Jump to content
SAU Community

Recommended Posts

Hi all,

I've posted this question in the Home Tuning Vipec and Link thread, but didn't get a response so hoping it would get a little more exposure in it's own thread. I've also posted the question on the Link G4 forum, and emailed the guys at Zeitronix, but so far haven't had a response. Sorry if this turns out to be a bit of a read, but I want to be sure I detail everything I have done.

I am having a bit of an issue with my Zeitronix ethanol content analyser and Continental flex fuel sensor. I have it all wired up and working, but the issue I am having is with trying to configure the input in the Link ECU. I just can't get the ECU and the Zeitronix display to read the same numbers.

I believe, at the moment, that the issue is somewhere in the way I have wired the setup. So to help clarify, here is a quick diagram I drew in paint (tried to embed, but the topic wouldn't post...)

http://www.linkecu.com/forums/G4Forum/941028398/689720745/zeitronix-eca-wiring-png

Basically, I have the Continental sensor wired to a switched 12v power source and earthed at the chassis. The installation manual says to wire it to the ECU power source, but I couldn't see a reason that was necessary so I just have it wired to an accessory 12v. Possible issue there?

Then, I have the signal output wire from the sensor running to the Zeitronix display in-cabin. From here, rather than using the analog signal output from the Zeitronix display, I simply spliced into the sensor signal wire and pinned it to the Digital Input 5 position on the Link XS loom. The reason I did this was because I want to keep the signal digital, because I don't have a free analog input for the ECU.

This all appears to work fine, until I try to configure the sensor in PCLink. I have selected the GM Siemens Ethanol Sensor option from the list, as per instruction from Link. Now if I turn the Internal Pull-up Resistor on, and have the 'Active Edge' setting set to 'Rising' then the fuel temperature reads 132 degrees celcius, which is clearly wrong. If I change the Active Edge setting to 'Falling' then the temp reads 18 degrees celcius. Which might be ok, except the Zeitronix display reads 12 degrees celcius. If I turn the Internal Pull-up Resistor off, and have the Active Edge set to Falling, then I go back to the 132 degrees celcius reading. Switch the Active Edge to Rising, and I get 23 degrees celcius, which still doesn't match the 12 degrees showing on the display. It should also be noted that I am not sure which reading is correct, I just know that they don't match up.

Now I am aware that the Zeitronix display has it's own internal pull-up, so I figured perhaps the display and the ECU are interacting with each other and messing up the reading. So I tried disconnecting the digital signal wire from the Zeitronix display, so it is only connected to the ECU. Like this, with the Internal Pull-up Resistor switched off in PCLink, I didn't get a signal from the sensor. With it on and the Active Edge set to Falling, I got the reading of 18 degrees celcius again.

So I believe the issue is that I have the ECU spliced into the digital signal wire, and the two units are confusing each other. Thing is, what can I do about it? I don't have a free analog input for the ECU, so I can't use the analog output from the display. Can I simply not use the Zeitronix display and have the ECU receive a digital signal? Or is there another way I can divide the signal so that both units function correctly?

Any help would be much appreciated, and apologies again for the lengthy post.

Cheers,

Martin.

Link to comment
https://www.sau.com.au/forums/topic/430645-zeitronix-eca-wiring-and-config/
Share on other sites

what about a spear digital output from ECU, now I have no deers eyes about computers so I probably wrong, but could you send the signal to the ECU then send a signal from the ECU to the display

Pretty sure this is what was just done to mine!

Not a bad idea, except I don't think it can be done with the Link plug-in.

From what I can see, there is no digital output from the ECU that can simply relay a signal. There are auxiliary outputs, but these are used to control solenoids.

Ok, so to confuse matters further I just tried disconnecting the ECU from the circuit. So with the output signal going directly to the Zeitronix display, the display reads 13 degrees celcius. With the output signal going directly to the ECU, the ECU says the fuel temperature is 18 degrees.

So the two units are disagreeing on the reading, even when there is no interaction between them. I am thoroughly confused.

There may simply be a difference between the way those two units interpret the fuel temp data out of the digital stream. The "calibration factors" are little more than values that someone has written into a config file. There is plenty of room for someone to have gotten it a bit wrong (probably on the ECU end rather than a gauge that is dedicated to reading these sorts of sensors) or for there to have been a firmware update (for want of a better word) in the sensor that has not been correctly followed up by the config in one of the instruments (again, you'd expect that to be the ECU rather than the Zeitronix box).

Why don't you see what happens when you put warm fuel in the sensor? Put a can of fuel into some hot water so you get it up to a decent temp like 40 or 50°C, tip some into the sensor and see if the gap between the instruments widens or narrows.

There may simply be a difference between the way those two units interpret the fuel temp data out of the digital stream. The "calibration factors" are little more than values that someone has written into a config file. There is plenty of room for someone to have gotten it a bit wrong (probably on the ECU end rather than a gauge that is dedicated to reading these sorts of sensors) or for there to have been a firmware update (for want of a better word) in the sensor that has not been correctly followed up by the config in one of the instruments (again, you'd expect that to be the ECU rather than the Zeitronix box).

Why don't you see what happens when you put warm fuel in the sensor? Put a can of fuel into some hot water so you get it up to a decent temp like 40 or 50°C, tip some into the sensor and see if the gap between the instruments widens or narrows.

Yes, I think you're right. Especially given the Link software is using the GM Siemens sensor for calibration, perhaps the new Continental sensors have changed slightly and Link haven't accounted for this yet. But to be honest, I do think the ECU's reading seems more reasonable. The ambient temperature today is 21 degrees, so 18 degrees isn't far below that but 13 degrees is. I've actually got some temperature sensors that I can use to determine which one is correct, so I'll try that.

I was actually about to try reconnecting everything the way I had it, and then doing some data logging with the car up to temperature to see what the ECU says the fuel temp gets to vs the display readings. Worthwhile, I would I be better off trying your experiment?

Sorry, I didn't get back to the question........whilst it may not be super quick and not mess or risk free, I would do my experiment......not least because you could measure the fuel temp with another thermometer at the same time and have a reasonable idea what the actual temp is. You have to keep in mind that you may want to keep the sensor warmed up in some way so that it doesn't suck the heat out of the fuel when you pour it in/through....but that's just details.

I cant seem to find any datasheet for it, what ecu are you using? Is there any analog inputs left you can use?

You might be better off trying GTSboy's suggestion to find the right temp

Using a Link G4 plug-in. No analog inputs left unfortunately, need to use the digital signal.

I will try to find which temp is correct. Got a reply from Zeitronix, but whoever replied doesn't speak English very well. The guys at Link think it will be a case of each device being off, one reading a little low one reading a little high. I'm not so sure, but I'll figure out what the temp actually is and go from there.

I might as well go and get some E85 and stick the sensor in it to see what the two units read. Then I can measure the ethanol content and temperature myself and compare it to see which unit is correct.

The fuel temperature itself doesn't actually worry me too much, I want to use it as an indicator but it's not critical. The ethanol content I need to make sure is spot on though.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • I know why it happened and I’m embarrassed to say but I was testing the polarity of one of the led bulb to see which side was positive with a 12v battery and that’s when it decided to fry hoping I didn’t damage anything else
    • I came here to note that is a zener diode too base on the info there. Based on that, I'd also be suspicious that replacing it, and it's likely to do the same. A lot of use cases will see it used as either voltage protection, or to create a cheap but relatively stable fixed voltage supply. That would mean it has seen more voltage than it should, and has gone into voltage melt down. If there is something else in the circuit dumping out higher than it should voltages, that needs to be found too. It's quite likely they're trying to use the Zener to limit the voltage that is hitting through to the transistor beside it, so what ever goes to the zener is likely a signal, and they're using the transistor in that circuit to amplify it. Especially as it seems they've also got a capacitor across the zener. Looks like there is meant to be something "noisy" to that zener, and what ever it was, had a melt down. Looking at that picture, it also looks like there's some solder joints that really need redoing, and it might be worth having the whole board properly inspected.  Unfortunately, without being able to stick a multimeter on it, and start tracing it all out, I'm pretty much at a loss now to help. I don't even believe I have a climate control board from an R33 around here to pull apart and see if any of the circuit appears similar to give some ideas.
    • Nah - but you won't find anything on dismantling the seats in any such thing anyway.
    • Could be. Could also be that they sit around broken more. To be fair, you almost never see one driving around. I see more R chassis GTRs than the Renault ones.
    • Yeah. Nah. This is why I said My bold for my double emphasis. We're not talking about cars tuned to the edge of det here. We're talking about normal cars. Flame propagation speed and the amount of energy required to ignite the fuel are not significant factors when running at 1500-4000 rpm, and medium to light loads, like nearly every car on the road (except twin cab utes which are driven at 6k and 100% load all the time). There is no shortage of ignition energy available in any petrol engine. If there was, we'd all be in deep shit. The calorific value, on a volume basis, is significantly different, between 98 and 91, and that turns up immediately in consumption numbers. You can see the signal easily if you control for the other variables well enough, and/or collect enough stats. As to not seeing any benefit - we had a couple of EF and EL Falcons in the company fleet back in the late 90s and early 2000s. The EEC IV ECU in those things was particularly good at adding in timing as soon as knock headroom improved, which typically came from putting in some 95 or 98. The responsiveness and power improved noticeably, and the fuel consumption dropped considerably, just from going to 95. Less delta from there to 98 - almost not noticeable, compared to the big differences seen between 91 and 95. Way back in the day, when supermarkets first started selling fuel from their own stations, I did thousands of km in FNQ in a small Toyota. I can't remember if it was a Starlet or an early Yaris. Anyway - the supermarket servos were bringing in cheap fuel from Indonesia, and the other servos were still using locally refined gear. The fuel consumption was typically at least 5%, often as much as 8% worse on the Indo shit, presumably because they had a lot more oxygenated component in the brew, and were probably barely meeting the octane spec. Around the same time or maybe a bit later (like 25 years ago), I could tell the difference between Shell 98 and BP 98, and typically preferred to only use Shell then because the Skyline ran so much better on it. Years later I found the realtionship between them had swapped, as a consequence of yet more refinery closures. So I've only used BP 98 since. Although, I must say that I could not fault the odd tank of United 98 that I've run. It's probably the same stuff. It is also very important to remember that these findings are often dependent on region. With most of the refineries in Oz now dead, there's less variability in local stuff, and he majority of our fuels are not even refined here any more anyway. It probably depends more on which SE Asian refinery is currently cheapest to operate.
×
×
  • Create New...