Mass Flo EFI suggestions for a FNG

[DonC]

Basics:
428FE @ 450 cu. in.
Mass Flo EFI has been on the car going into it's second season.
Overall very content with the way the system performs from seal level to 12,000 ft.
Installation was very straight forward with no surprises. Increase of 25 hp and 28 lb.ft. of torque over carb (Holly 750 mechanical secondaries - List 3310)
Have installed a Tweecer to make a couple of minor adjustments.
Closed loop AFR is around 13.5 and I'd like it closer to 14.5 or there abouts.
Cold start idle drops back down to around 850 within a couple of seconds. Would like to keep it around 1100 until I get about 25C coolant temp (about 75F).
Tweecer read the Moates chip that came with the system so I have a viable .bin file of the current tune.
Being brand new to the EFI world I'm soliciting suggestions on where to start nudging adjustments to arrive at what I'm shooting for.
Thanks,
DonC

[RICK LAKE]

DonC Don call them and them give you a certified shop for what you want. Way too many people get into the FI systems and screw them up big time. Look for a race shop with a dyno. Your A/F is OK at 13.5 unless this is idle but going to 14.5 is too lean IMO. I run a 13.5-13.8. For street cruising 13.1-13.5. WOT 12.5-12.7. Alot depends on your side pipes, street or track, Baro, thin air,etc. If you picked up 20+ hp and torque, there was something out in left field on that carb. A/F meters are one of the best tools for setting up cars. Call around and go to the 1/4 mile race tracks and ask questions. Make sure you get min of 3 guys that use the same shop and are not parked next to each other. There are EFI class from comp cams for what you want. Try EFI.com and see what comes up. A couple of 3 or 4 day courses and a couple of 2 day expert courses. Not Cheap, and I have no feed back on them, but info is info. Rick L.

[olddog]

Don - I think we have talked before. I have MassFlow on a 5.0/347 stroker. I have been thinking of going with a Tweecer. I keep waffling on going to a dyno tuner as Rick suggests or buying the Tweecer. Please post your experiances, as I am very interested.

From what I have read there are quite a few look up tables used by the EEC4. Ford chooses to go lean while warming the engine up to get it warmed up faster. It sounds like this happens in closed loop. They also go fatter as load increases. Also in closed loop (I think). As I understand it, Ford did not target 14.7 at all times in closed loop. Again from reading (no actual experiance) lots of tuners lie to the EEC4 on the air flow because they have installed bigger enjectors. If they put in 2x sized enjectors then they retune the MAF to only read 1/2 the actual air flow. This gets the air fuel correct, but then table that is used to determine what the engine load is is wrong. This screws up the timing and how rich or lean the engine should run. Also somewhere the EEC4 needs to know what the engine displacement is to be used in the load calculation.

Any way understanding what is going on with the information that is in your tuning is the first place to start in my mind.

Sorry I cannot be of more help to you.

[olddog]

I been reading some more stuff. I have been very confused, as different authors lead you to believe different things that they never state for certain. Many times I read that the factory O2 sensors can only read in a very small range around 14.7:1 AFR. No one ever says just how far from 14.7 they will read!

So when you are running at say 13.5 AFR, the big question is: can the O2 read that you are at 13.5 or is it out of range? When you read how the AFR is fattened up as the load goes up on the engine, you have to wonder if it is within the range of the O2. If not then it has to be running open loop. If the O2 range is as tight as some lead you to believe, then under most conditions your in open loop. It just so happens that under normal driving conditions in a factory stock car it is in a condition to run in closed loop (I understand that this so happend by ford engineers designs). But my point to this is that when we get into highly modified engines, cars, etc. we may rarely be in a condition that it runs in closed loop.

From your question on where your AFR is at, do you know what the O2 are reading? Is it open or closed loop at that time? You said your closed loop AFR is 13.5, but are you sure it is in closed loop or just assuming it is?

Wish I new more.

[vector1]

you've got your wideband sensors and you've got your narrowband sensors.

narrowband are usually used by oem's. wideband generally by the aftermarket.

narrowband 14.2-15 to 1

wideband 10-20 to 1

accel has an ect to rpm table to play with on cold start, don't know about your setup.

[DonC]

Thanks for your replies and information.
Looks like the system was not going into closed loop at all and the readings I was getting were while in open loop.
Working with a fellow that appears to know his stuff and in the process of "learning" along with very baby steps in making changes.
Advantage with the Tweecer is that I can keep the car on the road running a tune that I know works moderately well even if there are some problems while keeping the "play with" tune in a different switch position while it is in progress.
Still in the very early stages. I'll keep posting at things progress.
DonC

[olddog]

After Victor1 posted the O2 sensor range, I was pretty sure you were not in closed loop control.

If I remember correctly, you put the O2 sensors at the collectors. Several sources (not all) warn not to do this. Same claim that normal driving will not get enough heat to the O2. Maybe someone can tell us how to determine if the O2 is getting hot enough to allow the ecu to go into closed loop. I would guess that if you see the voltage output bouncing around it is working, but that is a guess based on a little knowledge.

I had a loose plug on my O2 sensor, and it tripped a code and turned on the light. It was something about the voltage not switching (it normally swings high and low). If the O2 is not working or not plugged in it will trip that code, but if it is not up to temp, it may not trip a code. I'm not sure.

[RICK LAKE]

olddog The O2 sensor housing needs a ground and also a large change in the millivolts without and varying will cause the SES light to come on. If you pulled the sensor out of the bung or allowed fresh air to make contact with it and there is no varying of high to low, The light comes on. Most sensor are narrow band and have a .448 MV for the middle of the rich, lean cycle. Untill the sensor reaches 600F most ECU don't use these readings to adjust the fuel and timing when cold or in open loop. This is why most cars and trucks now have heated O2 sensors to get the into closed loop and have the A/F mixture running cleaner and reduce emmissions. The only trick for an o2 sensor in the side pipe is to get it about 6-12" passed the collector so it gets all the cylinders exhaust mixed and not just one. The problem is no room. This is where EGT can come into play and help with tuning. NEVER unplug,remove, adjust a sensor on the car with the power on or running to the ECU, You can spike, loose step count, degree angle, or even blow a quad driver from unhooking a sensor or injector with power on or motor running. No welding without unhooking the battery and ECU also. Rick L. Ps narrow band sensors are about 11.8 to 15.5 A/F readings. The wide range are lower and about under 10 to 18 A/F readings. These are more for racing and power adders. They also cost about 3 times more.

[cobrarkc]

Just an FYI and if you have a MassFlo system Chris should have already told you this. THe Ford O2 sensors need to be 12- 18" from the exhaust port to function properly. If you have them in your collectors they will not heat up enough and you won't go into closed loop. Some guys on EECTuning.com have plyed with pulse timing to fool the ECU when using long tube headers. You can do a search over there and get some good information.

[olddog]

Originally Posted by RICK LAKE

olddog The O2 sensor housing needs a ground.

This one sent up a flag to me. With ceramic coated exhaust, gaskets, and rubber mounts, I would have to suspect the exhaust system would be poorly grounded. However when I think about it, my O2 are 4 wires. I assume 2 for the heater and 2 for the milivolt signal. I cannot imagine anyone would design a milivolt signal to use a chassis ground as part of that loop. Can you elaborate a little more on this subject?

Originally Posted by RICK LAKE

narrow band sensors are about 11.8 to 15.5 A/F readings. The wide range are lower and about under 10 to 18 A/F readings. These are more for racing and power adders. They also cost about 3 times more.

Interesting. Victor1 said about 14.2 on the low side and you said 11.8. I have never seen anyone give actual numbers just say a very narrow range. Now I see numbers and both are quite different. Is it that different O2 sensors have different ranges? How sure are you on these numbers?

Understand I am trying to learn - not put anyone on the spot here.

[olddog]

I had someone tell me that when putting an O2 sensor in a single pipe, you can stand the bung off the pipe (esentially use a deep well bung) so that the O2 barely goes into the exhaust flow. This reduces the flow restriction and still gives a good reading.

True? Comments?

[olddog]

Donc,

How well has the TwEECer worked out for you?

How hard or easy to learn and use?

Rick
AKA olddog

[DonC]

The Tweecer is working quite well for me in that it allows data logging and provides a way to try different changes to the EFI program. I've added the Binary Editor and EEC Analyzer software programs which are a great aid in making modifications to the program. Also borrowed and Innovate LM-1 wide band sensor to monitor air/fuel ratios during data logs which is extremely helpful. In a nutshell the Tweecer is easy to set up and use but it's only the tip of the iceberg.
Starting as I did from knowing essentially nothing about the EFI system I've learned a great deal about the system and what makes it tick but still a rank amateur. Pretty steep learning curve but I'm closing in on it. I've leaned very heavily and the very patient and knowledgeable folk at EECTuning.org and they've been extremely helpful in not only explaining some of the more esoteric aspects of the system to me but offering advice to keep me on path as I go along.
As it stands right now I've got the Open Loop side of the system pretty close to where it should be and am getting ready to start doing battle with the Closed Loop side. Our weather here in the northwest is getting ready to turn wet so it will slow down my progress considerably but I'll keep plugging along.

[olddog]

Thanks Don.

Is your O2 still in the collector?

If so, does it get hot enough to go into closed loop?

If you moved to a single pipe, does that work well?

[DonC]

Sorry to be so long getting a post in but I've been doing a number of end of summer runs and work around the house that takes valuable time away from the Cobra but the house is still worth more so it takes priority.
The 02's were never in the collector since Chris was insistent that they be within 18" of the flange. I've been using a wide band 02 with an Innovate LM-1 system to get the AFR logged and it's made acquiring data much easier and more accurate. The wide band 02 has it's own heater so I get reasonable accurate readings. It's mounted in a bracket clamped to the end of the side pipe.
Going to the closed loop side of the system has generated a whole range of anomalies to address. Nothing world stopping but it's back to the books and advice columns to try to work them out. Primary problem is all the data shows lean using the same MAF curve that worked quite well in open loop.
My gut tells me there's something in the closed loop side of the tune that is out of line since the closed loop curve ran quite well. Lean tip ins from idle and coming back on the throttle after decelerations are by far the largest issues.
I'll try to be better about updating in the future.
DonC

[olddog]

If the information I have found is correct, the factory (Ford) tune on an EEC4 for the 5.0 mustangs (which is what Chris uses) purposely runs the engine very lean at light load conditions, especially at low rpm. Perhaps to get the cats hot. The maps I have seen go as lean as 16:1. In my conversation with Chris, I got the impression that he feels the factory engineers know best and all engines are close to having the same needs.

With that said, the closed loop lean condition may well be that the maps are telling it to run that lean. That might have woked ok for a 5.0 with cast iron heads, egr, closed chamber with some squish in it, and mild cam. An FE most likely has very different needs.

[DonC]

I'm running the same MAP (also called the MAF Transfer curve) that runs correctly in open loop which is why I feel that there is something in the closed loop part of the program that's forcing the system to report very rich conditions. I tested a much leaner version of the MAP and, even though the numbers were still showing a rich condition, I experienced significant lean running indications.
I'm hoping to chase some thoughts down over the next couple of weeks although the weather and painting the inside of the house are going to slow me down a bit.
DonC

[DonC]

Cautiously optimistic that the very faint light at the end of the tunnel may not be an oncoming train.
I noticed that in open loop the 02 sensors were reading very rich even when the wide band was reporting near stoich. As soon as closed loop is enabled the 02 values play a huge role in how the system manages the fuel. With the high readings the system was forcing very lean conditions to try to bring the 02 readings down (just like it's supposed to do when installed in a normal engine).
Thanks to a lot of input from the very patient folks at EEC Tuning.Org I reset the 02 bias very high and increased the switch point for the 02 sensors and tried it again. Much better results. The 02's are still reading very high but the system is making a much more moderate approach to it's corrections and I was able to get a data log that showed the system running in the mid to upper 15's and mid to lower 14's for stoich. This I can work with.
With the more moderate system corrections it has all but eliminated the rich tip outs that were causing such severe dirveability problems it ran into on initially enabling closed loop.
As I said, cautiously optimistic at this point.
It has, naturally, been raining here for the last five days so I haven't been able to get the car out to work on further refinement and further progress is going to be slowed by this but I'll be getting out whenever there's a break.
DonC