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Advanced Ignition Timing Mod

385K views 2K replies 333 participants last post by  SLEEPYDUB 
#1 ·
Well, in my ongoing mission to thwart the ECU, I think I finally pulled one over on the little bugger.  The engine always felt a little lazy to me, and even in the worst conditions, I never heard any spark knock.  After reading the timing put in by the ECU, I determined the engine could benefit from more timing.  There are two ways to do this.

1. Flash programming the ECU to alter the timing map (not an available option yet.)
2. Alter the position of the crank sensor.

I chose option 2, as it's the only way at this point.  I went to examine the sensor, with the idea of modifying or making a new bracket for it to allow some adjustability, when lo and behold, Mazda had already done it for me with a nicely slotted sensor at it's mounting point.

After removing the belly pan and the passenger side splash shield, I turned the tire out to the right to allow a little working room.
The sensor was held in place by two 8mm bolts, one being partially obstructed by the A/C belt.

I then marked the sensor's original position, (wich was 3/4 of the slot down) with a permanent marker, and loosened the bolts.  Looking at the sensor thru the wheel well, I slid it counter clockwise all the way (down toward the ground) and snugged the bolts back up.  BE CAREFUL with these bolts!  They only need to be snug and are very easy to strip.

I then reassembled the splash shields and started it up.  The engine started smoothly, no CEL, and settled into it's usual idle.  After a short trip around the block, I heard a slight spark rattle when I approached 7,000, confirming the timing had indeed been advanced.  After a few more times to the redline, the rattle subsided, indicating the ECM was beginning to finaly utilize the knock sensor and pull a little timing.  The engine feels a little crisper, and hopefully I'll see a few more MPG.
 
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#6 ·
Re: Advanced Timing Mod

This is seen in the Ausi/VW world and there is a gain in power, or at least it feels. I haven't heard any long term issues with it though. Monzta is right about the bolts though. Longevity of the VVT unit may be questionable over time, but keep us posted. I would avise anyone wanting to do this to be careful though, the ECU is very delicate.
 
#7 ·
Re: Advanced Timing Mod

[quote author=superjudge link=topic=39020.msg566041#msg566041 date=1138932770]
This is seen in the Ausi/VW world and there is a gain in power, or at least it feels. I haven't heard any long term issues with it though. Monzta is right about the bolts though. Longevity of the VVT unit may be questionable over time, but keep us posted. I would avise anyone wanting to do this to be careful though, the ECU is very delicate.
[/quote]
To wit; the ECU isn't in danger, worst case scenario is you strip the little bolts and/or get a CEL, which is why you mark the position of the sensor so you can return it to its original position if needed. The VVT has nothing to do with this, as the sensor reads off the little teeth on the crank pulley. Just be careful with the bolts and this is probably one of the safer mods you can do.
 
#9 ·
Re: Advanced Timing Mod

No problem. I'm a little worried about fooling with the VVT yet, as I don't have enough information on it yet. There is some scan tool data I can't identify that I suspect is related to the VVT but I haven't proven it out yet.
 
#11 ·
I can't say for sure but I believe that when the knock sensor detects pre-detonation it will drop the timing much below what the timing would be set from the factory. This certainly has some potential, but I would adjust it until I would never hear detonation. Premium fuel would help in this as well. I am interested in this so I hope others will try this and give feedback.
 
#12 ·
[quote author=Titanium link=topic=39020.msg566118#msg566118 date=1138936186]
I can't say for sure but I believe that when the knock sensor detects pre-detonation it will drop the timing much below what the timing would be set from the factory. This certainly has some potential, but I would adjust it until I would never hear detonation. Premium fuel would help in this as well. I am interested in this so I hope others will try this and give feedback.
[/quote]

Yes that is typically the case with most timing systems on EFI cars that i know about. Hopefully it isn't knocking your timing down to stock or below levels otherwise there is no sense in this unless you use high octane.
 
#14 ·
Cool mod Monzsta!

Here is some data pulled from my scan tool when I was stock. The base timing varies from 6.5 to 10 degrees at idle. The ECU advances the timing to as high as 50.5 degrees at part throttle (1939RPM) and 46mph (74km/h).

0 mph
6.5 deg
699 RPM

0 mph
8.5 deg
694 RPM

0 mph
9 deg
689 RPM

46 mph
50.5 deg
1939 RPM

61 mph
47.5 deg
2598 RPM
 
#15 ·
This has actually been posted awhile ago, but retarding timing for the turbo guys.

This is a very simple thing to do, I'd like to see it done ona dyno.
I doubt there would be huge gains, if anything at all it will be very small gains, maybe drivablitly improvement.
 
#16 ·
i might try this after class 2marrow but can some give me a pic of the sensor just so i can be sure im messin with the right thing (i am the world champion f#$k up)
 
#18 ·
After the 80 mile beat down, everything's okay, the engine revs freer, no spark knock, it seems to be an improvement. (could be the new mod placebo effect) Next I'll see how much fuel I use during the next week. Feel free to try it. No pics yet.
 
#19 ·
I think that i will try this today.
 
#21 ·
this should give you the jist of it, though this is on a 6 and not a 3.  but you can see the sensor on the left side, just loosen the 2 bolts and move, retighten.



:::edit::: and i'm completely retarted (no pun there) which is why my sensor is pushed all the way up.
 
#22 ·
is it lil lever looking thing that u pushed up that is the timing sensor.
 
#23 ·
sorta, it's not a "timing sensor", it's a crank shaft possition sensor...the ecu actually manipulates timing according to the algorithm it gets from this sensor. yeah, pretty much the same, but not quite as easy.

and yes, it's pushed all the way up in the pic.
 
#24 ·
[quote author=MrTea link=topic=39020.msg576792#msg576792 date=1139686999]
this should give you the jist of it, though this is on a 6 and not a 3. but you can see the sensor on the left side, just loosen the 2 bolts and move, retighten.



:::edit::: and i'm completely retarted (no pun there) which is why my sensor is pushed all the way up.
[/quote]

I just want to make sure about this. you mention two bolts earlier is it the thing that is bolted to the ac belt thing or is it that lil lever that you see in the top right of the pic pushed all the way up?

sorry for the repeat ?
 
#26 ·
looks pretty interseting to me
 
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