letitsnow Posted January 20, 2009 Share Posted January 20, 2009 That looks JUST like the graph of a car I'm tuning. I don't have access to the car right now or I'd try the flyback noise reduction mod, I think that's what it is. This is the beginning of a 1/4 mile run, it's a TBI(2 low-z injectors) 305/700r4. You can see the voltage spikes triggering AE. Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted January 20, 2009 Author Share Posted January 20, 2009 A glimmer of hope!!!! I changed the injector characteristics to high-Z, and drove around a little, it seemed to make a difference in the battery voltage. I still got some occasional large, isolated spikes, but overall it seemed way steadier. I didn't get on it very hard though to keep the DC low, because I hadn't installed the dropping resistors. I think I'm going to do the resistors and stop messing with PWM. Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted January 20, 2009 Share Posted January 20, 2009 My car has high Z injectors so i actually bridge the legs of the flyback circuit and my car drove better when i did it. Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted January 26, 2009 Author Share Posted January 26, 2009 VICTORY IS MINE!!!!!!!!!!!!!!!!!!!! I wired up some resistors, ran the injectors as high-Z, and the voltage spikes are officially cured. Thanks to everyone who has helped!! I would have been lost by myself. jeffer, which components did you bridge? And what does that do? More current to the injectors? Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted January 26, 2009 Share Posted January 26, 2009 Yeah it takes out the resistors i think and gives your injectors full current. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted January 26, 2009 Share Posted January 26, 2009 Good news, man we have a lot of trouble with noise. This may call for a condensed noise sticky that outlines all known issues.... Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted January 26, 2009 Share Posted January 26, 2009 I think that web site i posted really hit the head with the separate power and ground lugs and the mod on the back of the board. I know mine was realated to my msd box but I still like the assurance that my voltage doesnt fluctuate so i know that im getting a consistent metering of fuel Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted January 26, 2009 Author Share Posted January 26, 2009 that was going to be the next thing I try if the injector resistors didn't work. On my last datalog the voltage fluctuated from 13-15v, but it did it smoothly, and I think it was just due to the alternator and current draw, so I'm going to leave it alone and just play with the voltage compensation a little if I need to. It seems to run alot better now, it starts easier, requires less duty cycle at the top, and my MAP signal looks quite a bit smoother. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted April 6, 2009 Share Posted April 6, 2009 I figured I should report that dropping resistors appear to have fixed my issue as well. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted April 7, 2009 Share Posted April 7, 2009 when i installed my ms a few years back i also installed an odessey battery in back.i installed the ms and the relay board on the bulkhead behind the seats.the relay board is directly wired( + and ground) to the battery,the only input from the old z is +key on from the ignition switch.the old z wiring has lots of possable volt drop points.my b+ output from my alternator is wired direct to the battery terminal on the starter-short wire = less wire loss.i used 00 welding cable for the battery .i ran a 00 ground from the battery to 1 of the starter mounting bolts-so the starter has both sides direct wired from the battery.havent had any problems.when i installed ms i i didn want it cobbled to old z wiring.i spent alot of time upgrading the rest of the car.take your alternator to a good shop that can scope the output and check for bad diodes.my only problem with ms is me screwing up the software Quote Link to comment Share on other sites More sharing options...
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