Fooboy

Hi from the land downunder!

I have recently had my engine rebuilt and got a little porting done at the same time. Not sure what you guys would call it, but the intake ports were made taller by about 0.5-1 cm and the exhaust ports just cleaned up.

I was told that this would run fine with the standard computer and my only other mods are DP, High flow cat and cat back exhaust (3 inch all the way).

Since the rebuild I have had an intermitant problem while cruising or on light acceleration below 3500rpm. (and no this is not the 3000prm hesitation it is a totally different feeling). The car will be cruising fine at a constant speed and then it will suddenly start sputtering and jerking. Sometimes it is just gentle othertimes it literally throws you around. The solution is to take my foot of the accerator or put my foot down and accelerate hard.

It also does this when accelerating lightly and will hiccup unless I really put my foot down. I also notice that the idle will hunt up and down between 1500 rpm and 800rpm for a little at traffic lights.

WOT is fine and the car boosts well and feels strong.

The other symptom is that the 17 error code comes up on the ECU. (that is o2 sensor one)

So far this is what I have ruled out as possible causes.
- Vacuum hoses as all of these were replaced as part of the rebuild.
- O2 sensor as I changed to a brand new one
- TPS sensor, voltages were tested at stand still and while driving and came within spec. Also voltage didn't do anything funny when car was playing up
- Spark plugs as I changed those 500km ago

Anyway what has this to do with my original question? Do you think the porting may be throwing the standard ECU out and causing the problems (even though they don't happen all the time). Should I be going for an aftermarket computer or should the standard computer handle the porting?

So do people run ports with the standard ECU?

Sorry for the long post and thanks for your help.

BoostedRex

I was running a large street port with the standard ECU and had no problems like the one that you described. I don't think it's because of your ports. May wanna start chekcing elsewhere. Just my .02 though.

Zach

boostedrotor

i ran like that for a little bit, with basically same mods plus a couple like flywheel, mp, & ignition, then i dropped in a rp ecu for all the mods + a m2 large and realized what the extra money for the streetport was for.....but my car still idles like *** and will bounce around @ a stoplight, it is rich as hell, but runs fine on the gas, i too get the bucking around when i gently accelerate, i was gonna try the o2 sensor, most likley still will.. .....i am going with the aem standalone in a couple of weeks and hopefully this will solve my idle problems.....