niner11 Posted August 28, 2007 Share Posted August 28, 2007 I have an MSII setup that mirrors the DIYautotune and Moby install on an 82 280zxt. I'm using hall effect via the factory 82 dizzy to trigger the ignition and it seems to be working since my timing light flashes when I crank the car. The problem seems to be with the injector circuit. After trying to run the car just a few seconds it appears that Q1 or Q5 fries itself. Matt from DIY suggested that it may be a shorted injector causing the problem so I checked them and all were almost exactly the same....about 14.7 ohms. Also checked the injector harness for a short and they dont have continuity....so okay there. I built the box myself so who knows what other variables there are regarding what is wrong but it checks out on the stim. My msq is borrowed from an almost identical setup from Cygnus (Dave). The timing is very close so I'm wondering if there is anything else I may have overlooked? I'm changing out my relay cord and double checking the relay board but other than that I'm not sure. Any ideas would be great, thanks. Chuck BTW.. the signal is inverted per the write up. Also, I had to ditch the TAYLOR wires since it was causing resets. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted August 28, 2007 Share Posted August 28, 2007 High or low impedance injectors? Mario Quote Link to comment Share on other sites More sharing options...
niner11 Posted August 28, 2007 Author Share Posted August 28, 2007 High impedance injectors. I was sure it was a bad injector but they all check out fine. Quote Link to comment Share on other sites More sharing options...
naviathan Posted August 28, 2007 Share Posted August 28, 2007 What version MS-II is it? If it's a V3 board you should be good as long as you installed the flyback circuits. If it's a V2.2 you'll need to add the flyback circuits. Aside from that I can't see why it would be blowing anything. Post your injector settings, code version, board version, etc... Quote Link to comment Share on other sites More sharing options...
niner11 Posted August 28, 2007 Author Share Posted August 28, 2007 Thanks for the replies.....It is a MSII ver3 board. I just went through the injector harness and found no shorts. Also individually grounded each injector on one side and 12v on the other. They all seem to operate fine. To rule one thing out I'm remaking the injector harness since I have been unable to find the problem so far. Quote Link to comment Share on other sites More sharing options...
naviathan Posted August 28, 2007 Share Posted August 28, 2007 Ummm, grounded one side? The injectors are ground fired so they should be getting 12V switched on one side (usually run from a relay) and ground side wired to the inj 1 and inj 2 wires in the harness. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted August 28, 2007 Share Posted August 28, 2007 Ok, so high impedance, are you using PWM control or resistors for the injectors? Mario Quote Link to comment Share on other sites More sharing options...
niner11 Posted August 28, 2007 Author Share Posted August 28, 2007 I'm about half way finished with this new injector harness.... Pretty new to this If you are running high-impedance injectors (greater than 10 Ohms), then set the: PWM Time Threshold to 25.4 msec, and the PWM Current Limit (%) to 100%. (The presence or absence of the active flyback circuit (v3) or flyback board (v2.2) doesn't matter for high impedance injectors.) If you have low impedance injectors (less than 4 Ohms), set the: PWM Time Threshold to 1.0 msec, and PWM Current Limit to 30% in most cases (all V3 main board with active flyback installed, and all V2.2 main board with flyback daughter board installed). Looks like with high impedance injectors I should be good regardless. As soon as I finish this harness i'm going to check the resistance of each injector circuit and go from there per Matt at DIY. Hopefully something is obvious then. Quote Link to comment Share on other sites More sharing options...
niner11 Posted August 28, 2007 Author Share Posted August 28, 2007 Well, I fixed the msII box and then hooked up my new injector harness. After a few minutes of cranking where the car almost ran I put the MS back on the stim and found the same problem. Only one of the two inj lights would blink. I have more parts coming in the next few days so I wil fix the MS again and try some more ideas. PLease...keep any of your thoughts coming. I appreciate the help from everybody so far. Chuck Quote Link to comment Share on other sites More sharing options...
niner11 Posted August 30, 2007 Author Share Posted August 30, 2007 Update. I replaced both Q1 and Q5 on my MSII a few hours ago and checked out everything on the stim board. Both banks of injectors operated normally....until I tried to run the car. I'm using high impedance injectors and the fuses for the injector circuit on the relay board are 5 amps. What I can't figure out is why these injector drivers (Q1, Q5) keep frying. MS should have several layers of protection from an alternator over volt or spike and with 5amp fuses the actual 20amp drivers should not fail. I checked amp draw on the injectors, remade my injector harness, swapped relay boards and relay cables and still have the same problem. Btw, I checked the relay board once it was mounted on the firewall and the case had no shorts. I'm starting to think that it is one of two things. Either the alternator is spiking through a power source or my MS has some un diagnosed problem Before the MsII went back in the car for this go around I ran a bunch of the trouble shooting tests on the entire injector circuits using an LED and per the megamanual. One one hand this is pretty interesting but its frustrating at the same time. I'll get it running eventually but if anyone has any ideas I'm all ears. Thanks, Chuck Quote Link to comment Share on other sites More sharing options...
datman Posted August 31, 2007 Share Posted August 31, 2007 Try connecting 1 injector to each bank at a time with the MS wired up to the car. Just run a couple of wires from the injector outputs up to the injector. The injector will need 12v on one side and the MS output will be Ground (switched) Quote Link to comment Share on other sites More sharing options...
niner11 Posted August 31, 2007 Author Share Posted August 31, 2007 Thanks, I'll try that once I fix my MSII. The injectors only draw about 2.15 amps per bank and together both banks only draw about 4 amps. I also checked the resistance of each individual injector. They all were identical at 14.7 ohms. Any ideas? Thanks, Chuck Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted August 31, 2007 Share Posted August 31, 2007 reload the firmare if you haven't lately. Then reload the msq file. Also do a fresh reconfigure Megatune in the configurator. This cleared up some problems I was having with lights not flashing/flashing during my bench tuning phase. Quote Link to comment Share on other sites More sharing options...
niner11 Posted August 31, 2007 Author Share Posted August 31, 2007 Thanks Dave. I just disconnected the alternator to take it out of the equation. Reflashed the cpu and loaded the new Msq file...the car now starts right up without damaging the injector drives but now I have resets The MS box resets even using the factory 7mm wires...I have magnecor's on the way but they have not been delivered yet. Any ideas? Thanks, Chuck Quote Link to comment Share on other sites More sharing options...
niner11 Posted September 2, 2007 Author Share Posted September 2, 2007 datalog: Could all of this be from the crappy wires I have? datalogspike issues.zip Quote Link to comment Share on other sites More sharing options...
datman Posted September 2, 2007 Share Posted September 2, 2007 looks like your RPM spikes are causing the VE and AFR to spike, Try placing a car stereo style filter on the supply line to the MS Quote Link to comment Share on other sites More sharing options...
niner11 Posted September 2, 2007 Author Share Posted September 2, 2007 Thanks for the suggestion. Right now I have the alternator disconnected to limit the variables a bit. Would that filter be just to quiet the alternator noise? Quote Link to comment Share on other sites More sharing options...
naviathan Posted September 2, 2007 Share Posted September 2, 2007 This looks quite familiar...What is your skip pulses set at? Quote Link to comment Share on other sites More sharing options...
datman Posted September 2, 2007 Share Posted September 2, 2007 Noise from the ignition coil caused me a few problems, most of the noise was from my injectors though so I had to cut the supply pins on the drive transistors and power them from a source outside the MS unit itself. My injectors are low impedance though so that's probably not the problem you have. Quote Link to comment Share on other sites More sharing options...
niner11 Posted September 2, 2007 Author Share Posted September 2, 2007 Welding up the exhaust right now..... Not sure about the skip pulse setting, I'll check in a bit and post it. I read a step by step article on how to do that Datman. I hope it doesnt come to that but I'm not ruling anything out at this point. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.