Pro-M meters and cobra meter calibration
- Thread starter 1BAD93SVT
- Start date
720 Terminal Rd
Lansing, Mi 48906
517-327-3900
517-327-3930 Fax
Lansing, Mi 48906
517-327-3900
517-327-3930 Fax
Thanks, I have another question I just put 306 in my car and I was wondering how should I have maf tuned? I have Long tubes, off road H pipe, GT40's with a 3 angle valve job stock intake. Also my idle is terrible the car isn't running right at all I had to retard the timing to keep it running.
Are you talking about the s/c calibrated MAF you are running right now? If so, then PMAS has a spec sheet for you to fill out. They'll do the "tuning" for you.
93Cobra#2771 said:
At WOT the computer stops looking @ your 02's, it looks @ fuel pressure. I've used a pro-m calibrated for 24's with 30# injectors & I've used c&l meters with no tubes @ all with no problems & with supercharger it made my A/F almost perfect as I needed the extra fuel but All I ever did was just adjust the fuel pressure a few lbs to zero it in. Aslong as your meter isn't calibrated for something either "way" too big or "way" too small you should have no problems dialing it in with a wideband, I never did.
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You are half right. While true the EEC no longer looks at O2's at WOT, it interpolates adaptive settings and applies them to WOT as fuel trims.
EEC has no idea what the fuel pressure is. It relies solely on O2 feedback during CL operation to know how to adjust injector pulsewidth. EEC assumes fuel pressure is 38-42 psi. If the O2's signal too little fuel is going in (due to the drop in FP), all the eec knows to do is to up the injector pulsewidth to make up for it. It then takes those CL adaptive fuel trims (KAMRF) and applies them at interpolated values at WOT/OL.
Initial FP changes will indeed show a change in WOT a/f. But go back to the dyno a few weeks later after some regular driving conditions, don't touch anything, and reverify your WOT a/f - I guarantee your a/f will change unless you have killed adaptive update in that range.
I have spoken with one of the original engineers that created the EEC-IV. He told me:
"We advised all the powertrain testing guys to disconnect the battery and clear KAM on all cars prior to drag strip testing. This removed any learned adaptive changes and allowed consistant testing of performance changes without adaptive messing with a/f at WOT."
I did not mean the computer corrects by looking @ the fuel pressure, I thought we both knew the computer does not do that, sorry I thought you'd understand what I was saying.
What I was trying to explain to you is that the computer does not trim fuel "injector pulsewidths" @ WOT. The computer stops looking at 02's @ 2volts over base ".98" on the throttle position sensor therefore anytime your @ say half throttle your computer goes into what's called open loop & A/F Ratio is determined by fuel pressure only.
I don't know anyone who made eec's or nothing but I've been doing this for 15 years & reprogramming computers in our cars for along time now.
For Instance: Just think about this, why would they make fuel pressure regulators & FMU's if they don't work, if the computer if going to undo "adaptive change" everything
oke:
What I was trying to explain to you is that the computer does not trim fuel "injector pulsewidths" @ WOT. The computer stops looking at 02's @ 2volts over base ".98" on the throttle position sensor therefore anytime your @ say half throttle your computer goes into what's called open loop & A/F Ratio is determined by fuel pressure only.
I don't know anyone who made eec's or nothing but I've been doing this for 15 years & reprogramming computers in our cars for along time now.
For Instance: Just think about this, why would they make fuel pressure regulators & FMU's if they don't work, if the computer if going to undo "adaptive change" everything
oke:
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OK. If for example, I lower my fuel pressure to lean out my a/f ratio. Make my dyno runs and notice increased horsepower. 3 mos later my idle kinda sucks and the car is no longer as peppy of the line. What has happened? Did the computer retain my new f/p and adapt to it, or does it change the fuel injector pulse (or whatever) to try to get it back to the way it was before my dyno run?
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Well if your too rich the computer will lean it out to acheive 14.7 yes but no ones going to try & lean there car out more then stoich, but this is immediate "not over time" but your WOT will not change & idle A/F ratio ain't gonna matter. If your noticing stumbling @ take off you got something else wrong, could be your tps sensor gone bad, 02's or any # of things but your a/f ratio is not going to cause your car to stumble if it's alittle bit off.
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bat-stang said:
That is exactly what it does (in bold).
Ray, I don't know where you are getting your imformation, but you are wrong. There are so many things wrong in that one single post, I don't know where to start.
The attempt to correct the lean or rich condition is immediate, but unless KAM is cleared, it takes some time to change the long term fuel trims.
Yes it will. Has been verified by numerous dataloggers, including myself.
Tell that to those with surging idle.
:lol: I've seen as little as .5 point off on the a/f cause a major stumble off idle. It's all in the combo. To make a blanket statement like that is simply irresponsible.
That's weird you having these problems, there must be something else wrong with your car. I almost 15 years experience have never seen such symptoms from just little A/F adjustment ".5" surging, stumbling & whatever else you said.
I'm not going to touch base on anything else you've said or waiste my time arguing with you about something that's right but unless it was a bad computer configuration or sensor or something that's the only thing that could cause them problems. Maybe that's your problem with yours :beer:
I'm not going to touch base on anything else you've said or waiste my time arguing with you about something that's right but unless it was a bad computer configuration or sensor or something that's the only thing that could cause them problems. Maybe that's your problem with yours :beer:
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Trust me, everything I have said is backed up by datalogs of eec commands, wideband readings, and most importantly of all other tuners who have seen the same things.
Don't even get me started on FPR's...
Don't even get me started on FPR's...
~Ray~ said:For Instance: Just think about this, why would they make fuel pressure regulators & FMU's if they don't work, if the computer if going to undo "adaptive change" everything
1) IMO. FPR's are made to correct your fuel pressure when you change fuel system components. Something simple as changing your stock 88lph pump for a 190 or 255 will drive your pressure up. Get an adjustable regulator and you can bring it back down to 39 psi base.
2) FMU's do work but they are only kicking in at WOT (or boost) and tend to overtax the injectors. I personally don't like driving 75psi behind the injectors.
I am not accusing of you not knowing this but there is a big difference in tuning for WOT and tuning for drivability on a modified car. Adaptive does play a critical role in the tuning of a mildly modified car.
Since you have been EEC tuning for a number of years you know that EEC tuning consists of MAF curve modifications, injector slope modifications, timing table changes, and fuel table changes. These changes are done for driviabilty and keep adaptive from f***ing with something as simple upping the fuel pressure over the long term.
With all that being said, adaptive can only change so much of what is occurring. I believe that adaptive can only change around 30% of fuel table commands based off what the 02's are seeing (of whatever a/f vs p/w is commanded in the EEC)
1: You sure about that, I just swapped a 90 for a 190 & mine did not change I don't think & my A/F ratio stayed exact "did not change @ all".
2: Agreed.
Adaptive if change is so little & besides the 02's are still going to trim to stoich so reguardless you'll be richer or leaner when you adjust the fpr as it goes from part throttle wich is stoich to fuel pressure.
I am currently using a Tweecer RT if that answers your question.
There only two things you need to change when tuning a car, fuel pressure & timing. Anything outside of this is fine tuning & is not necessary unless you need access to computer to be able to do part throttle things but you have to admit just being half a point off your A/F ratio will not make your car surge, stumble or fall on it's face as said above, member back in the day when there wasn't no dyno's & it was all by feel or recently when we'd have to wait ourselves till we can get to the dyno to see where our A/F ratios @ only to find out you are 2,3 points off to your amazement but your car still ran fine with non of the symptoms mentioned above :idea:
2: Agreed.
Adaptive if change is so little & besides the 02's are still going to trim to stoich so reguardless you'll be richer or leaner when you adjust the fpr as it goes from part throttle wich is stoich to fuel pressure.
I am currently using a Tweecer RT if that answers your question.
There only two things you need to change when tuning a car, fuel pressure & timing. Anything outside of this is fine tuning & is not necessary unless you need access to computer to be able to do part throttle things but you have to admit just being half a point off your A/F ratio will not make your car surge, stumble or fall on it's face as said above, member back in the day when there wasn't no dyno's & it was all by feel or recently when we'd have to wait ourselves till we can get to the dyno to see where our A/F ratios @ only to find out you are 2,3 points off to your amazement but your car still ran fine with non of the symptoms mentioned above :idea:
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~Ray~ said:
1) my fuel pressure jumped up 5 psi or so when I installed my 255 several years ago.
No I have only had very little surge when my a/f is off.
with my experience, managing my MAF curve and injector slopes have played a bigger factor than fuel pressure in all of my tunes. For example right now I having a major bucking problem when cruising. A/f's are still off by a point from what I am commanding (to the good side)
1BAD93SVT said:
looking back i have no idea why i posted this question. it doesn't make sense to me.
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