Megasquirt voltage fluctuation and wideband reading
Thread Starter
i play with my wankel
Joined: Jul 2005
Posts: 1,630
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From: North Manchester, Indiana
Messed with tps lag and now it idles great! No tpsaccel coming on at all. Only problem is lag factor is at 12, fuel ve in the idle bin is 90.... idles fantastic though but probably won't drive for anything
Joined: Feb 2001
Posts: 29,798
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From: London, Ontario, Canada
With that much jitter, you need to fix your underlying electrical problem. 
Also, lag isn't necessarily the best adjustment for this. The accel pump has a delta-TPS adjustment which defines when it starts to trigger.

Also, lag isn't necessarily the best adjustment for this. The accel pump has a delta-TPS adjustment which defines when it starts to trigger.
Thread Starter
i play with my wankel
Joined: Jul 2005
Posts: 1,630
Likes: 0
From: North Manchester, Indiana
I know, I've done almost everything I can think of aside from a new alternator. Any more suggestions on how to get this noise out, grounds are ALL good, any specific size capacitor between the ground and signal that would be best? Ill try adjusting the delta-TPS and see what happens. Thanks Aaron.
Thread Starter
i play with my wankel
Joined: Jul 2005
Posts: 1,630
Likes: 0
From: North Manchester, Indiana
Only one I remember is Aarons site. The chassis is completely regrounded, New powers new grounds everywhere. http://www.aaroncake.net/rx-7/grounding.htm
NativeBeggars, If you are unsure of how good your grounds are, take a set of booster cables and clamp engine block and chassis one side, and battery negative x2 on the other side. I've used this a number of times on FC RX7s to diagnose bad idling on OEM ECUs. Usually every car I dealt with needed a new ground going to the leading coilpack body ground. Some cars barely ran without having a new 4 gauge wire going to the coil mount.
rolfs_7, what kind of voltage are you seeing at idle now? 12.4 is minimum "charging" voltage. You should see around 13 to 13.5 volts.
rolfs_7, what kind of voltage are you seeing at idle now? 12.4 is minimum "charging" voltage. You should see around 13 to 13.5 volts.
Thanks Rolf. I totally forgot Aaron had a great grounding page.
Black, thanks for the info. I'll give it a shot for sure. I'm not having any idling issues or anything. Car runs fine. I just want to make the reat of my interior lights work.
Black, thanks for the info. I'll give it a shot for sure. I'm not having any idling issues or anything. Car runs fine. I just want to make the reat of my interior lights work.
Thread Starter
i play with my wankel
Joined: Jul 2005
Posts: 1,630
Likes: 0
From: North Manchester, Indiana
Woke up today and logged my 20minute drive to work voltage is a lot more steady than it used to be, my stock gauge in the car used to fluctuate pretty bad until I rewired the alternator. Now that I look at it in megasquirt it drops way lower that it ever should at idle especially for nothing load inductive kicking on. I'll swap my alternator tonight and post results. It doesn't seem like I'm getting noise in any of the other sensors though that's what I found weird. Thanks guys
Interesting.
I have seen Cummins ECMs refuse to start an engine during cranking. Voltage dropping is normal during crank load, but turns out the Cummins ECM will not fire injectors with under 10 volts.
It can be confusing, since it will crank over just fine, but will not fire at all.
I have seen Cummins ECMs refuse to start an engine during cranking. Voltage dropping is normal during crank load, but turns out the Cummins ECM will not fire injectors with under 10 volts.
It can be confusing, since it will crank over just fine, but will not fire at all.
Thread Starter
i play with my wankel
Joined: Jul 2005
Posts: 1,630
Likes: 0
From: North Manchester, Indiana
Put a cap in and it helped some but not completely, I may have to isolate the tps portion of the harness. Anyone think it could possibly be noise in the MS?
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cruise, flucation, fluctuating, fluctuation, lean, map, megasquirt, microsquirt, ms2, o2, reading, smooth, spike, spikes, voltage, wideband




