arrowhead_vtec

hey guys, need some feedback here. i ran out of ideas as to what is the source of my jerking problem.

scenario : cruising on the highway, suddenly my engine jerks (feels like a stuck throttle, suddenly released). then it ends there. it'll probably happen again sometime soon but as of today, there's no indication on what causes it to jerk. perhaps it kinda feels like not enough petrol getting to the engine.

scenario 2 : cruising again, lets say i'm at 30% throttle... suddenly there's like to response from the accel paddle (even though i'm actually pressing it down more gradually). then like after 2 seconds, the car just suddenly lurches forward (jerk)....

could the two above be related? anyhow i use to have this jerking problem and i knew how to make it happen... found out it was some crappy "mugen" chip i used... i changed/swap the following and i'm not on that chip anymore..

i) map sensor
ii) tps sensor
iii) plug cables
iv) spark plugs
v) distributor
iv) fuel pump
vii) fuel relay
viii) ecu

currently running on hondata s300 in an attempt to datalog the whole damn process, didn't really have much time, but i've managed a 30 minute recording but nothing happened...

any input guys? its frustrating... =(

Hondatherdm

my guess tps or accel pedal cable, try swaping good known TB

arrowhead_vtec

alright, ran thru my datalog with my foremen. this is what we noticed...

ignition should go up along with tps (throttle) yes? meaning to say, more throttle more ignition.... however, i managed to record a particular moment (i believe it was when my car jerked, as per scenario 2) the TPS was ever increasing, but my ignition went from 30 to 21. it stayed at 21 for like 2 seconds (tps still increasing) then suddenly the ignition jumps to like 38...

so my question is, what can cause insufficient ignition aside from distributor, spark plugs and plug cables?

Corksil

hmm, you say this only happens when the moon is blue?

could have something to do with an increased gravitational pull on the motor from a direction it is not designed to handle. like the tides changing or something. need more info, do you live by the ocean? perhaps if you drove with a girl on her period when the moon was blue, the chaotic energy fields between her and the moon would balance out the gravity and fix your motor. plz experiment and post back.

on a more serious note, check distributor, cap, and rotor. If you have enough money to have hondata in that b!tch, be sure to replace all the ignition components. H3ll, i even recommend a new distributor.

but i still think it has more to do with gravitational fields and blue moons.

arrowhead_vtec

hahahaha!

ok on a serious note, it does happen on a daily basis now... every day when i drive around it'll happen at least once...

will re-try to replace ignition related parts (distributor, spark plugs, plug cables). am i missing anything else?

Reyracer19

The girl on the rag...

Vindicator9000

I know everything points to ignition related problems, but I'd still recommending yanking your throttle body and cleaning it up good. It's free and easy, and might fix your problem.

I've had similar random bucking/lurching problems before, and they went away after I scrubbed out the TB really good with carb cleaner and a toothbrush.

MrExclusive

I know a friend who had the same issue just more severe. In his case he had some crazy vacuum leaks everywhere. In your case you probably just have a slight one???

arrowhead_vtec

alright. i shall clean my throttle body as well!

vacuum leaks, wouldn't my idle be sky high? my idles fine though..

mooze

not all the time i have vacuum leaks on my h23a and it idles just as perfect. had jerking prob before cause by icm going bad once and loose button another time

bakomack

I had a similar situation. b16 in an eg hatch. sometimes would be cruising and then would get like a stumble, it would only last a few moments. in those few moments it would happen thou I would gradually give it more gas to compensate for the descreasing speed then out of no where the car would lurch foward.

found out my reverse wires from the tranny were grounding out against the trans causing my stumble.

check for shorts or wires grounding out in your engine bay where head and time could have broken the coating off some wires and their touching

arrowhead_vtec

bakomack : your problem sounds like mine, i'll give it a check.

as for now, i disabled the launch control function on my s300 (assuming its the cause, which may not be).

reason being, i set it at 4k rpm, i notice my "jerk" comes in near 4k rpm... maybe.. just maybe its the cause.

i have a friend, who actually got his launch control pre-set at 2k rpm, and his car jerked at 2k rpm... removed it, no jerking anymore.

*fingers crossed*

sde780

mine did this and smoked, it was my rings going

but only after decel in gear down a hill

Hanmin

I have the same problem, but it recently got worst. I got lucky and actually got a cel, code 3, map. I switched out the map sensor, and it was a ll good until recently, it'll bog like crazy, the cel would turn on, then burn extremely rich. I'll let you know if I get the problem fixed.

arrowhead_vtec

as mentioned, i disabled the launch control function on my s300. so far so good, no jerking YET... but fingers are still crossed.

arrowhead_vtec

ok update. 2 days of casual driving.. no jerking so far... probably it was cause by the launch control function. i think i need to mail hondata to report this issue.

thanks guys. much appreciated.

chewyv

awsome! you launch WHILE you drive!

arrowhead_vtec

especially when u dont want it!

anyway, i'll put a switch, to activate the launch control function... xD

arrowhead_vtec

ok.. dammit.... it is back.... i know how to activate it now....

i mailed hondata regarding this issue, they told me to check my tps sensor, it should not read anywhere below -3% (was it % or degrees, cant recall) on minimum. well initially mine was -5. adjusted it to somewhere around -1/0. car drove well for few days...

its back again.. dammit.

it happens when i release the accel, then accel again, it jerks there. its as though when i accel - it doesnt register that i am accel-ing...

paopao

Post your timing map.

D Griff

I had a really similar problem, I replaced my whole throttle body with a brand new one, had no vacuum leaks, or ground issues. It ended up being an ecu problem. I'm more or less stock though, stock (P2P?) ecu on my D16.

paopao

Which makes sense. Not all engines operate the same, which is why ECU control is one of the best modifications you can do.

Since every engine is different, one program for all engines is not ideal. Some of the stock timing maps are funky and just need some smoothing out; and sometimes people mess with them too much without checking smoothness in 2D.

arrowhead_vtec

will post my map in abit... kinda busy