What he's saying is wire them in series, not in parallel.

 

I hate to bring this up from the dead, but just have a quick question about wiring the GM sensors to the existing EEC harness.

Looking at the attached diagram for an SN95, ECT is Pin 7 (LT GRN/RED), and IAT is pin 25 (GRAY). If I were to splice the GM sensors into the existing harness leads in the engine bay, do I splice both wires, or just splice the lead wire to the EEC and ground the other seperately. Is the other wire at the connector harness (GRY/RED) a ground wire (see bottom of pic for ECT & IAT sensors)?

 

Pin 25 (gry) and Pin 7 (lt grn/red) go to your MS.

As far as the other side GRY/RED, you can't tell from the diagram that you posted, where they go to. If they are ground, then your all set, if they go to positive, then you need to change it so they go to ground.

EDIT: Use your Ohm meter to see if they Gry/red wires go to ground. Or get a better wiring diagram.

 

Thanks!

 

Well, I finally got it working. For a while I had my tach trigger wire on pin 29 of the MS which didn't help anything. That, and I haven't been working on it as much as I was when I first started out. Oh well... it's working very well now.

I have some questions about tuning the spark table. Why is it that it says "xx degrees advanced" when I lower the number and "xx degrees retarded" when I raise the number in the graphical view. It is my understanding that the amount of degrees BTDC during idle would be higher than under boost or load so why is it that the charts tend to start low and go high? Is this similar to tuning the VE table in that the value is arbitrary?

I planned on making a rough map that starts around 25-30 degrees BTDC and retards down to 18-20, but I'm confused with how megasquirt words and displays my settings.

 

it's a glitch in the software. It is actually working the way it is supposed to, just labeled wrong.

 

I set the trigger angle to 60 and fixed angle to -10 and it's working off of my rough map. I was adjusting it on the laptop with my left hand and using the timing light in my right. I like how it takes effect immediately. The last car I fooled around with the timing had a vacuum advance and it would roam so much whereas this is very steady.

This is so cool!

 

Take a peek at this thread, basically points out what you are trying to do with the timing

http://boostedconcepts.proboards44.com/index.cgi?board=megasquirt&action=display&thread=1121230249

 

http://www.msefi.com/viewtopic.php?t=10731&highlight=retard

 

I've been trying to start the car for the last 3 days and no luck. Can someone please take a look at my datalogs, and MSQ file to see if something isn't right.

Right now the car still has the stock EEC in place, but I cut the wires at the harness that control the Injectors, PIP, TPS, 5VREF, ECT, and IAT and wired them directly to the DB37. I have MS wired to an MSD Digital6 for ignition (pin 30). I'm defintely getting spark (zapped myself checking for spark at the coil...LOL). The stock remote-mounted TFI is still in place, and so is the SPOUT, but I cut the wire for PIP at the harness (EEC pin 56) and wired it to pin 24 on MS.

The car cranks over and almost wants to start...kind of does a slight rumble then dies. I think I may have the injector wiring wrong, causing the injectors not to fire correctly (??). I wired MS pins 32+33 to injectors 1,2,5,6 (front bank), and pins 34+35 wired to injectors 3,4,7,8 (rear bank).

What else should I check for? Any suggestions?

Files are here: http://boostedfoxbody.com/stangs/mega/

Thanks in advance,
Mitch

 

You have to hardwire the distributor because the EEC harness has resistors in it, which will affect the signal coming into the MS. The spout shouldn't even be there anymore.
Did you not look at the distributor schematic on my site?

 

Well, I'm taking the PIP signal from the EEC harness (pin 56) to pin 24 on the DB37. Should I run a wire directly from the PIP at the TFI to MS, and bypass the EEC harness?

BTW, my TFI is not on the distributor, its remote mounted (SN95). What do you suggest?

Thanks,
MItch

#ad

 

You have the injectors wired wrong too.

Each side of the engine is a bank. Left bank is 1,2,3,4 and right bank is 5,6,7,8.

All the injectors on one bank should share the same positive and negative from the MS.

 

Drop in a dizzy from a fox body. Not sure how to wire an SN95 external TFI dizzy.

 

I tried it like that also, and it did not make a difference. Scott (dieselgeek) came up with a good reason to run front & rear banks, vs. left & right banks...

"On most V8s, the lean / rich cylinders aren't in separate banks - they're front to rear'¦ so I don't think there's any benefit to tuning banks separately - it is either altogether, or separate cylinders (in which case you are probably not running a MS, but a FAST or BS3).

One thing I didn't see here, is that you should consider running injector bank 1 with 2 cyls in one bank of the Vee, and 2 cyls in the other bank - and run 2-squirts alternating. This way you have twice as many pulses, at half the volume, for each fuel rail - on high power combos, you can REALLY notice the fuel rails hammering when you run all injectors on each rail simultaneously."

 

See if maybe Scott can help as far as the SN95 dizzy hookup goes. I haven't done one and really am having trouble gaining the motivation to wanna look into it(out of the mustang game).

 

Yep, I'm going to email him and see what he thinks.

Thanks,
Mitch

 

If you find out, let me know, I can put something up on my site.

 

Will do!

 

Anyone what to buy a Megasquirt ECU?

I'm almost about to give up on MS. I tried for almost a week to get the car started, and no luck. I've tried every possible combination and nothing works. The car comes close to fully starting, but then it just dies. I've gone through 2 batteries just trying to get the car to start! If I can't even get it started imagine my luck on tuning it. Oh well, if by the end of this week it doesn't start, then I'm making the move to a blow-thru carb system for my turbo kit, and ditching any kind of computer control.

Thanks for the help.