Diagbox query

[bnd]

Any members on here that know diagbox functions well?

I am trying to find if its possible to trim the mixture level and alter the idle speed via this diagnostic software. I cannot find a menu that allows (if at all) these adjustments. I can read the current idle speed but do not know what menus to go into to adjust it or the mixture. The BSI is showing the mixture is to rich. Any help from someone who has experience in this software would be deeply appreciated.

[RichardW]

What engine have you got? The mixture on a petrol is fixed by the O2 sensors, diesels don't care. Seems a bit odd you would have a BSI error, but no ECU error...

[bnd]

It's a 2007 207 cc 1600 GT (petrol) Both lambda censors have been changed out. No engine management light on dash and no fault codes. Just a message showing that the mixture is to rich and the idle rpm is 792.

[RichardW]

What sort of message? 800 rpm sounds about right to me.

[bnd]

The message states mixture to rich. The car runs fine. No problems with fuel pressure at the fuel rail etc. I'm just trying to find out in the repair section on diagbox is there a facility to set the fuel mixture parameters differently and/ or the idle. Cannot find anything like this so far with the software.

[RichardW]

Still don't understand the 'message' - is this a fault in the BSI when scanned, or does it appear on the screen in the car? Does it go away if you clear the codes? I can't imagine why the BSI would be reporting too rich, if the ECU is happy.

TBH if it runs fine and the EML is not on then I would tend to ignore it!

[wheeler]

You can't adjust the mixture with diagbox.
What readings are you getting form the oxygen sensors on a warm engine at idle?

[bnd]

Under the initial scan on the menu under injection when you read the faults it brings up mixture to rich. The codes have been de.eted and haven't come back. The micro carbon reading is a tad high but within the parameters to pass mot. The co2 is much the same. On a positive note,the guys in my local town who can re- map the ecu can change the mixture. Strange that disgbox cannot control these parameters. I think you have hit the nail on the head, leave it alone. Thanks for your input. At least we now know that diagbox has its limitations. I hope this helps anyone else out there with the same problem.

[ozvtr]

Strange that disgbox cannot control these parameters.

You will probably find that, for regulatory reasons, these parameters can not (should not?) be changed from factory spec. The dealers will only return the vehicle to factory spec and not perform "modifications". They would replace parts to get the engine within spec but not tune the engine ECU. I'm not saying it cant be done, I'm only saying that the dealer tools wont be capable because the car passed regulations in a particular configuration and they are not allowed to deviate from that (and still remain a dealer). However, there is nothing stopping anybody else from modifying your car (within reason).
I'm not an expert but I think you will find that most dealer scan tools for other brands of vehicles will be the same, for the same reason.

[bnd]

Thank you ozvtr. Indeed what you have said has made sense. I presumed that a fault popping up its head stating "mixture to rich" would indicate to me that a peugeot dealer would use diagbox and would return the mixture settings to the standard intended to meet the emission laws. The whole point my my post is that I cannot find where in diagbox the repair or reset function is on the menus for this fault. This is why I put out there the enquiry for anyone who is up to spec on the use of diagbox and how to put the mixture back to what it should be. Obviously the mixture setting is of due to the software bringing the fault up. I just want it back to what it should be although the readings taken physically on my computer metre are with in the tolerances to pass mot.

[RichardW]

You can't change the mixture as the system is basically set up to run at stoichiometric ratio (hence lambda =1). The O2 sensors swing from lean to rich in closed loop mode, and the ECU adjusts fuelling to average it out. If something is wrong then it will lean out or enrichen the mixture to try and keep lambda at 1. If it can't, or it has to go beyond a certain amount of adjustment then it will set the lean or rich codes (or sometimes both). Fixing the fault will get it back on spec.

[bnd]

Cheers Richard w. I have cleared the faults and all is well. I have also learned that one has to be careful of buying cheap after market lamda censors. As you correctly state the lamda sensors pre and post catalytic converter are sensitive in sending back information to the ecu which affects the mixture. Some of the cheap after market lambda tolerances are not great and sometimes their poor scope creates a fault. Just on a foot note, both the the pre and post catalytic converter lambda censors that I changed out were not genuine Peugeot. They could have raised the fault? I fitted genuine sensors and after clearing the fault it hasn't come back. Strangely enough, no engine warning light was present or lamda failure fault code raised. Anyway, all seems to well presently. Thank you once again for your input.

[ozvtr]

Thank you ozvtr. Indeed what you have said has made sense. I presumed that a fault popping up its head stating "mixture to rich" would indicate to me that a peugeot dealer would use diagbox and would return the mixture settings to the standard intended to meet the emission laws. The whole point my my post is that I cannot find where in diagbox the repair or reset function is on the menus for this fault. This is why I put out there the enquiry for anyone who is up to spec on the use of diagbox and how to put the mixture back to what it should be. Obviously the mixture setting is of due to the software bringing the fault up. I just want it back to what it should be although the readings taken physically on my computer metre are with in the tolerances to pass mot.

You cant adjust it back to spec, you need to repair it back to spec. If it's confirmed that a parameter is out of spec, it needs to be investigated and the offending part repaired or replaced.
You also need to understand that the engine ECU can only react to what it is given as input. If that input is bad...the ECU doesn't know that. So if the ECU indicates "mixture to rich", then, is the sensor faulty or is the mixture actually too rich? Either way something needs to be repaired to get the system back to nominal.
A "mixture too rich" error would probably indicate a bad injector. It might also be a vacuum leak but it depends on how the error was triggered. From the O2 sensor or the fuel trims? That a rhetorical question. But as you have discovered, a faulty sensor can send you on a wild goose chase too.

Also, the MOT tests don't just check the air/fuel ratio, some of the faults could be because the engine is burning oil. You might need to check with a mechanic as to what each of the results actually mean?

Having said all that, it is possible to get a "chip tuning" guy to reprogram the engine ECU 'maps' to change the performance of the engine. It's possible that they could fine tune the engine ECU to obtain better results from your engine. But this is outside the scope of any dealer scan tool for all the reasons I outlined earlier.

By the way the post CAT (or 'down stream') O2 sensor is only used to monitor the state of the catalytic converter. It is not used in the management of the engine at all. The only faults that you could get from it are a high or low volts error (faulty sensor) or an 'aging catalyst' error. However, again, a faulty sensor could throw a spanner in the works!

[bnd]

Thanks ozvtr. All points taken. The car was in a bad state mechanically when I purchased it. I didn't pay very much for the car. I had to fit a new cat as the anti pollution warning light was coming on and on further inspection the cat had been cut open and re-welded. A new cat was fitted and As I mentioned to Richardw above two new genuine Peugeot lambda sensors were fitted. The anti pollution fault has gone. Good point regarding the injectors. The hydro carbons are up slightly. I have got a feeling that a set of valve stem oil seals are due as it blue smokes slightly on start up. Compression is very good. More work

[ozvtr]

The catalytic converter is very delicate and could be damaged by excessive oil burning. There must be a reason why the CAT was replaced in the first place? Something to bare in mind.