Spitty Fueling Problems

[Nick Jones]

This is interesting and sounds a bit familiar. Since switching to ITBs I’ve lost the rock-steady consistency I’ve enjoyed for the last many years.

I don’t believe it’s the ITBs themselves that have caused the loss of consistency (though maintaining the balance is a bit tricky). Instead I believe it’s that I upgraded the firmware on the MS2 from the last version of the original B&G code (15 years old probably) to the latest MSnS code. This to take advantage of the “ITB mode”.  Since then it is, frankly, erratic.  One of the “features” is that it will appear to tune to the target table in auto tune. But once auto tune is off, it varies from day to day, even hour to hour, and doesn’t appear to be able to correct to the table even if given quite large EGO correction authority.  Also intermittently strange readings on the AFR display. This caused me to invest in a new wideband system, but the underlying problem remains.

Driving it yesterday it was persistently showing lean condition (up to 18 under light throttle cruise!), and while I struggle to believe it was that lean, it was a bit hitchy and hesitant, so definitely lean. Other days it’ll show rich and drive fine, but be a bit smelly. I’ve extensively messed about with the sensor calibrations and baro correction to little effect. Baro correction currently off. 
 

Thinking I need to re-flash the firmware and start again. Or try my spare MS1 on alpha N

[rogerguzzi]

Hello All

             I have worked out the mpg over 1687miles and it is 36.67mpg 

It seemed to get through a bit more yesterday but we were crawling in traffic for miles up to Bristol and again by Worcester and held a steady 70mph the rest of the time!

So not to bad overall considering we did some Very small mountain roads(a lot of 2nd/3rd gear)

I have look on Fleabay and I can get a Bosch one same number exactly as the original one for £53.39 or non brand for about £25?

I think I will take it out first and check all the wiring for damage!

Roger

[Nick Jones]

50 minutes ago, rogerguzzi said:

non brand for about £25?

Beware the unbranded - they tend not to work!

Can’t remember what breed of wideband you have….?

[rogerguzzi]

Hello Nick

                  This one but bought in UK and a lot less than that?

Zeitronix Wideband ZT-3 + ZR-1 AFR & Lambda Gauge Display Bundle (Red / Silver) | eBay

I suppose £56 is not a bad price for a Bosch one I have seen some at £100+ ???

Roger

[rogerguzzi]

May have bought it here?

Zeitronix wideband – EFI Parts (efi-parts.co.uk)

Roger

 

[Nick Jones]

Ok. £56 is a decent price for genuine Bosch. Just note that (as you are probably aware) there are (at least) two variants. LSU 4.2 and LSU 4.9. 
 

In most cases you need the one specific to your controller, so make sure you get the right one. The 4.9 is the more modern and often cheaper.

[rogerguzzi]

Hello Nick

                   I know and mine is the 4.9 type

Roger

[Nick Jones]

All good then 

[rogerguzzi]

Hello All

             Now I am confused ?

I thought I would try putting the old settings back into Spitty and see what happens!

Well it started ok a bit lumpy and after it warmed up the tick over was up and down like a fiddlers elbow I tried a few adjustments in the fuel table without much sucess.

Them I remember noticing I had set the EGO sensor type to Dual Wide Band by mistake (been like that for ages 13/10/2023)

So I set it to Single wide band and after a bit more tweaking to the Fuel table in the tick over area she was running quite steady and a quick blast up our bridle track she seems to be running ok again?

I set the Barometric correction to Initial MAP reading so there would be no correction from the second sensor

I am wondering if the Spain problems were because we had gone up to 3,000 to 3,500 feet and Dual EGO sensor(it was only set a one last year in Spain?(finger Trouble?)

I will take her for a run tomorrow and if the AFR looks as though it is working ok do a bit of autotune.

I am still thinking if you give it perhaps 15% authority it should correct from rich or lean?? 

15% of 14.7 = 2.2 so thats either 12.5 or 16.9 for lean or rich!

So what does the sideways brain think??

Roger

ps I hope saves me going under the car and £56 ??

 

[JohnD]

Ever ingenious, Roger!   Shades of the original Lucas Pi at altitude?

[Nick Jones]

58 minutes ago, rogerguzzi said:

I am still thinking if you give it perhaps 15% authority it should correct from rich or lean?? 

Yes, it should. But then you are at the mercy of your wideband. If it looses the plot you’ll be in trouble! I normally reckon 5% max.

3000 - 3500 feet is only about 1000m, so it should still run ok even without correction.

Dual sensor settings might very well have screwed things up and be the origin of your problems…….

1 hour ago, rogerguzzi said:

I hope saves me going under the car and £56 ??

Amen to that! Good luck 

[rogerguzzi]

Hello Nick

                 But If I can get the fuel tables a lot closer the wideband sensor fail would not be serious?

I suppose it would be like Moderns going into limp mode?

Roger

ps I have 3 weeks to get Spitty about right for the Alpine trip and Bloody high mountain passes!! (I must be Bonkers?? still as John says use it or lose it?)

[rogerguzzi]

Hello All

               I took Spitty for a run today and did about 55miles in autotune and I even changed the setting from Normal to Easy!

It was a mixed run but no motorway type running but plenty of holding it in lower gears and booting it a bit and holding throttle positions as long a possible!

It changed Bugger all in the fuel table??? the only one I can see are the ones I altered to try and get a more steady tick over?

So for the last 15/20 miles I disabled the EGO sensor and she runs much the same and the AFR reading look ok and on average in the 13.5 to 15.5 range depending on throttle position!

I filled up with fuel again and she onlt took 8lts and did 78 miles + all the warming up yesterday and messing and that gives about 44.5 mpg(a long run on Wednesday will be more accurate?

I will run it with the EGO still disabled 

I am wondering if the Lambda sensor got a bit sooted or something like that and I did put several tanks of the good stuff in when available(98)

I think the problem was probably caused by me some how setting it at Dual wide band and a bit of altitude?

Roger

ps the Fleabay man has offered me one for £50.72!!!!

[Nick Jones]

Auto tune isn’t changing things as it’s right already, except where you messed with it. Does sound like the dual wideband setting was the root cause.  Will have to check mine, though I’m fairly sure it’s set right….

Main thing is that you have it sorted!

[rogerguzzi]

Hello Nick

                  I have the over run fuel cut set to on?

I am wondering if this is why I get lumpy running sometimes?

Thing is what do I set it to?

Roger

[Nick Jones]

Looks ok to me. Can occasionally cause a bit of shunt if you are actually driving in the zone where it switches but not generally rough running.

[rogerguzzi]

Hello Nick

                 Thank's I will leave it as it is (must resist tinkering!!)

Roger

ps having a run out tomorrow will probably cover about 125/150 miles so will be a good test and see if the MPG is back up into the 40+mpg

[rogerguzzi]

Hello All

             We had a run out yesterday and covered 156miles and used 14.5lts = 48+ mpg !!!

I had left the sensor turned off so she was just using the tables so I am happy that if the Lambda sensor failed she is still driveable?

The only thing I found was that she tended to die on slowing down out of gear?

But I suppose that is because the close loop control would not be working with the sensor turned off?

Roger

[rogerguzzi]

Hello All

              I have turned the Lambda sensor back on(never off just no control over fueling) and went to vote in Spitty and all seems good and not stalling now.

I am happy the fuel table is ok for all normal driving if the sensor stops working.

So I have decided to give it 15% authority to change things in the hope when we are in the Alps if it goes rich or lean it should get it back somewhere close?

I recon it can change the AFR by 2.5 points so 14.7 + 2.5 = 17.2 or 14.7 - 2.5 = 12.2 so either way it will be back in the ball park figures I think?

Roger

ps what do you think or am I talking Rowlocks again?

[thebrookster]

I think I'm missing something elemental here?

Your AFR is based of the residual oxygen in the exhaust gas? So if you climb up high mountain passes, and therefore "less air" per cylinder charge, and your fuel stayed the same you would end up overly rich. However the EFI is surely adjusting the fuel to maintain the AFR table, so what is this authority doing? If you know the AFR table is correct, why do you want to let the system change it?

Or have I missed the point completely, and is this authority the amount the system is allowed to adjust the fuel to meet the AFR table? At which point it must be possible to calculate almost exactly how much authority is required to adjust?

I'm confused!!!

[rogerguzzi]

10 minutes ago, thebrookster said:

I think I'm missing something elemental here?

Your AFR is based of the residual oxygen in the exhaust gas? So if you climb up high mountain passes, and therefore "less air" per cylinder charge, and your fuel stayed the same you would end up overly rich. However the EFI is surely adjusting the fuel to maintain the AFR table, so what is this authority doing? If you know the AFR table is correct, why do you want to let the system change it?

Or have I missed the point completely, and is this authority the amount the system is allowed to adjust the fuel to meet the AFR table? At which point it must be possible to calculate almost exactly how much authority is required to adjust?

I'm confused!!!

Hello Phil

              Yes it will adjust but only to the amoumt you let it!

So my idea is the tables are good for normal so give it a good range to play with and with a bit of luck it will work?

Plus the other thing that confuses me is when it starts up it takes a baro reading as of now so presumable adjusts to that??

It's a Black Art!!!

Still one mate has 2 spare sets of plugs for his TR6(hope this enough as the amount of passes we are doing is at guesss 10 to 12 maybe more!!!

[mpbarrett]

8 hours ago, rogerguzzi said:

Hello Phil

              Yes it will adjust but only to the amoumt you let it!

So my idea is the tables are good for normal so give it a good range to play with and with a bit of luck it will work?

Plus the other thing that confuses me is when it starts up it takes a baro reading as of now so presumable adjusts to that??

It's a Black Art!!!

Still one mate has 2 spare sets of plugs for his TR6(hope this enough as the amount of passes we are doing is at guesss 10 to 12 maybe more!!!

with my experience of taking my old TR6 over the passes, I think one set per pass.... Also if there are NGK once they get rich there are never the same again.... so  one use!
Back to EFI, so the system makes a correction for air pressure when you start the car does at the bottom of the pass there will be no correction for the change in pressure going up the pass unless you stop and restart the car? Interested as I am taking my Herald on the 10CR this year. Last time it ran very rich on the very high passes but ok on the lower ones. It has two sensors but am not sure it has the correction table for the second table correction. Actually not sure how it should be set. Need to do some more reading.
Difficult to test in the UK! I suppose with the second sensor I could reduce the pressure, apply a slight suction to it, and see what it does? But I am not sure what it should do.

Will follow you Alps trip with interest. I think we need you to stop and start the car going up the passes to see what happens.  

mike

Edited July 6, 2024 by mpbarrett

[zetecspit]

10 hours ago, rogerguzzi said:

Still one mate has 2 spare sets of plugs for his TR6(hope this enough as the amount of passes we are doing is at guesss 10 to 12 maybe more!!!

On one of the 10CRs, James Cooper set his metering unit up to run weak at low altitude, and therfore had teh choke pulled out a bit to compensate. As he went up the passes, he pushed the choke in. He did have an AFR fitted, but even without it should be possible to do something similar. I have suggested a stepper motor and controller would do the same job, but that does sound more complex.

[Nick Jones]

10 hours ago, thebrookster said:

I think I'm missing something elemental here?

Your AFR is based of the residual oxygen in the exhaust gas? So if you climb up high mountain passes, and therefore "less air" per cylinder charge, and your fuel stayed the same you would end up overly rich. However the EFI is surely adjusting the fuel to maintain the AFR table, so what is this authority doing? If you know the AFR table is correct, why do you want to let the system change it?

Or have I missed the point completely, and is this authority the amount the system is allowed to adjust the fuel to meet the AFR table? At which point it must be possible to calculate almost exactly how much authority is required to adjust?

I'm confused!!!

Join the confused club….. that is was I used to think. However, see link to a fairly learned discussion on an MS forum (posted before but bears repeat). 

https://www.msextra.com/forums/viewtopic.php?t=63844&start=20

The thrust of their argument is the altitude is already allowed for on the inlet side, whereas the exhaust side, rendered by lower (atmospheric) back pressure is not. I’m not fully convinced, as only an actual air flow meter, which most aftermarket system don’t have, properly does this. However, some of the contributors to that thread live in places that give direct access to large altitude changes and thus direct, empirical experimentation. Their findings are that it goes lean, not rich.

Irritatingly, though I’ve been over many 2,500m passes with the Vitesse, with baro correction on and set to lean out (though not much), I’ve never had a working AFR display while doing so. So I can’t report what I saw, only that the car drove fine, but never would idle above about 2000m.

Roger to experiment and report back?

Ref the PI cars, which use manifold vacuum to determine fueling (as did my EFI during all my Alpine runs to date), there is absolutely no doubt at all that they go rich to very rich with increasing altitude. I’ve followed ‘em, coughing on their fumes, overtaken them as they struggle to proceed and handed out several sets of spare plugs when they fail to proceed due to soot-fouling. For me, this pokes a big hole in the argument for “going lean”, at least in systems that use MAP as the load reference.

 

[zetecspit]

1 hour ago, Nick Jones said:

 

Irritatingly, though I’ve been over many 2,500m passes with the Vitesse, with baro correction on and set to lean out (though not much), I’ve never had a working AFR display while doing so. So I can’t report what I saw, only that the car drove fine, but never would idle above about 2000m.

Roger to experiment and report back?

Ref the PI cars, which use manifold vacuum to determine fueling (as did my EFI during all my Alpine runs to date), there is absolutely no doubt at all that they go rich to very rich with increasing altitude. I’ve followed ‘em, coughing on their fumes, overtaken them as they struggle to proceed and handed out several sets of spare plugs when they fail to proceed due to soot-fouling. For me, this pokes a big hole in the argument for “going lean”, at least in systems that use MAP as the load reference.

 

My car runs TPS. And before I spent £25 on the "proper" map sensor for baro (literally had to plug it in, it was all pre-mapped) Gill would plug the lappy in and fudge by "increasing" injector size as we went up the passes. (thus reducing the actual fuelling) This was done while watching the AFR, and worked. Maybe MAP sensor work differently as it would partially correct?

Edited July 6, 2024 by zetecspit