Everything runs/works, but no SAW

reuben2002 · Post by **reuben2002** » Tue Oct 06, 2009 1:58 am

I have everything up and running, base 10 degrees, I have communication with the module, and it responds to engine load (MAP readings) and RPM changes according to my laptop communication, but the actual timing in the car doesn't change. There is no signal coming out of the SAW circuit on the MJL controller. I spent several hours today going over solder connections and checking/verifying connections and voltages. I have 96ohm resistance between pin 12 of U1 and the output of the SAW which appears correct from the 100 ohm R1. I have a 5V square wave coming out of U1, but R1 seems to kill the signal, with <.5V sawtooth output. I'm not sure what is wrong exactly. It seems to me that either the signal isn't strong enough out of U1, or R1 is dropping the signal too much. I'm an ASE master tech and halfway to a Mechanical Engineering degree, so feel free to talk technical to me, I'm just not super familiar with this design. Thanks for any help.
Reuben

NITROPIXIE · Post by **NITROPIXIE** » Tue Oct 06, 2009 8:43 am

Hi and welcome to the forum. What vehicle are you putting it in???

Are you 100% you have gone to the correct pin on the edis module. It sounds like it is grounding on something after the 100 Ohm resistor and my suspicision tells me its to the wrong pin on the edis module. Double check here first. Should be pin 3

Do you have cable shielding?? Try an insulation test between the shield and the pip line.

Hope this helps

DannyP · Post by **DannyP** » Tue Oct 06, 2009 12:00 pm

You could also have a faulty EDIS module. Try another one, check your pinouts and shielding. It can be REALLY frustrating, but really check your connections and stuff. I have been messing with electronics for over 35 years, and I made a couple of mistakes when I did my harness. I did figure them out though, and have been running a V3 for two years now with no problems. Erase all your assumptions, and look at it like you are checking someone else's work. Good luck.

reuben2002 · Post by **reuben2002** » Wed Oct 07, 2009 2:50 am

@nitropixie, I didn't think about the SAW being grounded on the EDIS side, I'll check it out tomorrow. I do have shielding, and I could see how it could get breached fairly easily at the splices. I'm running the V4 board in a 1970 BMW 2002, and I've been working on this conversion since July. It's been both exciting and frustrating.
@dannyp, I don't have access to another EDIS unit right now. This unit came off a running car that a fellow tech was scrapping, so I know it was good, but I suppose I toasted it, however these modules are quite rugged, and module failure usually causes some sort of no-spark condition. Thanks for the tip on checking someone else's work, I've found that an extra set of eyes can find the problem (usually something simple) rather quickly. I'll check the SAW wiring first, then I'll see if I can get ahold of another module (possibly borrow one from a customer's car) to see if there's change. I've heard good things about this type of setup with its reliability and such, so I'm sure it's something simple. Thanks.

NITROPIXIE · Post by **NITROPIXIE** » Wed Oct 07, 2009 6:03 am

Not a problem. If your still having a problem and want your EDIS testing then we can sort something out.

Ryan

reuben2002 · Post by **reuben2002** » Fri Oct 16, 2009 3:04 am

Sorry it took so long for me to get back to you guys. You were right, the SAW wire was shorted to the shielding at one of the splices. Looked to me like just one tiny strand got stuck in the joint, but it's enough to drop the signal. I got it running great now, better than it's ever ran! I'll have to play around with the map to get it all tuned right, but now I don't have to mess with the sticking advance weights in my distributor. Thanks for all your helps guys!

NITROPIXIE · Post by **NITROPIXIE** » Fri Oct 16, 2009 7:18 am

Not a problem, good to hear you have it running sweet