cre8tunes2

after pushing the car a couple times it sarts to jerk after awhile.
when driving normal it starts to jerk between 1,500 to 3,000 RPM. can anyone help me

thank you

chris_si98

is it a hard jerk? or more of a bog?

cre8tunes2

it's a hard jerk

imported_weiRtech

do you have a boost gauge? are you getting a boost spike? is your turbo internally gated or external? could be a spring problem possibly, or maybe a vacuum issue. what is it tuned with?

cre8tunes2

i think its internal my brother tried opening up the waste gate. something to do with more pressure being released or something like that. here's what we were wondering could it be the map sensor???

1sloweg

your giving us about as much information as a tree stump. Understand how the system works, then try to fix it.

What does the boost gauge do when you give it.....
What map sensor are you running.....
What are you tuning with.....
Motor.....
Turbo....

Now as your questions with the above answered and maybe I will be able to bestow some knowledge upon thee.

WankelWanker

definately sounds like a wastegate issue...with my old 2 rotor, she was bogging like mad...couldn't get her over 110 km/h...thought it was a cat problem but, the valve to the waste gate remained open so I had to change it out and all was fine.

imported_FlashPoint-Matt

You need to first figure out what your boost is upto, secondly, are you getting a CEL while this is happening, and thirdly what engine management setup are you running?

If you cannot answer these questions it may be best to take your car to a professional for analysis.

cre8tunes2

yea my brother the licenced mechanic is doing it. boost is at 7 pounds. stock computer with a blox racing fuel managment unit 12:1 Ratio.

imported_weiRtech

fmu

chris_si98

im with aaron

zeeman

iTrader: (1)

ya, i've seen cars with FMU's do funky things. I don' t know why some kits offer this as a solution for more fuel.
I've heard that raising the fuel pressure (which FMU's do, a certain amount per psi of boost) decreases the efficiency of your fuel pump (on a stock one at least).
Get a chipped ecu and bigger injectors, then get some tuning done. It sounds like a tuning issue to me, like the injectors are heating up from being pushed then acting up afterwards or something. Like i said i've taken a few FMU's off in favour of bigger injectors and a crome tuned, custom chip.
In stock form the map sensor can't see boost, you are probably using a missing link (or map sensor bypass, which basically bleeds the boost off before the MAP sees it), and the FMU ups the fuel pressure when boost hits, which is a super crude method of getting more fuel. But anywho, chip your ecu and enable boost in the program and the stock map sensor can see 11 almost 12psi of boost.

cre8tunes2

hey man thanks alot my brother actaully realised that it is a tuning issue i appreaciate all of your help and i hope to see you at one of the meets before they're over. thanks again