I've got a bit of a problem with my V6 - it drinks fuel like its 50p a litre..........average consumption is around 20mpg , no matter how I drive , with a similar setup to that which I ran in my Fury (and that would average over 30 , with a best of 41 !)

I figured I have to do something now , I just noticed the back of the car has a coating of black soot after a run up to Harrogate - cruising around 65 managed a stunning 24mpg.....

I'm using an LC1 and gauge , the AFR at cruise is around 15 - I suspected a dodgy sensor or LC1 , so I just swapped the one off my Fury , along with a new sensor - and the displayed readings are the same.......

I've tried three different sets of injectors , had numerous attempts at mapping it , even changed the entire throttle body setup..........and its official - I have no idea whats going on

First make sure there's absolutely no leaks in the exhaust, that can make the afr read lean when it's actualy running rich.

Ian

I thought I was having success tuning my car using a wideband sensor, when it went on a rolling road I gained 30bhp and the car was much nicer to drive.

Suggest you bite the bullet and get it set up on the rollers.

In my case I was adding to much fuel, I used autotune and tuner studio.

Regards Mark

Go and see Dale at Bailey Performance http://baileyperformance.co.uk/ Not that far from you and does an excellent job.

Regards,
Dave

Timing is just as critical as fueling. You may notice that even at idle if you change timing by 10 degrees you see huge swings in apparent AFR. For example, my engine runs at 800rpm, 24kpa idle at ~15:1 using something around a 1.3ms d/c but also at 15:1, 34kpa with a 1.5ms d/c (I think I remembered those the correct was round but I don't have the logs handy to check!

Email me a datalog of it driving for around half an hour at different speeds and the msq file
(Phil at extraefi . co . uk )
Phil

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Originally posted by daxtojeiro
Email me a datalog of it driving for around half an hour at different speeds and the msq file
(Phil at extraefi . co . uk )
Phil

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Originally posted by clairetoo

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Originally posted by daxtojeiro
Email me a datalog of it driving for around half an hour at different speeds and the msq file
(Phil at extraefi . co . uk )
Phil

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Computer numpty question coming up.........how do I do that ? I have been running megasquirt for best part of ten years now , and still havnt worked that one out......

I also seem to be suffering from `wondering map syndrome'........drive it from cold , its fine , do a bit of auto-tuning , and its fine . Switch it off for ten minutes , and it runs completely differently - usually so waek it will barely run , spitting back and stalling , AFR's of around 18 to 20.........or it will be black smoking , super rich ?

This is all pushing me towards Omex.........there is no way I would get it rolling-roaded , since the map will only last untill its switched off......

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Not wondering MAP.......wondering map(ping).........the fuelling is different from one start to the next . Its fine every time with laptop plugged in , but I cant just run it - it needs constant fiddling .

Check your air temp reading, heat soak (after a run) can heat up the sensor, on restart (due to a falsely high reading) puts less fuel in - causing lean mixture and poping. You then change something in the map to compensate.

Where is your air temp sensor?

Also, are your sure your throttle bodies are balanced spot on?

Hi,
have a look here for info on how to datalog:
http://www.youtube.com/watch?v=D889vh7La0w

email me if you need a hand and I can show you what to do,
thanks
Phil

As well as the air temp sensor/heat soak mentioned, that can also be a sign that you've got to much idle advance and a virtualy closed throttle. Less idle ign advance, open the idle screw slightly to get the tick over back and the idle afr is much easier to get stable/consistent.

Ian

Heat soak on the temp sensor was definitely a problem - its now moved to the rear of the airbox , in the airflow , and the readings are nice and stable .
I've tried backing off the timing at tickover - but how far can I go ? I'm down to 9 degrees BTDC , and its still ticking over faster than I like , despite being pulled back from 12 degrees........

The biggest problem is fuel consumption - no matter what I do with fueling or timing , no matter how I drive it , it does 20mpg..........and the rear of the car is covered in black soot , even running AFR's around 16 at cruise.

Are you running wideband control?

You ideally want a wideband lambada with AFR targets set, it will auto correct to the AFR set by you then.

Omex is a big step up from mega squirt. Why not look in to an emerald k3 or k6. They have plenty of options and all the map settings you will ever need plus Dave will probably be able to give you a fairly close base map to start with.

John

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Originally posted by clairetoo
I've tried backing off the timing at tickover - but how far can I go ? I'm down to 9 degrees BTDC , and its still ticking over faster than I like , despite being pulled back from 12 degrees........

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Where is the lambda probe? From what I remember you have dual exhausts all the way to the back.
Is it possible that one bank of cylinders is getting less airflow (hence rich, hence sooty) than the other bank, and you are measuring the healthy bank?

What do the plugs look like?


Wandering fueling, tricky. Fuel pressure regulator or some other source of variable fuel pressure would be my guess. Fuel tank vent valve, good quality pressure regulator, stable voltage to pump, clean fuel filters, no kinking of return line.

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Originally posted by jwhatley
Are you running wideband control?

You ideally want a wideband lambada with AFR targets set, it will auto correct to the AFR set by you then.

Omex is a big step up from mega squirt. Why not look in to an emerald k3 or k6. They have plenty of options and all the map settings you will ever need plus Dave will probably be able to give you a fairly close base map to start with.

John

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Sounds like it just needs some close attention on the mapping. I defy anyone to explain why Omex, Emerald or pretty well any other after market system is 'better' than your MS2 for the job it is being used ... simply not true. In truth there is very little between them other than the software ... and Tuner Studio makes most of them look like year 10 software projects!

Get Bailey to map it for you ... or at least get someone out in the car with you to map it while you drive ... or do some data logging and send it to Phil (daxtojeiro) ... it sounds as though you have a few minor map setup issues that are causing you problems ... I would strongly recommend sticking with it .. spending a small fortune on another version of the hardware in a different box just doesn't make sense.

Just my opinion of course, but I am an Omex trained and approved installer!!

I did get it on a rolling road for a full set up on Tuesday - with the emphasis firmly on smooth running and economy , not trying to squeeze every last horse out of it...........
It was very quickly found that the Lc1 wasn't reading right - and I had been relying on it for mapping.......
It now runs better , emissions and fueling along with timing sorted - and its made no difference

No matter how I drive it does 20mpg - and thats at 30mph , 60mph , or ragging the arse off it - everything points to running rich (black sooty exhaust) but its not ?

Okay ... so the lambda in the exhaust is showing good readings ... but you are using too much fuel ... have you checked the exhaust temperatures on each exhaust header ? You must remember that the lambda reading you are relying on is a combination of all cylinders output ... if all of the cylinders are not running equally .. then you may have one weak cylinder which is making the AFR read what is a very rich mixture on the other cylinders and appear correct. I have had situations where one injector was barely firing .. leaving the mixture very weak on that cylinder .. but the overall exhaust looked about right .. try using either a decent pyrometer or a good laser temp gun to check that all cylinders are of close to equal temp. Check the dwell settings for the coil packs ... if they are wrong that will cause lambda values to vary. Confirm TDC mark on the pulley with a check on #1 piston (whip the plug out and check that the piston is at TDC when the mark on the pulley shows TDC)
My best advice would be to run the following tests;

1) Check exhaust temps - they should be within about 30 degrees C really.
2) Check the timing - as described above
3) Check the dwell settings for the coil pack - In tuner studio - Ignition settings
4) Try pulling one injector plug off at a time and see how the AFR is affected - if pulling one of makes little difference you have probably located the fault.

If all else fails - Give me a ring!

Claire, where in the exhaust is your LC-1? Does it just read for one bank? If it does, it could be the other bank causing the problems but it won't show up. That's could also give a different reading between your LC-1 and a probe at the tail of the exhaust.

Have you got consistent fuel pressure?

I am mapping in Derby on Sunday .. if you want me to pop in on the way home I would be glad to take a look.

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Originally posted by shaunod
I am mapping in Derby on Sunday .. if you want me to pop in on the way home I would be glad to take a look.

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Originally posted by clairetoo

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Originally posted by shaunod
I am mapping in Derby on Sunday .. if you want me to pop in on the way home I would be glad to take a look.

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Feel free to pop round - there has to be something that no one has spotted yet................

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drop me a text and we can try and arrange a stop off. 07891512664.

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Originally posted by BaileyPerformance

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Originally posted by clairetoo

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Originally posted by shaunod
I am mapping in Derby on Sunday .. if you want me to pop in on the way home I would be glad to take a look.

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Feel free to pop round - there has to be something that no one has spotted yet................

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Are you sure it's not misfiring? You posted a vid ages ago of you driving the car - it was on 5 cylinders at best.
The suggestion of checking header temp is a good one, you may have a miss (one header much cooler that the rest)

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The point is it could well be missing at light throttle due to badly balanced throttle bodies (miss match between left and right banks) but pick up all cylinders as full throttle.
Spit on your finger and touch each header at idle, if one is much colder it will be obvious.

As suggest before unplugging injector plug at idle to see if rpm changes is a good test.

I will bring a temp gun with me.

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Originally posted by shaunod
I will bring a temp gun with me.

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Glad to hear it .. keep plugging away with the mapping .. you will have it perfect soon enough.

Sad news is......I was being a bit optimistic on what I saw to be better fuel consumption........that first guess was after mostly motorway and slow A road driving..........a week of commuting had the needle plummeting as normal .
I just filled it up , and it had managed a staggering 24.8 mpg................and that was with not going over maybe 15% throttle , and no more than 3000 rpm

I did have a thought tonight - the only part of the entire system that had not been run on my Fury , was the adjustable fuel pressure regulator . I still the ebay cheapy I ran before , but the hose take-offs would need to be modified to work , so I did the next best thing , and plugged the pressure gauge into a spare port on the new (far more expensive) regulator..........and the pressure reading was very different on the extra gauge !
Where I had the fuel pressure set to 40lbs on the new gauge , it read 55 on the old one . So I've dropped it to read 45psi on the added gauge - just about to nip out for a test run.............

Fuel pressure will have a big effect on the injector flow for a given PW.
But, assuming the fuel pressure is stable then you tuned at that pressure, the lowing the fuel pressure will just make the whole map leaner.

Is your FPR connected to a vac source? (Should be open to atmosphere)

How did you balance your throttle bodies?

You say a similar setup to your Fury and I'm not sure I've seen it asked..

Is the inlet tract from engine valves to the end of the trumpets shorter on this car?

When we were trying to map one of our engine combinations you couldn't fine tune the difference between it cruising and being on load so it drank fuel regardless!
That had a very short inlet tract (trying to squeeze everything under the bonnet) so we made it longer by extending the trumpets on and it made a massive difference to the mapping and economy.

Thye are quite short - but only a few mm shorter than the Fury , and only in the trumpets (the bodies that are on there now are the first set I made for the Fury , just with Pico type injectors instead of normal Bosch type)

I was running the complete setup lifted straight from the Fury , this is actually the third set of bodies I have tried , and the fourth set of injectors , along with two megasquirts , three Edis units , two coils ............ the FPR is the only part that hadnt been changed !

It is balanced spot on............the AFR's are fine...........it will tick over at 600rpm , and pull away clean at less than 1000 revs in second........but it drinks fuel , and the whole back of the car is covered in black soot

As an extra thing - as well as turning the fuel pressure down about 10psi , I also dropped the req' fuel a couple of points - did a short mapping run , and had to go leaner at low speed / cruise........ go figure......

You said the balance is spot on, how did you do it?

If you balanced just at idle, you need to chk at light throttle. You'll probably find one set of throttles are opening before the other - so, one side if engine is running leaner than the other.

How did you balance them and what did you use to do it?

Hi you got a wideband in left and right or just a common one?

The bottom line is ... if the AFR is 15 ish on cruise and 13 under load ... and it is drinking fuel ... something is wrong with the burn. The only real suggestion I can make is that the fuel is either not being ignited fully or at the wrong time. This is why I mentioned Dwell previously.
I don't have a definitive answer .. but that is certainly where I would start looking .. if you are absolutely convinced that both sides of the engine are burning equally and the mixture you are seeing in the exhaust is correct .. you would have to start asking if the cam timing is correct .. the ignition timing correct .. the list goes on ... but the answer will be there .. it always is.
Have you had it on an MOT gas tester .. if so .. what were the HC and CO readings at 14.7 AFR?

Shaun

Do you actually bother to read what I post........? Are you seriously trying to tell me that an un-noticable imbalance will half the mpg , but not effect drivabilty at all ?

Yes it has a wideband . Just one . In the exhaust as close to the collector as possible , just after the balance pipe . Oddly enough , pretty much the same as I ran in my Fury .

If you could at least think of something else , that may actually help , I would appreciate it . But going round in circles asking the same question over and over , and getting that same un-helpfull question answered over and over - is just not helping .

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Originally posted by shaunod
The bottom line is ... if the AFR is 15 ish on cruise and 13 under load ... and it is drinking fuel ... something is wrong with the burn. The only real suggestion I can make is that the fuel is either not being ignited fully or at the wrong time. This is why I mentioned Dwell previously.
I don't have a definitive answer .. but that is certainly where I would start looking .. if you are absolutely convinced that both sides of the engine are burning equally and the mixture you are seeing in the exhaust is correct .. you would have to start asking if the cam timing is correct .. the ignition timing correct .. the list goes on ... but the answer will be there .. it always is.
Have you had it on an MOT gas tester .. if so .. what were the HC and CO readings at 14.7 AFR?

Shaun

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Has the car got twin separated exhaust systems?
If so a trip to local MOT station as suggest would be good, note HC and CO from each tail pipe.

Another one I may have missed but a new set of spark plugs?..

We had a few sets in the pinto that would work fine on idle yet break down under load, the cores would become damaged internally so if you twisted the pip on the HT lead end you could feel movement even tho the pip was tight down.
Hence all the usual idle checks, balancing, timing, injectors, temps etc all checked out.

Yet when mapping I presume it was getting a cylinders worth of unburnt fuel shoved through it, (damn can't remember now if that made it show rich or lean) but it was leading me down the wrong track maybe a little like your findings tonight.

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Originally posted by clairetoo
Do you actually bother to read what I post........? Are you seriously trying to tell me that an un-noticable imbalance will half the mpg , but not effect drivabilty at all ?

Yes it has a wideband . Just one . In the exhaust as close to the collector as possible , just after the balance pipe . Oddly enough , pretty much the same as I ran in my Fury .

If you could at least think of something else , that may actually help , I would appreciate it . But going round in circles asking the same question over and over , and getting that same un-helpfull question answered over and over - is just not helping .

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Balanced with a syncrometer - and cruise is at 4 to 5 % throttle , so only just off the stop.........
I've lifted it to about 2% on the tickover screw and checked balance - no change . I've sat in the car , watching tuner studio , and pushed the peddle slightly , 1 or 2 % , and it picks up clean with no stumbling at all .

Just a couple of weeks ago it had new plugs , oil change and new filter ......... Exhaust temps are all the same at tickover , so no miss-fire or imbalance there........and it made over 200bhp on the rollers , so any timing problem would have to be pretty minor , surely ?
It may have four cams , but only two cam pulleys - if anything is out of place , then it probably left the factory that way (I have not had it apart , and judging by the look of the motor when I got it neither has anybody else !)

Are you sure the wideband sensor is reading correctly?

You could try disabling any lambda corrections and just run on a fixed map to see if this improves things if it's got closed loop enabled.

I haven't checked back thru all your posts, but I'm assuming you have swapped the Ecu with your other car?

You would probably see this on laptop while driving but any random acceleration enrichments firing? To make sure set the threshold to something like 900. (If MS2) 10 if MS1.(unwanted enrichments normally caused by noise)

Assuming you have V3.0 hardware, there is an issue with the injector fly back circuit that can hold injectors open slightly, you can end up with a longer PW on one driver.
Cut out the two large black diodes to the right of the processor, near the top of the board. This will defeat the circuit. It cannot be switched off in software.
There are no negative effects in doing this. When in order an Ecu I request they are not fitted, or if I build one myself I omit them.

Interestingly, my car started drinking fuel some time back. Made no sense as I had great reported AFRs, nice and rock steady and leaner than the stock setup. No notable misfires except at idle where one would creep in every 20 events or so, but the exhaust stank of fuel. Shifting timing about didn't seem to make much difference though it did change the AFRs, but then eventually my ringland failed. From the level of carbon deposits and marks on the piston I think the ringland had cracked about 18months earlier and finally gave up the ghost when I hoofed it. I always had great compression on the failed piston until the very last when a proper misfire developed.

I'm wondering if this cracked land may have been contributing to ongoing poor performance on that one cyl which lead to a ~15% increase in fuel use.