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Megasquirt - running too rich idle or stalling??
mackei23b - 29/4/15 at 06:17 PM

Hi there

I've fired up the Duratec (2l. standard cams with Jenvey 45s and ST170 injectors).

It starts fine and the exhaust looks a little rich, which is fine as it still running warm up enrichment and the AFR is 10.5 and it looks OK.....

Then as it continues to run the AFR stays around 10.5 and exhaust starts smoking quite a lot..... this is when it is running at circa 1200rpm and around 12-15 degrees ignition advance. If I lean of the mixture in the VE table (it was down to about 2ms injector pulse width) it has little effect on the AFR and then the engine then stalls (temp at 75-80 degrees as this point).

Other points for consideration......

- The plugs are oiled up apart from one which is full of carbon, see picture... (reflecting what I'm seeing on the AFR and the smoke out the exhaust.....so it's definitely rich...and I sit here smelling of fuel from the experience!!) The throttle bodies are not balanced yet, but I've check and they are not too far off, so the variation in the plugs could in be explained in part by either the throttle bodies being imbalanced or a lazy injector...?

Spark Plugs
Spark Plugs


- I'm running the ford fuel rail (no return) in a dead head configuration and I'm not sure how well the pressure is being regulated which could also lead to over-fuelling.....

I'm running an MS3 (I've set up an MS2 before in my previous car and tuned it OK).

What have I missed.....what should I look at next in my attemps to get the engine idling successfully?

Any help greatly appreciated...

Cheers

Ian

big-vee-twin - 29/4/15 at 06:42 PM

At 75-80 degrees the engine is not warmed up and the thermostat is still closed, so will still be running warm up enritchment. Thermostat opens at 85 degrees.

Mine idles at AFR 11 until wue is off then at 13.5 AFR.

You should get warm up enrichment set up correctly let it warm up fully then tune idle.

mackei23b - 29/4/15 at 06:52 PM

Hi there

Thanks for the post, yes the thermostat had not opened yet

I'd set the warm up enrichment so it was off at 70 to see if I could control the fuelling from the VE table and it was very smoky at 10.5AFR...you could see the smoke drifting across the driveway...

I agree that it may have been helpful to wait a little longer to get the thermostat open, but the fueling was so far off and fouling the pugs so much at start off.

Thanks

Ian

paulf - 29/4/15 at 08:04 PM

How are you regulating the fuel pressure if there is no return? I would fit a pressure gauge teed into the fuel line and monitor the pressure as there is no way the fuel table will be correct if the pressure is not steady .

mackei23b - 29/4/15 at 08:16 PM

Here is how I'm regulating, in the 'dead head diagram'

Dead Head
Dead Head


Cheers

Ian

Angel Acevedo - 30/4/15 at 03:58 AM

quote:
Originally posted by mackei23b
Here is how I'm regulating, in the 'dead head diagram'

Dead Head
Dead Head


Cheers

Ian



That may be the problem.
That setup may be prone to vapour Lock which in turn m ay lead to pressure/flow fluctuations.
The advantage of using setup 1 is that the return fuel carries away unwanted heat on the injector rail.
HTH:
AA

Chris_Xtreme - 30/4/15 at 08:15 AM

from my experience I have no problem with the dead head system . RV8 with 2 sets of honda cbr600 bike TBs.

What I found was balancing the TBs made a massive difference, I'd try getting them a bit better first, then see how you go.

SPYDER - 30/4/15 at 08:42 AM

quote:
Originally posted by big-vee-twin

You should get warm up enrichment set up correctly let it warm up fully then tune idle.


This is contrary to the manual IIRC. There is no point in setting WUE before getting the idle value in the VE table correct. The WUE refers to the idle VE value for its baseline. If you set the idle VE second you would have to do the WUE all over again.


OP... if the carbon covered plug is causing even a mild misfire then the sensor can show a lean reading regardless of actual AFR.
Firstly, save your present msq. You can easily go back to it.

Go into WARMUP WIZARD and set all bins above 70 degrees to 100%. This will ensure that you are running on the VE value only once you are above 70.
What are your warmup values? Could they be too high, causing the excessive richness?
Mine are 4 deg.....160%
16...........121
27............108
38............104
54.............102
70.............100

Make sure EGO control is OFF.
Set your VE idle value to a little above the stalling value.
Start engine and get it above 70 degrees or up to thermostat opening if poss.
Put a new set of plugs in.
Start up. Any difference?
If it fires then stops increase the idle VE value.
Unless you can get it running cleanly the sensor wont read correctly.

Are you running sequential, batch fire, bank fire ?
I had idle issues until I swapped over the injector plugs.

Is your sensor a long way from the engine?
What AFR controller are you using? Is it correctly selected in your tuning software?
Are you using TunerStudio?

You might try posting on the megasquirt forum as well as on here.

Chris_Xtreme - 30/4/15 at 08:48 AM

another thought - have you run through the sensor calibration ? on my innovate one I had to set it up so it knew what clean air was.

mackei23b - 30/4/15 at 03:28 PM

Hi there

Thanks for all the comments...

- O2 sensor is an LC1 - I ran it through a free air and heater calibration, even did a 2nd free air calibration before the last start
- EGO was set yo come in at 1300rpm, just above where the engine was idling - may adjust further to ensure at no condition there is feedback
- I manage to set the VE table just above the point it stalled - at this point I was down to 2ms injector time and an AFR of 10.5 and smoky
- Re temp it was circa 80 degree, but the thromostat had not opened
- It was running with no misfire
- running 'grouped' injection (Bank1 and Bank2)
- Sensor is just after the 4/1 collector
- Using Tuner Studio

When i take the plugs out 3 of the 4 pistons are wet and have the oiled plugs and one piston has carbon and the carbon plug.

The injectors are st170 (315cc), what injector pulse width are other running with at idle on a Duratec, this may help diagnose whether my fuel regulator / pressure is correct?

Many thanks

Ian

[Edited on 30/4/15 by mackei23b]

Chris_Xtreme - 30/4/15 at 03:46 PM

can you switch the injectors round to see if the state of the plug moves with the move of injector?

mackei23b - 30/4/15 at 05:41 PM

Yes I was thinking about moving the injector to as part of the problem solving........

avagolen - 30/4/15 at 06:10 PM

Having no experience with fuel injection, I cannot add any proven ideas - but...

If you have not balanced the airflow, how do you know that you are actually getting enough air
to the cylinders that are running rich? If - as with carbs the mix for those cylinders is so far out, they
will never burn cleanly - or at all.

Just my two penny's worth.

mackei23b - 30/4/15 at 08:38 PM

The next update......

I've swapped the injectors and..........all cylinder now look fine.....so may have been a bad connection to one of the injector pins...(I will need to monitor this......)

I checked the throttle bodies again (I did do a quick balance and they are OK... drawing in 6kg/hr at approx 1200rpm (I also took the EGO feedback totally off and the temp was 85 and the thermostat had just opened....)

Opening the throttle made the AFR did go lean...which is what I'd expect at this stage with an un-tuned VE table...but it looks like controlling the fuel at idle is an issue.....

Here is a video..... https://www.youtube.com/watch?v=9xPQ8LcQFuo

Cheers

Ian

chasmon - 11/5/15 at 11:37 AM

Is it only me or is 10.5 a bit low for for AFR?

Depending on how your LC1 is setup it may only read 10-20 right? I have a feeling mine defaults to 10.5 when out of range anyway. Could it be you are actually much richer than this?