Throttle steady but rpm stumble help

[Brule]

Hey I have had an issue for 3 years of owning the car with stumbling rpms.

I have gone from stock to rbs and now rb stealths ad intercooler all good quality parts and maintenance up.

It makes daily driving 9/10 for difficulty especially with a twin plate clutch.
Doesnt matter what fuel I'm using it still persists

Heres a datalog in neutral

http://datazap.me/u/brule/rb-stealth...6&zoom=109-258

What is happening is a dead spot when its loaded up in 1st gear, or any gear around 1500 rpm

if i hold the thorottle steady while in first or 2nd it has dead spot then jerks and get going again.

In my logs i have noticed the stft are going max positive and nearly max negative in this situation.

This happens on any tuning device or tune as I've had everything. Jb4, bb, cobb ots, ptf, buraq.

I have logged throttle only, it is smooth with no dead spot.
I dont have any symptons that i know of for a leaky injector.
i have been told my injectors may not have been coded and to check them( bought the new ecs scwaben tool) should be here in a couple of days.

I have new boost solenoids, coils spark plugs, vanos, oil etc

What do you guys think?

[TwistedTuning]

are you on a custom tune right now? is that log from it? first thing I notice is your AFR randomly going lean. if this is at idle it makes it that much more weird. AFR shoots up to like 17-19afr in this log like 3 or 4 times.

Almost resembles a pre-turbo vac leak on a MAF car. But obviously this Car is MAP. but still susceptible to vac leaks at the manifold. Mainly the charge pipe. Have you ever tried smoke testing the car? I'm willing to bet you have a leak somewhere. if not I'd check tune or look into new o2 sensors.

[Brule]

Just put new pre cat 02 sensors.
Never done a smoke test
The log is in neutral holding throttle about 10% showing idle going up and down and stft spiking
I have tried all different tunes and it still does the same thing

[TwistedTuning]

Just put new pre cat 02 sensors.
Never done a smoke test
The log is in neutral holding throttle about 10% showing idle going up and down and stft spiking
I have tried all different tunes and it still does the same thing

your AAC Pedal inputs match the change in RPM's. the ACC pedal input goes up and down between 4-9%. so you may think your holding it steady, but the log shows otherwise. and the RPM follows the pedal input in this log. Not saying you don't have a problem, just noting what I see in the log.

Try logging LTFT with or without STFT, LTFT is more important here I feel. Believe it or not downstream O2's will effect fueling as well. I would do a smoke test, that way you rule out any chance of a vac/boost leak in the system which can cause issues if there are any present.

[Brule]

In that log the rpm is sort of following throttle, its just coincidence,its only a couple of %. I have plenty of logs flat throttle with rpms rising and falling about 500 rpm.
Thanks for your help.

I have been told the rear o2 don't do anything for performance. I was always under the impression they were telling the dme how much the dp cats were working.

I've knocked rear o2s a few times against the exhaust etc. in my 2 turbo installs.

I'll log the ltft tomorrow and post log up.

[Velocity26]

I suffered with "surging" for about a year with nothing seeming to help. When driving, I would maintain a steady throttle and it felt as if the throttle were gently being pressed and released to maintain a similar speed. This was most noticeable at light throttle, but was also present on mid throttle too. When I learned that my car was eligible for the injector reimbursement, I purchased a new set of Rev 12's and put them in. Many of the symptoms that I had attributed to other causes were gone. No more erratic idle for a few seconds after start-up, no more surging, no more disparity in the STFT between bank 1 & 2, no more random/occasional misfires.

FYI, I started by replacing the spark plugs but they did not indicate an obvious injector problem. The old injectors all look "good" with no obvious signs of problems.

[Stucks]

I suffered with "surging" for about a year with nothing seeming to help. When driving, I would maintain a steady throttle and it felt as if the throttle were gently being pressed and released to maintain a similar speed. This was most noticeable at light throttle, but was also present on mid throttle too. When I learned that my car was eligible for the injector reimbursement, I purchased a new set of Rev 12's and put them in. Many of the symptoms that I had attributed to other causes were gone. No more erratic idle for a few seconds after start-up, no more surging, no more disparity in the STFT between bank 1 & 2, no more random/occasional misfires.

FYI, I started by replacing the spark plugs but they did not indicate an obvious injector problem. The old injectors all look "good" with no obvious signs of problems.

So index 12 injectors solved your issues?

[Brule]

Idle stays steady its just when I put the throttle down and rpms ate consistently dropping at 1500rpm and I have to put the throttle down alot to get it to raise above 1500rpm.

I thought the cats were blocked so I pulled them all out.
Got new pre cat o2s.

Above 1500 it drives fine any load, no oscilations etc

[Brule]

Found two leaks.

one on top of one of the turbosmart kompact dvs. Ive tightened it but i still leaks

and on the inlet manifold nipple, i tapped 3 years ago.

[Brule]

Never thought i hand any boost leaks as ive been on 20 psi for a few years. about 3000km all up

[Brule]

Didnt fix the issue.

did a 5 min test drive and its exactly the same

[Brule]

Log in neutral after fixing manifold leak and reseting adaptions after a 10 minute drive

http://datazap.me/u/brule/fixed-mani...&data=14-16-17

[Stucks]

I resolved my issue. bought 6 new index 12 injectors, and swapped the old ones out today. all was going fine until.....i saw this lol. upon pulling number 6 out, this is what i found. from left to right, 1-6. injector seal is completely gone.

[bradsm87]

Great news! That must be a releif. Well done. I hate car issues

[Brule]

That's good.

I'm thinking mine can only be map sensor now.