Bringing TBI and Multi Port Fuel Injection to a New Level.     EFI Conversions and Tuning! Seattle to Portland! E-mail Tuning Consultant!
Page 7 of 8 FirstFirst ... 2345678 LastLast
Results 91 to 105 of 106

Thread: Retrofit 24x reluctor to early V8

  1. #91
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    850
    I thought you were running only the pcm wired on a bench. Cranking the engine will bring down the voltage to 10volts range, so no need for further testing.

    I think you should change the injector and coil order to the engine specs you have. Stock ls1 uses different firing order than earlier SBC. It can be fixed in the software but you will need to get an obdlink device to flash the pcm.

  2. #92
    Fuel Injected!
    Join Date
    Oct 2013
    Posts
    964
    Yes, it should start firing plugs with the CKP when missing the CMP.

    With a failed CMP, I suspect the PCM will begin firing the injectors and plugs assuming the CMP signal is low and the engine began cranking on the #1-8-7-2 firing rotation. Then, when the CMP is supposed to go high to begin the #6-5-4-3 firing rotation it flags that it failed but just keeps going in the order it began. So, if the engine began cranking on the #6-5-4-3 firing rotation then the engine and PCM are off a rotation and the engine won't start. So, you stop cranking and hopefully the engine stops on the #1-8-7-2 TDC rotation so the next time you start crank the engine the PCM and engine rotation match and it runs.

  3. #93
    Fuel Injected!
    Join Date
    Feb 2020
    Posts
    44
    Actually I'm not sure it can be changed in the software. You can change the bank assignments but I believe that only affects the feedback from the knock sensors and maybe the O2 sensors. But never fear, I have done the correct pin swaps to match the 18436572 firing order for both the coils and the injectors. There are two pairs that have to be switched but I don't have that info handy. Maybe the 4 center cylinders?

    That cranking may have been (probably was) with the plugs out.

    I'm using the OBDLinkLX and TunerPro, PCM Hammer

    Jim

  4. #94
    Fuel Injected!
    Join Date
    Feb 2020
    Posts
    44
    Lionel, that's not quite what I'm seeing on the scope but I'll wait to see after the simulator is up. But it looks like maybe it runs through something like 4 cycles (8 rotations) before it switches. Again though, too early to say for sure.

    Jim

  5. #95
    Fuel Injected!
    Join Date
    Oct 2013
    Posts
    964
    Quote Originally Posted by kur4o View Post
    I think you should change the injector and coil order to the engine specs you have. Stock ls1 uses different firing order than earlier SBC. It can be fixed in the software but you will need to get an obdlink device to flash the pcm.
    This can't be fixed in the software. I can't recall what it is offhand, but there was something to set that appears to allow you to change it in software except it doesn't work. You must re-wire the injectors and coils to match the firing order LS 1-8-7-2-6-5-4-3 to the Buick 1-8-4-3-6-5-7-2. In other words, swap 7-4 and 2-3.

    Then, you set the bank select for firing order vs cylinder side so the O2 feedback on each side corrects the injector fueling on that side. The Buick firing order would use 01101001.

  6. #96
    Fuel Injected!
    Join Date
    Oct 2013
    Posts
    964
    Quote Originally Posted by Jim Blackwood View Post
    Lionel, that's not quite what I'm seeing on the scope but I'll wait to see after the simulator is up. But it looks like maybe it runs through something like 4 cycles (8 rotations) before it switches. Again though, too early to say for sure.

    Jim
    Thanks for confirming that. So, the PCM tries a bit then switches if you keep cranking. If you don't crank long enough then it'll be luck of the draw on the next start.

    And you beat me to the firing order and bank select post.

  7. #97
    Fuel Injected!
    Join Date
    Sep 2016
    Location
    Fort Collins, Colorado
    Age
    59
    Posts
    49
    I just wanted to say Thank You! to Jim who started this thread and all the others who have joined in. It's become super valuable information for me on my own quest to adapt the 24x crankshaft reluctor and 1x cam signal to my older V8 engine.

  8. #98
    Carb and Points!
    Join Date
    Mar 2020
    Age
    39
    Posts
    2
    Will follow along this thread, would like to contribute more but my own research is way more limited to what you guys got so far. Got covered the 1x on cam(on paper) but the 24x reluctor wheel seems to be more complicated as you guys have shown, great job in what you have accomplished.

  9. #99
    Fuel Injected!
    Join Date
    Feb 2020
    Posts
    44
    OK, now I have something for show-n-tell.

    The attached photo shows my now usable desktop simulator. Still a few things to do, I need to align the timing wheel to the cam sprocket and then do a little finer balancing, label the switches and test points, and as time passes I will add inputs and outputs to the test points, and probably some devices too. The one thing I really want at this point is a tach but I'm sure I can find something cheap online to fill the bill.

    As it stands, using the variac I can get just about any speed I want out of it (the toggle switches on the right give me 2 speed ranges) and I have test points for CKP, CMP, Tach, Coils, and injector outputs. Plenty of room to add.

    Should be able to give it a test run this afternoon I hope.

    Jim
    Attached Images Attached Images

  10. #100
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    850
    I am not quite sure but it looks like the crank sensor needs to be rotated 180 degrees. The tab should points to the front of the engine.

  11. #101
    Fuel Injected!
    Join Date
    Feb 2020
    Posts
    44
    The rotation is in the opposite direction (CCW) so that messes with the way it looks. If you took the entire tone wheel and CKP sensor and rotated them 180 it'd be like the pickup being at the original mounted position but both the tone ring and the pickup facing rear instead of the front. As it is, the front face of the tone wheel is facing rearward and so is the sensor. With it running backwards that is like looking at it from the flywheel end sort of. Yep, messes with yer head but think about it. Maybe I haven't got it right yet but I think I do.

    OK, so moving the whole shebang to the front of the engine and rotating the sensor around to the driver's side, no big deal, keep the sensor pointed to the front just like original. Running backwards, the relationship of the tone wheel and sensor stays the same so sensor pointed to the front side of the tone ring. Flip 'em both around. Rotate on the shaft as needed. Yep, I think that works.

    For the CMP sensor I think it makes no difference except that the sprocket is spinning backwards, a leading edge is still a leading edge and I don't think the rotational position of the sensor matters. But tell me what you guys think.

    Here's a couple more shots. I have a 30sec clip of it running but the balance needs a little more work. I'm headed back out with the laptop to hook up the scope, hope to get a trace or two this afternoon.

    Jim
    Attached Images Attached Images

  12. #102
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    850
    If you flip the wheel and sensor 180 degrees, and switched the rotational direction of the crank you will be good.


    That setup looks nice, Do you plan to make a full bench simulator. With the 4 channel scope you can make very good test station for discovering new stuff in the ls1 pcm. Like confirming EOIT target and dwell times and so on.

  13. #103
    Fuel Injected!
    Join Date
    Feb 2020
    Posts
    44
    Yeah, I'm having a little trouble with the scope. For some reason now when I plug in the USB cables to the scope modules my touchpad gets hinky and I can't control the cursor. Acts like an interrupt problem but there's nothing else connected to the laptop so I don't quite get it. Maybe I can get into the control panel and find some way to manually set IRQs or something. That worked back in the old days but with windows 10 who knows?

    Anyway, with just one module plugged in (2 traces) I was able to look at the trigger pulses and cam pulse, then using the cam pulse as the trigger, checked each spark output. (The test point grid makes that really easy to do.) Looking at them in sequence for the 18436572 firing order they were all in the right places, the pulses were nice and square at 4ms duration, and I saw no evidence of erratica. I'm going to look at it tomorrow with a longer pulse train, then go to cranking speed and see what it does. I also plan to add a series of diodes so that I can look at the full 8 pulses on one trace, maybe split 4 and 4 also. It'll cut down the voltage a bit but I don't think that's a concern.

    As for refinements on the simulator, yeah, over time I will be adding functions, like TPS and other sensors, IAC and other outputs. If I can find the old schematic for the panel maybe even add in the nixie tubes. But first I think I will take the tone wheel off and weld slugs into the holes to get a closer static balance. Adding weights in the back side of the mounting flange is only doing so much and I want it running a lot smoother than it does now. That can wait until I finish getting the car to run.

    Which is what I'm back to now. The test I ran today demonstrates that the ECM in the car is OK and gives the correct outputs. So now the question is, why doesn't it do that in the car? I'm pretty confident that my leads to the coils are good. I used terminated wires pulled from a GM harness so they are factory crimped and the correct colors. They are well protected. But I will run continuity and grounding checks as a first step.

    If that tests good, what else could be the cause? Back to trigger signals? Supply voltages, grounds? The answer has to be there somewhere. This is assuming of course that the cranking tests tomorrow on the simulator give the expected outputs. I guess that is step one.

    Jim

  14. #104
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    850
    Open device manager and see if the usb device is not installed as a ball point mouse. I had some issues with serial com usb device install as a mouse.

    Now that you have confirmed that there is a good spark signal, next step will be to check injector pulse, if it there is any and it is consistent overtime.

    If all is good a step by step in car troubleshooting should be done. First will be to test for spark, than for fuel and work from there.

  15. #105
    Fuel Injected!
    Join Date
    Feb 2020
    Posts
    44
    Thanks, I'll try that next trip out. For now it's working OK on just one O'scope module and that's working out for me.

    So the diode trick worked just fine even though I used 15v zeners, just because it was the only thing I had more than a dozen of. I guess LEDs would work just fine too, I have a bunch of those. They are just less robust. I paired up 1,8,4,3 and 6,5,7,2 and then put another diode from each of those two test points to a third, making it the full ignition pulse train. Kinda like those old Sun engine oscilloscopes in grampa's garage. Makes it real easy to look at the pulse train. Then I cranked up the speed while on the "8" test point until the pulses overlapped. I'm guessing that may have been around 4-5K rpm but I didn't measure the time interval and with no tach, well... Then I slowed it down to a crawl, adjusted the time base and switched the motor on and off a few times. The pulse train is real stable and it looks like it begins firing within a turn or so but I'll try spinning it by hand just to see when it starts. I just didn't think of it. The pulses never varied in width as far as I could see, or at least not by much. Looking at the "8" TP (TP-8 I think will be it's designation from now on) it's easy to see why COP is an advantage.

    So I'm thinking I need to use the simulator to generate the CKP and CMP signals for the system in the car and see what sort of pulse train I get. That could get a little tricky as they are on separate batteries and both ECMs will be connected since I only plan to carry the signal leads and a ground over, but I don't think there will be enough of a voltage difference to matter. I probably should make up a combiner cable for the coil pulses though as it'd be handy to have the full pulse train. So yep, I'm gonna work on that for a bit. This way I won't need to be concerned about all that cranking on the starter.

    Anyway, I should have known this but you can't really run the battery charger while testing. Luckily I have both a power switch for that and one for the battery so I can just switch it off rather than having to unplug. Running on the battery the traces are nice and clean.

    Jim

Similar Threads

  1. 85 K5 Blazer with TBI retrofit
    By rokcrawlin85 in forum GM EFI Systems
    Replies: 34
    Last Post: 03-21-2016, 08:58 PM
  2. Late Model BBC Vortec(?) EFI retrofit to Mark IV BBC
    By BBPanel in forum GM EFI Systems
    Replies: 6
    Last Post: 04-09-2015, 06:08 AM
  3. duraspark reluctor phasing
    By mmigacz in forum GM EFI Systems
    Replies: 3
    Last Post: 12-28-2013, 04:26 PM
  4. Replies: 3
    Last Post: 09-07-2013, 09:00 PM
  5. New 24x reluctor kit for CNP ignition and 512kb PCM for $199
    By Hog in forum EFI Parts, Supplies, Software and Reviews!
    Replies: 0
    Last Post: 09-02-2013, 08:20 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •