chillin014

iTrader: (67)

thanks. I grounded mine out today and went for a short drive, I think I just might feel an improvement! I have tampered with my TPS which I believe is going bad however so the car is acting differently due to that as well. I'll get a new one and see how it feels.
I can drive around with it like this and not worry about anything, right? I have a wb02 w/ a gauge so I can watch my mixture if that is the only fear.

Weimar Ben

iTrader: (5)

I've done the resistor mod and haven't seen any difference either on the butt dyno or with my scantool. What's really crappy about the 4th gen ECU is how much it pulls the timing in the midrange. With WOT around 3500rpm, I only have 13-16* of advance whereas below and beyond that, I have 23-25*. I need a dam* EU. Maybe part of the problem is how freaking pig rich I'm running. At times, the STFT on both banks is -25% and I'm running the 4th gen FPR w/vacuum. The LTFT is usually around 9-10%.

chillin014

iTrader: (67)

yeah i need a frickin EU too mayn.

whlimi

iTrader: (11)

I remember reading somewhere that Jime had advanced his ignition timing up to 40* and it never knocked. With a stock map you should be safe as long as you're using 91+ octane and your motor is in overall good health (no overheating issues, severe carbon buildup...etc) and you're not running lean.

chillin014

iTrader: (67)

oh dang. Cool thanks, my motor runs fine and always gets 93. get a dyno! i want to see what your timing alterations do!

whlimi

iTrader: (11)

Ya I got similar results in that rpm range. The motor just fell flat on its face from 3000-4200 rpm. I have somewhat smoothed it out by adding lots of timing in that range, anywhere from 10-13* to bring total timing to around 26-28*. The results is much smoother acceleration without the lull. What's your fuel pressure at?
KRRZ350 mentioned somewhere that running FP at 32-34psi at idle with vacuum hooked up can result in AFR at or near 13s at WOT.

whlimi

iTrader: (11)

A dyno is not going to be happening anytime soon. I have some other issues with the car that I need to take care of first.

What I could do when I find some time is run the car with the dynolicious application for the Iphone. I'll do a before and after on the same road at the same time and see if the application can pick up the difference.
I will also log 60-100mph times on the EU and see what kind of difference in times I might get.

JClaw

iTrader: (17)

Unplug the TPS I drive mine with no TPS. I should also mention that I use 94 octane for safety all the time. I might mix with 91 to get 92.5 but I just use 94 for peace of mind.

whlimi

iTrader: (11)

How are you running with no TPS? I have tried driving with the TPS unplugged and it runs like garbage.

JClaw

iTrader: (17)

Mine is 5-speed with 96 GXE 5-speed ECU & wiring and it runs fine with no TPS. Autos have a problem with no TPS.

Weimar Ben

iTrader: (5)

According to the FSM page EC-82, a TPS circuit malfunction (P0120) causes the ECU to go into fail safe mode. I have a 97 5spd and when my TPS was malfunctioning, I couldn't start my car unless it was push started. After it got started, it wouldn't rev past 1500rpm.

whlimi

iTrader: (11)

I'm running the suprastick so unplugging the TPS doesnt affect my shifting as long as i'm in manual mode. The problem is the car is more sluggish and doesnt pull as hard as when the TPS is disconnected.

Its funny how all these cars behave differently. I wish there was some kind of consistency with these 3.5 swaps.

chillin014

iTrader: (67)

I would notice this timing "increase" at partial throttle acceleration, right? Ever since I grounded the sensor the car has felt excellent even in 5th gear at 25% throttle and less. The throttle response is great, its like the bogging and hesitations are gone entirely. I cant imagine how it must be for those who can increase timing past stock via the EU.

Product_Of_Korea

iTrader: (8)

And i thought 20* was pushing it

Weimar Ben

iTrader: (5)

All depends on throttle position, MAF voltage, and RPM. 40* is nothing at small throttle openings. 40* at WOT at low RPMs would kill the engine. The mixture burns at a uniform rate, but the higher an engine speed is, the less time there is to burn the mixture. That's why timing advances with rpm. At 6500rpm, you're having 3,250 combustion events per minute, or 54 per second per cylinder. You have to get combustion started earlier.

Product_Of_Korea

iTrader: (8)

i see now thanks for the skinny. so in reality your saying that it would be safer to advance in the higher rpms(wot) vs the lower rpms cause you would need combustion earlier due to the fact that your engine speed is much higher?

whlimi

iTrader: (11)

I meant 40* total advance, not 40* on top of the regular map

The stock map has timing advance above 20*past 4000 rpm at WOT.

Product_Of_Korea

iTrader: (8)

lol thats what i thought you ment

So then i am pushing it when i am at 50* total.............

whlimi

iTrader: (11)

I believe that with the 3.0 ECM you can advance the timing significantly in the lower RPM as well due to the fact that the 3.0 ECM is tuned for VE based on the USIM. On a hybrid swap where you lose VCT and you also have it SSIMed, you get a big drop in VE in the lower RPMs. If you look at the 350z timing maps, they have more advance than the 3.0 ECM. But as far as how much advance you can add, you would need to dyno to find out. In the lower rpms (3000-4200) i've advanced the timing between 10-12 degrees and its really only useful for first gear as second gear lands me at 4800 rpm.

whlimi

iTrader: (11)

How are you at 50* total? I would be cautious if you were running 50* advance under heavy load at any RPM but if you're at high RPM under very light load ( off throttle) then I wouldnt be too concerned but dont quote me on that.

Product_Of_Korea

iTrader: (8)

For some odd reason when i reinstalled the EU on my 96 when i put in a value for the timing map it would double the advancement. So when i put in 10* it would do 20* advance.



sorry guys for getting kinda off topic but i was intrested in jime's 40* Total advance.

chillin014

iTrader: (67)

whlimi, do you notice the timing advances at lower rpm's during partial throttle /light acceleration? Sorry for not understanding the basic concepts of timing. I also wasn't sure if you were even tuning at anything other than WOT

whlimi

iTrader: (11)

I'm not advocating advancing to 40*. I only brought it up to show an instance where the vq35 didnt knock with 40* advance at WOT. I wish I could find that thread. IIRC Jime has stopped making power past mid 30s. Someone correct me if I have this information wrong.

whlimi

iTrader: (11)

It all depends on your setup. I do notice a pretty significant difference with more timing advance under light/partial throttle. Below 30% throttle I have my timing ramped starting at 2* advance up to 4* advance before getting more aggressive as it approaches WOT. I'm using MAF voltage, just using TP as an example. I bet I could advance the timing some more under partial throttle because of my setup. Aggressive cams with lots of overlap at lower RPMs will lower your VE in the lower RPMs so you can probably get away with more advance.

Jime

iTrader: (10)

When I was using the 3.0 timing stuff and the EU I advanced as high as 40 but low 30's seemed optimal.

Now with the full swap I have gone as high as 32 but 26 seems optimal for it. That is where I run all the time now, 26 from launch to 7k. 22 when spraying.


When I quote timing #'s its WOT only, the rest of the time I let the ECU take care of it. Don't try to outengineer the engineers.

PS The difference in the timing between the 2 setups, results from the lack of variable cam timing in the 3.0 setup.

chillin014

iTrader: (67)

Damnitttttt. The car was feeling consistently great, responsive. For the first time I felt content with the straight line performance. But as of 2 days ago it feels like how it used to feel with timing problems. Nothing is loose or disconnected...I've still got my Knock Sensor bolted to an extra battery cable which is tapped to the negative terminal of the battery. Any ideas?
The knock sensor kind of rests on a metal surface in the engine bay under the intake tubing, would this cause any ill effect? I'm disappointed now.

whlimi

iTrader: (11)

you could try eliminating the knock sensor and using a resistor. See how that works out. What codes do you have?

chillin014

iTrader: (67)

Yeah I think that is going to be my next step. My codes are 3.5 swap related...like EGR crap and 02 sensor IIRC. I get a jolting at very low throttle but just replaced my TPS. Maybe my MAF is starting to go bad...again.

whlimi

iTrader: (11)

By jolting, do you mean like a throttle shock? When you give it a bit of gas it's like someone kicked the back of your seat?? I have that with my auto but it only happens when the TC is locked up. I dont know if there's something wrong or if that's how it is with the VB mod.

chillin014

iTrader: (67)

not quite. Its like if I'm cruising under 5% throttle it feels like I just dropped the clutch or something. I can see the mixture leans out for that quick second and then it usually continues on its way fine after that. It feels too hard to be a misfire. It only does it at very light throttle and maybe 5 times a day.

chillin014

iTrader: (67)

Okay I finally got around to doing the resistor mod since the car has felt absolutely BALL-less these past couple weeks. I'm about to take it for a drive so I'll report back with any results. But I'm not expecting anything crazy since I have a MAF code and can tell its on its way out (again :-/)

One weird thing that I cant get off my mind...when I was doing the resistor mod I was stripping the OE electrical tape down to get more length of the KS wires and came across this bare stripped wire wrapped around the two KS wires. I know I've seen something like this before when I was removing tape off another harness somewhere in the car I just can't remember where....it just seemed bizarre. I dont think its a wire that goes to anything but I just left it alone. Anyone know?

pmohr

iTrader: (26)

http://en.wikipedia.org/wiki/RF_shielding

All it is is shielding around the wires. Keeps any noise out of the line.

If you ever see this (what I've highlighted in red below) in an FSM wiring diagram, just means that same shielding is around those wires:


Generally only used for 'critical' or emissions components, or anything that the ECU reads a signal from.

chillin014

iTrader: (67)

ahhh, thank you very much! I hope its not too crucial, I didnt remove it but I dont know how well it was in there when I taped over everything again. And I'm trying to remember if I ever cut that wire when I saw it before....I think it was when I stupidly hacked up that transmission control harness.

throttlehappy46

The easy way of disconnecting the Knock Sensor There is also another option in the timing maps for changing when the ECU listens for knock in individual cells. The secondary timing map can also be accessed to change the amount of timing pulled in each cell value so if you want to keep low rpm high load KS protection, then you can adjust the secondary map for pulled timing but keep your midrange and high rpm timing maps at hgih values

Stock ign timing maps usually have a very static advance figure on light load from 4000rpm to rev limit. Depends on the engine of course and how much compression etc it has. For example, the SR20DET GTiR motor has a flat 50* of advance from around 2400rpm to 7200rpm at less than 21% throttle

Sounds like you were advancing timing based on crank position and not cam position

chillin014

iTrader: (67)

man this car is really pissing me off. I soldered the resistor in there and now have a knock sensor code.......

still have a MAF code as well after replacement. I'm officially pulling my hair out.

also, when yall say "470k-ohm" we are talking about the half-watt resistors, right? Just trying to figure out how the hell I got KS code...I soldered the resistor between the two wires wtf could go wrong.

Product_Of_Korea

iTrader: (8)

I think it was doing it cause i still was under the old 97 settings. Since then i have figured it out.

whlimi

iTrader: (11)

You need to solder the resistor between the KS signal wire and ground. The ground wire on the KS subharness is NOT grounded. What you could do is remove the subharness and then solder the resistor to the main harness which has a grounded wire.

chillin014

iTrader: (67)

damnit, I knew I was doing something wrong. I dont know that I want to go all the way down to the main-harness just yet. Let me get this straight though. There are two wires coming to the KS harness. I should be soldering one end of the resistor to one of these wires (which one?) and then grounding the other end of the resistor? And then leave the other wire open?

sorry, the stickies are vague. "If you locate the knock sensor sub-harnass and disconnect it, you can stick a standard 470k leaded resistor into the connector and then tape it into place."

Jime

iTrader: (10)

Just disconnect the ks and on the other end of the connector that goes to the ecu install the 470k resistor. There are two slots in the connector, signal and ground, bend the resistor wires 90 deg and stick one end in one slot and the other end in the other slot.

No need to solder anything. Put some electrical over the resistor to ensure it stays in place. If you do it this way you can easily just remove the resistor and plug in the ks if you want

A picture is worth a 1000 words. I just quickly stuck it in there so you get the idea.

chillin014

iTrader: (67)

That's what I've already done though except with solder. (Connected the harness wires via the resistor).