Hey guys, I have a quick question. I daily drive my turbo FC and everytime i start it after its been sitting for a couple hours or what not the idle bounces between 700-900 rpms, makes a brap brap brap brap sound and the engine shakes pretty noticeably. I dont believe its ported and when i let it warm up for a little and drive it it usually stops bouncing and idles at about 800-900RPMS and doesnt shake.

Also when im driving it sometimes and i approach a red light and let it idle itll kinda bog and go down to about 600 rpms then go back if i give it a little gas. There has also been times when i floor it and the car will bog in 4th gear and act as though the fuel cut off, then go back to normal. Im totally confused and have no idea what to do. PLease help me out guys, i hate sitting in a shakey *** car.

my mods are Haltech E8 standalone, all the haltech sensors. stock s5 turbo motor and turbo. s5 remanufacted injectors. supra fuel pump.

Id also like to mention, the shop that tuned my car made a relay for my car because i relocated the battery to one of the bins, i find when i start the car the voltage is at 9-10 and when i rev it up the voltage will go up to about 14v. Idk if this has anythign to do with the idle and bogging, it was kind of a shotty job and i thought id let you guys know.

thanks
-mitch

 

tps maybe? idk random guess i know my NA needs a new one and does something similar

 

yea check tps adlustment but i dont know about a haltech also look into a fuel pump rewire if u dont have it done already
check fuel filter also look for fuel leaks near lower rail around fpd fuel pulsation dampner

 

The car needs to be tuned properly.

There is a bin in the cold start enrichment that is too lean.

The accelerator pump settings are probably too rich.

Decel cut may be too aggressive and your idle too lean. Or there are a series of bins to the left of your idle that are too lean.

Putting the battery in the bins isn't an issue as long as thick cable (at least 4 AWG) is used. I don't know what you mean by "made a relay". It sounds like the connector at the back of the alternator may be disconnected or missing.

 

alright thanks, yeah i think it may be running to lean, everytime i leave it running more than 10 seconds in my shop at work everyone bitches that it smells like pure gasoline is bveing dumped out of my exhaust.

sweet so i paid 500 dollars for a shitty tune.... good to hear

 

Who tuned it? I better damn well have a smooth running car after 500 dollars worth of tuning.

 

rotary reliabilty and racing tuned it. they're stationed out of santa ana california. Yhea he said 500$ to get it tuned to the best it could run no matter how long it took, otherwise its 140$ an hour or something, i dont really remember the rates, so i went with the best way of tuning as any intelligent person would and it looks like i got screwed. shibby.. what should i do? drive it back and say wtf is this and tell him everything or what?

 

That would indicate it is way too rich. Do you have any kind of AFR display in the car?

I know people who have paid a lot more for truly terrible tunes. I've corrected a few cars that have had thousands poured into the tunes from very well known tuners. They ran so poorly on the expensive tune that I would not consider them drivable.

I'd hate for you to run into a shop and start screaming at them because of this thread. Keep in mind that cold start is something it takes a while to tune just right. You only really have one chance per day to tune cold start and it will change every time the main fuel map is tweaked (with most ECUs). It is absolutely not unusual for a car tuned by a "rent a tuner" to still display horrible cold start issues. It just takes more then one tuning session to get right.

The accelerator pump is another one of those. It takes some street driving in various conditions and at various loads to get the acell pumps just right. Same with transitions to and off of idle. Most "rent a tuners" spend their time tuning on the dyno in boost, where it is hard to tune for drivability.

 

My car does this at times, it wasn't the fuel filter. new fuel pump. It could most likely be the tps. Try some electronic cleaner, that seemed to help. I do still have an exhaust leak. I think it's the timing.

 

alright ill take all your info and go into the shop and ask some Q's, maybe hell hook it up. thanks guys