smackhead999

iTrader: (5)

ok here is the deal. i didnt ground the shielding. what i did do is test the cas resistance. within spec 168ohms. when cranking it jumps up to the upper 200s as the teeth pass. the cas is fine. with the cas unplugged i get a 2.5v+/- at the cas+. but with the cas plugged in... i only get .4-.5v. weird huh? well at the cas- in either situation(plugged or unplugged) i get .4-.5v. their should be no voltage here when unplugged. so both my cas+ and cas- are producing voltages, at the ms and at the cas plug. so there is voltage at cas-. not good. im going to post some pics of my board, both sides. also my cas for the hell of it. files are too big tho.. i will link them.

smackhead999

iTrader: (5)

these are them.. hopefully this works. something must be wrong on the board. the vr circuit is installed but inactive. the previous owner couldnt get vr to work so he went with missing tooth.

81WideMariah

iTrader: (8)

I'm no expert... but that second VR circuit is WAAAAAYYYY bad looking.... looks like poo! those components look way out of wack... mine looks way different... QUASAR posted a good example of what it should look like... that board looks pretty jacked up..... I know I'm not much help but those are my $.02...

toplessFC3Sman

iTrader: (1)

well, most of the problem I see with that 2nd VR circuit is that there are all sorts of un-insulated leads running to 5v, ground, and different pins, and probably some of them are touching where they arent supposed to be. This is also the case with a bunch of the other jumpers... id be worried that they could ground out on something or accidentally get pushed into a random pin underneath them, or that just the swaying of the wire over time would be enough to crack them (for the coil outputs going from the LEDs to the IAC pins, at the pins specifically, and that resistor bridging the gap from the proto board to JS8)

Some of the solder joints look a little cold, but not terrible (altho im by no means an expert on soldering), and id doublecheck and make sure that none of the small transistors has been unintentionaly bridged or shorted out thru excess solder or drip, some of them look close.

The coil output bits look correct (the 3 LED's, I'm assuming that the harness connects them to the coil properly) These don't really have to do with signal noise though.

As for the 2nd VR circuit, It doesnt look like its been completed... no wonder it doesnt work. To be clearer, look at Rotary MSextra ignition manuals at the V3 pcb internal mods. f refers to farads, Z to ohms. You dont need to connect these things if you dont want to run the second trigger, but if its already there, then why not?

Pin 1 is fine (not connected to anything)

Pin 2 (with pin 1 being the one with the dot, counting around the outside from there counterclockwise) doesnt seem to be connected to ground like it should be. You should also connect G- to this one. Essentially its grounding G-, but very close to the LM circuit, so there shouldnt be a ground offset voltage.

Pin 3 looks like its connected to the 330pf (i cant see the value in the picture, its supposed to be 330pf) capacitor, which is then connected to ground. However, pin 3 should also be connected to an 18kZ resistor, which is then connected to both the G+ signal and a grounded 300Z resistor (330 will work, and is more common).

Pin 4 seems to be fine (not connected), altho i cant tell with that wire going overhead in the 2nd pic.

Pin 5 also seems fine (not connected). As T2GTUS pointed out, connecting this to 5v may raise the noise threshhold, but you arent using this circuit yet anyway, and with a normal CAS (especially the 2-tooth G sensor), it shouldnt be needed.

Pin 6 is also fine (n.c.)

Pin 7 is a real PITA to tell whats going on, it seems like the 1 MZ resistor and .33uf cap are in parallel (correct, but cant confirm cap rating in picture), but I cant see if they are then connected to ground or not. Maybe ok...

Pin 8 looks like its connected directly to 5v, but is missing the .1uf cap to ground.

Pins 9, 10, & 11 look correct, but that bare ground wire running right over the bare 5v wire really, really scares me.

Pin 12 should have a 4.7kZ (aka a 4k7, or yellow-purple-red) resistor going to 5v, which may be there standing straight up under the green coil wires, and the bare resistor hanging there to JS8 kinda looks failure prone to me too, but it looks correct (if that really is a 4.7kZ).

Pin 13 looks ok (n.c.)

Pin 14 seems to be using an 82kZ resistor in place of the 39kZ (shouldnt be a problem i dont think) to 5v, and if that big green thing is a 0.01 uf cap, one side shoudl go to ground and the other side shoudl go to the pin (its hard for me to follow it in the pictures)

For the hanging resistors and uninsulated wires, what i did was i just took a hot glue gun and dabbed a bit of hot glue around the resistor or wire til i made a foundation or support between it and the board, and to keep it from vibrating. I also made sure to coat the bare wires with it to keep them from accidentally touching something and shorting.

There isnt too much work to do (and nothing to un-do) to get the 2nd vr circuit running, but if you dont want to go that route, i'd clip the resistor that goes from the 2nd vr circuit to JS8, just to make sure that its not interfering.

turbo2SE

iTrader: (1)

MS factory harness
pin 19 ground harness ground
pin 26 TPS 2A
pin 21 water temp 2I
pin 20 intake temp 2L
pin 23 o2 sensor 2D
pin 33 rear pri injector 3C
pin 35 rear sec injector 3F
pin 32 front pri injector 3E
pin 34 front sec injector 3H
pin 28 main relay 3I
pin 22 throttle sensor 2G
pin 8 ground 2C
pin 9 ground 2R
pin 10 ground 3A
pin 11 ground 3G

pin 2 VR2 ground CAS -G 1P
pin 3 VR2 CAS +G 1N
pin 7 CAS -Ne 1Q
pin 24 CAS +Ne 1T

pin 37 fuel pump check wire fuel pump test connector under hood

led 14 pin 25 or 4 IGt-L 1V
led 15 pin 27 or 5 IGs-T 1U
led 16 pin 29 or 6 IGt-T 1X

That should help you make a plug & play harness



AC LINKS im having trouble finding pin 2 on my MS universal harness pin 2 is missing . did you have to add a line to the harness and go from there or am i missing something that i have over looked?

smackhead999

iTrader: (5)

dude... i know the lm looks bad.. i think i will just clip it. but the other stuff you said, like, pin 3, 7, 9, 10, 11, 12... i cant trace where these go. they dissappear into the board. i pulled the map up so i could see the bottom of it... but i still dont see what you see aparently. as far as things crossing and grounding and whatnot, i check this before and nothing actually touches and i was also gonna use hot glue... my favorite stay put tool, after i knew it worked in the condition it was in. i know it looks horrible, i didnt do it. starting to think i need to pull everything and redo it. but i really dont have time like that and this thing needs to hit the road. there probably is some wrong components on this board, but i cant understand where you are seeing what you are seeing. i assume these pins "travel undetected" across the board to somewhere and i cant find a dummy diagram.

AC LINKS

I added pin 2. You can buy a pin extractor for D sub conector. Just get the kit.

81WideMariah

iTrader: (8)

There are some easier ways to do the above.... MS pin 25 can be used for G+ signal simply by wiring the input of your 2nd VR vircuit to the terminal marked IAC1A on the underside of your board (V 3.0) as for the G- input, yes you will have to install a new wire into your DB-37 harness and as AC mentioned it can be done pretty easy. Go to Radioshack and ask them for a D-Sub series pin extractor/inserter tool, and also a D-9 female socket kit( it will come with the pins needed to add to the db37.) Installation is straight forward. If you'd like to use pin 3 for your G- input then run a wire from the ground of the 2nd VR circuit over to the terminal marked SPRCHNL1 (or something like that) and you wil have your 2nd vr signals wired up proper.

toplessFC3Sman

iTrader: (1)

oh, no, all those pins i listed were on the LM1815N chip, not on the DB37 connector! That is just why the 2nd vr circuit wasnt working.
Looking more closely at the 2nd vr circuit, a wire seems to be run (the uppermost green wire) for the G- signal, but none for the G+ (although i think it came in originally on DB37 pin 25, since that one is bridged)

Your pin-outs seem to be as follows:

1
2
3
4-----IGT-L, Leading Timing, neg. LED 14----------------1V
5-----IGS-T, Trailing Select,neg. LED 15----------------1U
6-----IGT-T, Trailing Timing,neg. LED 16----------------1X
7----Ne- CAS white--------------------------------------1Q
8----Ground-------------------------------------connect to below
9----Ground-------------------------------------2R (which is ground per FSM)
10---Ground------------------------------------3A (which is ground per FSM)
11---Ground------------------------------------3G (which is ground per FSM)
12
13
14
15
16
17
18
19---Sensor Ground-------------------------------------2C
20--Intake air Temp---------------------------2L
21--Coolant Temp Sensor--------------------2I
22--Throttle Pos. Sensor Signal-------------2G
23--O2 sensor----------------------------------2D
24--Ne+ CAS red----------------------------------1T
25--seems like it was originally wired to accept G+ -1N
26--Throttle Pos. Sens. Ref. voltage-------2A
27
28--Main Relay-------------3I
29
30--BAC valve------------2Q
31--Seems like it was originally wired to accept G- -1P
32\___Primary injectors_____________/3C
33/.................................................. \3E
34\___Secondary injectors__________/3F
35/.................................................. \3H
36
37--Fuel Pump Relay---------located in emissions harness, brown wire

T2GTUS

on the backside pic ... is that 1k resistor from your second vr out??? ... if so, it looks like it is going to js8 ... that should go to u1 pin11.

toplessFC3Sman

iTrader: (1)

on the V3 board, JS8 is U1 pin 11 (well, its a trace for it, same thing). Its correct.

T2GTUS

< too much 2.2 stuck in head lol.

smackhead999

iTrader: (5)

i clipped the jump resistor from js8. temporarily. i will eventually try to get the lm1815 to work. but for now i need to concentrate on why i have .5v on my cas-Ne. i dont understand this. with 2.5v at +Ne, pin 24 with the cas not connected, and then with only .5v when connected. something is wrong. the cas tested to be fine. is it possible that the +Ne 2.5v is disrupted by the .5v at the -Ne, when cas is connected. thus knocking the voltage down to .5v? im not to much of an electronics whiz. but the -Ne is where the rpms/tacho signal is input right? while cranking the 2.5v that should be at +Ne, should be transmitted through the cas and return on the -Ne. the cas should disrupt the resistance. like a blip as the teeth pass by. there shouldnt be any significant voltage drop that i can figure. i even ran my own cas wires directly soldered to the db37 and then to the cas plug. no difference. so it isnt my harness. so unless -Ne is a grounding point on the board, the pin7 on db37 is receiving a voltage from some source. i cant see the runners for pin 7 to figure where it leads to on the board. how could this pin receive a voltage with no source? unless it leads to this spot F2 capacitor right behind it. i belive this is why i have no rpm signal. if the ms is trying to decipher a resistance change over the supplied 2.5v, and there is already another voltage source with no resistance supplying .5v to pin7 then it cant read the cas. but even further i dont understand how this is when the stim worked.does anyone have any idea how this is possible?

toplessFC3Sman

iTrader: (1)

i dont *think* there is supposed to be any voltage on those pins, but i've never checked it. The way I understood it was that the tooth passing the sensor induced a current (and thus a small voltage) in the wire (same way metal detectors work, but smaller), and this induced voltage was sensed on the Ne+ wire. If theres already 2.5 volts there, the induced voltage is probably getting lost in there somewhere. where is the 2.5 v measured between? try measuring it again between the ground holes above the proto board and the Ne+ wire. Then look at the voltage between the 5v holes and the ground holes, to ensure that theres actually 5v there and not some big short. Lastly, check between the ground holes and the Ne- wire for voltage and continuity. The Ne- wire is essentially grounded at the MS, but as close as possible to the related circuitry to prevent a ground offset. And when testing, use very short unshielded (but twisted) cables or shielded cables.

The stim works because it provides a much stronger signal than a normal VR sensor does and there is nowhere near as much noise as a running engine, alternator, pulsing coils, BAC and fuel injectors etc.

smackhead999

iTrader: (5)

good stuff i will try all this. you mean use twisted or shielded cables when testing cas right. im just using a multimeter to test the voltages and a continuity tester to test the cont. i was testing the pin 24 and pin 7 at the db37 and the cas plug but grounding to the chassis. maybe the problem, but my readings were consistant. not really any jumping around. so i will test using grounds on the board, and everything you listed. can i run my own cas wires and purchase some shielding from radioshack or the likes?

toplessFC3Sman

iTrader: (1)

eh, your best bet is to run new shielded cable (, or just use the stock FC front harness... it has the shielded wiring in it stock, and its already taken care of for you. Im not sure you can purchase just the shielding.

If you really wanted to make your own, i guess 4 wires (or 2 in your case right now) twisted together with a bench vice and a drill, and then fully wrapped in one continuous sheet of tin foil that gets grounded at the ECU end, then wrapped in harness wrap, tape, or cellophane (to keep the ghetto kitchen product usage) would work... but really... yea.

smackhead999

iTrader: (5)

how strange. so on the stim i have 8.9v at the battery, 0v on cas- pin 7 and .011v on cas+ pin 24. ground is ground and 5v is 5v, pin 7 has cont. with ground.

toplessFC3Sman

iTrader: (1)

that sounds right to me, have you hooked it up to the car's harness and checked the voltage at those pins again with respect to the MS ground?

Also, in reference to my last post, I just got done having to repair some shielded cable from my LC-1 making friends with my driveshaft, and it involved wrapping the wires in aluminum foil over the affected area, clamping down onto the existing shielding at each end, and wrapping the whole mess in electrical tape. No cellophane unfortunately.

smackhead999

iTrader: (5)

i just hooked up the harness to the ms. still no cas signal to megatune. didnt have a chance to test the grounds like this or the pins 7 and 24. i didnt this with the new wires i ran, however these wires arent shielded. but they do not pass over or near any other harness. its just those two wires. i suspended it over the engine bay and through the pass door. i did cut the resistor to js8 for the 2nd lm curcuit. do you think it would help at all to completely remove this curcuit from the proto to ensure its not wrong and putting a voltage to the grounds? i know what i have posted in this is inconclusive with out me testing for voltage at the these pins or continuity.

toplessFC3Sman

iTrader: (1)

no, dont remove the circuit, its not going to help anything, and you'll just need to re-do it in the future sometime

At the very least, stick one end of the wires in a vice or something, and the other in a drill and twist them together. This will help shield them anyway.

smackhead999

iTrader: (5)

ok, here is the deal. got to the shop today to test this ms. i went back to the factory harness for the cas. with my multimeter on 200mV, i get like 2-5mV on pin 24 while cranking. from what i can understand, this is the induced current from the cas. pin 7 reads 0V during cranking. while not cranking, i get 0V on both. i tested continuity the only way i can, with resistance, i got a relative resistance through pin 7 and ground(ms). like a .7ohms. but i tested resistance between ground(ms) and pin 24... i get like 174 ohms. now if i got this right, there shouldnt be any resistance between ground and pin 24 becasue they arent connected. right? but reguardless i still have current from cas on pin 24 and zero current on pin 7, while cranking. still no rpm signal. i dont understand how this can be. where does the current read on pin 24 go to on the board? maybe i can see if this current is going where it is supposed to. or maybe its an error in my settings. does anyone have any ideas? pleeeeeeeaaaaaaaassssse!

smackhead999

iTrader: (5)

sadness.... weekends suck

smackhead999

iTrader: (5)

anybody?

toplessFC3Sman

iTrader: (1)

i dont think there should be a connection to ground (at least not a direct connection) between pin 24 and ground, I doubt that there would even be a pull-down resistor there, and if there was, it would have to be of a very high value, 174 ohms is way too low. At this point you're getting past my knowledge of the MS, so I can still give educated guesses, but no certain facts

smackhead999

iTrader: (5)

maybe i should get on the megasquirt forum. but i dont think im gonna find out whats wrong with this now. maybe i should just buy a new one. are there still Plug n Plays available? i was reading he roubleshooting on the megasmanual... and it says for a vr sensor input to turn the pots out like 6-8 turns... i will try this too. the most i ever went out was 3 turns