Hesitation/Stuttering at 2,000 to 3,000 RPM

k20ex · Post by **k20ex** » Sat Mar 29, 2008 8:33 am

I need some assistance on an issue that I am having. I am running KPro with the latest update, and am experiencing a hesitation/stutter at low partial throttle in the 2,000 to 3,000 PRM range. I experience this both accelerating and decelerating, except when I am giving it enough throttle to exceed the condition.

I was told to adjust the TPS ignition retard to all 100% across all gears, and that it would solve my issue. Before I do this, I wanted to know if there are any negative effects with doing this, and if you all had any other ideas on what could be causing this hesitation. Thanks and I look forward to the intelligent responses!!

fonz600 · Post by **fonz600** » Sat Mar 29, 2008 9:52 am

Have you tried running it in open loop and datalogging around that rev range?
If your part throttle tune ain't too good it can be a bit jerky as the ECU tries to hit target values in closed loop.

cranny · Post by **cranny** » Sat Mar 29, 2008 10:05 pm

i bet your too rich in that area of the map , and when the ecu momentarily goes into open loop , it gets rich and causes your studder.

k20ex · Post by **k20ex** » Sun Mar 30, 2008 7:41 am

This is my most recent datalog, BTW. Let me know what you think, I have been adjusting the Low/High Speed Fuel Tables with the Fuel Adjustment option.

cranny · Post by **cranny** » Sun Mar 30, 2008 9:11 am

yeah you need some tuning done is all. open that datalog and start at far left , slowly drag the bar right and keep your eye on your short term fuel trim reading. at times over 20%.

fonz600 · Post by **fonz600** » Sun Mar 30, 2008 2:10 pm

Your running pretty lean at a few bits in part throttle.
Uploading your map will help.
Load up that datalog against your existing map and use labda overlay to adjust your fueling. It's mainly your 30 degree cam angle and a little 40 degree at times.
You also have a rich point at 5k on 20 degree.

Do an open loop run for 10-20 mins with no WOT and just tune the partial throttle with lambda overlay

k20ex · Post by **k20ex** » Mon Mar 31, 2008 6:15 pm

OK, I will try to look more into those suggestions. Won't be this week, but I will be reading up before I do anything more. Thanks and more comments are welcome. Any advice on changing the TPS igniton retard to 100% for all gears?

fonz600 · Post by **fonz600** » Tue Apr 01, 2008 9:06 am

I'd leave it alone and work on your fuelling mate.

rsxmachine · Post by **rsxmachine** » Sun Apr 06, 2008 7:31 am

[quote="k20ex"]OK, I will try to look more into those suggestions. Won't be this week, but I will be reading up before I do anything more. Thanks and more comments are welcome. Any advice on changing the TPS igniton retard to 100% for all gears?[/quote]
you probably mean -100, that will prevent the ECU from retarding ignition advance on throttle tip-in. then if it feels too jerky you can back that off to something like -75 or -50

you should also look at your ignition tables in the areas where it's hesitating. a combination of too much fuel and not enough ign advance will definitely cause the hesitation you describe

Axix23 · Post by **Axix23** » Fri Apr 18, 2008 2:19 pm

too little fuel and running lean will also cause you to hesitate and bog...

Bflaker · Post by **Bflaker** » Thu Apr 24, 2008 1:17 pm

I am experiencing this same problem. It seems to only occur when going down an incline and the amount of throttle required to keep a steady speed is almost 0%, but you are still just barely giving it gas to maintain your speed. It feels like the car is bucking back and forth and as soon as you give it just a tiny bit more gas, it goes away. It does seem to occur right on the edge of open and closed loop operation. I've been able to duplicate the problem in gears 2,3,4,5,6. 1st is so short and you hardly ever cruise in it, so it may do it in 1st, I just haven't confirmed it. It feels like a lean condition bucking. So I drove around and watched where the bucking was occuring in the fuel maps. It was always in columns 1,2, and sometimes 3. So I tried adding massive amounts of fuel in that area. Didn't help. I am stumped at what it could be. All I do know is that it is a major pain in the ass. It feels like something is wrong with car, but there isn't. Could it be too much igntion advance? Too little ignition advance? Too much fuel? A problem with TPS ignition retard? I'm stumped. HELP!!!!!

jimmyjames · Post by **jimmyjames** » Fri Apr 25, 2008 7:45 pm

I get the same thing.
Could be related to this?
http://www.hondata.net/forum/viewtopic.php?t=7841

cranny · Post by **cranny** » Fri Apr 25, 2008 9:34 pm

Bflaker wrote:I am experiencing this same problem. It seems to only occur when going down an incline and the amount of throttle required to keep a steady speed is almost 0%, but you are still just barely giving it gas to maintain your speed. It feels like the car is bucking back and forth and as soon as you give it just a tiny bit more gas, it goes away. It does seem to occur right on the edge of open and closed loop operation. I've been able to duplicate the problem in gears 2,3,4,5,6. 1st is so short and you hardly ever cruise in it, so it may do it in 1st, I just haven't confirmed it. It feels like a lean condition bucking. So I drove around and watched where the bucking was occuring in the fuel maps. It was always in columns 1,2, and sometimes 3. So I tried adding massive amounts of fuel in that area. Didn't help. I am stumped at what it could be. All I do know is that it is a major pain in the ass. It feels like something is wrong with car, but there isn't. Could it be too much igntion advance? Too little ignition advance? Too much fuel? A problem with TPS ignition retard? I'm stumped. HELP!!!!!

for you , id first recommend setting your TPS minimum and max reading.
you probably need partial throttle tuning as well.

fonz600 · Post by **fonz600** » Sun Apr 27, 2008 2:01 am

I''d try locking 0,10,20,30 degree low cam angles and spend alot of time on fuelling in open loop on each angle.

macer · Post by **macer** » Sun Apr 27, 2008 3:52 pm

I had the same problem, had two tuners play with the fuel etc with no joy I set the TPS ignition retard to all 100% and the problem went away. Have heard of the the same issue on a few cars.