TWEECER NEWBIE HERE! Need help fine tuning: Idle & Bucking problem

[mustanggt94]

What I've got is in my sig (plus J4J1 cal on T4H0 EEC, CBAZA), and the car seems to be running real strong, but the idle likes to surge every once in a while, after warm startup especially. Surges from 400rpm to 1100rpm, almost stalling. Once you get on the road it's okay, except it will always hang around 1500-2000rpm when coming to a stop, for about 5-10 seconds before it drops down to normal idle, then it's okay. Also, starting out most of the time involves some bucking, plus I've noticed it sounds like the engine is missing a bit....i notice that just cruising speed on the highway. I did some datalogging but since I'm new to all this I don't know what to do with it!

Another weird thing, when I drove it around and it got to running a little warm, like slightly past halfway on the temp gauge, the car started running like crap and wanted to die and buck A LOT, also for some reason my power brakes went out! That was fun! So I got it home, did some datalogging in the garage, still ran like crap, so I get it cool down and took it back out and everything was fine, had power brakes again and everything. Even took it out for about 1/2 hour around town and so far so good, but it also didn't run too hot then either. I don't know what was up with that, but can anyone help me out? If you live around Indy you could just come on over, that would be awesome! THANKS!

 

[final5-0]

Kinda sounds like you might have a v leak since your brakes are off and on at times.

Lots of the time surge is caused by being too rich. You may need to lean out the maf curve idle points a tad or you may need to force OL at idle due to your lt's.

Lots of the time bucking is caused by having too much spark at that moment or during those driving conditions. If that is so then you will have play with the spark tables.

I know that stuff is very generic but each combo is different and you'll find that several things can usually be tried to solve drivability issues.

Search using words that describe your Q's on the various tuner sites and you'll find stuff to try and over time it will all come together.

That stuff might not be what you wanna hear but it is the truth and everybody who has learned to self tune has to become friends with the SEARCH button to get an idea of whats goin on with the pcm.

btw......Welcome to the world of self tuning!!!

Later
Grady

 

[mustanggt94]

Geez Grady, you're starting to scare me! I'm starting to feel like I'm going to have to learn most of this on my own, but I have faith! I just don't want to mess anything up.

Yeah I was thinking it was a vacuum leak too at first but I couldn't find one anywhere, and this motor doesn't have many vacuum lines at all since there is no emissions stuff. I also noticed that the KAMRF's are both 1.000 exactly at idle, then they fluctuate between .8-1.000 when you rev it or drive it. It seems that it never goes above 1.000 at all....doesn't that seem weird? I've seen some posts of people that cannot get the KAMRF to move at all but mine does it just won't go up any.

 

[final5-0]

Geez Grady, you're starting to scare me! I'm starting to feel like I'm going to have to learn most of this on my own,

I'm gonna tell you like it is with no scare tactics intended

You ARE gonna have to learn most of this stuff on your own.

I had to learn most of this stuff on my own and everybody I know that self tunes had to learn most of this stuff on their own.

Now after being brutally honest with you I also will say ...... I don't mind helping you and I know for certain other peeps who will help you simply because of this fact.

Everybody has gotten some help when they first started out with all this self tuning stuff but here is the key to building some good relationships and credibility with other self tuning folks.

Since everybody has had to do their Do Diligence with all of this self tuning stuff it can be frustrating to see a new self tuner ask stuff that is common knowledge and after seeing a few questions from him it is obvious to everybody that he wants to be spoon-fed the same knowledge that everybody else had to dig up on their own.

You may not know it but......this stuff we speak about (knowledge about how the EEC IV pcm works) is knowledge that has been hacked, stolen, etc and there is no book or class that tells all one needs to know to self tune in a few easy chapters or sit down sessions with some guru, lol.

You have to dig it out from where ever and make the search button become your very best friend

Kinda similar to a newbee showing up on this site and asking if he should go with 355's or 373's ...... don't ya think???

I want to make it perfectly clear that I don't think you are one of those spoon-fed kinda guys that I was speaking about, lol. It is my hope that you see from what I've said that you'll get more help from others if they know you have put some of your own effort in what you are doing or trying to do before you ask for help.

Just an obversation of what I've seen and heard from others in the self tuning community I guess.

but I have faith! I just don't want to mess anything up.

You don't need faith to self tune......just read lots of old threads

You don't wanna mess up so remember just one bad thing not to do......

Don't have too little fuel with too much spark
Pistons don't like that kind of chit

Yeah I was thinking it was a vacuum leak too at first but I couldn't find one anywhere, and this motor doesn't have many vacuum lines at all since there is no emissions stuff. I also noticed that the KAMRF's are both 1.000 exactly at idle, then they fluctuate between .8-1.000 when you rev it or drive it. It seems that it never goes above 1.000 at all....doesn't that seem weird? I've seen some posts of people that cannot get the KAMRF to move at all but mine does it just won't go up any.

The range of K's you speak about tells you this, if you are describing a light load driving condition, putt around town kind of cruise, or driving around like your granny might drive. Those kind of driving conditions would produce a drive that for the most part would be in Closed Loop conditions and the K's range of .8 to 1.0 tell you that the pcm's adaptive strategy is removing fuel so you are too rich. Look at some posts that talk about adaptive strategy and you'll find lots of info about stuff to do and what the objective is with having the K's stay close to the 1.00 mark.

I do want to encourage you to keep at it and remember that you can't learn it all in a day or two......might take ya ...... a week or two

Hey you just...............................

learn a little-tune a little...learn a little more-tune a little more...

Later
Grady

 

[GRGT1994]

So tell me this. After struggling as long as you have, Grady, have you learned tuning well enough to get your car running where you want it (idle, street driving, and racing).

Not trying to be a pain. I just want to know how well you can get a tweeked motor running, after lots of work.

 

[final5-0]

So tell me this. After struggling as long as you have, Grady, have you learned tuning well enough to get your car running where you want it (idle, street driving, and racing).

Not trying to be a pain. I just want to know how well you can get a tweeked motor running, after lots of work.

Well

Look at the way you see it...

Struggling

Look at the way I see it...

Fun, intriguing, & a skill I wanted to learn to be in control of my combo tune.

I've really have had a lot of fun with learning some of this stuff and while it was a challenge, I just did not see it as a struggle or burden or anything negative like that. Maybe its just my personality type but I like knowing that little silver box ain't hiding any secrets from me

Seriously, I just picked up a little here and a little there and as it started to make sense, I built on that start to where I am today.....where ever that is, lol. IMHO, its no different than when you start to learn about 5.0 Stangs......you just start picking up stuff and build on it for more knowledge.

Its just not as bad as you seem to think AFAIK

Tuning for max power is so easy compared to tuning for drivability issues but
here are some of the things that are a result of the Tweecer:

Stable idle as low as 750 rpm
No surge or buck at any speeds or rpm
No smelly fumes from being too rich
No probs with cold or hot starts
No ping
Except for cam lope, the car behaves like a stocker with more power

Even with my cam, which has a lsa that peeps on this site every day say is not 94-95 pcm friendly, I've been able to make a couple of things happen that at one time, I would not believe could be possible, and they are:

1) On a level road in 4th gear at a cruise of say 1200 rpm I can go to the floor with the skinny pedal with nothing but a smooth, steady pick up in speed & rpm's.
2) On a level road I can hold a steady cruise of 1200 to 1500 rpm in 5th gear.

These kinds of things are not uncommon or just about me and my car as lots of other peeps have done the same kind of things so don't think I'm some kind of execption or anything like that.

I don't think your being a pain or anything like that cause I had those kind of Q's myself once upon a time, as they say.

Hope this stuff answers your Q's and lets you know whats possible

Later
Grady

 

[mustanggt94]

Thanks for the reality check, Grady! I'm not trying to ask for exact numbers or anything, but I guess I'm just wanting to know what tables and scalars you had to change to get your results. I guess I could figure it out myself, but you and I both know that there are 200 or so things to change, so that might take a while! Okay, I guess I do want to be spoon-fed!

I can understand how most of the scalars work and what the curves do but I just don't know where to start. It's kinda overwhelming (sp?). I know I'll get there eventually, but for now, I'll take any advice I can get to get there. Thanks guys!

Danny

 

[final5-0]

Thanks for the reality check, Grady! I'm not trying to ask for exact numbers or anything, but I guess I'm just wanting to know what tables and scalars you had to change to get your results. I guess I could figure it out myself, but you and I both know that there are 200 or so things to change, so that might take a while! Okay, I guess I do want to be spoon-fed!

I can understand how most of the scalars work and what the curves do but I just don't know where to start. It's kinda overwhelming (sp?). I know I'll get there eventually, but for now, I'll take any advice I can get to get there. Thanks guys!

Danny

Danny

Overwhelming you say

Believe me I understand how you feel cause I remember feeling just the same a while back myself. Maybe it will help if you know that you only work with about 10 to 15% of all that stuff.

I've talked to many who self tune and they all say the same thing about getting started. You just start reading old threads (focus on CBAZA strategy family threads only at first) and it all kinda sorta starts to make sense after a while.

Look at all the faqs on the various sites and use peeps names who have cars & combos like yours.

Don't just stick your big toe in to test the self tuning waters...............
Jump in there and get this stuff all over you

Later
Grady

 

[mustanggt94]

Lol....thanks Grady! It's so hot here right now I cannot concentrate enough to get this thing tuned.


I've got an update: I tried to set the TPS (using 93 style intake setup) to the recommended 0.99V, and after that the car would not idle, it would still fluctuate but then die. So I set it back to where it was at about 1.2V and it's back to the crappy, but stable, idling from before. I don't understand why setting the TPS where it's supposed to be is making it worse.

I went out to the track, hot night, and the car was puttering pretty badly, but would make decent runs. Still hard to keep it idling, though. I don't think this car responds well to hot weather at all. What table should I mess with to fix this idling and puttering? When I got to the line, revved it up to redline, the car was noticeably puttering badly, thoughout all the RPMs, but still got consistent 13.1's. It's also bucking most of the time when warm, making creeping though the line at the track tricky and embarrassing!

Danny

 

[final5-0]

Lol....thanks Grady! It's so hot here right now I cannot concentrate enough to get this thing tuned.


I've got an update: I tried to set the TPS (using 93 style intake setup) to the recommended 0.99V, and after that the car would not idle, it would still fluctuate but then die. So I set it back to where it was at about 1.2V and it's back to the crappy, but stable, idling from before. I don't understand why setting the TPS where it's supposed to be is making it worse.

Danny

Not sure about this so I'm just thinking out loud, ok? The pcm has no knowledge about the Fox tb and tps so I don't see why you should be too concerned about the tps setting like the Fox boys are. I'd put it back to a little under 1.00 and reset the pcm and take a look in a datalog and see what you end up getting.

Lets try this!

GTJake......WhiteDevil......Rootus

Yall got a Fox tb on a SN...............what are yall doing about the tps???

I went out to the track, hot night, and the car was puttering pretty badly, but would make decent runs. Still hard to keep it idling, though. I don't think this car responds well to hot weather at all. What table should I mess with to fix this idling and puttering? When I got to the line, revved it up to redline, the car was noticeably puttering badly, thoughout all the RPMs, but still got consistent 13.1's. It's also bucking most of the time when warm, making creeping though the line at the track tricky and embarrassing!

Danny

What all have you done so far with the tune?

Are you using ProM's cheat method or have you loaded in your maf curve and told the pcm you got 30's?

Your extra motor size will be drawing a bit more air at idle. Have you told the pcm about the extra cubes?

If your surging, you could be too rich and might try to back down a bit on the maf curve cells just before, during, and just after idle conditions.

Do you have that rich smell during idle?

Do you have a wb?

Later
Grady

 

[mustanggt94]

So far with the tune I've adjusted the CI to 347, changed the Maf function using a Flowsheet I got of someone on Corral that has the same meter, and disabled EGR and Thermactor.....that's about it. I set the idle a little higher to 800rpm, and raised the rev limiter and raised the global spark adder to 5. Would the spark have anything to do with it? I thought maybe with the bigger cam the spark timing could be off, but I do not know what to do to compensate for the cam yet.

The meter I have is Pro-M 80mm cal'ed for 94 cobra with 24# injectors, and that's the sheet I used, then set the injector slopes to 30. I tried to lean out the maf function a bit at the lower points, but didn't seem to help any. I don't want to mess it up too much but I guess it doesn't hurt.

It does seem to run a little smelly, but it just might be because my garage doesn't vent very well. I do not have a WB....what exactly is that needed for? Can't I read the A/F off the stock O2's?

What do I need to look at in a datalog to check my idling and bucking problems? Thanks a bunch for your help.

Danny

 

[final5-0]

So far with the tune I've adjusted the CI to 347, changed the Maf function using a Flowsheet I got of someone on Corral that has the same meter, and disabled EGR and Thermactor.....that's about it. I set the idle a little higher to 800rpm, and raised the rev limiter and raised the global spark adder to 5. Would the spark have anything to do with it? I thought maybe with the bigger cam the spark timing could be off, but I do not know what to do to compensate for the cam yet.

Here is a thing or two you can try

Yes the bucking could be caused by too much spark so for now, put the adder back to 0. Be sure the dizzy is at the factory value of 10 & if you've got an afpr, go back to the factory value......39 I think.

The meter I have is Pro-M 80mm cal'ed for 94 cobra with 24# injectors, and that's the sheet I used, then set the injector slopes to 30.

OK then, first off, you might want to compare your curve to one you'll find on the maf transfer function page by clicking on load maf and loading the ProM24 to see if they are similar. This way you'll have a 2nd curve to kinda verify the other guys curve with. The curve is one of the most critical things about all of this stuff btw.

30 low & high is an OK value on the slopes for now.

I tried to lean out the maf function a bit at the lower points, but didn't seem to help any.

Tell you what......if those two curves are pretty close then just use the one you got loaded in there for now. Go back to the original maf values and upload them with the spark global adder value of zero. After that, reset the pcm.

You don't have a wb but......we CAN check what the pcm's adaptive is doing and use that data to adjust the fuel ratio at idle which most likely will help the buck and surge.

After the pcm reset drive the car around for say 15 mins with very light throttle and some periods of idle.
Pull over and at idle, do the following:

Look at what the KAMRF's are doing ...this is the adaptive at work btw
1.00 is considered to be perfect
less than 1.00 means the adaptive is removing fuel cause your too fat
more than 1.00 is the opposite

Say you see .95xx K's...watch them for a couple of mins btw
You then lean the maf idle transfer points by 5% to drive the K's up 5%
You just told the pcm that the maf is sensing less air at xxxx idle volts OR...
Don't You See...5% less air will command 5% less fuel...make sense

I don't want to mess it up too much but I guess it doesn't hurt.

When you wanna make a change your not sure about, just keep it small until you know your on the right path to where you wanna go, lol. You can save each change to a new file name, that way you can simply go back to where you were if you need to by just uploading the older file

It does seem to run a little smelly, but it just might be because my garage doesn't vent very well. I do not have a WB....what exactly is that needed for? Can't I read the A/F off the stock O2's?

The stock O2's work in such a narrow band of operation that they can't be trusted. The farther away from that range of operation the more they are off and that explains the benefit of the wide band O2 as it is accurate for a wider range. Besides that...the nb O2's only do their thing in Closed Loop and your in Open Loop when you got the skinny pedal down so they are not much help during those happy times

As for the readings from the stock O2's which will show up in your datalogs under the cloumn as LAMBSE ...... those values are NOT your af ratio. LAMBSE is the commanded fuel value or the derived ratio value from O2's, fuel tables, Air Charge Temps, Engine Coolant Temps, yada yada yada.

What do I need to look at in a datalog to check my idling and bucking problems? Thanks a bunch for your help.

Danny

I done told ya Danny and .............................

I'm gonna put the SPOON away for now

You got plenty of stuff to try for a while so......have fun & good luck

Later
Grady