daves12secV6

iTrader: (3)

at idle its fine,dead on at 900 rpms,verified against my tach.the problem is at very light loads/in nutral/park if i hold down the gas a lil bit.
say i hold the motor to 2,000 rpms my tach in megatune will jump up around 4,500 rpm.

at heavy throttle/higher loads the tach signal does not jump around
ive disconnected the alt and it still does it

it also seems that when the tach signal jumps the motor misses,could this be due to the motor having a misfire /or would this be more related to a noisy signal

im running a ms1 v2.2 using ms1 2.98 controlling fuel only

Toehead

how are yu triggering the ms.

daves12secV6

iTrader: (3)

i have the ign wire/white wire with the shielding aroind it hooked to the neg side of the coil, hooked to the side of the coil with the harness that connects the coil to the dizzy/same polace u would wire in an aftermarket tach

pizza_guy

I'm 95% sure the motor miss is from the input noise, not the other way around.

Any paricular reason your triggering off of the coil neg.? From what I understand, that is a worst case scenario for getting an rpm reading. And I thought you were using an HEI module anyways?

I'm sure you'd rather just fix the current setup, but sometimes it's easier to use a different method instead. Besides, if you ever want to control spark timing, you'll have to change the setup anyway.

Any reason you couldn't use the pick-up coil on the dizzy? This could trigger the VR circuit and is a bit more reliable than coil neg. The HEI module would work just as well, as long as it's not a cheap-o one.

I don't know if MS1 V2.2 would support it, but for the ultimate in accuracy, a simple 36-1 toothed wheel on the crank snout would be the ticket. It's more work, but than again, we don't buy Megasquirts cause it's easy, right.

daves12secV6

iTrader: (3)

isnt the wire i have it hooked to from the pickup coil?
the coil has 4 wires with 2 connectors, the front connector is power and ground
the rear connector is the one from the dizzy, i have the wire attached to that connector were my aftermarket tach used to be connected

i dont want to controll timming right now, i wanna wait till i get the fuel tunning setup pretty good at first

pizza_guy

It sounds like your triggering off of the ignition coil(the piece that provides the 50,000 volts), not a VR sensor. I'm sorry, what I meant by pickup coil is the VR sensor on the inside of the dizzy. The VR sensor has a two-wire connector only. On stock HEI setups, the VR sensor plugs straight into the HEI module.

If your using shielded wire to carry the signal, I'm not sure of much more you could do to calm down any noise from the coil.

Are you still using the HEI module inside the dizzy??

daves12secV6

iTrader: (3)

yes i didnt touch anypart of the stock harness going into the dizzy,when i looked at the wiring diagram for my megasquirt it showed the ign lead going to the neg side of the coil,though it had a pic of an oldschool round coil. so thats were i hooked it to.

can i hook it directly to the vr sensor without taking timing control away from my stock ecm

pizza_guy

You could go directly off of the VR connector, but if your using a 7-pin or 8-pin module, there is a "rpm output" pin that would be the most convienant. It's the purple/white wire in the harness. If you have the 4-pin, then the VR sensor is your only other option I believe. The ->HEI information<- page at the MS site is a great read and can give you all the options.

As far as splitting the signal, it can be done. It's hard to say if it'll work "as is" or if you'll need to amplify it. It's pretty application specific, and depends what else is connected.

Your getting to the point of your install that you really should be addressing this in the Megasquirt forums. The people over there are miles ahead of me when it comes to very specific issues. I love this board and have learned a wealth of knowledge from TGO, but when it comes to electronics related questions(i.e. noise, rpm drop-outs),->http://www.msefi.com<- is the place to be. Over there, Lance, Bruce, Grippo, and Jim are your best friends. I'm sure there are others, but those are the guys that helped me the most.

daves12secV6

iTrader: (3)

grippo helped me out today,and ur not gonna belive what the problem was
the guy who built the ms unit left out some key components in the tach signal circut
heres a pic showing what was left out

d5 and r10 were not in place on my board if u look at the img i posted there was a jumper wire going from xg1 to the far side of were d5 should have been
and also another jumper wire jumping one side of r10 to r11.

i noticed this and then posted on msefi 10$ and a half hour later i was up and running,though i am going to pull my ecu and take it to an elctronics repair place and have them resolder the diaode and resitor i put in just to be safe,ive never soldered on a circut board in my life before lol.

i figured i would ask here as well as there since the msefi board is kinda slow

pizza_guy

That's nuts. Who's "the guy" that built the 'squirt? Did you get it from a commercial entity??

If it functions now that you've soldered it, there shouldn't be any need to have it redone. A second pair of eyes never hurts though. Just be sure to clean off the residue and give it a coating to prevent moisture damage.

Msefi is a little slow, yes. But those guys running it are also working furiously on some completly amazing products that I can't wait to get ahold of.

I've found soldering electronics to be one of the great joys in life, and incredibly rewarding. I have trouble convincing people that my electronic toys were actually built by me. They swear there's no way I could've done some of the stuff I've done on my KITCHEN FLOOR. Still don't have a garage.

Included on the list:

Wideband O2 gauge (<$10)
Digital/programmable home thermostat (~$20)
Motion sensing home lighting (okay, this one cost a bit more, but fun none the less)
LED light bulbs (initial cost ~$6/bulb, but long term energy savings end up cheaper than compact flourescants, and NO MERCURY)
Automatic watering system for my house plants that actually measures the soil moisture instead of a time delay. (priceless, cause now I can stop buying plants)
I'm working on my custom, false-alarm-proof, undefeatable, car alarm/immobilizer. (~$20 in parts, but not quite finalized)

It all started with one book and my inability to water my plants.