Car horribly tuned after 30# inj, +25% Ltrims, 4 deg knock
07-11-2003, 01:29 PM
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Car horribly tuned after 30# inj, +25% Ltrims, 4 deg knock Im having some real trouble getting my car even CLOSE to tuned with ls1edit...
After swapping the 30# injectors in the car, i dynoed it and the whole curve was very low through the mid-low range.
I went out and autotap logged for the first time last night.
The car would run @ +25% both banks LTFT at all times when idling or light throttle from stoplight to stoplight cruising around town...occasionally i would see it dip to 20% or so for a second and go right back to 25%.
On the freeway cruising at a set speed 65 mph, they would goto 18-21%.
Then i did some WOT testing. The moment i hit WOT it goes to 4 degrees knock retard solid, from 1st gear till i let off at top of 3rd. The moment id hit WOT timing would pull to 12 degrees, and stay between 12-18 degrees of timing the entire 1/4 mile run.
Fuel trims would stay @ 25% anytime the car was @ WOT.
I set my injector flow rates to :
0:4.36 5:4.39 10:4.41 15:4.45 20:4.47 25:3.73 30:3.75 35:4.55 40:4.58 45:4.59 50:4.63 55:4.65 60:4.68 65:4.70 70:4.73 75:4.76 80:4.77
[b] What is the correct way for me to tune the car from this point? Do i start multiplying the MAF table until the LTrims come down? or do i start modifying the injector flow table? If i do need to change the injector flow, then at what point do i quit using the injector flow table to bring them down and start changing the maf table to change it?
Im always confused on when to use one table or the other for tuning. Which one is for WOT tuning and which one for part throttle?
I thought i should modify the injector flow until part throttle LTrims go to -2 to -8 and then use the MAF table to adjust LTrims @ WOT?
After swapping the 30# injectors in the car, i dynoed it and the whole curve was very low through the mid-low range.
I went out and autotap logged for the first time last night.
The car would run @ +25% both banks LTFT at all times when idling or light throttle from stoplight to stoplight cruising around town...occasionally i would see it dip to 20% or so for a second and go right back to 25%.
On the freeway cruising at a set speed 65 mph, they would goto 18-21%.
Then i did some WOT testing. The moment i hit WOT it goes to 4 degrees knock retard solid, from 1st gear till i let off at top of 3rd. The moment id hit WOT timing would pull to 12 degrees, and stay between 12-18 degrees of timing the entire 1/4 mile run.
Fuel trims would stay @ 25% anytime the car was @ WOT.
I set my injector flow rates to :
0:4.36 5:4.39 10:4.41 15:4.45 20:4.47 25:3.73 30:3.75 35:4.55 40:4.58 45:4.59 50:4.63 55:4.65 60:4.68 65:4.70 70:4.73 75:4.76 80:4.77
[b] What is the correct way for me to tune the car from this point? Do i start multiplying the MAF table until the LTrims come down? or do i start modifying the injector flow table? If i do need to change the injector flow, then at what point do i quit using the injector flow table to bring them down and start changing the maf table to change it?
Im always confused on when to use one table or the other for tuning. Which one is for WOT tuning and which one for part throttle?
I thought i should modify the injector flow until part throttle LTrims go to -2 to -8 and then use the MAF table to adjust LTrims @ WOT?
07-11-2003, 01:38 PM
#2
Re: Car horribly tuned after 30# inj, +25% Ltrims, 4 deg knock What ever you do, don't adjust your MAF, you want to adjust you Main VE table.
Since you have heads and a cam, you have to tell the computer that you have more volume of air coming into the engine.
Take small steps when doing this, add 10% at first, to your lower RPM's and see how that goes...
Since you have heads and a cam, you have to tell the computer that you have more volume of air coming into the engine.
Take small steps when doing this, add 10% at first, to your lower RPM's and see how that goes...
07-11-2003, 02:13 PM
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Re: Car horribly tuned after 30# inj, +25% Ltrims, 4 deg knock I thought for LTrim tuning you adjust the "MAF vs Freq Calibration" table??? Ive never heard about changing the Main VE Table. I just looked at the main ve table, where do you even begin to tune in there? Im not familiar with editing that table.
I have a GSS340 fuel pump and everything should be good.
Yea i run a shop but ive been building carbed SBC/BBC, mopar, ford etc for years but im so new to EFI that its killing me
I have a dynojet chassis dyno, ls1edit, wideband o2 etc. If only this ls1 was carbed, id have this bitch tuned in 10 minutes....
Where do i start here?
I have a GSS340 fuel pump and everything should be good.
Yea i run a shop but ive been building carbed SBC/BBC, mopar, ford etc for years but im so new to EFI that its killing me
I have a dynojet chassis dyno, ls1edit, wideband o2 etc. If only this ls1 was carbed, id have this bitch tuned in 10 minutes....
Where do i start here?
07-11-2003, 02:57 PM
#5
Re: Car horribly tuned after 30# inj, +25% Ltrims, 4 deg knock Don't use the VE tables if you are using a MAF.Use the injector flow rate tables .Scale a lower # -i.e. multiply by 85-90 %. PCM will then add more fuel and LTFTs will come down. What is your fuel pressure??? At 58#s this should work. KPA 0 5 10 15 20 25 30
3.62 3.64 3.66 3.69 3.71 3.73 3.75
KPA 35 40 45 50 55 60 65
3.77 3.80 3.81 3.84 3.86 3.88 3.90
KPA 70 75 80
3.92 3.95 3.96
Hope you can unscramble that! Sorry.Good luck! post back.
joel (Bink)
3.62 3.64 3.66 3.69 3.71 3.73 3.75
KPA 35 40 45 50 55 60 65
3.77 3.80 3.81 3.84 3.86 3.88 3.90
KPA 70 75 80
3.92 3.95 3.96
Hope you can unscramble that! Sorry.Good luck! post back.
joel (Bink)
07-11-2003, 03:03 PM
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Re: Car horribly tuned after 30# inj, +25% Ltrims, 4 deg knock
I thought i should modify the injector flow until part throttle LTrims go to -2 to -8 and then use the MAF table to adjust LTrims @ WOT?
joel(Bink)
07-11-2003, 03:20 PM
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Re: Car horribly tuned after 30# inj, +25% Ltrims, 4 deg knock Just read this on another board...is this correct?
MAF table:
"If you are trying to lean your mixture and bring your LTFT's down into a -2 to -8 average range from a positive value for cruising RPMs, do not subtract from your MAF table, instead add. (Note, max I was able to scale was around 15%, and had to do it to get the LTFT right with this damn Pace MAF(VVM))
Once you get your LTFT's to a decent range, then you can start scaling your PE vs RPM table to tune for WOT runs"
Now should i be going after injector table or the MAF table? The PE vs RPM file has values of 1.1-1.24 What is the correct way to adjust this table?
I was always under the impression that Injector Flow Rate tables should never be touched if you have stock injectors. Since i have larger i used a spreadsheet on here to calculate my new injector flow rates for the new injectors.
And i was told to tune the MAF table for cruising part throttle and the PE vs RPM table for WOT. Is this incorrect?
Binksz06 Those values you gave me are the stock values that were in the computer with the factory 28.8lb injectors. Now im running 30# accels which are in the 35-36lb range @ 58 psi....
MAF table:
"If you are trying to lean your mixture and bring your LTFT's down into a -2 to -8 average range from a positive value for cruising RPMs, do not subtract from your MAF table, instead add. (Note, max I was able to scale was around 15%, and had to do it to get the LTFT right with this damn Pace MAF(VVM))
Once you get your LTFT's to a decent range, then you can start scaling your PE vs RPM table to tune for WOT runs"
Now should i be going after injector table or the MAF table? The PE vs RPM file has values of 1.1-1.24 What is the correct way to adjust this table?
I was always under the impression that Injector Flow Rate tables should never be touched if you have stock injectors. Since i have larger i used a spreadsheet on here to calculate my new injector flow rates for the new injectors.
And i was told to tune the MAF table for cruising part throttle and the PE vs RPM table for WOT. Is this incorrect?
Binksz06 Those values you gave me are the stock values that were in the computer with the factory 28.8lb injectors. Now im running 30# accels which are in the 35-36lb range @ 58 psi....
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07-11-2003, 04:26 PM
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Re: Car horribly tuned after 30# inj, +25% Ltrims, 4 deg knock These engines do NOT use the VE tables other then for starting, do not muck with it the engine is MAF driven, not MAP.
Fuel is adjusted by injectors flow not MAF.
Your asking for problems as I stated in another post of your's that your using the SLP MAF, take and throw it away and use a stock ZO6 MAF if your using a Z06 PCM flash file.
Or unsolder that cheapo 1 penny resistor SLP puts in what is really a stock 01 MAF because they are clipping the outut freq so it looks like a 75 mm MAF and you end up with unmetered airflow that is then seen only after the fact by the 02s.
Also I am not sure it an Accel 30 is 30 lbs at LSX fuel rail pressure, it so they are too small, if they are 30 at 43 lbs then they are OK to use but no way then would it be +25 lean so it again points to your MAF and its table are way out of line.
Tune with stock MAF and you'll not have these problems.
Fuel is adjusted by injectors flow not MAF.
Your asking for problems as I stated in another post of your's that your using the SLP MAF, take and throw it away and use a stock ZO6 MAF if your using a Z06 PCM flash file.
Or unsolder that cheapo 1 penny resistor SLP puts in what is really a stock 01 MAF because they are clipping the outut freq so it looks like a 75 mm MAF and you end up with unmetered airflow that is then seen only after the fact by the 02s.
Also I am not sure it an Accel 30 is 30 lbs at LSX fuel rail pressure, it so they are too small, if they are 30 at 43 lbs then they are OK to use but no way then would it be +25 lean so it again points to your MAF and its table are way out of line.
Tune with stock MAF and you'll not have these problems.
07-11-2003, 06:13 PM
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Re: Car horribly tuned after 30# inj, +25% Ltrims, 4 deg knock You can tune your fueling via MAF adjustments or IFR - the IFR will only alter the fueling, while the MAF will effect a few other components. Obviously if the inaccuracy is coming from the MAF then you would want to alter that, if it's coming from the injectors, you would want to change those.
Since realistically you don't know I would use whichever way works best for you. The IFR is probably a little "safer" to start out with.
As has been mentioned, the VE tables are only referenced during cranking and if the MAF dies/is disconnected - otherwise there is no point in touching them.
Your numbers are actually on the small side for injectors - so if anything you should be at negative l-trims instead of positive (too much fuel).
The fact that you are railed out at +25 should tell you that something is not working right - either
1) MAF is bad/faulty/incorrect calibration
2) Injectors are bad/faulty/incorrect unit
3) Fuel pressure is not being maintained
4) You have a massive exhaust leak
5) O2's are dead
I would suggest first swapping to a stock MAF and seeing if the problem goes away. (I am assuming fuel pressure *is* being maintained properly?). Next I would dump the Accell 30lb/hr injectors - I have seen more problems with crappy Accell injectors than just about any other brand - or all other brands combined. I would sell them and pick up a set of SVO 30's.
Check for exhaust leaks, and watch your O2 voltage to make sure it is swinging properly when in closed loop (O2's aren't dead).
Since realistically you don't know I would use whichever way works best for you. The IFR is probably a little "safer" to start out with.
As has been mentioned, the VE tables are only referenced during cranking and if the MAF dies/is disconnected - otherwise there is no point in touching them.
Your numbers are actually on the small side for injectors - so if anything you should be at negative l-trims instead of positive (too much fuel).
The fact that you are railed out at +25 should tell you that something is not working right - either
1) MAF is bad/faulty/incorrect calibration
2) Injectors are bad/faulty/incorrect unit
3) Fuel pressure is not being maintained
4) You have a massive exhaust leak
5) O2's are dead
I would suggest first swapping to a stock MAF and seeing if the problem goes away. (I am assuming fuel pressure *is* being maintained properly?). Next I would dump the Accell 30lb/hr injectors - I have seen more problems with crappy Accell injectors than just about any other brand - or all other brands combined. I would sell them and pick up a set of SVO 30's.
Check for exhaust leaks, and watch your O2 voltage to make sure it is swinging properly when in closed loop (O2's aren't dead).
07-11-2003, 09:19 PM
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Re: Car horribly tuned after 30# inj, +25% Ltrims, 4 deg knock Ok I just got off 2 hours of playing on my dyno.......
the car dynoed a PATHETIC 345 rwhp. A/f Ratios were a solid 12.5:1 all the way across, going to about 12.8:1 @ 6800 rpm. But when i autotapped the car last night i was seeing 12-15 degrees timing all the way across and tons of knock retard... geez im confused...Ive got the injectors close...so would that timing cost me that much HP?
Rear wheel torque was 305 , horsepower peak @ 6800 345 rwhp.
I put the stock tuning back in the car (for 28.8 injectors) and nothing else but a rev limiter change and the car made 306 rwhp.
My th350 /w 3800 converter cant be robbing me of 50-60 rwhp can it? this combination of a 227/230 Thunder cam, CNC heads (flow 290), ls6 intake, longtubes, 3" h-pipe/catback etc should make over 400 rwhp with no problem..i really dont understand whats going on...
the car dynoed a PATHETIC 345 rwhp. A/f Ratios were a solid 12.5:1 all the way across, going to about 12.8:1 @ 6800 rpm. But when i autotapped the car last night i was seeing 12-15 degrees timing all the way across and tons of knock retard... geez im confused...Ive got the injectors close...so would that timing cost me that much HP?
Rear wheel torque was 305 , horsepower peak @ 6800 345 rwhp.
I put the stock tuning back in the car (for 28.8 injectors) and nothing else but a rev limiter change and the car made 306 rwhp.
My th350 /w 3800 converter cant be robbing me of 50-60 rwhp can it? this combination of a 227/230 Thunder cam, CNC heads (flow 290), ls6 intake, longtubes, 3" h-pipe/catback etc should make over 400 rwhp with no problem..i really dont understand whats going on...
07-13-2003, 02:58 PM
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Re: Car horribly tuned after 30# inj, +25% Ltrims, 4 deg knock 5-6 degrees of knock retard can cost you up to 20rwhp loss! Right now I am having the same problem as you are with the Ltrims being at 25%. The first thing I am going to do is throw the SLP in a local lake and get a calibrated MAF and retune. I would suggest you find a local lake to!
Doug
00 Pontiac
Doug
00 Pontiac
07-13-2003, 05:49 PM
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Re: Car horribly tuned after 30# inj, +25% Ltrims, 4 deg knock found that the knock sensor connector was unplugged...someones bad joke...but the car is running permanently in low octane mode...probably because of my car being a swap...ill copy the maps over...
