MAF Table ?
MAF Table ? In the MAF table do you increase the numbers to make add fuel or do you decrease the numbers to add fuel?
The reason I ask is that my low RPM cruising and low RPM throttle tip in are choppy(burps and farts). I have gone on several 20+ minute runs datalogging and my STrims and LTrims are very good(-4 to -6 with stock maf and -7 to -9 with my non-stock maf). This is really killing me because is sounds like butt and keeps unlocking the converter on the highway.
Please help
Josh
The reason I ask is that my low RPM cruising and low RPM throttle tip in are choppy(burps and farts). I have gone on several 20+ minute runs datalogging and my STrims and LTrims are very good(-4 to -6 with stock maf and -7 to -9 with my non-stock maf). This is really killing me because is sounds like butt and keeps unlocking the converter on the highway.
Please help
Josh
The MAF table is stock right now...haven't touched it. But the poor performance is at low RPMs only(under 5500hz on the MAF frequency) so I figured I would tweak the table from 1500-5500. Is that bad idea?
Anything above 2500rpms and the performance is nice and smooth so I did not think adjusting the IFR table would concentrate the change in my problem area.
Thanks
Josh
Anything above 2500rpms and the performance is nice and smooth so I did not think adjusting the IFR table would concentrate the change in my problem area.
Thanks
Josh
OK, back to the top.
I have tried to adjust the MAF table in the problem areas and I still have the low rpm studder. I have run my LTrims anywhere from -1 to -12 depending on the MAF values. At first I had the LTrims in the -4 to -6 area but I was getting the studder so first thing I did was put my stock MAF back on. It changed my LTrims a little but the studder was still there. So next I tried adjusting the MAF table by small percentages in the problem areas (under 5500hz) and still I have the studder. Right now my LTrims are hovering around -12 and the studder is still there.
This studder is causing my converter to unlock while cruising on the highway. It only happens under 2500 rpms at light load or throttle tip in(under 5500hz on the MAF).
Please help me solve this tuning issue.
Thanks
Josh
I have tried to adjust the MAF table in the problem areas and I still have the low rpm studder. I have run my LTrims anywhere from -1 to -12 depending on the MAF values. At first I had the LTrims in the -4 to -6 area but I was getting the studder so first thing I did was put my stock MAF back on. It changed my LTrims a little but the studder was still there. So next I tried adjusting the MAF table by small percentages in the problem areas (under 5500hz) and still I have the studder. Right now my LTrims are hovering around -12 and the studder is still there.
This studder is causing my converter to unlock while cruising on the highway. It only happens under 2500 rpms at light load or throttle tip in(under 5500hz on the MAF).
Please help me solve this tuning issue.
Thanks
Josh
Stock '98 injectors and the IFR table is copied from a 98 PCM so it should match the injectors.
Example:
Stock 99 table first block in IFR table= 3.11
Stock 98 table first block in IFR table= 3.16
The injectors did sit for about 8 months with out being used so I guess they could be gunked up. But I did hand clean them and use machine oil on the ends before storage.
Do you think I should go back to the stock MAF table and adjust the IFR table?
Thanks
Josh
Example:
Stock 99 table first block in IFR table= 3.11
Stock 98 table first block in IFR table= 3.16
The injectors did sit for about 8 months with out being used so I guess they could be gunked up. But I did hand clean them and use machine oil on the ends before storage.
Do you think I should go back to the stock MAF table and adjust the IFR table?
Thanks
Josh
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From: Texas, it's like your state, but better.
Josh,
if you've got stock tables in there, i'd go back w/ a stock maf, and adjust the IFR. you can do this, and just read the plugs to get it right.
i didnt realize that you were in san antonio.
im going to be at the SAR the next 3 weekends running the brackets in my uncles buick. just a stock eliminator ol bracket brick runnin 11's. should be fun. it'd be cool to meet ya if you make it out there every so often. ;D
if you've got stock tables in there, i'd go back w/ a stock maf, and adjust the IFR. you can do this, and just read the plugs to get it right.
i didnt realize that you were in san antonio.
im going to be at the SAR the next 3 weekends running the brackets in my uncles buick. just a stock eliminator ol bracket brick runnin 11's. should be fun. it'd be cool to meet ya if you make it out there every so often. ;D
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That is what I am going to try next. Hopefully I can get this thing dialed in.
Tell me the dates that you are going to be there and I will try to come out, new motor needs some miles on it anyway. I have been looking for an excuse to go(I was deployed for 4 months so I have been going through track withdrawals).
Thanks
Josh
Tell me the dates that you are going to be there and I will try to come out, new motor needs some miles on it anyway. I have been looking for an excuse to go(I was deployed for 4 months so I have been going through track withdrawals).
Thanks
Josh
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Originally Posted by NO CATZZ
In the MAF table do you increase the numbers to make add fuel or do you decrease the numbers to add fuel?
The reason I ask is that my low RPM cruising and low RPM throttle tip in are choppy(burps and farts). I have gone on several 20+ minute runs datalogging and my STrims and LTrims are very good(-4 to -6 with stock maf and -7 to -9 with my non-stock maf). This is really killing me because is sounds like butt and keeps unlocking the converter on the highway.
Please help
Josh
The reason I ask is that my low RPM cruising and low RPM throttle tip in are choppy(burps and farts). I have gone on several 20+ minute runs datalogging and my STrims and LTrims are very good(-4 to -6 with stock maf and -7 to -9 with my non-stock maf). This is really killing me because is sounds like butt and keeps unlocking the converter on the highway.
Please help
Josh
Have you made changes to the VE table in the problem areas. If VE is too lean, at a given kPa/RPM, not enough fuel is added on throttle transitions-> learned from NoGo- He is the MAN!!! You get a flatspot or bog.
Is this what you mean?? joel
The only VE changes I have made are for startup...in other words 1000 rpm and below.
Good news. I put my MAF table back to stock, changed my IFR table back to stock(had the wrong one loaded) and the studder is almost gone. Throttle tip in and part throttle cruise is much smoother now but I still have the converter lock up issue. It will lock up intermittantly but will not stay locked up for more than a couple minutes.
So progress is being made and things are getting better.
Vents, PM me with the times and I will see if I can make it out there.
Thanks,
Josh
Good news. I put my MAF table back to stock, changed my IFR table back to stock(had the wrong one loaded) and the studder is almost gone. Throttle tip in and part throttle cruise is much smoother now but I still have the converter lock up issue. It will lock up intermittantly but will not stay locked up for more than a couple minutes.
So progress is being made and things are getting better.
Vents, PM me with the times and I will see if I can make it out there.
Thanks,
Josh
I did some minor tranny adjustments. Line pressure is still stock but I raised the lockup points and shift points. 2.73 gears and a 3500 stall don't mix well when it locks up at 25 or 30 mph. The thing is that this tranny setup worked perfectly with the old motor combo. I do have a bigger cam now...could the MAP be messing with the lockup performance?
Thanks
Josh
Thanks
Josh
What you call a stutter sounds like misfires, and it may
be due to something besides the MAF (which from the
trim info seems perfectly normal). What about the
ignition side? What about low-pulse-width injector
balance? The MAF is a global actor and I think you
have a "lumpy" problem.
be due to something besides the MAF (which from the
trim info seems perfectly normal). What about the
ignition side? What about low-pulse-width injector
balance? The MAF is a global actor and I think you
have a "lumpy" problem.
jimmyblue,
It does act like a misfire but I just attributed it to improper fueling. For ignition I am running NGK-TR55 plugs and MSD wires, everything else is stock. I have not looked into the pulse width yet but maybe I should.
Update:
After the changes made above my LTrims are +2.3 on both sides. The stutter/misfire is still there but not as bad as before. I may have to look into some fuel issues...the car sat for about 8 months while I did the rebuild so my fuel filter, lines, and injectors may need some attention. It sat with a 50/50 mix of 93 and race gas so it should not have gummed up too bad but you never know. I wish getting injectors serviced was not so expensive. I did run some injector cleaner through the last tank of gas but we all know that is marginal maintanence at best.
Thanks to everyone that has helped and please keep the advice coming.
Thanks,
Josh
It does act like a misfire but I just attributed it to improper fueling. For ignition I am running NGK-TR55 plugs and MSD wires, everything else is stock. I have not looked into the pulse width yet but maybe I should.
Update:
After the changes made above my LTrims are +2.3 on both sides. The stutter/misfire is still there but not as bad as before. I may have to look into some fuel issues...the car sat for about 8 months while I did the rebuild so my fuel filter, lines, and injectors may need some attention. It sat with a 50/50 mix of 93 and race gas so it should not have gummed up too bad but you never know. I wish getting injectors serviced was not so expensive. I did run some injector cleaner through the last tank of gas but we all know that is marginal maintanence at best.
Thanks to everyone that has helped and please keep the advice coming.
Thanks,
Josh