[OneDrone]

Hi Guys,

I have an issue with the wideband showing rich on decel. I believe the MAF transfer is fine and I have the correct injector settings as per its spec sheet. The car starts and drives fine (I'm slowly working on increasing my spark table) but once you let off the throttle, lambse demands less fuel but the car gets rich. It gets to the point where lambse is asking for an AFR of 19 but I am still getting 10-12s. Once you get back on the throttle, if you get on it slowly the car commands lean till the remaining fuel is gone and then it goes back to normal. If you get on the throttle too quick, the car hesitates and sputters probably because there is too much fuel there and it goes lean quick before it comes back to normal. I tried increasing injector low slope from the sheet spec of 46lbs to 50lbs and it didn't seem to have much effect. I read I could play with the battery voltage vs offset but I am not sure that would make any difference as my understanding is that if I reduce all those values by a certain %, it will reduce pw for both high and low slopes? I don't seem to have a problem with my high slope and when I'm on the throttle, lambse is quite close to matching AFR on the wideband. Ideas?

Cheers

[OneDrone]

Just read a post by cgrey8. Re: rich on closed throttle decel. Sat Dec 27, 2008 12:12 pm

I will try increasing my low slope still until I notice a difference. If no success I will play with injector offset. I'm still not 100% sure I understand injector offset. Does it just influence low slope or both slopes? If it just affects low slope then it makes sense to adjust that table. If it also affects high slope then any adjustment you make to the injector offset will affect it as well so if your high slopes was good, changing the offset will stuff that good work up?

[OneDrone]

Solving my own question on the fly lol

Found another post to reference if anyone looks this thread up

Re: rich on closed throttle decel.
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Post by cgrey8 » Thu May 07, 2015 4:46 am

Changing offset does affect injector pw globally. However the offset function does not influence high slope very much. It has the biggest effect on low slope. Drop all points on the curve by 0.1-0.3ms and see how it affects your tune. Keep reducing to view any change. Thanks mate! @cgrey8

[motorhead1991]

Good info... I need to do the same.

[skunk]

If your running a small breakpoint of around 2 you won't see much of a chance adjusting LS. You need to bump that way up to around 6-8. Then re adust your LS up. You will also need HS down to around 40-41 or whatever you determain is required up top to compensate for the new fuel characteristics you've created.

John

[OneDrone]

Thanks John,

As far as I can tell I don't have an injector breakpoint setting as described. There is a setting called injector breakpoint however it is a fuel trim and not a real breakpoint commonly understood to be a point/switch between high and low slopes

[skunk]

Function or Scaler? If your basing that tidbit on what is on the internet about GUFB ...... I can assure you it is not accurate information. It is in fact an intersection of 2 straight lines representing the angle of each slope. If I am correct about your setting of Breakpoint.....you are running entirely off the HS except in high vac, very low load conditions such as engine braking.

John

[motorhead1991]

Could being up against the injector clip (in my case, around 40 being EEC-V) also have that same effect? I'm running unscaled injector settings currently with 60lb settings.

[skunk]

I have no experience with the clip but if it will only recognize up to a 40 lb slope....you will definitely be rich running 60's with an unscaled tune.

John

[skunk]

Alright, I had a few minutes to work up some numbers.

You are basically running on your HS with very little influence from the LS. Using a 2.12 BP puts you around 0.66 ms/rev for the transition to the HS. Now consider your idle PW is probably somewhere between 1.3-1.8 ms...... You will be rich everytime you let off the throttle.

Compare that to using something like a BP of 6 with the same LS of 46 puts you around 1.8 ms/rev. This allows you to adjust fuel for Idle and off throttle conditions as well as ensuring your positive throttle fuel requirements are met.

Keep in mind these figures are just an example and not at all accurate for a tune. It's much easier to make use of the factory fuel tune by simply scaling up the BP, HS and LS while leaving the Battery Offset stock and make fine adjustments to those parameters after getting the MAF as close as you can get it.

John

[Bossxr8]

Thanks John,

As far as I can tell I don't have an injector breakpoint setting as described. There is a setting called injector breakpoint however it is a fuel trim and not a real breakpoint commonly understood to be a point/switch between high and low slopes

Same car.

From what I can remember our injector breakpoint is a small decimal 0.00023 as an example. I have never been able to make sense of it, and mine goes a little rich when getting off the throttle at low loads, and very lean getting off the throttle after WOT. But it corrects itself within a second or 2.

I have left it as is as the MAF curve is perfect and it doesn't effect anything. I figure it's more important to have the fuelling correct when on the throttle rather than off it.

[skunk]

The breakpoint is a small number and depending on the definition it can be expressed as 0.000023 or 2.3e5. it's the same thing.

More importantly is it a single entry scaler or muti-entry function like in GUFB

I hope you understand off throttle fueling will effect on throttle fueling... therefore your fuel and MAF are not correct. That 2 seconds to clear is enough for me to have concern, might be my OCD, But hey...to each their own.

John

[Bossxr8]

The breakpoint is a small number and depending on the definition it can be expressed as 0.000023 or 2.3e5. it's the same thing.

More importantly is it a single entry scaler or muti-entry function like in GUFB

I hope you understand off throttle fueling will effect on throttle fueling... therefore your fuel and MAF are not correct. That 2 seconds to clear is enough for me to have concern, might be my OCD, But hey...to each their own.

John

Multi entry. But it's all the same bar the top value changes from 0.00 to 16. The breakpoint 2.56 eg is in the right column in all boxes.

[OneDrone]

Just as an update, I dropped the offset across the board and kept dropping it and I am currently at 50% of the recommended settings for my injectors. It has had an effect, the car goes down to 12-13s on decel as opposed to 9-11s. I thought I might have expected a better improvement from the amount I have dropped it. I will keep going and see how I go. At WOT the AFRs still seem ok. I definitely have had to bump up the MAF curve at low voltages because I was starting to run lean with each drop in pw vs offset. I'll keep going and see how I go.

[OneDrone]

Going to try going back to my spec injector battery offset vs pw and then change the breakpoint and see what effect that has

Standard is 3.039837/10^5 at all table values

My injector spec sheet says it should be 0.0000212 which would be 2.12/10^5

I don't know why I didn't input that value in the first place.. Will give that a crack

[skunk]

Ok so it's a Function and works exactly like GUFB A9L Its even using the same BP value.

If you read my other posts you should realize dropping the BP down to 2.12 will have the opposite results. You will moving even farther away from ever using the LS. Those specs don't even jive with what Ford used on the Lightning for the same injectors. I believe they used something around a HS of 40 and LS around 50. The Battery Offset was also higher than the specs. Just goes to show you ......give it what it wants.

I know I'm likely beating a dead horse here since it's not the over analytical methodology....... Simply set the Battery Offset back to stock and scale the HS, LS, BP and MAF to represent the Injector size change. You will be much further ahead going this route. The factory has already done the work for you.

John

[cgrey8]

If you have an Injector Offset curve from another tune that uses the same injectors, this is probably the best strategy.

For me back in 2006, that wasn't an option. I had the stock EV6 Explorer injectors still on the engine, and without any info on them, I kept using the stock Mustang's 19lb Injector Offset curve. As a result, I was coming up with high slope values in the 17-18 range, but low slope values in the 70 range! That's not really bad on the surface, but what was bad is this suddenly makes tiny changes to the breakpoint huge. A breakpoint value change from 3.2 to 3.3 was a VERY noticeable thing in the drive. The disparity was caused by the Injector offset curve adding so much more pulse that it was making the injectors look huge at low pulse conditions, but then as the PWs got longer, they started behaving more like themselves.

Once I eventually figured this out, I substantially lowered the offset curve until I had low slope values that were very near the high slope value. I think I ended up with like 17.9H/19L. With the slope values so near each other, a breakpoint change of 2 to 3 was unnoticeable.

My point being if you start noticing that your low slope is calculating, in EA, to be significantly higher than your high slope, then consider dropping all points on Injector Offset curve and see what result that has. The closer you can get these values, the less relevant/sensitive the breakpoint becomes. When high and low slope values are equal, the breakpoint value is irrelevant.

[skunk]

Chris, I'm glad you brought up the comparison between 19# injectors. When I post from work...I can't always complete a thought. Anyway.....your example shows me that the only way the spec sheet will be close to accurate is when displacement increases around 2.21 times. Since displacement is not changed drastically.... you have to make a large injector behave with a smaller output that resembles what the engine is capable of using. Let's face it these engines will still run well on 19# down low....it's up top we need all the extra fuel especially with power adders. I found I could manipulate all fuel parameters to get what I needed but always came up short of being correct indicated by surging and KAM correction always wanting to add fuel during steady state cruise then wanting to remove it for all other conditions for that same MAFV. I began tuning slopes, BP, Offset specifically around that point and ended up looking very much like a scaled version of the stock settings. I eventually gave in to just putting the scaled values in and tweaking from there. The results were so good that it's my starting place for every tune I do now and cuts time down to just a few datalog sessions.

John

[OneDrone]

If you read my other posts you should realize dropping the BP down to 2.12 will have the opposite results. You will moving even farther away from ever using the LS.

Hi John,

Many thanks for your help! You are correct in that the breakpoint did have an effect and it seemed to be the opposite. It's certainly not that I didn't believe you! I wanted to see for myself what the effect would be putting all the parameters as per my injector spec sheet - that has given me insight into relying on spec data sheets for injectors. There has been some great learning on my part. This also confirms that others posts I have read regarding the breakpoint setting is not consistent with my trial and error. I will now try increasing the BP first and monitor that effect.

[skunk]

Cool......keep us posted.

If its any help.....I have just begun a tune for a guy with a similar setup and currently sitting with a HS 42, LS 55 and BP of 6.50. Battery Offset is stock and MAF is scaled 42/19.64. I'm waiting for him to get his wideband set up and logs forward to me before going any further. So far closed loop looks pretty good but I've only gotten a couple of logs to work from. Once MAF is dialed in I will correct what fuel error persists with slopes and BP.

John

[OneDrone]

I had a quick play and bumped BP to 16 and LS to 61. It is better but still gets rich to 10-11s however it doesnt' stay in the 10-11s as long as it used to. It will come down to 10-11s then climb back up once the revs drop to a certain point. I think I am getting closer, when I shift up through the gears it is much smoother. Obviously low end of MAF transfer has leaned a bit with those adjustments. I might look at the scaling now as suggested and see what figures I come with and try that. The tricky part is the fact that I am running a C&L MAF with a stock sensor with a sample tube to ensure it doesn't peg. I have some thinking to do on how to scale that transfer properly.

[skunk]

Those changes should have had you running really lean. You might want to verify it's not something mechanical with fuel delivery. Look at fuel pressure to make sure it's drops instantly around 5 psi when the vac line is connected......I'm assuming it's a return style system with vac referenced regulator? If pressure isn't dropping under vac you will be rich until the fuel clears or demand increases.

John

[OneDrone]

Yeah it's not really making much sense to me at the moment so it could be mechanical. I tried the scaled settings and not much improvement.

I then dropped LS to the same as HS and had to drop the offset considerably (75% of the 42lb spec) to get it working a bit better. If you drop offset too much you notice that when you get off the throttle it goes lean straight away into 17s then it instantly goes back to rich around 12s when decelerating in gear and goes to as low as 10 if rpm is low in any gear. I might be chasing my tail - the wrong tail

[skunk]

Just for kicks you should be able to load the GUFB A9L on the QH and see if it behaves the same. I am just wanting to rule out an error in the definition file or corrupted tune...

John

[Paulie]

In your signature it says you are running a blower. What does your air inlet track look like and where is the maf? The C&L meter is not going to deal with turbulence very well.

[xd41efisc]

Just for kicks you should be able to load the GUFB A9L on the QH and see if it behaves the same. I am just wanting to rule out an error in the definition file or corrupted tune...

This will not work on the EEC he is using. It will only work on EB/ED EEC IV not EF/EL EECV, I have tried it before.
It will also work on some of the US EECs, But the EECs need to be similar in the hardware set up.

[OneDrone]

Could be the MAF. I'm only using it because that is what came with my kit but I'm happy to source another - especially one with a known flow curve chart to start off with.

I've got a photo of my intake setup in the link below.

https://www.dropbox.com/s/72wj0wkwwkq4z ... 5.jpg?dl=0

[Paulie]

Could be the MAF. I'm only using it because that is what came with my kit but I'm happy to source another - especially one with a known flow curve chart to start off with.

I've got a photo of my intake setup in the link below.

https://www.dropbox.com/s/72wj0wkwwkq4z ... 5.jpg?dl=0

I see 2 issues. One is the bend after the maf and the other is the return for the bypass valve being relatively close to the maf. Both will create turbulence. The C&L meters measure at the outside edge of the tube and are very susceptible to turbulence. Read here for some more information https://eectuning.org/forums/viewtopic.php?f=1&t=19821
I would suggest a slot type maf. I use a PMAS slot type maf and like it a lot.

[OneDrone]

Yeah I have been aware of those 2 issues but since I really don't have too much space was hoping that it would work with what I had . Yesterday I tightened the SC pulley while warm and to do that I have to remove the maf to get the spanner in to those bolts. I then clocked the maf a bit and tried to make the pod as straight as possible. I'll take it for a drive tomorrow and see what effect that has.

I have a slot style maf, it is a fomoco one but the part number was ground off. It is mounted to a bit of 2.5" pipe. It might be easier for me to get a maf that already has a slot in it with 4" in and 3" out. Alternatively it looks like I can get a LMAF slot style sensor and put that in my existing housing. I will have to have a look if you can do that with a C&L and remove the sample tube altogether.

[OneDrone]

Rotated the MAF a bit and had to modify the maf table quite a bit.. Very time consuming. I will purchase another MAF to eliminate that as my problem. Any other MAF recommendations? I can get an 90mm LMAF locally quite easily. Anything else may have to come the good ol' US