supersilverdc2

hello!

I am running an lsvtec turbo 81mm bore (all stock bottom)

just a little 300hp street friendly grocery gitter...

question... car starts fine, idles normal untill warm....

I have replaced the entire throttle body with a known working one

I have replaced the dizzy from a known working one...

problem disapeared for about 3 months... now its back...

I have cleaned IACV many times and replaced that too....

I HAD the voltage checked 3 months ago on the TPS, it was said to be good from the Tuner....

Now I woke up today to go to work, the car idled fine... as soon as it warms up and i shift it into first, it wants to die, so i give more gas... in traffic its a bitch, it jerks and seems like its overall performance just sucks....

this is a brand new build....

seems to be running a little more rich and the idle sounds like a subaru when it gets hot....

NO CEL!!! i threw a TPS once.... but under suspicion I looked and the plug was loose, I tightened it and it went away...

any thoughts?

Subaru IDle / jerking on low accel near 1500-2000 RPMS.....

replaced dizzy during tune 3 months ago because last one would POP at high RPM not able to handle good spark .... (dizzy from attarco off b20 OEM)

DDTECH

tuned..?

supersilverdc2

of course!

using chrome.

it ran like a champ, then all of a sudden this issue.... then it went away for a good month.... now its back and not going away

DDTECH

Sounds like a Chip issue, get a new SST chip and reburn ur map, see if that changes anything.

Turbo-LS

iTrader: (4)

X2 had a similar issue with a customers car and new chip corrected it.

supersilverdc2

any reliable dealers to you can reccomend to cali?

supersilverdc2

goddamit, i decided to change fuel filter AGAIN, and now its better.. i poured out the gas and it was clear.... then i tapped the hell out of it... and black **** everywhere...

supersilverdc2

welll, no.... nope not fixed.... it was kewl for about 100 miles.... but now its back at it.... almost as if there is a fuel restriction ... i have to give a little extra gas before 2K rpms in order for it to hit the motor is what it feels like..., it idles great, then randomly it will feel like its choking and its almost as if the ECU sees it, then it over compensates for gas , goes up to 12oo , evens out idle, then back down to 900 and starts the cycle all over again,

supersilverdc2

the walbro 255 has been in there for about... 2-3 years, maybe its time for a new one?

supersilverdc2

i have had thiss issue FOREVER

wantboost

iTrader: (2)

Subaru idle normally means a broken ringland on one or more cylinders

Only way to verify that is to do a compression test. You'll know immediately because compression will be nonexistent

To check the tps you need to measure voltage with the throttle closed and wide open and check this against the service manual to make sure the values are within range and adjust if needed

Normally a distributor problem would present all the time and affect top end performance (breaking up, stuttering, etc) what plugs are you using? How old and what gap, same for the wires. Might try taking the cap off and checking it for wear and corrosion on the pickups inside the cap, also check the rotor for wear

Check the coil for any signs of excessive heat, browning/darkening of the potting/epoxy material and see if any cracks are present that could cause the coil to arc instead of providing spark to the cylinders... but again an issue like this would present almost constantly... normally

I suggest doing a compression test and checking mechanical timing. Sometimes if a cam skips a tooth it can cause similar issues

supersilverdc2

compression is good all the way across the board, also did a leak down test. swapped out TPS and voltage read fine with snap on meter, same for dizzy we swapped it for a better one noticing the tune, high rpm popping... so TPS , COMP , DIZZY all check out so far..... new plugs gapped by tuner, i dont know what he gapped them to, they are the ngk 7 s

supersilverdc2

also took a snap on camera and looked inside cylinders at walls, they look brand spanken new, still have a fresh hone on them. mind you build is less than 7K miles, its weird cuz the car fires up great every single time.

wantboost

iTrader: (2)

If all that checks out then it is weird

Have you tried datalogging so you can get a visual of various engine parameters when the problem starts? That would be the best thing to do for us (and you) to fully understand what is happening. Simply screenshot the logs and post up the pictures

supersilverdc2

ok ill try

wantboost

iTrader: (2)

On a sidenote we just bought a similar camera/borescope.... aren't they the best things ever? We use it on our road race z06 to check inside the motor after a hard day of driving. Makes it super easy to check for cylinder wear, piston health and to make sure the flame front travels across the piston without issue. Also makes it easy to physically see any signs of detonation a knock sensor might not pick up.

I think almost everyone should invest in one of these. Hell even the ones they sell at home depot and Lowe's are small enough to fit through a sparkplug hole and even have leds built into the camera. The handheld screens also offer good image quality. Some even allow you to record to an sd card that you can view on a pc for even better resolution

supersilverdc2

they are cool but its hard to use them in the sun, my screen is not very bright.

wantboost

iTrader: (2)

That is the one drawback. Glare kills the screens.

Let us know how the datalogging goes. You'll want such values as rpm, tps, timing, injector pulsewidth, engine load, voltage, air/fuel ratio, and anything related to those particular systems displayed so you can see every engine parameter in detail when the problem starts

supersilverdc2

bump added spark plug pics! XD

supersilverdc2

bump for video, this is when the car is HOT, runs perfectly normal when cold...

reset ECU today, immediatly got CEL code 7, I took the plug out, tapped on the TPS, plugged back in and restarted.. code gos away...

http://www.youtube.com/watch?v=0nr2J...ature=youtu.be

wantboost

iTrader: (2)

What's the voltage on the current tps read? Between high underhood temps and engin/chassis vibrations while driving could be causing intermittent signal issues from the sensor or causing random, temporary tps failure

Also check the wiring from the tps harness plug to the ecu for continuity and resistance. This will show any isses with the actual wiring

Also have you had the chance to datalog the car yet?

supersilverdc2

OK here I have found out FINALLY it was not the TPS. I bought used, then I bought new, NOT A TPS issue...

I replaced the IACV again, and this time it helped out a lot for the bouncing idle...

I also found when I dissected my new dizzy was a phillips attatchment for one of those interchangable tips on a screw driver...... WTF and how did that get in there? I dont use those...

The idle bounce has gone away, however, I now seem to have a low idle issue when hot around 600rpms.... If i hold the gas to about 1500 rpms, and let it drop when cold it will die.

I will replace OEM spark plug wires with NGK blues next weekend.

I am curious if since it was tuned on that old IACV, since the NEW iacv was put in, maybe it needs to be retuned because he did make adjustments to the idle last go round.

Next on my list is shifter bushing replacement and turbo replacement.