The V8 Owners Forum -

I have a 4.6 about to be fitted with MS3X. It is a basic engine not a race or performance engine - while I want it to be as efficient as possible it does not have to have the last HP rung out of it.

An important part of the engine management process is the O2 sensor - ideally a wide band sensor for each bank would be preferable but they are expensive. So will a single wide band sensor in the exhaust, downstream after where the exhaust from each bank goes into one be OK or must I have one for each bank noting this is not a hi tech engine with standard induction, heads and exhausts?

Thanks

Garry

If you think about it, what sort of fault would cause one bank to run at a different AFR than the other, with port injection? And if they were different, how would you correct it?

With batch injection, you don't group the injectors right and left bank anyway. And with fully sequential, you'd ideally want to measure each cylinder individually.

One where the pipes combine will be fine. You will need to set the distance from the exhaust ports compensation in the MS software for best VEAL results.

DaveEFI wrote:If you think about it, what sort of fault would cause one bank to run at a different AFR than the other, with port injection? And if they were different, how would you correct it?

With batch injection, you don't group the injectors right and left bank anyway. And with fully sequential, you'd ideally want to measure each cylinder individually.

One where the pipes combine will be fine. You will need to set the distance from the exhaust ports compensation in the MS software for best VEAL results.

Intake air leak, exhaust leak, lifter issue, cam issue, rocker/valve/pushrod issue, injector issue, ignition issue....

Pretty much anything engine related could cause one cylinder, one bank, whatever to run differently.

So whilst one wideband is better than none, of course one wideband per bank is better than one per engine.

And there is no real need to monitor each cylinder unless it's some sort of extreme application.

But yes if you can accommodate it, one wideband per cylinder is better than one wideband per bank.

But just monitoring each bank, it would be very obvious if one cylinder was causing a major issue...as you'd be able to compare running/parameters to the other bank

If only looking at a combination of all 8, pinpointing any issue would be more difficult....and it would be better masked by the other cylinders.

One is minimum two ideal, The megasquirt will run fine with one, it's really only used on the go if you are using the auto tuning part. If you have a gauge fitted obviously you can monitor for issues. Any decent tuner mapper tends to use their own monitoring equipment shoved up the exhaust pipe when mapping.

I!ve two innovate wideband lambdas fitted and have a dual gauge to fit also. If I was to do it again I would probably use spartan lambda systems as I've got through about half a dozen sensors and a controller. Running megasquirt from extra efi hasn't helped with ongoing issues with it. I rue the day I bought it. If it's not too late and you value your sanity, I would strongly recommend going emerald or omex, both high quality products with proper after sales support.

Thanks for the input - varied thoughts but very helpful.

I am not looking to do any monitoring myself from the drivers seat - I will leave that to the ECU to adjust mixture etc as required based on the O2 sensor.

Cheers

Garry

Thanks for the input - varied thoughts but very helpful.

I am not looking to do any monitoring myself from the drivers seat - I will leave that to the ECU to adjust mixture etc as required based on the O2 sensor.

Cheers

Garry

Any of those faults - headgasket, manifold leak etc, will surely make the engine run badly? If you need two widebands to help you diagnose it, fair enough.

I just consider it an essential tuning aid. Although I do have a dash display which reads constantly.

DaveEFI wrote:Any of those faults - headgasket, manifold leak etc, will surely make the engine run badly? If you need two widebands to help you diagnose it, fair enough.

I just consider it an essential tuning aid. Although I do have a dash display which reads constantly.

Depends on the severity of the problem.

If you have the ability to monitor both banks...it makes no sense just to either do one, or merge all 8. Widebands are just so cheap these days.

Obviously if you've little interest in the running or tuning side, then you could just as easily run no widebands or any feedback once it is tuned too.

Each to their own really. For me information/data is important. If fitting any widebands....I cant see any sense in having no visual display for the driver though....especially if you're allowing closed loop control via external controllers.
Some widebands are less reliable/trustworthy than others and when an ecu uses an external controller....it has very limited means of recognising any faults so it will know to stop trying to "correct" based on what it sees.

At least with a visual display, the driver should be able to see something strange is going on and hopefully do something about it.

As I said - this not a race car - it is a lumping little Landrover Truck with a top speed of 70mph and a 0-100 time of about 5 years. I just need it to run well as efficiently as possible without going overboard. Plus I really dont have the room for an additional gauge - I already have two pods sitting on the top of the dash cluttering up because of a lack of instrument spots.

So unless an O2 gauge provides something the ECU cannot manage on a day to day basis I think I can do without it - afterall few if any vehicles have one as standard.

Cheers

Garry

garrycol wrote:As I said - this not a race car - it is a lumping little Landrover Truck with a top speed of 70mph and a 0-100 time of about 5 years. I just need it to run well as efficiently as possible without going overboard. Plus I really dont have the room for an additional gauge - I already have two pods sitting on the top of the dash cluttering up because of a lack of instrument spots.

So unless an O2 gauge provides something the ECU cannot manage on a day to day basis I think I can do without it - afterall few if any vehicles have one as standard.

Cheers

Garry

True.....but OEM vehicles are tuned by usually tuned/setup by professionals and with abilities to report most faults and behave themselves reasonably well during a fault

But as long as tuning is good with no silliness involved, you could quite happily run with no gauge, no widebands, very little really.

A dash gauge is the best toy I have fitted to my car. I am on this forum because my car is a toy to me. One gauge for each bank and when something is not right or gradually changing you get some early warning. I probably wouldn't bother if it was a bog standard plodder but lean mixtures in a flyer may well result in an expensive disaster.

Bit late to the party on this one!

I have a single wideband on each of my two MS'd vehicles, one of which is my 90 running MS1, and my P6 which is on MS2. The 90 used to be my daily, before the P6 arrived.

In both cases I bought and modified a cheap (£5-10) RS232 USB adapter from ebay to work with the ECU.

With this I can easily connect my phone to the ECU using "MSDroid" and have a quick check on what's going on if and when needed. No requirement for an extra physical gauge on the dashboard.

Must admit I like having a dash display you can read at all time - I built my TechEdge one into the OBC unit on my SD1.



BTW, you can get BlueTooth adaptors for MS.

DaveEFI wrote:
BTW, you can get BlueTooth adaptors for MS.

That looks cool in the dash!

Yeah I know you can buy them- but I'm a cheapskate

Quagmire wrote:

DaveEFI wrote:
BTW, you can get BlueTooth adaptors for MS.

That looks cool in the dash!

Yeah I know you can buy them- but I'm a cheapskate

RS232 over USB gives much better read rates than BT, circa 1.5-2x more reads per second on MS1.

Regards,
David (who implemented the USB code in MSDroid )