Fuel Only, distributor noise, tunerstudio

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toyotaspeed90
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Fuel Only, distributor noise, tunerstudio

Post by toyotaspeed90 »

Having some massing distributor noise. Done quite a bit of reading and understand that I need to work with it, not a big deal.

Vehicle runs and drives, acceleration and driving is a bit rough. It is at the basic stages of beginning to tune (with a WB).

Have tunerstudio ultra.

SBC350, TBI, vacuum advance distributor, coil neg for signal, ground looped through an extra pin back to the engine with shielded wiring.

I cannot find the menu for noise filtering in Tunerstudio.

MS1 V3.0, 029y4.

Ignition options/wheel decoder all set to off, nothing else in the spark tab is available.

This sounds like a stupid question, but I've looked through every menu option and cannot find anything. The search field in Tunerstudio also finds nothing.
slow_hemi6
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Re: Fuel Only, distributor noise, tunerstudio

Post by slow_hemi6 »

There is no Noise Filter in the MS1. It was introduced with the MS2. Do a data log and post it up.
Find the Manuals up top under Quick links: Manuals. :RTFM:
Cheers Luke
toyotaspeed90
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Re: Fuel Only, distributor noise, tunerstudio

Post by toyotaspeed90 »

Well that explains it (this is my first fuel only setup, previously always on EDIS).

Might decide to go HEI sooner than planned....

I will get a data log ASAP. Vehicle has no top or doors, and weather has been all over the place. Plus, the laptop that I've used almost daily for about 5 years had the charger call it quits after my last drive in the FJ40.
toyotaspeed90
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Re: Fuel Only, distributor noise, tunerstudio

Post by toyotaspeed90 »

I'm all brand new to datalogging - and pretty darn new to Tunerstudio.

This is not only my first fuel only MS setup, but also the first Megasquirt I've set up that isn't in an MR2 running EDIS (those I've done several of, but about 6-10 years ago).

With that said, the logs don't look right.

One is recording during the cranking/start, idle, and a little revving at the end.

The one with "afterstart" was another short idle run, with just idle no starting/revving.
toyotaspeed90
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Re: Fuel Only, distributor noise, tunerstudio

Post by toyotaspeed90 »

As a side note - I partially pulled the cap (not enough to pull wires and get a good inspection), but the rotor had some spring to it, and there was a little slop in the gear, but I'm guessing it's all within expected tolerances. It's probably 5 years old or so, but hasn't seen a whole lot of use (especially the last 3 years of mostly sitting around)

there's a possibility that the vacuum port I'm using (on the front of the TBI) isn't the best, so I have a vacuum manifold for my brake booster and transfercase that is plumbed to the center of the intake manifold - with several open ports... I may pull vacuum from that for the dizzy and see if that helps.

The 'analog' tachometer on the dash reads steady
slow_hemi6
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Re: Fuel Only, distributor noise, tunerstudio

Post by slow_hemi6 »

The other sensors seem really quite good and there are no resets so that is all a positive.
Find the Manuals up top under Quick links: Manuals. :RTFM:
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Re: Fuel Only, distributor noise, tunerstudio

Post by toyotaspeed90 »

I read that some have had issues with interference from other sensor voltages..... and was found by unplugging sensor and watching a change - did that and no change in the rpm spike.

Have also read that the backwards zener diode may not be the right value, or to try putting components on the coil neg side.

I'm also curious about the jumper wire that is required that runs over the board to xg1... Could also be a culprit...

So I have some things to try. I want to tune, but with that rpm spike causing a long fuel pulse, I can't imagine the tune would be even remotely accurate...
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Re: Fuel Only, distributor noise, tunerstudio

Post by toyotaspeed90 »

A little disheartened....

Swapped the 22v backwards zener for a 32v 1w (after awaiting a digikey order since radio shack is my best bet and has nothing useful).... and an immediate issue is present - Which is 40k rpm cranking speed.

Tried moving wires, etc..... swapped back to a 22v zener and back to normal, but noisy as ever.

Tomorrow I will post a MSL of it starting, but it's nasty.

My readings on using zener diodes in series ups the voltage - so I'm a little concerned of the suggestion to use the 5.6v diodes in series on the tech wire.....

Thoughts?
slow_hemi6
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Re: Fuel Only, distributor noise, tunerstudio

Post by slow_hemi6 »

Is it a points or electronic distributor? Points can be awfully noisy.
Find the Manuals up top under Quick links: Manuals. :RTFM:
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Re: Fuel Only, distributor noise, tunerstudio

Post by toyotaspeed90 »

It's electronic with vacuum advance.

I'm going to try the 5.6v zener on the coil line itself, and if (when) that fails I will probably just go MS&S since I have that dizzy ready to go.
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Re: Fuel Only, distributor noise, tunerstudio

Post by toyotaspeed90 »

Tried 5.6v zener diodes on the coil - wire (started with 1) up to 4 in series and no change. When I had 2 in series and flipped the direction over, I got the 40k rpm signal again.

Frustrating, to say the least.
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Re: Fuel Only, distributor noise, tunerstudio

Post by toyotaspeed90 »

In searching for the variance between coil input and hall sensor within the assembly guide, there was a glimmer of hope:

If you are going to use the negative side of the coil to trigger MegaSquirt® (I.e., you are not using ignition timing control), then install and solder C12, the Ed capacitor (399-4202-ND, 0.001 µF, 102 marking}. This is located above "Bowling" in the copyright notice. The value of this capacitor may need to be increased if there are noise problems with the tach signal - values up to 0.1µF will work. The 0.001µF value is a good starting point.


I happened to have 102, 103, and 104 values - oddly 103 was the best, but still noisy.

Then I read this at the end of 50a:
This input circuit is also used - with the modifications below - if you want to trigger off the negative side of the coil, since the points control the negative side of the coil's primary circuit. However, you can only trigger off the coil's negative terminal if you are NOT trying to control ignition timing. Do either 50a or 50b, not both.

Then this gem at 51.....
As we noted in step 50, there are two input circuits for the tach signal. One takes the square wave input from a hall sensor, optical sensor, or points.
In most cases, you should install both circuits, and make the selection between them with jumpers



So.... do only either 50a or 50b... but by 51 you should have done both?


Then further reading says the GM HEI signals can be dirty.... so, seems like I'll need MS2 functionality of cleaning the signals up electronically either way.....

Bummer.
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