retro Posted December 18, 2023 Report Share Posted December 18, 2023 Hi there, I have an odd issue that I THOUGHT I solved but the customer has said has come back. G2 Link plus running a rover v8 (he's injected it) Car ran fine for past 15 years but cold start was always horrid. (I'll get a log and add it here and the map when the car comes back) Plugged in using 3.31 software and road tuned the car, adjusted cold start a lot better. (but couldn't see engine RPM or ECT anywhere) Drove for about 40 mins or more perfectly no issues. NOTE: LC-1 wideband was NOT plugged into the laptop during this road tune (just a gauge) Few days later opened the map in latest 3.40 software (as I noticed that had RPM and ECT available) uploaded that to the ECU. Started the car and went for another road tune. I can see ECT and RPM now YAY (but notice I can't select them from datalogged record values.... (suspect some odd stuff with changing versions from an older one) PROBLEM: Everything was going well, we have the Link G2 plus connected to the laptop serial comport 1 (no adapter as this is an old laptop) LC-1 connected to the laptop USB port using a quality Serial to USB adapter I've used for years. LC-1 powered separately off the cars main relay power. (nothing wired to the link in terms of wideband signal or power/ground etc) 5 minutes into the tune and the car starts bucking/jolting by itself as we are driving along at constant rpm and throttle. Checking all logs and I can't see any sensors reading badly BUT injector pulse width spikes when this happens..... TESTING 1: Change back to 3.31 software and start car again and drive. SAME ISSUE!!! so surely ruling out software weirdness..... Possible cause: The only time I've EVER seen a car do the exact same thing is when we used a 12volt to 240v inverter for the laptop power. It was powered off a cars cigarette lighter, however the wideband was powered from the ecu main power and ground. It was back feeding through the laptop to the ecu and causing injector spikes and all sorts of weirdness. This car with the Link G2 feels IDENTICAL to this. TESTING 2: Drive along and get the car to do the same thing, then unplug the Serial to USB adapter for the LC-1. Jolting stops 1 second after unplugging, drive for about 20-30 mins without the issue EVER coming back. Finished tuning and removed the wideband and unplugged the laptop etc. Got a call from the guy today that he started the car just fine, but once it got warmer the VIOLENT jolting came back and never went away Any ideas? Either this is a coincidence, or the laptop was somehow back feeding power down the serial port to the link g2 plus and has caused issues with the ecu.... Quote Link to comment Share on other sites More sharing options...
retro Posted December 18, 2023 Author Report Share Posted December 18, 2023 Connected and ecu information on version 3.31 software and tune put back to how it was BEFORE issue started (issue still occurring now without wideband connected) Quote Link to comment Share on other sites More sharing options...
Adamw Posted December 18, 2023 Report Share Posted December 18, 2023 The injector PW calculation is pretty simple in these. Basically Master fuel x MAP x fuel table x warm up enrich + accel fuel + deadtime. I would say the most likely would be a bad connection somewhere, causing a spike on one of those 5 variables, you should be able to log all those. Quote Link to comment Share on other sites More sharing options...
retro Posted December 18, 2023 Author Report Share Posted December 18, 2023 Thanks for responding. I’ll be happy if it’s a bad connection (which means not my stuff up haha.) What I was worried about is somehow I’d stuffed the ecu from uploading a 3.31 map using 3.40 software. I was going to try create a fresh map in 3.40 and copy paste all the values over. Or somehow voltage backfeed down the serial com1 to the link (however I’m doubtful of that…) So you don’t think it’s either of these two? it’s VERY violent when it happens (like timing all over the place kinda feeling) (but not misfiring) Also only at low ish TPS, no backfiring as such, just speed up slow down speed up over and over… I’ll get a full log over next 2 days and see if I can spot which sensor is erratic Quote Link to comment Share on other sites More sharing options...
Adamw Posted December 18, 2023 Report Share Posted December 18, 2023 G2 is a bit before my time, but as a general comment Link has always maintained good backwards compatability - that is you can generally use the lastest software version for a particular generation ecu running any prior firmware. The software first looks at the firmware version when it connects (or when you open a map offline) and only shows settings and functions that apply to the firmware in use. If the inj PW is changing it will likely be one of those I mentioned. The other possibility is a trigger error which could retrigger the crank enrichment. Quote Link to comment Share on other sites More sharing options...
retro Posted December 18, 2023 Author Report Share Posted December 18, 2023 "The software first looks at the firmware version when it connects (or when you open a map offline) and only shows settings and functions that apply to the firmware in use. " Ok good to hear, I'd just spotted a few interesting things. The map in 3.31 I didn't have ECT or RPM available to display anywhere.. 3.40 I can see those values in the live tuning dashboard BUT I still don't have them in the pick list to add to datalogging recordings... Opening the G2 sample Map I do have those options. So I suspect quite a bit of weirdness (its prob a SUPER old basemap 3.29 etc) Also the last tuning session, I stored to the ECU once finished then also saved the map to the laptop. Opening that map again on the laptop today, I see the firing order table greyed out ? (so can't change it) not that I want to.... Will test the car tomorrow and hopefully find the cause. Cheers Quote Link to comment Share on other sites More sharing options...
retro Posted December 19, 2023 Author Report Share Posted December 19, 2023 I've found out how to make the PC Link software not let you see ECT under AN inputs, or Engine Speed under triggers as available parameters to datalog. Open the G2 Sample map, go to Analogue outputs and change Aux 10 to Stepper Direction. Save as a new map. Close and reopen software Open your saved map go to datalogging setup, notice you can no longer see ECT or Engine speed as an available parameter to datalog.. This is why I was confused about those items as we have Aux10 as stepper direction in this vehicle... Quote Link to comment Share on other sites More sharing options...
Adamw Posted December 19, 2023 Report Share Posted December 19, 2023 Is there anything actually wired to aux 10? I suspect that function might be a legacy control for a separate stepper motor driver box. Quote Link to comment Share on other sites More sharing options...
retro Posted December 19, 2023 Author Report Share Posted December 19, 2023 Good question, I'll see if I can find out today. But that aside, it seems a little weird software bug that was confusing me. Car will be logged and connected tonight and hopefully have a result. Thanks for your help so far. Quote Link to comment Share on other sites More sharing options...
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