Mi16 Spitting Flames

[M_R_205 5 1 Cars]

Now that my mi16 is ran in i have started giving it some hard revs, and on about thursday last week it has decided to start poping flames, quite alot too, it only happens when the throttle is closed and while engine braking,

 

For the past 3 weeks iv been mapping the injection map using the "adaptive" feature of the emerald and it has been slowly leaning it off quite alot, so this was obviously my first thought, so i saved the adapted map and re-programed the origional map from the roling road session, No change

 

I then thought about advancing the spark when the TPS was at 0% as is was quite retarded (around 8* ), this made no difference at all, so i changed it back.

 

Today i was chatting to a mate (a bmw mechanic) who said he had a cooper s with the same problem and it turned out that the cam belt had slipped by about 2 teeth over the exhaust pully,

 

Now before i go arseing about with the cam belt and pullys is there anyone else who agrees that this could be the cause? or if anyone has any other ideas as im prety much at a dead end....

 

Cheers

Paul.

[Richie-Van-GTi 71 2 Cars]

its still fueling too much on overun by the sound of it, never used emerald software before but look for anything that can switch it off. Failing that you need to focus on the fueling table in the areas where RPM is way too high for TPS.

[Tom Fenton 1,542]

Go into the Emerald software, tick the box that says "Fuel cut on overrun".

 

You may also need to play with the overrun throttle pot position.

 

Also check that your pot hasn't moved, so check you can get full throttle position, and that off throttle is position 0.

 

Make sure that your AFRs in the lambda setpoint for overrun are super lean- or else it will be trying to put fuel in those areas, where you don't need it. Ideally turn overrun areas (high vacuum, assuming you are running a MAP sensor?) out of adaptive and into open loop.

 

When we were at the 'ring my mate decided flames would be entertaining so un-ticked the fuel cut on overrun box. The resulting fuel consumption was not so entertaining so we switched it back on!

Edited October 26, 2009 by Tom Fenton

[M_R_205 5 1 Cars]

Thanks for the replys guys,

i have enabled the "cut fuel on over run" and it has improved things quite alot, however it is still doing it, i have had the cam timing checked and it is fine so thats not a problem,

 

do you think that possibly one of the injectors is sticking slightly and so weeping a little fuel into one of the bores??

 

Also if the exhaust is slightly lose at one of the joints causing it to draw in air, could that be a possible cause?

 

And finaly i have been able to data log a few drives and at afr sits between 15 at idle and 12 at full throttle, when i lift off it jumps to 22 (obviously no fuel going through) but on idle it jumps about abit from 15.2 up to 14.6 which could support the leaky injector theory???

 

Il post the logs up when i get home tonight let you all have a little look

 

Cheers again

Paul.

 

 

Make sure that your AFRs in the lambda setpoint for overrun are super lean- or else it will be trying to put fuel in those areas, where you don't need it. Ideally turn overrun areas (high vacuum, assuming you are running a MAP sensor?) out of adaptive and into open loop.

 

by overrun setpoint do you mean the 0% throttle on the injection map? and no im not running a MAP sensor, though i think it may be worth fitting one!

Edited November 11, 2009 by M_R_205

[petert 586]

Post a copy of your fuel table.

[Tom Fenton 1,542]

Also copies of your lambda/closed loop tables.

[Galifrey 1]

Also copies of your lambda/closed loop tables.

 

Check the TPS calibration?

[RossD 44]

You're going to need a lot of ignition advance also in the closed throttle areas to prevent this, it's not just down to the fuel table. Of course, if the Fuel cut-off is enabled, it should stop it.....

[M_R_205 5 1 Cars]

You're going to need a lot of ignition advance also in the closed throttle areas to prevent this, it's not just down to the fuel table. Of course, if the Fuel cut-off is enabled, it should stop it.....

 

i think off the top of my head the engine has 7* advance at 0% throttle from 3000rpm up to 7000, and slightly less at lower revs bout 5*, and -1 at idle,

 

also i will post up shots of the various maps tonight,

 

Cheers

Paul.

[Galifrey 1]

You're going to need a lot of ignition advance also in the closed throttle areas to prevent this, it's not just down to the fuel table. Of course, if the Fuel cut-off is enabled, it should stop it.....

 

This is why I suspected the TPS out of calibration.

 

If it is not closing properly, it may well be still allowing fuel in on overun. Does the emerald use the MAP sensor to distinguish between idle and overun as well?

[M_R_205 5 1 Cars]

I have just checked the TPS and when is sht it reads 17, so i will adjust that now, however the over run cut off kicks in when the TPS is less than 20 and over 1500 rpm,

Also i have calibrated the TPS "range" in the ecu setup menu (17 shut, 752 fully open)

 

Also i have taken some screen shots of the injecttion table and ignition table for you all to take a look at and i have 2 data logs for 20 min drive but they are to big to upload... so if anyone has any ideas how to get them up that would be cool

 

 

Cheers

Paul.

[Tom Fenton 1,542]

Well for start -5 along the top row of the ignition map is NOT helping things!

 

Change these to something more like the next row down for a start.

 

Also post screenshots of the AFR target, Feedback Mode, Closed loop settings, screens.

[M_R_205 5 1 Cars]

Cheers Tom, il give ethat a try,

the settings above a prety much exatley the same as when i got it back from the RR near me, can you think of any reason why he would have set it so retarded??

 

the advance reduces with load, should i set 0 load to about 33* above 3500 rpm then 30, 20 18, and 10 down to 1500 rpm?

 

 

Cheers

Paul.

[Richie-Van-GTi 71 2 Cars]

Not familiar with emerald but what does it measure the TPS in? % or ohms etc?

Are you using a potentiometer or a switch TPS? systems Ive worked with have worked in voltage range from 0-5v for potentiometers. Looking at the AFR table then it will still be trying for a rich misture on over run if the signal isnt getting through thats its on over run.

[M_R_205 5 1 Cars]

Not familiar with emerald but what does it measure the TPS in? % or ohms etc?

Are you using a potentiometer or a switch TPS? systems Ive worked with have worked in voltage range from 0-5v for potentiometers. Looking at the AFR table then it will still be trying for a rich misture on over run if the signal isnt getting through thats its on over run.

 

I may be wrong, but i think it messures the resistance/voltage difference, for instance at 0% throttle the ecu is reading 17 (i dont know what unit the 17 is be it ohms volts or banna skins lol) and then you set the tps ub by giving it WOT which messures at 752 which is 100% throttle so it should know when the throttle is closed as it will have a value of 17,

 

at the weekend il will rotate the tps till the value at 0% throttle is 0 as apposed to 17, see if this makes any difference,

 

Also i am about to go out with the new ignition settings to see if that has helped things.

 

Cheers

Paul.

[petert 586]

Some observations that aren't related to your problem but need attention. Your fuel mapping appears to be still very rough. For example, why would it need the same amount of fuel in the 0 and 500 ranges as it does at 7000 rpm? The fuel load should taper off after the peak torque (5000-5500?) but yours keeps getting richer all the way to 8000. Also, the total ignition advance seems a bit low to me. If the ECU timing has been verified with a timing light, then I would expect more like 25-26 degs. rather than 21 deg.

 

Attached is a fuel table (load via MAP sensor) in msec. It idles at approx. -60kPa/1000 rpm which is 2.600ms. Peak torque occurs at 0kPa/5000-5500rpm which is 7.226ms. Apply the same percentages to your table, but keep in mind TPS load is is more log than linear. So load increases dramatically off idle, then flattens out from 50% onwards.

Edited November 18, 2009 by petert

[Tom Fenton 1,542]

Screenshot of Feedback mode please.

[Galifrey 1]

I have just checked the TPS and when is sht it reads 17, so i will adjust that now, however the over run cut off kicks in when the TPS is less than 20 and over 1500 rpm,

Also i have calibrated the TPS "range" in the ecu setup menu (17 shut, 752 fully open)

 

Cheers

Paul.

 

That was fine, it was calibrated correctly.

[sub205 5]

I may be wrong, but i think it messures the resistance/voltage difference, for instance at 0% throttle the ecu is reading 17 (i dont know what unit the 17 is be it ohms volts or banna skins lol) and then you set the tps ub by giving it WOT which messures at 752 which is 100% throttle so it should know when the throttle is closed as it will have a value of 17,

There are only 2 common units used:

 

% Percent

or

Integer

 

Integer is a value between 0 - 255 (with 8bit ADCs) or 0 - 1023 (with 10bit ADCs) and corresponds to 0 - 5 Volt on the input pin of the ECU.

You never reach 0 or 5 Volts, so your values will be somewhat away from these boundaries.

 

a step of 1 corresponds to a voltage change of 5/256th volts or 5/1024th volts.

[M_R_205 5 1 Cars]

Cheers for that sub205 and peter, when i get my laptop back il i create a new map use your values, run a data logg and see how it looks,

 

heres a feed back mde for you tom

 

Cheers

Paul.

[Tom Fenton 1,542]

OK, so the 0% throttle readings are in closed loop, making the ECU want to fuel at whatever the target AFR is on the other table. So you need to make sure that the ECU is seeing overrun when you lift off the throttle and so then cutting fuel.

 

I think in this case it is the -5 in the advance table that is your problem, I think the fuel stuff looks OK.

[M_R_205 5 1 Cars]

OK, so the 0% throttle readings are in closed loop, making the ECU want to fuel at whatever the target AFR is on the other table. So you need to make sure that the ECU is seeing overrun when you lift off the throttle and so then cutting fuel.

 

I think in this case it is the -5 in the advance table that is your problem, I think the fuel stuff looks OK.

 

Cheers Tom, when i get my laptop back il set the ignition to what i mentioned earliar and try and get the fueling imilar to what Peter has recomended and take it from there

 

Thanks again

Paul.

[M_R_205 5 1 Cars]

Ok its oficial, im a d*ck,

 

On wednesday the engine devloped a misfire at idle, after a quick investigation i realised one of the plugs was damaged (probably through me droping them into the head, 4 new plugs, car runs great and the poping/flames seem to have stoped, must have been giving a very poor spark and very very poor burn

 

Im still going to change the map as advised just to try and get the car running better as i cant afford an emerald session just yet

 

Thanks again

Paul.