Me and Nismology went out to log my ignition timing tonight.

We tried (just for reference, using stock 270cc FWD 3.5 injectors/ Walbro190 set to 55psi. All pulls were done on 3rd gear. Air temps (IAT) were mostly between 140*F(initial flooring) to 131*F (redline). Coolant temp held between 197*F to 201*F.)...

Scenario1- A32 MAF, A32 Sensor Input, Previous A32 Tuning
Scenario2- A32 MAF, A32 Sensor Input, ZERO Correction (on this run, inj duty cycle peaked at redline at 80.1%... ouch!)
Scenario3- 3" MAF, Q45 Sensor Input, Current Tuning
Scenario4- 3" MAF, Z32 Sensor Input (since its almost identical in size), A32 Corrections

(OT- The 3" MAF feels WORLDS better than the A32 MAF. Now that we were able to drive with both back to back, wow. What a difference. One dies off before hitting the limiter, the other just rams into it full steam- very accurate comparison btw. Stock redline is killing me on this aspect, lol)

Here's what I did on Excel tonight (excuse the sloppiness, work and school are taking a toll on me, lol). We were not able to upload the data from the laptop due to hardware complications, so I wrote down the values and made my own graphs...

Tables


Corresponding Graphs


Notice that the 3" MAF has promoted alot of mid-range timing advance (relative to the other scenarios here, from what I can recall, 15* is normaly the lowest value on a bone-stock 3.0 ECU with a properly working motor). However, between all the different pulls, timing at redline is the same.

With as much -% corrections that I have I SHOULD be in the high 20s/ low 30s by redline, yet my timing at redline is pretty constant with all the runs. The program had no way to monitor Knock, which was our initial thought (either way the motor sounded just fine). Anybody have any educated ideas/ suggestions as to what may be causing my timing from increasing like it should be?

 

Just incase anybody wanted to look at my torque curve to see how it related to my timing curves....

 

can you invert the colors on the graph in your second post? its very hard to read...

 

He actually did the opposite so that it would be easier to read.

Here's where it first appeared.
http://forums.maxima.org/showthread.php?t=517640

 

Power lines are pretty easy, the a/f i know it still a bit blury. but trust me when i say its 13.5-13.8 the whole way

NMexMax, were you ever able to log your timing with/ without the big MAF?

 

95BLKMAX, just curious if u decide to stay w/ the big maf, r u going to raise ur rev limiter to 7200 to unlock the xtra potential and if so, how do u plan to do that?

 

What choices does he have aside from EU & JWT?

I'm planning on doing that tonight. A few WOT runs w/ stock MAF, and a few w/82mm. Anyone have any input as to what parameters I should log in comparing them? Also, it will be nice to see what kind of difference in whp this will gain you (A32B)

 

Well im in limbo when it comes to that right now. I COULD get the EU and do it like that (I'll never pay for an ECU reflash, self-tuning FTW!), but thats $550 that could go towards buying the M3 I want....

but then again....

The EU can be used on the OBD1 M3s (95 is what Im looking for) with no problem from what I've researched around (the E36 M3 crowd seems to be in the same boat us maximas were in just 2-3yrs ago- everybody had to get an ECU upgrade/ reflash, self-tuning was too expensive cus you'd need a stand alone bla bla. But a few in there are pushing the benefits of self-tuning, so it'll catch up there like it did with us).

So idk, maybe I will get it now, maybe I'll just wait to get it until after i get the M3, time will tell, not worried about that for now.

But either way, even if I was getting it, I would install it until I knew what was going on with my timing right now to begin with. In theory as best we understand it, with as much correction as Im using I should be in the high 20s/ low 30s ign timing at redline. So to me, something is going on. Using EU right now to control timing would be like adding thicker oil to cover up valve ticking- doesnt fix the problem.

NMexMax- Have fun with that, I'll be on standby. BTW, I did ~6 pulls on 3rd gear that nite with Nismology..... the motor chugged exactly 1/4 tank !!

 

Have you completely ruled out the knock sensor as the culprit?

 

I get where ur coming from becuz the EU and wbO2 sensor u will need to tune is pretty pricey, so its better that u find ur problem first instead of trying to cover it up. Keep us posted on the progress, btw let us know when u pick up that German beast as well lol.

 

Well I dont even have the ghost code for it. Last time I had it was when i changed it back on the 3.0. Whats on the motor currently is the stock 3.5's KS.... Im gonna wash the car right now, i guess I could take a peek inside once it cools off and try to pull it out.

If anything, what do you think of "cheating" the ECU by laying a thin bead of silicone bet'n the block and the KS? lol Its a maybe for tonight tho, I'll see once I go out there.

MaxBlack97- That wont be for a few months, but yes sir, will do (thats the reason for this thread -->http://forums.maxima.org/showthread.php?t=524942)

 

Ok I didnt get to pull the KS, I was too tired by the time I finished washing and hand-waxing the car. Tomorrow I have a game to go to, so maybe weds nite I'll get in there and see whats going on with my KS (if anything).

 

I just pulled out the KS. Got the normal cuts and burns along the way FTL. Anyways, KS has been overruled, its in perfect condition and so is its harness.

 

How's the torque on the KS? Within spec?

 

yes sir. Sorry for the delay, internet took a crap at home.

 

you are using the 3.5L KS that came in the 3.5L....

I suggest using a (new) 3.0L knock sensor and a new 95 KS harness (been known to cause problems), since you are using a 3.0L ECU. the 3.5L KS is different. just a thought.

very interesting data btw

 

The only thing I remember (re: swap KS situation) was when JClaw was using an old 3.0L unit, and when he changed to a new 3.5L unit, the car was 100% better.

 

So is it right that the q45 runs a better timming curve?
How well would it work with bigger injectors like say 555cc.

 

Question for everyone...

I've been brainstorming this and I wonder- Yea Im changing the MAF IN on the SAFC, but, because the OUT isnt changing, does that mean that (not EXACT) but OVERALL throughout my scenarios, my ECU is receiving pretty much the same airflow curve from the SAFC?

I didnt record the airflow readings bet'n the scenarios (being OBD2 output, it reads what the ECU gets, which is data already been fooled by the SAFC as far as airflow is concerned), but I did look at them, and they look ALMOST identical.

Could THAT be the reason why my ignition timing isnt changing much in the higher rpms (which is where from what I recall, the airflow graphs were pretty much the same bet'n all scenarios)?

Perhaps if I leave the MAF IN and corrections of my current setup (scenario3 on 1st post) but CHANGE THE OUT to the Z32 ECU, Im not sure how that would affect my ignition timing, but I have a feeling it might work . Im gonna see if streetz is down to lend me his laptop again and I'll give it a try.

:IBcrossingmyfigersarmstoesandlegswtfmatey0!

 

Fine then! Forget the last question lolz

Here's a brainstorm for ya gurus...

"When driving around or just reving the motor (be it to redline or just tapping the gas), as the engine revs down to idle, it goes down smoothly, gets to about 1000rpm and slows down considerably, almost hovers there for a split second, before it gets to the actual idle speed of ~850rpm.

Here's the thing, as it does that hovering, it sits right at 15* timing, the moment it drops down to the "real" idle, timing drops and stays at just 5*.

Of course, the retarding of timing causes my idle to drop down..... What happens there at idle that COULD causes that retarding? AFAIK, at idle it should sit around those 15* and stay there, never heard of it dropping to 5*. Its def electrical.

Notes- No IACV, does it with AC on and off, does it with and without electrical load (headlights, AC defroster, hazards and sound system all at once, lol).

Im sure if I can figure this out, I can figure out whats going on with my ign timing throughout my powerband.

 

Although we have very different software configurations coupled with some hardware differences as well; my idle value drops considerably when @ idle in "P" or "N" and it goes very lean. I have to add ~ 12% if I want to sit @ 14.7ish in P or N.

I will need to check the timing in order to verify that our problems are related.