Injector instability is a pain. I typically see batch injected cars stabilizing around 13.5AFR and the beauty of sequential injection is that you can usually achieve those nice lean idle AFR's so it'd be tragic to miss out on that luxury due to injector issues. Good idea dropping the rail pressure a touch to compensate!
1991 Turbo 306 coupe MS3/PiMPxs tuning adventure
- Thread starter wiseguyk
- Start date
It truly is a shame these injectors are very linear in nature so once this issue is sorted out things should start moving quickly. @5.0Thunder have you done any testing with map sampling? I was thinking we may want to sweep the map sampling angle and see where the signal has the least mapdot...... right now we are using event average and I feel as though gains could be made here if we always sample from the same angle with the intake valve closed... what I mean here is that if we can find the angle where the signal reaches the ECU for sampling where it is most stable this could possibly help with idle quality.
I don't understand how PW is read/calculated, and thought we were looking for the PW to change. I just wanted to make sure I datalog correctly and wasn't sure if I should have one log while lowering the pressure, or a log after it's already lowered.
Thanks for all your help guys, I wish I could be at the shop right now to test it out instead of at stupid work lol
Just a heads up, I should be able to make it to the shop for a few hours tonight after work so if there's anything else you guys would like me to try while I'm there please let me know. First thing I'll do is adjust fuel pressure down to 35 and try to get the idle AFR closer to 14.5 and see how it does. Datalogging everything, of course 
Ya know, I did look in to this a while back but only saw advantages where the map signal was largely deviated within a cycle, such as what you'd see on a 1 or 2 cylinder engine. With 8 cylinders and sampling from a common plenum, I never thought it to be very advantageous in theory, and I never bothered to test it on my car due to how stable my map value seemed. I guess if you're able to build a table and really determine a good window to sample, it may be beneficial, but i'd imagine it wouldn't be too far off from the event average for mild-ish cars like ours.
I sorta came to the same conclusion when i made the histogram for the injection timing events. the fact that i had to set the mapdot sampling so close to 0 proves your theory i believe. in reality a mapdot below 5 is almost no change in signal.
Hey guys, I just ran the car on Rev 2.1.0 and adjusted the fuel pressure to 35psi with the vacuum disconnected. I then tried adjusting the idle VE to get it to run leaner than the I think ~12.5 it was first idling at to see if I could get it leaner.
It seemed to act like last night where it would get to the mid 13 afr rang and then start oscillating pretty badly. I've attached the current version of the tune with my small VE tweaks here as well. Let me know if you see any improvements with the fuel pressure lowered a bit. Thanks!
It seemed to act like last night where it would get to the mid 13 afr rang and then start oscillating pretty badly. I've attached the current version of the tune with my small VE tweaks here as well. Let me know if you see any improvements with the fuel pressure lowered a bit. Thanks!
Hey guys, so it was a hell of a night lol. I pulled out the distributor to put the MSD break-in lube on it that I forgot to do when I installed it and had trouble getting it to come out all the way (as @General karthief and @Noobz347 know because they helped talk me through it). After a little pulling I was able to get it out, but the damn oil pump shaft came out WITH the distributor 
No bueno! I tried to look in with a flashlight and used a small magnet to try and see if I could pick up the clip (or likely pieces of it) but was unsuccessful.
As much as I hated to do it, I just went ahead and put things back together because there's no way I can pull the oil pan at this point. I started it up and oil pressure was good and I didn't hear any strange noises or anything so I went ahead and set the initial timing and took a datalog.
I'm just hoping that the clip/pieces fall to the bottom of the pan and stick to the magnetic plugs and I can pull them out with the next oil change. If you guys have any recommendations, please let me know. I know it's silly to chance it but I JUST changed the oil from the first several days of idle tuning and really don't want to change it again already :/
No bueno! I tried to look in with a flashlight and used a small magnet to try and see if I could pick up the clip (or likely pieces of it) but was unsuccessful.
As much as I hated to do it, I just went ahead and put things back together because there's no way I can pull the oil pan at this point. I started it up and oil pressure was good and I didn't hear any strange noises or anything so I went ahead and set the initial timing and took a datalog.
I'm just hoping that the clip/pieces fall to the bottom of the pan and stick to the magnetic plugs and I can pull them out with the next oil change. If you guys have any recommendations, please let me know. I know it's silly to chance it but I JUST changed the oil from the first several days of idle tuning and really don't want to change it again already :/
Agreed.
I have not had the chance to check the datalog yet, @5.0Thunder did you see anything that points to the erratic idle issue when leaning it out? I know we are running a fairly extreme idle advance correction curve but it was needed to clean the idle up. I have played with the thought of lowering the idle by reducing the total timing at idle, this would force us to run the throttle open further leaning the idle (assumption).
A second set of eyes would be appreciated..
I have not had the chance to check the datalog yet, @5.0Thunder did you see anything that points to the erratic idle issue when leaning it out? I know we are running a fairly extreme idle advance correction curve but it was needed to clean the idle up. I have played with the thought of lowering the idle by reducing the total timing at idle, this would force us to run the throttle open further leaning the idle (assumption).
A second set of eyes would be appreciated..
Great idea! Damn I'm tired, it seems so obvious... Thanks man, I'll do that tomorrow night.
I'm gonna try to get down to the shop as much as possible this week after work so just let me know if there's anything in particular you guys would like me to try and datalog that might help. Time for bed
you have to wait for the engine to be fully warmed up.... cold engines do not like to idle lean.
I am going to make a few alterations and we can give it a try.
Do you have WIFI at the shop??? I could remote in and help..... Or we could just let it idle the way it is and you can drive the car to me
Ok thanks Steve. What is an acceptable idle AFR? I just didn't want to fowl out another set of plugs so that's why I tried leaning it up.
Haha you know, I've thought about asking you that! I was gonna ask today if you think we could move on towards tuning the car while driving because I have an appt Thursday to have my stifflers stuff and exhaust welded up. They're really close to the shop but would definitely like to feel better about the tune in the "normal driving" range if possibleDo you have WIFI at the shop??? I could remote in and help..... Or we could just let it idle the way it is and you can drive the car to me
during warmup even my wifes mini cooper likes to be rich almost 12 AFR What i did was alter the VE table and then reduce the warmup enrichment% I had to guess at a number so i removed 5% if the car is idling way lean on startup you can add up to 5% to this curve, the last bin MUST BE ZERO or you will have a permanent 5% enrichment
Yes we can lets work on the idle one more time, then you can take the car for a drive while datalogging and we can tune the cruise range and a number of other things.Haha you know, I've thought about asking you that! I was gonna ask today if you think we could move on towards tuning the car while driving because I have an appt Thursday to have my stifflers stuff and exhaust welded up. They're really close to the shop but would definitely like to feel better about the tune in the "normal driving" range if possible
Ok sweet, I was just being paranoid It definitely was happy rich when warning up.
Oh and yeah I've been tethering to my phone at the shop to upload files while you've been helping me so you could remote in any time that works for you. I'm planning on being there again tonight
It definitely was happy rich when warning up. Oh and yeah I've been tethering to my phone at the shop to upload files while you've been helping me so you could remote in any time that works for you. I'm planning on being there again tonight
As long as you have some kind of unlimited data plan, we will use a ton of data in a short period of time.Ok sweet, I was just being paranoid
Oh and yeah I've been tethering to my phone at the shop to upload files while you've been helping me so you could remote in any time that works for you. I'm planning on being there again tonight
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