Tuning Help??

[Z1500]

Originally posted by larryd
what do you mean, "with the line off" ??

I don't know what kind of crack these guys are smoking but the "line" you want to have off is the vaccum line that goes to the fuel pressure reg. With that line off, you want to see 43psi.

Kevin

[NJGSX96]

Originally posted by Z1500


I don't know what kind of crack these guys are smoking but the "line" you want to have off is the vaccum line that goes to the fuel pressure reg. With that line off, you want to see 43psi.

Kevin

Isn't that what I said? I ain't on crack... yet

[larryd]

wow.. you guys are really confusing me on setting the fuel pressure.. I didnt actually set it.. Wes did but I assumed you would just set it and look at the fuel pressure gauge I have on the rail and it should change shouldnt it?? Do I have to remove hoses and what not to set it??

Also tjh-dsm, Ive never even looked at the LTFTs.. Im gonna have to read that tuning guide on DSMlinks site.. I didnt realize there was one there..

[Z1500]

Sorry, last line of your post said that. I guess I need to change my crack dealer. Too much crack for me!!

Kevin

[jw]

Yes, you set your base fuel pressure by removing the vacuum hose going into the FPR. It will see 14.7psi atmosperic pressure (which is 0psi gauge pressure) and adjust the screw tighter yield higher pressure because it preload the spring inside vice versa for lowering pressure. After some the adjustment, you should put the hose back and pull it out again just to make sure the pressure didnt change. Some FPR require you to do it a few times to get a more accurate setting.

P.S. You will want to do it with the car running at idle

[jw]

Also by saying 14.7psi atmospheric pressure. I meant 1atm=14.7psi.

[larryd]

ok so one last time.. take the vacuum hose that goes to the fpr off the car is sitting at idle and adjust the screw so its at 42psi correct??

And another thing.. I was looking inside DSMlink and I dont see anything on LTFT's in the values so im not sure how you see this?? I havent read the 2G install guide quite yet but Ill do that tonight.

[jw]

Yup, that's how I would do it for 2G.

As for DSMlink, sorry cant help. They wont even allow non DSMlink owners to join the group to learn about the product. What a bunch of dorks .

[larryd]

yeah i know.. makes it a lil difficult

[RocketBoy]

with the dsmlink hooked up to the car open up the dsmlink program and log on. then go to "ECU" and scroll down and click on "Stream data." Here you will find a plethora of other values that aren't being shown to you right now. Move the LTFT values to the right side of the screen and then you will be able to log them. Hope that helps.

[larryd]

hmm wierd.. so you have to have stream on to get that on the values list then.. wierd.. ok Ill try that.. thanks

[larryd]

Originally posted by tjh-dsm
I know this was mentioed previously, but you didn't reply to it, so I don't know if you've addressed this.

Before you do any tuning w/ DSMLink, you should get your cruise and idle LTFT's near zero. If they're not, then it will affect all your tuning afterwards. First, -35% global seems a little high for 650's. I have 650's and use -31% global, but -32% is good also. If you haven't done the LTFT zeroing procedure, you should do it now. Bascially, you want to adjust your dead time until the cruise and idle numbers are almost identical, then adjust your global to get them near zero. You have to drive at cruise for 10 mins, check your LTFT's, then idle for 5 min and check it again. Took me 4 days of this to get it all perfect, but the car ran much better.

It's all in the 2g Tuning guide available at the DSMLink site.

ok.. i ust read the "Tuning a 2G DSM ECU" now I have a few questions.

You said I should adjust my dead time until my cruise and idle LTFTs are nearly identical correct? I know right now my dead time is set at 180 so would I go up with that or down with that or what to get them closer? I guess I dont really understand what the deadtime is and how it effects the LTFTs.

then once I get my LTFTs for cruise/idle nearly the same I want to adjust the global to get them as close to zero as possible. But once again how do i adjust it, up or down or what?

Once I get the LTFTs set Im gonna be all about learning how to adjust the fuel/timing as thats a whole nother issue from reading that guide tonight

[RocketBoy]

LTFT = long term fuel trims. If i remember right, there are three of them that you can log. Go to dsmlink's website and download ALL of the instruction that you can find (i think there's 3). There should be one set that is about 5 pages long that talks about a/f ratios and give two graphs of timing vs. air flow and something else (sorry, haven't used dsmlink for a long time). If i remeber right it talks about LTFT's in there. If not, then it's in one of their other instruction/tuning "manuals" available for download directly off of their site.
Basically, you need to look at your cruise LTFT and idle LTFT (by clicking on stream data and selecting them). Log idle and cruise. You want those numbers as close together as possible (this is done by playing with deadtime). Once they're really close together, you then want to get them as close to zero as possible (this is done by playing with global).
Once this is done then you can move onto fuel/timing adjustment. Also, your a/f ratio will be much more accurate when this is done. Again, this is really stressing my memory, so if someone else has anything to add, please do.

[RocketBoy]

Directly from the instruction download (it's not in the 5 pg. one):

The Dead time area of the Fuel Adjustment dialog is where you can make adjustments to this dead time figure. The value entered into this area gets added to the value calculated by the ECU. While there is a way to calculate what this value should be, a trial and error approach tends to work best. Use the long-term fuel trim (LTFT) value calculated by the ECU as your guide. The following outlines a good procedure for getting the dead time right for your setup.

1.Car must be fully warmed up then must be operated at cruise for about 10 minutes followed by idle for 5 minutes to get stable LTFT values.
2.Compare the LTFT at idle and cruise. You want both to be right about zero.
3.If the two are about the same, dead time setting is good.
4.If they are equal but non-zero, adjust the global setting.
5.If idle LTFT is more positive than cruise LTFT, increase the dead time, less, decrease.

The following table can be used as a rough guide when trying to dial in new injectors. The dead time values are provided as examples of what we have found to work well in the cars we have tested. Your particular set of injectors may need slightly different values, but these should be close.

Size (cc/min) Global (%) Dead time (ms)
550 -18% 180
660 -31% 180
720 -38% 450

[red91tsiawd]

is 40 psi (fuel pressure) okay?

[tjh-dsm]

Also, those 'dead time' values vary WIDELY, they vary alot between injector manufacturer's. My FP 650cc injectors have 300 deaq time, way different than 180, so that has a big effedt on tuning. After my battery is disconnected then reconnected (restting the ecu), I can feel a difference in how the car runs, and the only thing different is the dead time (haven't tuned yet, waiting for FMIC to get here).

[larryd]

thats great guys.. I appreciate it.. my car is down for the week as Im waiting for a part but next week once I get it running again Ill get right on this setting the LTFT at cruise and idle then I can start tuning

[supereclipse]

Hey larry ill be putting my dsmlink in within the next week or so keep us up on the tunning man ill just be getting started as well.

[larryd]

first im going to replace the ignition system with a new coil pack, new plugs, and new wires.

then Im going to put the higher pressure spring in the AFPR and turn up my fuel pressure to 45psi with the hose off.

then im going to see what DSMlink can do for me