the MAF was bad. The tech changed it out and prest...problem solved. SO I say try swapping out the maf if you have another one readily available.....It can even be your buddy`s maf out of his turbo as the swap is only 10 minutes. That way you know for sure

 

OP said he just installed new MAF.

 

If you want, you can just pull the MAF completely to do the test....no need to put another one in. I still do not like the idea of randomly (or non-randomly for that matter) pulling components and replacing them especially when the response variable of interest is did the issue go away. This is not scientific. The issue could have gone away as a result of random variation, the act of removing and re-installing the component, re-starting the car, etc. This is no way to conclude the causal nature of the original problem nor the whether the fix was appropriate. You should have logged data on your car with your MAF before and after to see if changing the MAF actually changed anything...to say you changed the MAF and presto... problem solved means nothing.

 

MC Tuner

You are correct that once you have your software installed it will not change, however some hardware parts may wear. It will however try to adapt to changing conditions, which may include anything from ambient conditions to a sensors growing in accuracy. I think that mikerosi 's suggestions is fine, as a failing MAF sometimes presents the symptoms you described and it is an easy thing to test if you have a friend with the same MAF. Before and after logs will give you even more info if you have something to log with. Another thing that can cause this would be a vacuum leak, but it would have to be pretty small not to throw a code. Was there anything that corresponded with the change in the car? An added part? Change in climate? Is this a very recent phenomenon, could you have a bad tank of gas. In these services, do you know if your plugs have been changed in the last 10,000 miles?

On a side note, we have a lot of safeties in place for the DME to react if key parameter values are different than expected. For instance, if based on MAF, assorted temperature, knock activity, pressure, and other inputs your air fuel ratio is not what was requested then the DME will try to correct, but it will also try to protect the motor. The same is true for when the boost is out of range of what the DME has asked for or if their is too much noise detected from the knock sensors. In such cases, our program may lower timing and/or boost, add fuel, and or close the throttle, all of which can make the car surge. If your car behaves like this after running well for a long time with no software or hardware changes, then the idea of a new flash fixing the problem of how the car feels would be achieved by softening or not employing one or some of the a fore mentioned safeties. This is not a solution that we and many other tuners believe in or practice. We always incorporate these safeties for our Porsche Turbo customers and we never desensitize the knock sensors and knock control on these cars either.

Give us a call. 949-724-0014. We may be able to help you trouble shoot, especially if you do have the ability to send over some logs. Also, we have a car here this week with similar if not the same turbos (ramp up, peak boost levels, and wastegate duty cycle are the same) and stock injectors. Looking at it in our facility with our test equipment, we have found a little room for peak power and area under the curve.

 

+1. Been there. Upgraded to 700 with GIAC file, then GAIC file with Hitachi MAF. Still very problematic. Now have GT700 with EVOMSit. You want this. Your stock MAF can only read 480 HP worth of air. Above that it's guess work. Time to move on.

 

Guy turned away good advice; I'll just leave the troubleshooting up to Andrew.