Timing at idle
06-27-2008, 12:30 PM
#1
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Timing at idle
Ive been doing some tuning with my car for e85 and I cant seem to get the car to idle very good. It kind of bounces between 900 and 1300 RPM. Could this be a timing issue? How does changing the timing at idle effect things?
06-27-2008, 02:45 PM
#2
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Timing at idle works as a second idle air controller. Its faster than the iac motor is at responding to over and under target idle.
Post a log of the car idling cold and warmed up or email it to me, and I can probably tell you what needs adjustment.
I will also need to know what exactly you modified to get the tune to work with e85 as there are a couple of ways to go about doing it.
Post a log of the car idling cold and warmed up or email it to me, and I can probably tell you what needs adjustment.
I will also need to know what exactly you modified to get the tune to work with e85 as there are a couple of ways to go about doing it.
06-30-2008, 06:56 PM
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Timing at idle works as a second idle air controller. Its faster than the iac motor is at responding to over and under target idle.
Post a log of the car idling cold and warmed up or email it to me, and I can probably tell you what needs adjustment.
I will also need to know what exactly you modified to get the tune to work with e85 as there are a couple of ways to go about doing it.
Post a log of the car idling cold and warmed up or email it to me, and I can probably tell you what needs adjustment.
I will also need to know what exactly you modified to get the tune to work with e85 as there are a couple of ways to go about doing it.
http://home.comcast.net/~jared111481/hot_idle.uni
http://home.comcast.net/~jared111481/cold_idle.uni
On the cold idle in the first half of it I had my wideband reading into the a/c output. I disconnected it half way through b/c it was turning the fans on and off.
For the e85 I changed my injector constant, cant remeber by how much exactly, but I think it was by about 20% so it add more fuel. I also added 3* of timing throught the whole rpm range.
06-30-2008, 11:28 PM
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Well for starters, your left o2 is bad and throwing a dtc so you're staying in open loop GET THAT FIXED. For two 20% is not enough extra fuel for e85... its more like 30-33% for a baseline. Just take whatever your injectors are rated at and then multiply by .70 and use that as your injector constant. You are running very lean your working o2 sensor on the right side is just sitting in the low 100's because you're so lean.
The surging is from it being in open loop and lean and the map fluctiations at putting you into an area where the a/f ratio is set to a richer number in both ve and open loop tables... the car gets enough fuel and speeds up and vacuum picks up it changes target a/f ratios in the open loop table and then leans out and slows back down. Basicly the car is chasing its tail.
Go into your closed tps advance settings and set the 400-800-1200 column to about 27-28* after you fix your o2 sensor and injector constant. Then go into the idle over and underspeed spark advance tables and zero it out about 50rpm above or below target idle to further steady your timing.
Do not drive the car until you at least readjust your injector constant for propper fuel supply and fix the o2 sensor thats dead so you can see how you're doing on fuel trims.
BTW is there a reason you're running the car in speed density mode instead of maf mode? It would be alot more forgiving for you just to verify everything is ok in maf mode before you start tuning.
My advice for you in the future is to do more research before you start tinkering with something like this and consult with people who are experts first. Otherwise you'll be needing a new motor real soon, tuning a high performance engine is one place where you dont get do overs. Once a motor is hurt its hurt.
The surging is from it being in open loop and lean and the map fluctiations at putting you into an area where the a/f ratio is set to a richer number in both ve and open loop tables... the car gets enough fuel and speeds up and vacuum picks up it changes target a/f ratios in the open loop table and then leans out and slows back down. Basicly the car is chasing its tail.
Go into your closed tps advance settings and set the 400-800-1200 column to about 27-28* after you fix your o2 sensor and injector constant. Then go into the idle over and underspeed spark advance tables and zero it out about 50rpm above or below target idle to further steady your timing.
Do not drive the car until you at least readjust your injector constant for propper fuel supply and fix the o2 sensor thats dead so you can see how you're doing on fuel trims.
BTW is there a reason you're running the car in speed density mode instead of maf mode? It would be alot more forgiving for you just to verify everything is ok in maf mode before you start tuning.
My advice for you in the future is to do more research before you start tinkering with something like this and consult with people who are experts first. Otherwise you'll be needing a new motor real soon, tuning a high performance engine is one place where you dont get do overs. Once a motor is hurt its hurt.
07-01-2008, 08:24 AM
#6
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Well for starters, your left o2 is bad and throwing a dtc so you're staying in open loop GET THAT FIXED. For two 20% is not enough extra fuel for e85... its more like 30-33% for a baseline. Just take whatever your injectors are rated at and then multiply by .70 and use that as your injector constant. You are running very lean your working o2 sensor on the right side is just sitting in the low 100's because you're so lean.
The surging is from it being in open loop and lean and the map fluctiations at putting you into an area where the a/f ratio is set to a richer number in both ve and open loop tables... the car gets enough fuel and speeds up and vacuum picks up it changes target a/f ratios in the open loop table and then leans out and slows back down. Basicly the car is chasing its tail.
Go into your closed tps advance settings and set the 400-800-1200 column to about 27-28* after you fix your o2 sensor and injector constant. Then go into the idle over and underspeed spark advance tables and zero it out about 50rpm above or below target idle to further steady your timing.
Do not drive the car until you at least readjust your injector constant for propper fuel supply and fix the o2 sensor thats dead so you can see how you're doing on fuel trims.
BTW is there a reason you're running the car in speed density mode instead of maf mode? It would be alot more forgiving for you just to verify everything is ok in maf mode before you start tuning.
My advice for you in the future is to do more research before you start tinkering with something like this and consult with people who are experts first. Otherwise you'll be needing a new motor real soon, tuning a high performance engine is one place where you dont get do overs. Once a motor is hurt its hurt.
The surging is from it being in open loop and lean and the map fluctiations at putting you into an area where the a/f ratio is set to a richer number in both ve and open loop tables... the car gets enough fuel and speeds up and vacuum picks up it changes target a/f ratios in the open loop table and then leans out and slows back down. Basicly the car is chasing its tail.
Go into your closed tps advance settings and set the 400-800-1200 column to about 27-28* after you fix your o2 sensor and injector constant. Then go into the idle over and underspeed spark advance tables and zero it out about 50rpm above or below target idle to further steady your timing.
Do not drive the car until you at least readjust your injector constant for propper fuel supply and fix the o2 sensor thats dead so you can see how you're doing on fuel trims.
BTW is there a reason you're running the car in speed density mode instead of maf mode? It would be alot more forgiving for you just to verify everything is ok in maf mode before you start tuning.
My advice for you in the future is to do more research before you start tinkering with something like this and consult with people who are experts first. Otherwise you'll be needing a new motor real soon, tuning a high performance engine is one place where you dont get do overs. Once a motor is hurt its hurt.
A little more background would have been helpful. The car is intentionally in open loop, I dont know if its placement of the O2s or what, but they always read lean! I have a close eye on my wideband, there is a lean spot here and there when it fluctuates at idle. I know the left side O2 is bad. Also, it is a turbo car, very common to tune with no MAF. 20-25%% more fuel has been fine for part throttle driving on my car. I have added about 35% WOT.
Ill check out the closed TPS advanced settings. That I dont think I have touched those.
Thanks
07-01-2008, 09:42 AM
#7
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Well that makes a little more sense then. As long as you're seeing fine readings on the wideband you should be ok. Its just interesting that your idle kicks up at the exact same time as your narrow band shows going rich.
Look in your open loop a/f ratio table around idle rpm and see if theres kind of a gap where you idle where it comes from a normal a/f to a rich one. If there isnt look into the ve table and try to smooth it out around where you idle at. Adding or subtracting here will add or subtract fuel and richen or lean the idle.
You dont need to change the fuel injector size because you're adding or subtracting the necessary fuel with the open loop portion of the tune. If you went into closed loop and could trust your o2's you would be dead lean.
I didnt realize you were on boost. I never use a maf on a boosted car either. Where are your o2's located at? It really doesnt matter as long as your wideband is showing you lamba = 1 during cruise.
Look in your open loop a/f ratio table around idle rpm and see if theres kind of a gap where you idle where it comes from a normal a/f to a rich one. If there isnt look into the ve table and try to smooth it out around where you idle at. Adding or subtracting here will add or subtract fuel and richen or lean the idle.
You dont need to change the fuel injector size because you're adding or subtracting the necessary fuel with the open loop portion of the tune. If you went into closed loop and could trust your o2's you would be dead lean.
I didnt realize you were on boost. I never use a maf on a boosted car either. Where are your o2's located at? It really doesnt matter as long as your wideband is showing you lamba = 1 during cruise.
07-01-2008, 09:58 AM
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My O2s are in the manifolds before the turbo. I am wondering if there is just to much heat and pressure there for them to work properly. My Wideband is in the downpipe. Next time I have the downpipe out Im going to weld in a couple of bungs and move the o2s there to see if it helps any.
Ill check out everything you mentioned above. Thanks again.
Ill check out everything you mentioned above. Thanks again.
07-01-2008, 02:32 PM
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Also considering this being a turbo build, i would shoot more for 23 degrees or so of timing at idle, 27 may be too much and cause the engine to build too much heat in traffic.
I would say there is probably way too much heat in the manifolds for the narrow band o2's to deal with it as they are not heat referenced.
Another tuning strategy you might consider is that you could just put your injector constant in as what the injectors are rated at if you plan to stay in open loop. Then just command stoich or max power a/f ratio for e85 in the open loop a/f tables. The downside to that is you'd lose all the calibration you have done so far.
I would say there is probably way too much heat in the manifolds for the narrow band o2's to deal with it as they are not heat referenced.
Another tuning strategy you might consider is that you could just put your injector constant in as what the injectors are rated at if you plan to stay in open loop. Then just command stoich or max power a/f ratio for e85 in the open loop a/f tables. The downside to that is you'd lose all the calibration you have done so far.
07-01-2008, 03:28 PM
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With my injector constant set to what my injectors are reated for I dont have enough range in the VE tables to keep it rich enought WOT. Would it be better to change the target a/f in the open loop table than change the injector constant?
07-01-2008, 04:23 PM
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What i was suggesting is to set it to what its at.
Then change the target a/f ratio in the open loop tables.
Then adjust ve as necessary.
If you do it that way it should give you plenty of range to get it adjusted. By changing ve you're just altering the amount of air it thinks its getting vs the target a/f ratio.
Basicly what the computer does since you're in sd mode open loop is; it has its target air fuel ratio in the open loop table. That tells it how much fuel to add against airflow. It uses the values in the ve table for a certain rpm and map reading to decide how much air you are flowing at that moment. So you can get your a/f in line by then adjusting the ve table in that map/rpm cell until your a/f ratio on the wideband agrees with what your target a/f is in the open loop table for that rpm.
The caveat to all this is: if what you have is working for you besides the idle and it all makes sense to you tuning wise, just go with it. If your a/f is all in line then you're good to go it doesnt matter how you get there just as long as its correct.
Then change the target a/f ratio in the open loop tables.
Then adjust ve as necessary.
If you do it that way it should give you plenty of range to get it adjusted. By changing ve you're just altering the amount of air it thinks its getting vs the target a/f ratio.
Basicly what the computer does since you're in sd mode open loop is; it has its target air fuel ratio in the open loop table. That tells it how much fuel to add against airflow. It uses the values in the ve table for a certain rpm and map reading to decide how much air you are flowing at that moment. So you can get your a/f in line by then adjusting the ve table in that map/rpm cell until your a/f ratio on the wideband agrees with what your target a/f is in the open loop table for that rpm.
The caveat to all this is: if what you have is working for you besides the idle and it all makes sense to you tuning wise, just go with it. If your a/f is all in line then you're good to go it doesnt matter how you get there just as long as its correct.
07-01-2008, 05:38 PM
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Depends on the cell actually but its usually upper 90s in the upper rpm and map pressure.
I think Im going to do some more work on my 2 bar tune. Ive got the sensor and Ive got the base tune started but I was just so sick of tuning at the time that I put in my 1 bar map so I could drive the car.
I think Im going to do some more work on my 2 bar tune. Ive got the sensor and Ive got the base tune started but I was just so sick of tuning at the time that I put in my 1 bar map so I could drive the car.
07-01-2008, 10:02 PM
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I think the closed TPS timing table was the trick, I had never touched it before. Car idles nice and smooth and my A/F doesnt bounce around anymore!
The weather was actually kind of cool here this afternoon and I got my 2 bar tune to a point where the car is running pretty good.
The weather was actually kind of cool here this afternoon and I got my 2 bar tune to a point where the car is running pretty good.
07-01-2008, 10:41 PM
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I wouldnt be totally sure unless you let it warm up to temp pretty good since target ratios are related to coolant temp. Also it probably made your map much more stable at idle with the steady timing. I would still take a look at your ve table around idle and make sure it was nice and smooth. The issue is probably still there you're just not having enough map fluctuation to get into it anymore. Display your ve table along with the 3d graph of it and look for the area around where you idle in the graph and try to keep it pretty smooth in that area. You will probably see an issue pretty easily with the graph.