Building the Brains for a Budget Racer: Jaguar A7 #42

Andy's GM DIS centric hardware design! Also works as a fuel controller for EDIS and distributor applications.
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m2cupcar
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Re: Building the Brains for a Budget Racer: Jaguar A7 #42

Post by m2cupcar »

Yes- D2 zener. I did bridge the outer two holes. It looks to me that the top outlined square pad is JP1, the very next round pad below is 5v and the bottom round pad is 12v. Of course your reference to the HSD/FP/LSD jumper makes sense. If the Ignitor jumper was labeled similarly: 5V/JP1/12V (like below) I assure you I wouldn't have bridged the two outer pads. That said, I pulled the power immediately when I saw smoke. Applied it again after removing the ignitor leads from ground (thinking that was the problem) and got smoke again. No other visible carnage at the time. I've already pulled D2, so no chance of checking it with the JP1 fixed, but CEL was still flashing the when I pulled power the final time, so that gives me some hope.

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My jumper folly for your entertainment:
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Re: Building the Brains for a Budget Racer: Jaguar A7 #42

Post by Fred »

Feedback noted! The thing is, the large text near a set of pads like that is the name of the set, not one of them. Perhaps leaving JP1 where it is, but making it read 5V/IGN/12V would be best?

Glad it's still flashing. Sounds like D2 was a winner. We ummed and arrred about that diode a lot, and eventually left it in as a sort of "it won't hurt" but sounds like it didn't just not hurt, also saved you! :-D

You can run it without the D2 diode once you fix the jumper situation (or just remove it for now). All D2 does is clamp excess voltage, and if you don't have a willing and ample supply of it, it does exactly nothing.

IE, fix the fopar, fire it up and continue on with BenchTest firmware etc :-)
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Re: Building the Brains for a Budget Racer: Jaguar A7 #42

Post by m2cupcar »

Fred wrote:Feedback noted!...making it read 5V/IGN/12V would be best?
Agree. That'd follow the same convention as HSD/FP/LSD4 - logical for a newb.
Fred wrote:You can run it without the D2 diode....fix the fopar, fire it up and continue on with BenchTest firmware etc :-)
excellent
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Good News

Post by m2cupcar »

Corrected jumper at JP1, applied power and have an active/flashing CEL.

Still missing the #4 injector LED on the startup. But going to load the benchtest firmware first before troubleshooting.
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Re: Building the Brains for a Budget Racer: Jaguar A7 #42

Post by Fred »

Great news. :-)

As I said, bench test should flash nothing on startup, and a random firmware will flash whatever is configured to be fuel outputs.

With the benchtest firmware on it, you will have to send it a packet, but should be able to see all of your pins flashing in the style of the command sent.
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Re: Building the Brains for a Budget Racer: Jaguar A7 #42

Post by m2cupcar »

BenchTest fw load success:
Image

Powered off the A7, removed load jumper, powered on, and ran EMSstudio. A7 loaded immediately (thanks to the Windows FTDI Serial Speed Settings post: viewtopic.php?f=54&t=2568&p=39879&hilit ... ngs#p39879). Opened the BenchTest wizard, clicked start and it returned error: Command Failed Command failed with error: unimplementedTestMode. I also tried with Megatunix 0.9.2.4- which crashed when "find my ecu" is clicked. While crashing it manages to produce two other windows (one is live data). I bumped the baud up to 115200 in the port settings which is how MegaTunix has it listed, but it still crashed. I had some notes "keep trying" for Megatunix from the A3, so I tried five more times and Megatunix then connected to the A7. It was stable enough to run the benchtest packets. I got four injector flashes and a constant CEL "pulse". None of the other LEDs flashed - can't remember if they should? Putting both RPM to ground turned them off. Here's the video: https://youtu.be/4H0we3NHkQc

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Re: Building the Brains for a Budget Racer: Jaguar A7 #42

Post by Fred »

Glad the loader worked well for you. I guess I need to spin out a fresh one in the next few days. I might add a couple of basic utilities to it for the two Robs. One each.

In terms of stuff flashing, none of the generic IO stuff should flash, the two ignition LEDs closest to the fuel ones shouldn't, but the other two near the wires should. I wonder if your only casualty was the FET driver IC, or whether the LEDs are on backwards, or something else.

To find out, play with the bench test dialogue and slow the test way down so you can easily watch the pulses on your multimeter (you might be able to without slowing it down, try first if you want). Check this on the fuel outputs, you should see at least a few volts with the LEDs off (not the full 12, though), and a solid 0.0 with them on. The ignition is the opposite. You should see a full 12V for the pulse and 0.0V for the gap between pulses. Given you don't have an LED to watch, I would align the pulses with the injector outputs so they all flash together, rather than sequentially as is default. Then when the fuel LED lights, you should see 12V on your ignition output.

Those ICs are only a couple of dollars each, and easy to replace. But as I said, LEDs could be in backwards and simply not lighting up. They're hard, but perhaps possible, to check visually. There might be a tiny dot or something at one end.

Rather than replacing, if you can verify the other two channels work still, then you could simply jumper the inputs across and move your output wires there. Test that with 5V into the inputs of them. They're weakly pulled to ground on the inputs. Doing it this way you should be able to get a solid 12V out the whole time you have 5V in, easier to test with a DMM.

I guess it's also possible that you fried those two CPU outputs. If so there is still a way out, but you'll be semi sequential and wasted spark by stealing two of the known working outputs from the injectors and bridging the injectors inputs into pairs.

Looking at my list of "might have died"s, only the MAP/AAP and high side driver remain.

With bench test still loaded look at the MAP/AAP values in emstudio numeric values display and make sure they have numbers (possibly wrong due to different config, but you should be able to make them move with a hose and your mouth/a syringe).

It's possible to control the fuel pump using bench test, but none of the tools do it. So for that, throw any normal build on there and you should see it light up for 2-4s at boot up.
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Re: Building the Brains for a Budget Racer: Jaguar A7 #42

Post by Fred »

I just went through the code looking to see why you'd get that error, and it seems to me that you must be using some incompatible hacked version of EMStudio or something. You said it was on Windows. I am unaware of a current good version to use for Windows. Maybe I gave you something dodgy a while back and forgot? In any case the test mode is something you can't control through the UI (in the version I have) and simply related to what you're doing. EG one of the modes is attached to the stop button, another to the bump button, etc.
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Re: Building the Brains for a Budget Racer: Jaguar A7 #42

Post by m2cupcar »

This A7 came with SMD components installed. All the IGN LEDs are oriented the same direction. And I assume Andy saw these work before he shipped the board.

ALL Injector outputs show 12v off and drop to around 7v when "firing" on the benchtest.

I have verified that all the Ignitor smd LEDs are good. All cathodes are on the right with ignitor area at the top/up (as pictured below.)
Image

LED resistors R64 and R65 both check out at 2.4kohm.

R91 and R92 both check out at 160ohm.

So I assume the next thing to check is pin 7 (OUT-A) and pin 8 (OUT-B) on IGN1/2 IC to see if there's any voltage. Which I assume there is not given nothing else bad working backwards from the leds.

Hooked up a 12v t10 LED to both IGN leads (one at a time) and got flashing I'd expect (appeared coordinated with injector LEDs.) Video (different event speed for each): https://www.youtube.com/watch?v=nI_Ub8whhSM

Both AAP and MAP are functioning- accurate for ambient and change with some pressure per numeric data.
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Re: Building the Brains for a Budget Racer: Jaguar A7 #42

Post by Fred »

Disco party fiesta at Rob's house! :-D

Ummm, if that blue blinder was connected to the ignition output leads, then everything's working fine. If the LEDs are also connected there, and no traces are broken, and the resistors are good, either they're toast or all backward? :-D

I don't suppose you tried 5v into the other two channels to light them up, did you? Should see 12V on the outputs if you jumpered their jumper correctly (didn't need to, so may not have done it at all). Or 5v if you jumpered them the other way. The third possible way, as you know, is bad :-)

If you don't care about those LEDs, you can just continue on without them or retro fit something in the engine bay with the ignitor so you can verify it without opening the case? Your call. Earlier iterations of the Jaguar did not have LEDs for ignition at all, so they're kind of a bonus. Nice to have, though.

That just leaves the HSD chip, but given everything else survived, it's almost certainly fine. GO D2! You're a winner! :-D

You have email re the little guy. XXOO

Fred.
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