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Need some guidance getting spark with MSII L28ET


motomanmike

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I just got my MSII back from DIY. They fixed an injector driver. Thanks again guys! Matt has been really great to deal with. I thought I had my relay board all ready and I might be able to fire this car up today but i was wrong.

 

 

I have good injector pulse. While the starter is cranking my noid light fires on all leads. My fuel pump works. It kicks on and primes then cuts off. While cranking the fuel pump kicks on.

 

Currently I am using the following items

 

1982 L28ET distributor wired up using the mobythevan's writeup.

MSII v3.57 pre assembled board with no mods. It is how it was coming out of the box.

MS relay board with assembled harness

4 pin GM HEI module(used to replace a burnt stock ignitor on my old stock ECCS setup and worked that way)

Stock 280ZX coil

 

 

I have good cranking pulse, rpm sits at roughly 200rpm when cranking. I see the timing advance needle move in tunerstudio so all seems fine there. Tunerstudio recognizes "cranking"

 

Other than using the L28ET distribuor I have my coil wired up with a 4 pin HEI like in the picture below the picture below uses a VR sensor, I didn't go that route.

 

I have the 1k ohm resistor on the 5v ref, feeding the pin G on the HEI with the spark output tied to the pin G on the HEI. Pin C going to coil - Pin B going to coil + being fed with switched 12v. Pin W going to body ground

 

When I turn on the key, tunerstudio immedietly recognizes MS is plugged in and shows the values. As soon as I turn the key on I get 1 fat spark. As soon as I turn the key to crank I get one fat spark. I get no spark while cranking but the noid lights flash or blink. I verified my 5 volt ref stays steady with voltage while cranking, and keyed switched signal to the relay board stay above 11-10.7 volts while cranking.

 

I have my output going LOW, normal.

 

 

I really don't want to have to modify the board to direct drive a basic coil. I bought this board reading and asking questions beforehand because it was supposed to be able to create spark in this fashion out of the box.

 

Please help me guys. I'm starting to get really discouraged.

post-8916-014134200 1349571458_thumb.jpg

Edited by motomanmike
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What is the voltage on the G and W pins doing while you're cranking the engine?

 

I've wondered why the HEI module works in this application, since it is designed to use a falling voltage on either G or W pins (I can't remember or never knew which pin does what) to trigger when it crosses zero. I could be wrong here also, maybe the 4 pin uses a rising crossing. Regardless, even though it works often, it's not the way it was designed to be used. I would guess that a square wave getting to zero is what's triggering the spark in this usage. You might have a ground loop on the G and/or W pins that never lets the voltage get to zero, or something along those lines.

 

Something to look at. What the module expects is well-described in its usage with the VR distributor, in the Megamanual. You might read through that section and see if you can figure out what's missing in your application.

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I'll check in the morning and report back. I researched this set up and chatted with quite a few people including Matt and it was theorized this set up would work with MSII v3.57. The HEI worked with the old ECCS but they are different signals I think. I'm also wondering whether a stock L28ET ignitor would work without modifying the MS at all since it is a different design than what an HEI was designed for? I'm not too keen on soldering on the MS board. I did the connections on the relay board pretty cleanly but its just not my fortee, I don't like doing it because my hands are pretty shaky I could never be a surgeon. I'd probably send it out again :( Its really close NewZed. I've gotten everything else done. Just need to get fire, and tune.

 

Its odd to me, I had spark before I sent the MS back to get the injector driver fixed. Wired just like this. To the point of if I sprayed ether in the breather she'd fire up. In the downtime i figued i'd clena up wiring and bought the relay board and harness and redid all the wiring. Cleaned everything up nice, now i've had to pull it all back out and test and make a mess of it all. I'll get it firing before I clean up anything again, that is for sure.

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I couldn't wait until morning. Pin C stays to cranking voltage around 10.7-11 volts. The trigger pin is the curious one. I have my 1k ohm resistor right at the end tip of the wire on the 5v ref. Currently I removed everything else from the 5v ref to test (tps sensor ref) With the spark output S1 of the relay board hooked up to the trigger wire on the opposing end of the 5v ref, end of resistor. visually you would have in flow 5v ref to 1kohm resistor other end of resistor to trigger wire to HEI and S1 spark out put from MS. With the S1 wire hooked into the picture the voltage drops to 11 milivolts at rest or cranking with key on really odd to me. Unhooking the S1 spark output and immedietly the voltage jumps back up to 4.89 volts on the other side of the resistor and for a split second the sparkplug fires. I thought maybe the resistor was bad so tested with a new one. Same result. As soon as you hook up the S1 output or spark output the plug fires one time, and the voltage drops from 5v to 11 milivolts.

 

This might not work, well apparently it won't work I guess. Other posts i've read about the stock ignitor and it didn't work either. Hmmmmmmm

Edited by motomanmike
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I couldn't wait until morning. Pin C stays to cranking voltage around 10.7-11 volts. The trigger pin is the curious one. I have my 1k ohm resistor right at the end tip of the wire on the 5v ref. Currently I removed everything else from the 5v ref to test (tps sensor ref) With the spark output S1 of the relay board hooked up to the trigger wire on the opposing end of the 5v ref, end of resistor. visually you would have in flow 5v ref to 1kohm resistor other end of resistor to trigger wire to HEI and S1 spark out put from MS. With the S1 wire hooked into the picture the voltage drops to 11 milivolts at rest or cranking with key on really odd to me. Unhooking the S1 spark output and immedietly the voltage jumps back up to 4.89 volts on the other side of the resistor and for a split second the sparkplug fires. I thought maybe the resistor was bad so tested with a new one. Same result. As soon as you hook up the S1 output or spark output the plug fires one time, and the voltage drops from 5v to 11 milivolts.

 

This might not work, well apparently it won't work I guess. Other posts i've read about the stock ignitor and it didn't work either. Hmmmmmmm

Is your tach output set in tunerstudios to fidle?

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I ordered the coil driver mod kit, BIP373 from DIY. I'll see how it goes. I'm sure it will work, most others have gone this route. I keep telling myself i'm sure it will work, one day I won't be lying to myeself. Again, thanks NewZed. You've been reading my posts from the very noob beginning. I've had a crash course the past three months and have more useless knowledge of fuel injection systems and datsun cars than i'll ever need !!!

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  • 2 weeks later...

I'm having the EXACT same problem. I had my car idleing and would start up great. Then I started to clean up some of the wiring and now i get just one spark when I turn the key over and one spark one I turn the key off. No spark while cranking. Everything was fine till I unhooked the wires to the module and ditributor and hooked them back up, And I have checked over and over again to make sure everything was hooked up right and it is . Could it be the be sensor in the distibutor

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