^^^ Mojo im sorry for getting upset as well... just didnt want this turning into a meaning less thread where nothing gets solved.

And when I put it in 5th gear, its not at such a low RPM to where it bucks.. Its at a reasonable cruising speed.

If i put it in 5th gear and it idles at 2200 rpms I still get the bucking ... whether I SMASH the pedal, or just try to maintain the speed limit.

 

Yes SiC,

When I smash the pedal in 3rd and 4th gear, she is fine, no bucking or anything. Its only when im barely on the pedal, trying to maintain speed limits and driving normal that im experiencin this problems, and its the worse between 1800-2600 rpms... It happens when im about 1/4th on the pedal that this starts.

So instead of bucking down the street ive had to resort to being in 3rd gear at 4k to be driveable.

 

Hmm, so the problem seems like it only occurs in closed loop (low RPM low load). Once you boost, does the problem go away? If the answer is yes, then my initial thoughts may be correct. Do you have a wideband O2? When this happens, does the AFR jump around being rich and lean? If you can log STFT, are those numbers fluctuating a lot also?

 

Well when I put it in 5th gear and holds at 2k rpms... If I smash the pedal it will hits about 4 psi and thats it, 4 psi and stuck at 2k even tho ive burried the pedal.

And yes, if I just start in 1st and do a 1st through 4th gear pull starting from a dead stop, she goes fine.. its only when i want to take it easy and just cruise around that this problem occurs.

I am unable to log anything atm because I dont have a laptop. I am bringin my car to another tune shop soon and just going to have them look at my ROM and take them for a ride to see if they can pinpoint the culprit.

And also SiC, I looked into my tune and looked at the Open Loop Throttle Low Load and the Open Loop Throttle High Load and they are exactly the same, thought that may be contributing to my problem.

 

That doesn't sound like latency problems now, sounds more like surge.

 

Well how the hell do I eliminate surge? There has to be some other underlying factor. And when a tuner "scales injectors" are they supposed to just take numbers off line and plug them in, or are they actually supposed to dial in the numbers through trial and error?

 

Ok, when it bucks do you hear a sound sort of like a BOV releasing air excpet the noise flutters? If you do it's surge, if you don't it's not. Someone can correct me if I am wrong about that. Also, is lean spool disabled? I have had cars have problems with bucking rich at low rpms with it off which is why I ask.

 

no i dont hear my bov releasing any air at all. and how do i check to see if lean spool is disabled?

 

if your tuner knows what he is doing, he can guess on the injector latencys and be within 5% STFT the first try. so yes, he can take numbers out of his butt and put them in the tune and it will be ok. however, if your tuner doesn't know what he is doing, it would be best to take known numbers for those injectors and do the trial and error method with a wideband for feedback.

but again, cruising in 5th gear uses a pretty good size pulse width, and changes made to the latencys are tiny (usually adjustments are made in the 14V range by .1ms or less).

i've confused as to when the problem happens now though. at first i was thinking it was at full throttle. but now your saying it only happens at part throttle when your holding steady? or it happens all the time no matter what throttle in 5th gear?

is your 5th gear messed up?

 

Any update on this? Send me your rom if you want me to check on lean spool.

 

Ok so after a couple weeks. and going back and forth from shop to shop.

We fixed a couple boost leaks, and I recirculated my bov. Also I was throwing a p0134 ( bank 1 02 sensor no activity ) and p0172 ( too rich ). Also installed a Wideband.

So im still throwin a p0172 code. My afr's read 10.0 or lower when my rpms are 2300 and lower. The higher up in rpms I go (without boosting) the leaner it gets. At idle it bounces from 10.0 all the way to 15.7. When I come to stop signs its burried at 10.0.

It seems as if my car always stays in Open Loop and just dumps excessive fuel. Is there something that I am missing?? Some way to fix the always in Open Loop??

 

Uhh, thats way too lean at Idle. Your AFR should be 13.5 -14.7 at Idle and should only get richer as you add throttle and should be something like 10.8-11.2 during WOT. Very lean during engine braking is normal. Cruising AFR can be around 14.7 if tuned well.

 

May be a bad O2 sensor or MAF.

 

my 02 sensor was bad... I replaced it 2 days ago... my MAF also was bad.. and I also replaced it too..

after both of those.. it did idle a little bit better, but it still bounces off 500 rpms when I come to a stop sign, and still is super rich under normal driving conditions, almost as im still in open loop, seems like my car just isnt makin the switch from open to closed loop ..

 

Latency's are definitely off. You need to log short term fuel trims and have them fixed!

casper lean at idle would not be 10.0 or lower at idle like he said! Lean at idle would be 18 to 20 afr's!