F355 sometimes runs better than other times

My F355 is a 95 with Hyperflows. GruppeM intake and Challenge chip from a Challenge car. There are times when the acceleration from any gear is fantastic. Just touch the throttle and the car accellerates with terrific power in any gear at any rpm. Other times it seems not to be as responisive.When it is very responsive the throttle seems to be very smooth. I know about the sticky throttle. It is not a matter that when the throttle seems smoother that it is easier to press the pedal. It seems like something else. Could it be fuel pump, throttle position sensor, timing not advancing as well as other times, bypass? The car always runs great, it just seemss at times it is so much more respsonsive than other times.

 

Where do you acquire one of these?

 

I got it 3-4 years ago form a guy who was running a challenge car in New York. He had an extra chip and I bought it. Really improved the car and is much faster than other F355's that I have driven.

 

You can have the ECU reflashed to perform as a CH chip, I believe

 

How many "chips" did you buy? You should have gotten 2.

The 1995 2.7 ECUs (plural) use a removable chip. You remove the chip and burn a new one and reinstall the new chip. "Flashing" implies reprogramming the ECU memory through a port, which is for 96-99.


Jay

 

The 95 has a chip in each computer. You replace the chip instead of burning a new one. It is removable and easy to replace.

 

I'm kind of guessing this has been discussed before so forgive me. It seems I could purchase blank chips and program the chips myself with the right equipment. Am I correct? But where would I get the CH program?

It seems like it could be a cost effective upgrade in power... That is as long as you don't need race fuel to drive it!

 

Powerchip charges what....like $2K?

 

Dosnt look like your question is getting answered but you would have no trouble selling your ch chip(s) Have you tried rebooting your 2.7 motronics? Make sure you have your car fully warmed up and then turn it off. Turn the electrical power off under the front hood right side for 20minutes. After 20 minutes, start the car and dont touch the throttle and have everything turned off. Let it run for a little more than 10 minutes. During that time the motronic is rememorizing all the faults and corrects itself. This will not effect your chip as my car has one too. This is just one of the many benifits of owning a 95. The Challenge chip is amazing. My car is faster than a 360 no problem.

 

According to the WSM all that is effected by rebooting is the resetting of the idle parameters. Is this not true?

 

No that is not true.....I reset my(95) 2 to 3 times a summer and it runs totaly different.

 

Does anybody know of a good source of a battery disconnect switch to disconnect the battery? Mine is in the rear and a pain to get to. Griot's sells one, but it is for the negative terminal, would that work in resetting the ECUs? I have CEL on and off that I'm trying to figure out....

 

As I have said before there is no such thing as a challenge chip at least not from ferrari. All the ECUs for 355ch are the same as the road car versions.
All the cars have seals on each of ECUs and they were checked at every race to verify no one tampered with the "stock" ECUs. In fact the boxes from one car would be switched to another car running in the race so there would be no advantage to try to mod the ECUs. ie; you would be helping your competitors

 

Talk to No Doubt. He has done some work with the 2.7 348 chips, I believe.

 

Where do I find the Challange Chip...I have a need for more speed.

 

The "learned" fuel/air maps and error codes are erased on reboot of the M2.7; you go back to the fixed fuel/air tables.

 

Llenroc has spoken the truth and this fantasy about some super chip for the CH is not reality. If you want verification then pull this supposed CH chip and copy the data to your PC....now do the same with the street car version 2.7 chip.....Now compare the 2 programs and see if there is in fact a difference.

This is the ONLY way to resolve this never ending debate once and for all.

 

I think the challenge chip that I have was made by one of the teams in NY. The guy was a winner of the series one year. They developed the chip for the car after the series was over and used it for track work. They called it a challlenge chip because it was on a Challenge car. I can't speek for availablity of a "Challenge chip".

 

I'm like to try your rebooting, but I have a stupid question. I'm just an owner trying to learn a little more about my car, so please forgive my ignorance in this matter.
FIRST: Is the electrical switch under the front hood the round dial...and
SECOND: after the 20 minute rest-period and before you start the car again for the 10 minute restart, do you turn the power switch back on or do you leave it off? Sorry, I don't even know if the car will run with the switch in the off mode. I've read so many nightmares about our 355's that I'm afraid to try anything that might send it back to the shop without asking first.
Thanks for your help.

 

Recalibrating the computer as was said, did the trick. The car runs consistant and throttle is instant. Thanks