Lei Siew Long

I have a problem with violent jerking with my car when I'm cruising and the car is under vacuum. The problem is intermittent and mainly happens when I'm driving long distance 90+ miles or so, or when I'm driving the car really hard under boost and as soon as it under vacuum a little after boosting, the car would jerk violently and uncontrollably.

Mods: Built and sleeved LS engine, Bosch 550 cc injectors, t3/t4 turbo, intercooler, AEM fuel rail, upgraded fuel lines, SARD fpr, Tial wastegate, cam gears, 3.00" exhaust, Bosch intank fuel pump, MSD 6AL, MSD blaster 2 coil, Hondata 2B, 3 BAR map sensor, Apexi AVC-R....

Fuel, electrical or ignition problem?

Lei Siew Long

i know someone has experience the same, or a problem very similar.

bigjangin

does it happen right after you let off the throttle? I had the same problem and it turned out to be a boost leak. Check for leaks, it cant hurt and odds are that you have a few, even if that isnt the problem.

Lei Siew Long

how would i check for boost leaks? also, it happens when i run the car extremely hard or during long distance trips at cruise the whole trip.

rjardy

a boost leak will not cause a violent jerking like you described. What fuel management are you using?


Rob

rjardy

okay sorry you have hondata, its probably in your tune. Ar you running lean when it happens?

Lei Siew Long

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rjardy &raquo;</TD></TR><TR><TD CLASS="quote">okay sorry you have hondata, its probably in your tune. Ar you running lean when it happens?</TD></TR></TABLE>

unfortunately, I don't have a wideband in the car and don't know if it is leaning out. hopefully, that isn't the case.

i believe the problem could be caused by these parts (feel free to correct me if i'm wrong):

-distributor

-3 BAR map sensor

-MSD external coil

-MSD 6AL

-ignitor

-injectors

-fuel pump

-FPR

tylerteg

i was having the same problem and ran a diagnostics for the check engine light.. Turned up being an 02 senser problem. I looked under the car and found that one of my sensor wires was ripped in half, so i twisted it together and it fixed the problem

Lei Siew Long

that is the thing that is frustrating, no CEL at all.

raene

My guess is definitely O2 sensor problem. I had a similar problem, only surfaced after long trips. Turned out the longterm fuel correction factors has changed to a point that the car was running so lean it was misfiring. Fixed the O2 sensor problem and never had an issue since.

Lei Siew Long

is there a way i can test the 02 to see if it is actually the culprit before i fork out the $180-200 for the sensor?

thanks

Lei Siew Long

annnnnybooooody??