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L76 E38 Wiring Questions
Trying to tidy up a few things with my tune\wiring that have never been quite right.
Does the ECU need brake and clutch inputs? Ive never had them as Ive assumed they were just used for cruise control and "clutch to start" options, however, I read elsewhere they are needed. Fan wiring - Fans run all the time, not a big deal as you cant hear it anyway, but anyone else have this problem. I suspect it could be the lack of A\C throwing up a fault that makes the fans run, however, no fault showing on the ecu. Fan comes on when running , not just when ignition on, so it is switching from the ecu. Speedo. ECU not getting a speedo signal. I piggybacked the feed stright to the speedo and it works fine, but without a speed in the ECU I cant get the reverse lockout the work. Any tricks I may have missed. Its basic VZ Commodore, witht he VSS input on Pins 71\72 on X1 connector. I have have them reveresed, could that be it? Cheers |
Have you tried reversing them?
You can't damage anything (I know because I had mine arse about) |
Andy, my Fan runs off the High Speed fan circuit - the on/off temp for this was set to 100 C on and 90c off by my tuner.
I think the HS fan circuit is used because the LS fan is run by the Body Control Module which we don't run on a Cobra. cheers gregg |
Gav, Yep Ill give it a go this arvo.
Gregg, Yep that is pretty much how I have mine set up. I still reckon it could be the A\C fault problem. Do you know if you ecu takes a brake or clutch signal? Stumbled across the brake\clutch thing last night and wondering if that is part of the reason the new tune has made it run like a hairy dog. |
Mine doesn't have brake or clutch signals. Also don't remember anything in HP tuners about A/C being deleted but I could be wrong there. Have you had a look in HP tuners at what settings are enabled?
When you say there are no faults do you mean the MIL light is off, or a scan tool says no faults, or both? The VSS on the gearbox outputs a high and low, so yes they could be backwards. I have an LS3, but it's an E38 ECU. Can you define "hairy dog" please :) |
Andy. I don't have any brake or clutch signals into my EFI either.
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Its fine...
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Andrew, mate, don't worry about the tune...it'll sort itself out at the Nationals...can't have you driving too fast... |
Hey Ben,
No mil and no codes from the ecu, but found this on another forum for the same problem: "turn off codes 532 and 533... they are failing cause of AC missing more than likely and so ECU turns Fans on high to stop overheating make X - not reported" Hairy dog: Low spots on acceleration. Hold in 3rd at 3500, floor it and it just dies for half a second before go. Tuner is going to adjust dynamic fuel. |
If your tuner didn't know about those AC codes, maybe get another tuner.
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I suspect you might be right Ben. Ill double check he turned them off, but cant think what else it could be.
Took another look at the VZ wiring diagram - for the brake\clutch ecu inputs. Can anyone confirm what the switch position symbols mean on this. ie. Is the brake switch NC or NO. I would have thought NO, but looking at the symbols the 2 for the clutch inputs are one of each? Wondering if the ecu thinks Im driving around with the clutch in or brake pressed all the time. http://i231.photobucket.com/albums/e...psxzhwdlwp.png The reason Im asking is because I stumbled across this in my research: "Also, for a manual transmission tune to function properly the PCM will require input from both a clutch switch and a brake switch." https://forum.efilive.com/showthread...l-transmission |
I messed around with the brake input a few years ago and I couldn't detect any difference.
I can only assume that it's for cruise control perhaps? |
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I'd say some of those inputs are for Cruise control. The trick is the switch may say NC, but is that in the "resting" position? e.g. The pedal switches are normally "depressed" until the pedal is pressed in to the floor. So in theory the switch is OPEN until the pedal i pressed to close it. A bit confusing really. (And I might be totally wrong but its my recollection from when I did my LS1 Cruise controls switches). |
I think the brake input to the ECU expects 12v hot while the pedal is NOT pressed.
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Yep - If you were to look at this other part of the wiring diagram, the input from the Stop lamp comes from a NO switch - which makes sence, so those other ones are NC, so I think your right Ben.
http://i231.photobucket.com/albums/e...psh5lrryna.png So with no 12v on those inputs, it looks like Im driving around with the brake on, and if that isn't tuned out of the tune then that might be an issue. Its an easy fix to add that in regardless, and certainly wont hurt things. this is the stock commodore brake switch with multiple outputs as well, so Im assuming 2 are inverted. http://images.oreillyauto.com/parts/...alternate1.jpg cheers |
Cornetto I do not believe the brake switch (nor clutch switch for that matter) will matter one tiny bit to your tune. There is no such option to disable this I believe, it's just a matter of what is this signal used for, and I think it is just for ABS/TC/ESC etc, and even then in a Dunnydore all that is handled by the BCM. I don't think you need these ECU inputs. Happy to be corrected!
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You're probably right Ben, just going off that one post on the efilive forum that indicated it was important.
Anyway the tuner is confident he has it sorted in the latest tune file, so I will see how it goes before making any changes. Cheers |
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Maybe thats my problem :-) |
I wonder if it's something to do with coast mode. With the LS1 ECU (from memory) when you lift off the IAC wont drop the idle back down to the stationary idle, it leaves the throttle cracked slightly. I think it does this so the car drive is smoother and not so jerky when you lift off the gas and coast (less engine braking). Once the speed drops to a certain number it disengages.
I remember Garret having trouble with it on his blown setup as the mode was causing the motor to keep pushing under brakes and he didn't have a lot of engine braking. The tuner disabled it. It may be the ECU looks for the signal from the brake pedal to disengage the coast mode on the later ECU. This is all just hypothesis as I have no experience with the e38 ECU. Cheers |
Andrew's driving has been pretty jerky both in and out of the car so you may well be onto something Mike.
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e38
Andrew,
I have the same setup on mine i.e L76 with E38 and my fans run all of the time. I remember the tuner had great trouble trying to get them to come on at an appropriate temp, but they just stayed on. So no biggie there. Pretty certain mine does not use the brake and clutch inputs. Speedo- not sure on that. Sideshow did my wiring of GM harness.. Cant remember if i have that wired into the ecu...Sorry that doesnt help. Also a note about that new cam..You will have to run it in at less than 2500 rpm until at least October 5th... weird that it specifies a date... Quote:
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