VEMS Community Forum
VEMS => Software => Topic started by: fphil on May 15, 2017, 11:28:20 am
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Hello,
After having replaced the old Weber injector by new EV14 ones and the sparkplugs for less resistives I got the folowing error messsage poping on when recording and running the car:
"Communication error. Please plug off the serial connecto"
No message engine not running.
Does it tell something for some one of you ?
Regards
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Why less resistive? That pushes alot of noise back to the ecu.
Modern plugs all use about 5k resistors in them, go for that. I can´t see how the coil would need a less resistive plug unless it was absolultely terrible.
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I changed the Denso Iridium IW24 for classical NGKBP8ES ones which appear to be less resistive than the Denso. Anyhow the cable Beru connector is resistive on the coil side. The noise is more probably induced from the EV14. Possibly the 30V standard flyback is not enough in my case.
I did not say that I use the PS/2 cable option for wheelspeed.
Indeed when I put the PS/2 ground on a strong earth I do not have these error, although I have connected pin26/36 as it should (10cm etc ..)
Apart that the Ecu runs good.
I believe that this message comes from the Genboard which accumulates the errors before sending the message. The thing to do is to quit everything and restart if not it pops up even more frequently.
I also believe that this message seems useless.
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Change to BPR8ES instead and you will get rid of the noise!
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Yes possibly, same resistance than the IW24 about 4.5 k, but I prefer to work out first a solution on the genboard side.
Ignition with Marelli Microplex ecu + BP8ES is OEM. I see no reason why a modern ecu could not work good with the same plugs.
This is mostly these weird messages which are an issue
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nothing wrong with the gen board, use resistor plugs.
http://www.ngkntk.co.uk/index.php/technical-centre/spark-plugs/resistor-plugs/
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Yes I know about resistor plugs, although this is mostly used to damper the ectromagnetic field. Besides the noise may come from the new EV14 as well.
The topic is more about the PS/2 cable which may work as an antenna, the plugoff message which is not a simple alarm to be acknowledged but which stalls VT and the need of a good GRD.
I have scoped the spikes at the PS2 cable, quite impressive, the GRD can jump up to 3V. In fact Iwould be surprised if the source is only electromagnetic.
Anyway I would supress the PS2 (anyhow said as "not recommended"), make the wiki wheelspeed circuit with zener and lowpass filter and go for a "stronger" GRD earth... Last note, the Genboard V6 seems to be more sensible than the V8 ...
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Yes I know about resistor plugs, although this is mostly used to damper the ectromagnetic field. Besides the noise may come from the new EV14 as well.
The topic is more about the PS/2 cable which may work as an antenna, the plugoff message which is not a simple alarm to be acknowledged but which stalls VT and the need of a good GRD.
I have scoped the spikes at the PS2 cable, quite impressive, the GRD can jump up to 3V. In fact Iwould be surprised if the source is only electromagnetic.
Anyway I would supress the PS2 (anyhow said as "not recommended"), make the wiki wheelspeed circuit with zener and lowpass filter and go for a "stronger" GRD earth... Last note, the Genboard V6 seems to be more sensible than the V8 ...
Put normal spark plugs in place not some shit :)
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What is more normal than the NGK 2912 BP8ES? :)
https://www.ngk.com/product.aspx?zpid=9418
(as I said there is already a resistor on the conector -coil side- of the Beru ignition cables)
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What is more normal than the NGK 2912 BP8ES? :)
https://www.ngk.com/product.aspx?zpid=9418
(as I said there is already a resistor on the conector -coil side- of the Beru ignition cables)
BPR8ES....... it's the same plug as used in the classic mini, just two points colder on the heat range.
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As for ps2 cable. Fit a Ferrite choke to the cable
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I will suppress the PS2 cable but the choke self is a good idea. Can easily be tested on the Digitus USB cable - just in case.
There are indeed several options. Another one, I think, is to set right pull up resistances on digital inputs so to define thresholds above the GRD noise level
Interesting to know if other people has even got such plugoff message and alson the logic which generates them.
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I will suppress the PS2 cable but the choke self is a good idea. Can easily be tested on the Digitus USB cable - just in case.
There are indeed several options. Another one, I think, is to set right pull up resistances on digital inputs so to define thresholds above the GRD noise level
Interesting to know if other people has even got such plugoff message and alson the logic which generates them.
usually people use spark plugs with R letter in name and don't have such problems
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Certainly the EV14's w/ 30V flyback is not the issue here. They work flawless with VEMS 30V flyback circuit.
I don't see why anyone would want to run non-resistor spark plugs.
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@Notorious VR. Have you experienced wheelspeed from PS2? Do you know about this USB plugoff message?
I know that resistor sparkplug are ok, but I do not know why non resistor sparkplugs still exist :)
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Non resistor spark plugs is for lawn mowers and methanol cars with dummy ignition ;)
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Still on the subject, has someone ever observed one second time jump in their log records?
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You were right, definitely one needs sparlplugs with 50k resistance.
I first did not believe it since there was already 50k on the ignition cable (Beru connector).
I thought that the noisy speed given by Vems through the PS2 input was not related to the USB messages and comes from a noisy GRD. I improved the GRD, made a stronger pullup on the signal, the speed comes a little better.
Then , I thought to improved the grounding of the RS232 cable, nothing ... I scoped the coils for resistive versus a no resistive plug. nothing relevant.
Then I changed the plugs... The only way to protect the Vems circuit from any electrostatic transient voltage seems to be damping the transients at the origin.
Even if it could be obvious, I believe the recommendation for resistive plugs should better be put in the documentation (if not already there ;-))
btw. Another one should be to feed the IAC from an inj output. Then idle is fast tune. If fed from ign output, one (me) spares a lot of time and may need to work out as well the VE/Ign map at the idle point.
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@Notorious VR. Have you experienced wheelspeed from PS2? Do you know about this USB plugoff message?
I know that resistor sparkplug are ok, but I do not know why non resistor sparkplugs still exist :)
Sorry only have experience w/ wheelspeed as configured by HU (on EC18)
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You were right, definitely one needs sparlplugs with 50k resistance.
I first did not believe it since there was already 50k on the ignition cable (Beru connector).
I thought that the noisy speed given by Vems through the PS2 input was not related to the USB messages and comes from a noisy GRD. I improved the GRD, made a stronger pullup on the signal, the speed comes a little better.
Then , I thought to improved the grounding of the RS232 cable, nothing ... I scoped the coils for resistive versus a no resistive plug. nothing relevant.
Then I changed the plugs... The only way to protect the Vems circuit from any electrostatic transient voltage seems to be damping the transients at the origin.
Even if it could be obvious, I believe the recommendation for resistive plugs should better be put in the documentation (if not already there ;-))
btw. Another one should be to feed the IAC from an inj output. Then idle is fast tune. If fed from ign output, one (me) spares a lot of time and may need to work out as well the VE/Ign map at the idle point.
50K Ohm spark plugs?
Normally they are 5K and it makes a gigantic difference, I have had to do alot of work related to that and the return feedback is tons less with a 5k plug vs 0k plug
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Glups, yes 5 kOhm for the NGKBPR8ES, you are right. Same that the Denso IW24 which were mounted before on the engine ( I have not seen Denso saying their plugs are resistive)
I hardly saw any difference with a standard scope. Did you use antenas for measurements?
I understand now why the ignition gates are sometimes deported far away from the ECU.
About the wheel speed circuit vs ps2 cable. Stupidly I wired mine that I attached on the board after taking the cable off. When finished I realized that everything is already there on the board just needing one solders some plugs ! ::)
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for the feedback you need to measure voltage and current.