my mototron 60lb injector offset experience (o2's work again)
04-14-2005, 04:37 PM
#1
my mototron 60lb injector offset experience (o2's work again) I recently installed some mototron 60lb injectors. After getting the car up and running I noticed from logging that they o2 sensors would just hang rich at idle. I know the injector offset on these will be different vs the stockers and the 42lb injector I just pulled out.
I'm still in trying to get these things dialed in correctly, but so far i've been able to get better idle quality out of them by reducing the 55-80 Kpa by 20% as well as setting the short pulse limit to 1.505
My injector time would only go down to 1.8 mS before, but now it will dip to 1.7 mS occasionally.
This brought most of my idle LTFT's right back in line and caused my o2's to start cycling again.
I'll post up when I find out more.
I'm still in trying to get these things dialed in correctly, but so far i've been able to get better idle quality out of them by reducing the 55-80 Kpa by 20% as well as setting the short pulse limit to 1.505
My injector time would only go down to 1.8 mS before, but now it will dip to 1.7 mS occasionally.
This brought most of my idle LTFT's right back in line and caused my o2's to start cycling again.
I'll post up when I find out more.
04-15-2005, 11:17 AM
#3
OK, these mototron 60's are starting to frustrate me. I've done around 20 tunes in the last 2 days and I still can't get them right... grrr. I've started to do something very different from most, it goes against how the ECU works too. Unless someone has a better idea.
What i've notice as i'm sure everyone else has is that changing the IFR table does very little to affect LTFT's. My problem was way rich (-LTFTs) at idle and high vaccuum (-LTFTs) and way lean at close to atmospheric. What was really odd was that the split from rich to lean was right around 50 kPa. My idle and cruise O2's would also not cycle.
What I have been doing is moving away from adjusting the IFR table to get the LTFT's dialed in and instead changing the injector offset table. While this goes against every bone in my body it does seem to be working. I've basically changed the way the offset table works and have started to use it to pad or cut my fuel delivery needs depending on vacuum/boost.
Since my LTFT's are posative at low vacuum (closer to atmospheric) what i've done is add more time to the 50-0 kPa areas in the offset table. This adds more fuel to the calculation since the ECU now thinks that the injector has a signal to open time of 1.9 mS. Same deal goes for the high vac areas 50-80 kPa. but instead of adding to those areas, i've subtracted. This has netted me a good idle with cycling O2's under almost all conditions. The one exception being where i'm in cruise at very low throttle < 7-10 % and not in DFCO. I'm working to figure this one out still.
The main reason i'm using the offset table is because I don't believe it affects any of the other calculations since it's a constant table. I think that it just adds the constant to what ever the calculated injector pulse is. This way i'm not changing other constants that affect the other calculations the ECU does. The other reason I've tried to justify to myself is that the 2mS offset i'm running in the 0 kPa column is that I will never need less than 2mS of injector time at 0 kPa since most of the time the injectors will be at >50% duty cycle.
I know this method is unconventional, but it seems to be working for me. My car has great drivability so far. Just have to get it completely dialed in. I'll keep plugging along and see if I can get it to work good. If not, I guess i'll be going to a boost referenced regulator setup (should probably do this anyways).
Thoughts comments?
What i've notice as i'm sure everyone else has is that changing the IFR table does very little to affect LTFT's. My problem was way rich (-LTFTs) at idle and high vaccuum (-LTFTs) and way lean at close to atmospheric. What was really odd was that the split from rich to lean was right around 50 kPa. My idle and cruise O2's would also not cycle.
What I have been doing is moving away from adjusting the IFR table to get the LTFT's dialed in and instead changing the injector offset table. While this goes against every bone in my body it does seem to be working. I've basically changed the way the offset table works and have started to use it to pad or cut my fuel delivery needs depending on vacuum/boost.
Since my LTFT's are posative at low vacuum (closer to atmospheric) what i've done is add more time to the 50-0 kPa areas in the offset table. This adds more fuel to the calculation since the ECU now thinks that the injector has a signal to open time of 1.9 mS. Same deal goes for the high vac areas 50-80 kPa. but instead of adding to those areas, i've subtracted. This has netted me a good idle with cycling O2's under almost all conditions. The one exception being where i'm in cruise at very low throttle < 7-10 % and not in DFCO. I'm working to figure this one out still.
The main reason i'm using the offset table is because I don't believe it affects any of the other calculations since it's a constant table. I think that it just adds the constant to what ever the calculated injector pulse is. This way i'm not changing other constants that affect the other calculations the ECU does. The other reason I've tried to justify to myself is that the 2mS offset i'm running in the 0 kPa column is that I will never need less than 2mS of injector time at 0 kPa since most of the time the injectors will be at >50% duty cycle.
I know this method is unconventional, but it seems to be working for me. My car has great drivability so far. Just have to get it completely dialed in. I'll keep plugging along and see if I can get it to work good. If not, I guess i'll be going to a boost referenced regulator setup (should probably do this anyways).
Thoughts comments?
04-15-2005, 12:58 PM
#4
i HAVE a boost referenced regulator and mine still acts like yours...PLUS my base fp is at 55psi with the hose disconnected. I may try your method...dunno if it could get any worse....dunno how others have zero problems idleing...my cam is only 215/215 114lsa
Trending Topics
08-21-2005, 08:55 PM
#10
TECH Fanatic
iTrader: (9)
Join Date: Nov 2004
Location: Bucks County, PA
Posts: 1,376
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by wait4me
Change your injector minimum on times.... It will fix your problem. Not the offset tables. The injectors dont have permission to slow down past a point unless changed.
I have 1.277 all the way across the board. 0-8000rpms
08-21-2005, 09:15 PM
#12
without changing the prop closed loop fuel you are introducing too large of a fuel shot for oscillation.
136.00000 316.00000 480.00000 604.00000 691.00000 734.00000 752.00000 728.00000 685.00000
try those values in the closed loop prop fuel. you may need to decrease them a bit from what i have. these are my settings for 38# gm injectors
136.00000 316.00000 480.00000 604.00000 691.00000 734.00000 752.00000 728.00000 685.00000
try those values in the closed loop prop fuel. you may need to decrease them a bit from what i have. these are my settings for 38# gm injectors
