SD tune w/ Light Throttle exhaust popping from 2.8k to 3.2k can't fix please help!

[jeffstar]

Guys I'd like some input from the experienced guys out there that may have seen the problem I am having.

My car is a H/C car and the dyno numbers and all that jazz are great. What is not great is 5-22% throttle and 60-75kpa load around 2600 to 3200 RPM. The car pops/hesitates in those areas under light load.

I have some logs I can post from HPtuners later but for now I can tell you this. I've made this popping and hesitation get better with less timing in the middle area of the timing map. I've got the timing down to about 17 degree's in those areas and the problem has gotten better but not gone away.

The wideband shows the car is slightly over fueld or right at 14.6:1.

Could I have an issue with my 42lb/bosch injectors?

Do I need some sort of special settings for these injectors?

Is it not related to injectors at all in your opinion?

The popping and such goes away with MORE or LESS throttle but right there in that medium load spot it does it until I hit 3100 RPM. My tune is posted on my site but I'll post the tune and the log from today on HPTuners site in a few hours.

If anyone has seen this before and has some tips on what to look for it would be appreciated! Again only taking out timing seems to help but only so much.

A few things that I've read could be:

Oil consumption? (oil in the chamber?) I do not have a catch can and there is a bit of oil in the intake itself...
To hot of a plug? These are TFS heads milled to be 58cc combustion chambers could the TR6 be too hot for that (11:1 CR)

[NOS500]

I'd try doing some light throttle driving and log the LTFT on the histogram, if the fuel trims are out it will show negative or a solid number for positive fuel trims, then all you do is copy, paste special, multiply, I don't know if you have tried it this way but this is how i set up my light throttle fuel trims on head & cam cars, it may take a while but try to do all light throttle tunong on the same day, when your finished use the bi directional controls and re set you fuel trims.
With a head and cam car you shouln't have to change your timing on light throttle, set it back to what is was and do the fuel trims.

I have had this problem before and this is how i usually fix it.

Dave

[jeffstar]

I'd try doing some light throttle driving and log the LTFT on the histogram, if the fuel trims are out it will show negative or a solid number for positive fuel trims, then all you do is copy, paste special, multiply, I don't know if you have tried it this way but this is how i set up my light throttle fuel trims on head & cam cars, it may take a while but try to do all light throttle tunong on the same day, when your finished use the bi directional controls and re set you fuel trims.
With a head and cam car you shouln't have to change your timing on light throttle, set it back to what is was and do the fuel trims.

I have had this problem before and this is how i usually fix it.

Dave

It's an OPEN LOOP SD Tune, sorry didn't say that.

[jeffstar]

There are my logs. Notice the short but frequent lean spot before the AEM A/F goes back to stoic. How do you adjust that sort of situation.

[jeffstar]

Anybody want to take a look? too hard?

[NOS500]

I'll have a look when i get back to work.

[shimp]

Man I am a newbie, but I wanted to follow along this thread, so i was looking at your log files and trying to figure out where the popping occurs. Is it occuring when the AC Pressure (I assume you have your WBO2 there) is reading around 4 volts or so? It shows that your TPS is dropping out to 0% at that point. Such as at frame 652. Your AC Pressure voltage goes up to 4 shortly after that. The cars speed never changes. So could your TPS sensor have a dead spot in it? Or loose connection or something? It only drops to 0 for 1 frame. Goes from 7% to 0% then back up to 11% in the next frame.

I am probably totally wrong but I thought I'd try to learn how to read the scan logs better and saw this as a good oppurtunity to learn something.

[jeffstar]

Man I am a newbie, but I wanted to follow along this thread, so i was looking at your log files and trying to figure out where the popping occurs. Is it occuring when the AC Pressure (I assume you have your WBO2 there) is reading around 4 volts or so? It shows that your TPS is dropping out to 0% at that point. Such as at frame 652. Your AC Pressure voltage goes up to 4 shortly after that. The cars speed never changes. So could your TPS sensor have a dead spot in it? Or loose connection or something? It only drops to 0 for 1 frame. Goes from 7% to 0% then back up to 11% in the next frame.

I am probably totally wrong but I thought I'd try to learn how to read the scan logs better and saw this as a good opportunity to learn something.

Thanks for taking a look. No, nothing wrong the TPS actually. Good observation though. In that frame I'm coming off the throttle to get the car to start the popping again. At least SOMEBODY took a look at my file It's hard to get help in here sometimes but the LS1tech.com board has been very helpful.

[jeffstar]

Strangest thing. I turned OFF the Throttle Cracker and re-built the timing map (put in a lot MORE timing) and the problem is almost fully gone. Any ideas on that guys?

Weird because 2 weeks ago it was the other direction. Pulled a ton of timing out?


Check revision 11.5 in this link

[miami993c297]

Strangest thing. I turned OFF the Throttle Cracker and re-built the timing map (put in a lot MORE timing) and the problem is almost fully gone. Any ideas on that guys?

Weird because 2 weeks ago it was the other direction. Pulled a ton of timing out?


Check revision 11.5 in this link

Hi Jeff,

What did you extract from the infos I sent you a while back?

In your last tune did you proceed the changes systematically one after the other to separate the effects and reaction of each parameter?

The Throttle Cracker had a ton of effect in my tune, and Russ point me in this direction (for the best in my case) you are using now...

Waiting to hear from you
Christian

[jeffstar]

I changed the throttle cracker settings and things got much better. Then I tried another timing map and the results were great. Now the car is pretty good and nearly perfect. I need to mess a bit now with the throttle follower.

[miami993c297]

I changed the throttle cracker settings and things got much better. Then I tried another timing map and the results were great. Now the car is pretty good and nearly perfect. I need to mess a bit now with the throttle follower.

That's cool Jeff,

I am interested in your results for sure, will you update your website with your last bin?

Christian

[WS6FirebirdTA00]

Well first of all, your timing tables are really messed up. How did you set that up and what was your reasoning? Your VE also looks a little screwy. Most people prob didnt look because you didnt post anything on your conversion factor for your wideband so we can actually get a reading. When asking questions its best to post all this information up.

[WS6FirebirdTA00]

Your PE table is also off, you jump to a different commanded fuel at 3200, thats not good.

[jeffstar]

How can it be un "screwy" ?? just smoother? It's pretty close to on the mark as of now except a few spots.... I've had about 8 hours total of tune time.....please take a look at the latest file. I think I straitened out most of the timing issues there. Let me post the config. Do you mean on the PE enable TPS table (HOT)?

Why are the timing tables so jacked, because it was the only thing I could do to reduce the popping/noise/hesitation I'm posting about. With the throttle cracker OFF almost 100% of it is gone but there is still "some" left.

Please have a crack at making some changes you think will have a positive effect I'd love to see what your spin is!

As of now it's MUCH better with the tune I attached in this post. The logs are from the old tune I originally posted about I have not made logs with this tune but I can tell you the driveability is much better.

Crazy how easy it is to tune the idle and WOT but how hard it is to get the mid ranges tuned right.

Thanks for offering some help and not just making fun of my tune

[jeffstar]

I want to amend the above information. The hesitation is all gone only thing left is some popping out the exhaust. My exhaust system may be the cause of that because I have TSP TD system with custom extensions it may have altered the dynamics of the exhaust to cause "some" popping out the exhaust.

[WS6FirebirdTA00]

so when exactly does it pop? It is common on some exhausts, from what I have seen.

[jeffstar]

so when exactly does it pop? It is common on some exhausts, from what I have seen.

Say, between 2600 and 3100 RPM moving about 65 g/sec air into the cylinder ....

[WS6FirebirdTA00]

so, when you step on the gas or right when you let off from that area?

[jeffstar]

When I GIVE the engine throttle and the RPM's are climbing upwards it would pop/crack/hesitate like it was super learn but wideband showed it wasn't. Like I said above, I turned OFF the throttle cracker (not sure why that was ON) and changed the timing map and it drives MUCH better but it's still popping a tad out the exhaust but NOT hesitating or making a cracking sound....

Do you think you could take my file and change the PE values that are "messed up" and post it so I can see exactly what you are saying?

Also how can the VE table be "un jacked up" ?