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mobythevan

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Posts posted by mobythevan

    LT1 opti spark wiring help

    in MegaSquirt

    Posted

    Well, I feel like a noob:mrgreen:. I guess I just didn't have everything connected correctly at the same time in my tests. With the pullup resistor now the low res functions fine on the scope. It is curious to me that the hi res does not need a pull up to function. I could only guess that it is different circuitry for the higher frequency toggle rate. Thanks for the help guys.

    LT1 opti spark wiring help

    in MegaSquirt

    Posted

    No pull up Matt, that was something I tried with the first unit when I didn't see anything. I did not try that with the second unit. One of my buddies says he searched a lot and the low res failure seems to be common so he wants to try taping the hi res slots to get a low res type signal.

     

    Matt, I notice in your writeup on the diyautotune site a pullup is used on the v3 mainboard. I am using the v2.2 mainboard so the references didn't make since to me for the pullup. Are you putting a pullup on the low res signal??

     

    I did go through various scope triggers and settings. I also spun the dizzy at slower speeds by hand, but hi res functioned fine for my time scale and I got many pulses on the screen.

     

    Maybe the units have debri or rust blcoking the low res opto detecter? More experimenting to come.

    LT1 opti spark wiring help

    in MegaSquirt

    Posted

    Well, anyone who has worked much with megasquirt can understand where I am at now.:icon45:

     

    With everything connected on the first opti spark I can see the high res signal on the scope but not low res. Grabbed a second optispark from my friends engine and hooked it up, same thing, see high res but no low res. Took the second optispark to the bench and wired a custom connector to run from my 12 volt power supply I use for the stim board. We figured maybe the wire harness on the engine had a problem. Turn the opti by hand to confirm and see the same thing. High res OK, no low res signal. I have seen some strange things so far with all my megasquirt setups and this one is right up there. What do you guys think? Both optisparks are bad with the same sympton, seems odd

     

    My test setup supplies 12 volts to ignition feed, grounds reference low signal. High and Low res are connected directly to scope probes, the probes are grounded to reference low. I also reversed the scope probes which yielded the same results.

     

    If I can't think of something else to try I guess we will either put magnets on the damper or an EDIS trigger wheel, but I would rather stay with the simplest setup of using the optical wheel in the optispark.

    MSII Confusion

    in MegaSquirt

    Posted

    Yep, this is where the wideband pays for itself. Turn off O2 correction, I always go in and set the active above rpm to something like 7000 rpm so no correction occurs. Then you can start adjusting the VE table for idle, light throttle and then start driving and tuning. Once all of that looks really good you can start tuning on warmup enrichments and ASE, etc. Also remember to turn off acceleration enrichment to tune on the VE table. It is best to follow the procedure in the manual. If you don't turn off the correct things or start tuning pieces out of order you will be re-doing it all. I have been through that cycle where I tuned and realized accell was on and had to re-tune.

    Whats wrong with this bracket??

    in Gen III & IV Chevy V8Z Tech Board

    Posted

    That bracket looks correct for an LS1, but your lower pulley and water pump pulley don't look like an LS1. By referencing my other vehicle turbo rx7 thread I can see that your lower pulley and water pump pulley do not seem to put your belt in the same place as an LS1. They look like different pieces and will likely not work with the LS1 alt mount.

    MSII Confusion

    in MegaSquirt

    Posted

    Did you have all the injector connectors unplugged at the same time for your test? The way they are wired they could share some connections if you wired them just like the picture you posted earlier in this thread. If you test one but another is still plugged on it is possible you will see 12 volts.

    How does one get the girlfriend in the loud "scary" Z car...?

    in Non Tech Board

    Posted

    I feel bad for some of the people whos significant other doesn't share an interest in the car hobby. My wife rode with me at the dragstrip racing against my brother in his truck. It just happened to be my fastest run, that was cool. fortunately I was slow enough to have a passenger. With the turbo LSx rx7 she asked me one day if it was going to be too fast for her to ride at the drag strip. I told her we could always try to get away with it on the first run, but the tech guys will likely poo poo the situation and claim it will be faster than 14 seconds. :-D

    LT1 opti spark wiring help

    in MegaSquirt

    Posted

    I think the only real difference is the low res slots of the optispark are not all the same size so you have to be sure to trigger off the correct edge

     

    That is why I wanted to scop it before connecting up to megasquirt, just to be 110% sure which edge. I haven't got back to the garage to try again, but if it doesn't work I am going to pull the unit off so I can play with it on the bench instead of cranking the starter.

    LT1 opti spark wiring help

    in MegaSquirt

    Posted

    I am hooking up an LT1 opti spark to the scope to look at the low res signal before wiring it all up to megasquirt. I have the ignition feed wire to the opti supplied with 12 volts. I have left over the "ref low" wire and the "low res" wire. I cannot see a waveform when cranking the engine. I see the low res wire setting at 12 volts, but it never goes low. Do you guys have any ideas? I assumed that ignition feed gets a 12 volt signal when the key is turned on, so that is what I am giving it. It is a red wire and that is usually a switched 12 volt in a chevy harness. I also assume that ground is occurring inside the opti unit to the engine block. I tried the scope between low res and ref low. I also tried it between low res and engine ground. It doesn't seem like I need to suplly a pullup like the nissan turbo dizzy because low res is already at 12 volts when the opti is powered. I dunno:hs:

     

    The opti only has four wires that go to it:

     

    high res

    low res

    ignition feed

    reference low

    Bad Break up(Resets,Grounding,Noise Problems)

    in Megasquirt

    Posted

    We worked on my friends truck today and I think it is fixed. All the caps had been added as noted earlier in this thread (also notice that I added a bold note because I think one cap was listed wrong). He was still getting resets, but what we found is that they were related to low battery voltage. The PO had wired the cooling fan to run all the time so it was always draining the battery after being parked until it pulled down the coolant temps. We put a relay so it only runs when the truck is running and re-charged the battery. It runs great now. We will see if he gets any more resets in the next few weeks. I think it was a combination of adding caps and having a charged battery in his case.

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