Rich idle problems
 

Now I think I have the timing Sussed I am still having a issue with rich idle.. I cannot get idle below around 10.8-11.2 AFR. It is definitely rich and a bit smokey like this but if I try and go down even a click on the idle mix it starts stumbling and stalls. It is like the injectors stop? Is this a common problem for big injectors on idle. I have Bosch EV1 1600 cc secondary and primary with microtech ltx-12. These are Low impedance I think. Does it make a difference if it is high or low for the ECU? Should I be able to get better cleaner idle with these or do I need to use some tricks or buy some smaller primary injectors like 1000cc or 850cc? I think I have way more injection for what I need. Aiming at about 600bhp flywheel?
How much advance can I add in at idle before it's a problem. I know this will help but maybe only a bit. It had around 15 degrees advance before from static and idle was still rich. Idle is set around 950rpm. Brought it up from 750rpm to try and help!
Currently my T-rpm is like this
500_ +05
1000_ 0
1500 _+08
2000_+20
2500_+25
3000_+25
..ETC
Should peak timing be just after peak boost of just before. Obviously that will vary per gear. I estimate around 3500-4000rpm 3rd gear onwards.
also I gather peak can be a max of about 30degs advance? Which is my engine is timed to -5 leading mark then that would be up to +35? I would only use more timing if the engine wanted it anyway.

back to the point. To try and improve idle if necessary I was thinking maybe something like this?
500_+7
1000_+10
1500_+14
2000_+18
2500_+20
3000_+22
3500_+25
....
etc

Can I close the firing gap on the plugs up? Anything else anyone can suggest. The only other thing I wondered was messing with fuel pressure?

Thank you
Lee

As I mentioned in the other thread, your primary injectors are way too large to be controlled with an ECU of such poor resolution as the Microtech. Keep your 1600CC secondaries and swap out the primaries for 550CC or 680CC.

Will carry on the chat on my other thread for injectors! Would like some input on timing at idle and the transition/trend up the way if you can offer anything? See above or my map posted on the other thread. Also if timed static at 5ATDC (leading mark) Does this mean the map values are all relative to this? i.e -5? so+5 in the map is in fact 0? in which case do I need to set the Static value in the settings to +5 to make it all relative of leave it at zero and time it to TDC? How do you do it? I have read various preferences!

Thank you
Lee

That T_RPM looks fine. Actually you won't want to mess with T_RPM very much. You'll make your adjustments to T_MAP. At idle you should be running about 8 - 12 degrees. Then around 2000 RPM have it about 20 degrees. End up at about 32 - 35 degrees in your cruise area.

And now you'll run into the silly model the Microtech uses because you are adjusting multiple overlapping curves so each adjust effects one another. As opposed to the 3D timing table every other ECU uses.

Locking at 5 degrees looks at 5 degress. Your leading mark is 5 degrees so line them up.

Hi Arron, Is that to say my current T-RPM settings look good or the ones I have suggested look better? I am guessing the ones I have suggested based on you saying idle (950rpm ish) want so to be around 8-12degs? The current table is sat at 0 for 1000 then goes up at 500? and up of course into the rpm range after that. My timing has been set to the -5 leading mark and the static value in the ecu settings is currently 0? Is that the best way to have it? If I understand right it just means that everything in the table is relative to -5? I.e if the value says 10 it in facts means 5? if that is the case it might be clearer to time it to the TDC 0 mark I have and then everything in the table is an exact value?

Thanks
Lee

What I mean is, don't change your T_RPM from factory settings for now. Instead make your corrections with T_MAP. Think of T_RPM as your mechanical dizzy advance. T_MAP is the vacuum advance which is also capable of understanding boost.

If the ECU knows the base timing is -5, then the timing value you set is the timing value you get. Only if you locked the timing and then say set the CAS to -10 would the value not match. This is why we adjust the CAS so the ECU lines up.

You should leave the timing until fuel is set up on the ECU.

But in order to get a few more degrees at idle, you'd increase the idle timing map (I don't remember if there is such a thing, don't have my manual handy) or increase the T_MAP at the vacuum point where the engine idles.

Thanks Aarron, so chuck a bit of advance in at vacuum on the T-Map. I get it.. So would the trend for that usually have a bit more timing either side of the idle vac level or would it tail off below idle? I am pretty sure there is no T_idle map.
Also the thing I don'get with the -5 timing is there is no ability to put minus numbers in the Timing tables as I recall? So you time at -5 but the engine is never using -5 in that case as the lowest value timing you can have is 0 in that case? i think this is where all the arguments start on the various threads I have read. They say the -5 setting is so there is always a -5 safety factor on the timing? Just seems a bit odd to me. At the end of the day you add timing util the engine can't take more but still seems a strange setup?!

Do you know if my current T_RPM is factory on the rpm values. I honestly cannot remember if I changed the 8 value now? or if someone else has for that matter! I know all the 25 values are factory.

T_Gap was the other one I wondered about changing for better idle. I read some posts where people had been messing with this? any mileage in it? I wouldnt touch anything outside of the idle range.

Cheers for all this info.

Lee

I would honestly have to fire up my Microtech to take a look at the timing tables.

From what I remember all timing tables are simply listed as absolute advance past the zero point you lock in during CAS stabbing and adjustment with the timing light.

So there isn't really -5 or +5, there is just 5 degrees. Which is 5 degrees advanced from zero. You can't retard timing below zero.

All the values of T_RPM are not 25 from the factory. It starts at zero and does a very quick linear increase then flattens out at 25 degrees. Like a dizzy mechanical advance, which it is based on. A silly model. Very limiting to the user.

Don't adjust gap at all yet. That is something your tuner will help with.

Honestly, I'd leave timing mostly alone. It is reasonable from the factory to run the engine reasonably well and safe. Leave it up to your tuner. This isn't a piston engine that responds to tiny timing changes with huge differences. The rotary combustion chamber is so long that a few degrees at this stage matters not.

Just get your fuel setup so the engine runs.

But you stab you CAS in at zero and time it with a light to -5?! So surely the ECU is starting at -5? On a factory EcU is that not what the engine fires at? In which case if your table says 0 is it 0 or -5 at the engine? I guess easy way to check is run the engine and see what the timing light reads vs the number in the table?
Anyhow.. If you have a chance to read out some factory T-rpm settings please maybe I will check against mine and make sure the values are all back at factory setting before starting. I will check T map at idle instead and try a few degrees there if needed for better idle. Other than that tuner can and will take care of it!
This is all good learning for me! Really appreciate it!

To stab the CAS you rotate the engine until the leading (-5) timing mark (orange on the FCs, not sure how 20B marks it) lines up with the pointer. Then stab the CAS with the dimple on the gear lined up to the pointer on the CAS body, holding the CAS wheel with your fingers. May have to rotate it a degree or two in either direction to get it to fall into place.

Then start the car and lock the timing in the Microtech. Now adjust CAS position with timing light on L1 until the leading mark lines up with the pointer. Lock the CAS down, recheck, then unlock timing in the Microtech. Basically the same procedure with any standalone to establish true timing.

Because the Microtech is pre-programmed by the factory for the engine it is to be used on (and unchangeable by the user, lovely) I have always simply assumed that timing lock on a rotary configured Microtech locks at an assumed -5. So lining up the pointer makes sure the CAS is where the Microtech expects it to be.

I guess if you had a fancy enough timing light that can verify timing advance, you could set the Microtech to T_RPM 15 degrees, zero the other timing maps and verify on the engine you are seeing 15 degrees advance.

Timing lock aside, you're not going to see massive changes on an unturned fuel map by changing timing. It is generally best that as long as timing is in the ballpark, tune the fuel and then revisit timing. The Microtech is going to limit what can be done to the timing curve anyway, unlike every other ECU that uses a 3D table allowing timing to be set wherever to whatever the tuner wants.

Okay.. So I got the car run up today finally after fitting my new Deka injectors! They turn out to be 875cc. although I work it out at 840cc? as they are rated at 80lbs. But any how. Was a bit of a fiddle to get the car going but got there. For now I set the Staging at 80% on recommendation from Microtech or 75-85% range for my setup. I increased Revstg to 3500rpm and made Mapstg 0" as you suggested Aarron.
So I am still not really much better off.. it is very odd.
Once it was all up to temp I manage to the idle quite smooth at mid 12 AFR's my AFR was messing abut as battery voltage was a bit low. 11.8v. not sure if the Alternator should be putting more noticeable charge than this at idle? Anyway. Maybe another story but thought I would mention it.
So I had my idle map values set around
13hg 1.10,
24hg 1.24,
18hg 1.19,
12hg 1.24

Seems to sit on 18hg for idle. Off idle Around those cells I had to add in quite a bit of fuel the minute I hit the pedal otherwise it died and stumbled. It would jump up to the 12hg and 6hg with a small amount of throttle and off hand I thin I had to bring these up around 2.10 and 2.14 for it to rev? There was not a jump like that before so I found that a bit odd?

If I try and bring idle values lower a click it will run for a few minutes and then litterally just lean and stop pretty much instantly. If I lean it a couple of clicks it straight away leans off and dies. Much above this it starts to hunt and smoke! So I left it at that.
Then I switched off for a few minutes to get my timing light set-up to double check timing. and also bung my FPR pipe to check fuel pressure.
Literally 5 minutes.
I switched back on and it wouldn't idle properly without me adding more fuel in?! So I had to jump the values back up to
24Hg 1.33
18Hg 1.24
12Hg 1.33
Also had to add similar into the off idle cells?
Now this is really confusing and nothing changed. Still full temp?
Seems to run fine but after a while I would say is verging on rich again amd maybe wanting a touch of fuel back out?

What is happening?! Any thoughts please?

It is almost as if after say 5mins something trips and changes the fuel requirements?

My TPS seemed to be doing something a bit funny when I first turned on the ignition as well as I had to adjust it back again having had it set just fine last time I ran it up? Could it be TPS issues? I didn't notice it flicker once I had reset it? but I had to adjust it once and then a few minutes later it was flickering a value again. so I did it again. Then seemed fine?

Thank you
Lee

If you are seeing 11.8V, then fix that first. Should be closer to 14V. Maybe the two pin connector at the back of the alternator isn't connected? Or the alternator is bad.

The reason after the re-start it needed more fuel was because it was heat soaked. Without some form if more advanced idle control like an idle valve, you'll just have to either tune the engine always too rich, increase the fuel in the AIR map to compensate (you will find IATs are very high after the restart event) or manually hold the idle high for 30 seconds with your foot.

If the engine likes mid 12s to idle, then mid 12s it is. Honestly with the Microtech, you'll probably end up there anyway because it can't compensate for other loads so you tend to have to tune rich. A more advanced ECU with more compensations and an idle valve can idle closer to 14.00.

Does your engine still have the thermowax on the throttle body? That will nudge the TPS when the engine is cold, resulting in lack of calibration when it is warm.

Make sure the TPS is physically tight.

The Microtech uses it to determine when to enter the idle map. So if it is not reading zero * then you will be reading from the load map, hence the changing tune.

I'd really recommend switching the ECU to matrix mode.

Like Aaron said fix the voltage first.
Why do you have an underdrive pulley?
Your current map is pretty average so you need to consider doing another or getting your tuner to do it. There are 13B basemaps on here but not sure what differences there would be for 20B.
Your idle values are too high for those injectors but probably caused by low voltage.

Thanks for info.. Will give it a charge and see what difference that makes. it has underdrive as it was originally set-up like that withe FD pullies. Since then I have fitted and Pineapple racing idler pulley and swapped the water pump back to stock but not found a ally stock size alternator pulley to use. Might just have to use a steel one and spray it black or something!
I think you mentioned my fuel values were high for my old injectors too? Anything else that could effect this from car to car? When you say high how much do you think? It should have voltage compensation of some sort on the ECU so I am told by microtech. So looking at my injector data I would imagine worst case it would be out maybe 10%?

What sort of values do you have Aarron as your setup is quite close to mine?

Also what were the thoughts about the jump in values from idle map to load map? is that usual for similar Hg values? My old injectors did have a jump but less. Which I guess as they were double the size is to be expected!?

I will be dropping my tuner a line very soon to see when he can fit me in!

Cheers
Lee

Also .. The water temp controlled Thermowax is removed. The dashpot thing is still on there though? Could this cause any issues? I am hoping the funny TPS response is down to the low voltage as it was fine before.
Will feedback after the weekend.. Would be good to know what air temp you would expect to start having to add a little fuel back in so I can monitor this and have a bit of a clue what to look for too?
Could partly be this on restart but I also think it is like something switches on or off on the ECU and instantly changes the AFR.. There is no real gradual change unless that is just the poor ECU control generally. It will be fine one second then AFR will suddenly drop and it will stall out?

Id leave everything as is until you get the voltage sorted.Dont worry about air temp at the moment its a very very minor tuning issue and a lot run 0 across the board.
Are you 100% sure your ecu has voltage compensation.
Even if it does 11.8V could be outside its range.
I run matrix mode and dont really need tps accuracy.
The TPS are very old and its pretty common for them to drift out of adjustment.

Check fuel pressure. Id expect your idle to be about 1.00mS in the idle table.
Change Af_StE to 10. If everything else is mechanically sound you should be close.
If it still stops after a few mins let it cool off. Restart and watch gauges especially water temp and AFR for when it stops.

double post

Thanks for advice. I plan to give it a go again this weekend all going well. Will set battery on charge tomorrow evening make sure that is juiced right up. Should underdrive still allow alternator to put out near 14v at idle if not I could be stuff from the off!
I have a other alternator with stock pulley I could swap but no belt I don't think.
anyway can always check the other issues With the tune and set up water temp compensation better. I am pretty confident I won't get my idle Ms down where you are saying that is about 20% less fuel than it currently has! I am interesred to see what Aarron thinks of the values too. Not sure if something else would impact this?
How does matrix mode worry less about TPS input? I just thought that gave you a more advanced 3D map to play with?
One other quick point. On free revving ans constant throttle when stationary am I right I. Thinking I should be aiming at 13-14AFR? Or as close as I can get and the car be happy!
ohh and was the jump in Ms value from idle to load map to be expected too?

I have been doing a bit of reading on matrix mode. I will get the manual out and try and have a proper read and see if it explains it any sense. But when you go to matrix mode is this something you then keep the ECU in and it loads back to that whenever you reconnect or can you flick between normal mode and matrix mode for making basic adjustments and maybe correction tables? Do the values in the matrix mode come from the normal mode or are you starting fresh again? And then visa versa if you flick back to normal mode after fine tuning? I.e you make a basic load map in normal mode then flick to matrix to fine tune it? The TPS comment has me thinking once you are in You are in? Before this I had Apexi with a hand commander on my old car so I guess that is very similar to matrix mode?

Okay guy's so I think I am finally making progress!
I just finished running the car up and setting the water temp correction somewhere near correct after charging the battery last night. Correction values are way less now than they were previously with the big injectors? Maybe that is to do with the revStg% setting being different. That is just a side note anyway.. So during warm up it seems quite easier to keep a nice smooth plume free idle now. You tend to find that from one side of a correction value to the next it seems to run richer or leaner at times and I struggled to hold a constant value. Not a huge issue I don't think as in reality it spends little time warming up.
So to start with water temp was about 10 degs and air was 0degs.
ir never went about 10degs at all even after a stop starting. bonnet was up and doors both end of the garage open to get some air flow!
As it got to 82degs it was clear the idle map needed fuel back out from last time.. So maybe the voltage issue did make the injectors run leaner. The car stationary gets up to 90degs quite quick on the ECU display the dash cluster gauge seems to read about 10degs lower? Is this picking up from a cooler part of the engine. has always been the case.
Anyway at this sort of temp all corrects are of course off and I managed to get the idle cells down like so:
13hg 1.10,
24hg 1.10,
18hg 1.05,
12hg 1.10.

Idle still highlights 18Hg cell. Was happy like this for a while with mid 12's AFR. Now water temp creeps up to 98-99degs. It does seem to run warm like this but then it is stationary in the garage. I would say takes about 15-20mins to get there. The fans kick in at 99-100degs on my car. Just as it did this the car idle dropped very slightly as you would expect. then normalised and then the AFR started to lean more and once it does that is leans right off and stops!
Could maybe be the fans pulling the voltage down momentarily enough to lean it a bit? Then once it starts to stumble and miss there is no catching it. If that is the case maybe the Idle control valve would help if I can suss it out?
Initially I had to add fuel back into the map so:
24hg 1.19,
18hg 1.14,
12hg 1.19.
This gets it running fine but after maybe a minute is is clearly rich and wanting the fuel back out again. So I compromised on the values and it seems okay a touch rich.
Obviously it could be better just need to figure if how I can overcome what ever the issue is?
After a bit of playing I found that if I fired it up and keep the throttle open a bit for 20-30secs as I think Aarron said it seems to allow me to keep the compromised fuel setting of
13hg 1.10,
24hg 1.14,
18hg 1.10,
12hg 1.14.
Is this where the AFt_St compensation comes in? Does it hold extra fuel for a period of time? Mine was set as +2% and I tweaked it up to+06 so far but was worried I might end up with a flooding issue not being entirely sure what this value does?
RX3Sum you suggest going to +10%? please confirm how it works? I will give it a whirl if you guy's think that will help or at least not hurt!?

Really the questions are is voltage drop when fans kick in and out causing the stalling or should I have some water tep correction added bck in at 99degs? not sure if it is common for these engines to generally run around this temp when cruising anyway but as I cannot drive it on the road yet I don't know what to expect. I don't want to to be running permanently on correction if possible. and being that water temp only drops to about 94degs after the fans have tripped off and it seems okay at that once it has sorted it self out adding fuel back at 99degs will mean I am constantly on correction even if only a small amount? maybe that is what it needs?
Other than that it is try and figure out the Idle control valve which is incidentally all wired in just not active!

So I am close. Time to speak to my tuner and see when he can fit me in and also maybe look more into matrix mode and see if it is something I want to tackle myself.

Good that its better whats the voltage now?
After start enrichment adds fuel for the first 5-10? secs after startup to stabilise the engine.Yours was at 2 for the rich 1650s tune so will need to go higher somewhere around 10 from the basemap should be right.
Id set the fans to come on at 92C and there is a function to add fuel and air when the fans come on.
You dont need an operational idle control valve and i personally dont use one but the car will idle and idle up better with one.

Okay.. So I will wind up the Aft-St as you suggest then. Will no doubt help but not sure it will solve the issue. Is there cranking fuel addition to start the engine too? Should I need to change that after the new injectors? I ask because I am pretty sure before it started with no pedal. Now I need to use a little for it to fire? Could be idle is a bit lower as well maybe.
Voltage wise when it is warm and idling nicer getting around 13.8v now bit less when idle is slow and It's cold. Will get a stock size pulley on there as soon as I can. Should help a bit.
my fan is controlled by an FD stock fan switch. As I recall you can use the aux Output to control the fans or idle valve. Mine is wired to the idle valve as I want to try and get that working once I am as close as I can get without it. Temp wise I am hoping to get a turbo FC fan switch which kicks in around 90-95 from memory. Hard to come by here though! So not sure if you can still use the add fuel and air function without the aux fan operational? I guess not? If anyone can offer any pointers on setting up the idle valve I will give that a go. Should have the same effect anyway when the fans come on if set right?
I started a thread on it goes ago with little feedback. Might bring that back up to date to keep info in relevant places!

Another slight side note.. When I hold throttle at constant say 2500rpm no load. I cannot seem to pull enough fuel out without then effecting the throttle response as it must pass the same cell in basic mode. Am I correctly informed this is where the RPM cruise map would be used? I noticed this has some correction values put in it currently. Should I zero this off for the time being until I get the rest of the map sorted and then come back to it? I think this will help with getting better AFR at constant throttle. Struggling to get much better than low 11's when I guess I am aiming more like 13.5-14?

cheers
Lee

If its starting and running for the 10 secs at all temps with afterstart at 6 leave it there.
Your map was setup for 1650s so was very rich and any fuel adders such as pump and afterstart were set leaner to compensate.
If you are going to tune yourself try and get a 20b basemap and start from there.
Yes there is a crank map for initial starting of the car.
With larger injectors the only things that should change are the idle and load map as well as the staging setup. Everything else should be similar to the basemap.
Holding the throttle at 2500 is where the cruise map comes into play.
Matrix mode does away with the cruise and WOT map.

At the moment I don't think it will run without throttle unless I richen it up a bit. So I guess that is the way to check. Add AFT_St until it runs with no pedal. Then if it stalls after 10 secs or so there is something else at play.
The Map doesn't look to have been messed with too much I don't think. So hopefully I can tweak Cruise map for the 2500rpm bit and go from there. I will certainly leave the rest to my tuner though. I don't want to start messing with lots of different screens and then make it tricky for my tuner. I gather there is a rough process and order to go through things and I imagine cruise maps and pump throttle response are one of the last things when the rest of the map is nailed unless of course they are too far off to start with!
To clarify do you think my crank map should be left alone or might need fuel adding?
Should be posted on my other thread where I screen grabbed everything!
I will speak to my tuner about matrix mode.. Still not had a chance to read up on it. mainly I want to know if it is a map that get's is base values from the basic mode and you can flick between the two or if once you enter into matrix mode it is like entering a separate mode entirely that you stay in and the car is then tuned through and hence if you flick back to standard mode you go back to an old basic map as you left it?
i.e if My tuner will work in matrix mode in the end am I just wasting my time doing what I am doing or is it useful to get the basic values for the matrix mode set?

Thank you so much for taking the time to explain bits and bobs I am learning so much and the more I learn the more I then start to work out for myself seeing how one value effects another and what setup values link to what tables and so on.