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serfma
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Effect of long tubes, and general questions

Post by serfma » Mon May 03, 2021 6:50 pm

I am running a 96 Mustang Cobra, 4.6L 4V, CDAN4/LLX3. I am painfully new to the tuning world. I am curious since I've been unable to find the answer of: What effects do long tubes have on how rich / lean the car will run? My issue: Running past 3k - 4k RPM in 1st (haven't tried other gears) results in black smoke. I've tried data logging at operating temp for idle since I've no wideband and it's looking like I'm overall running lean, seemingly more so on the driver side bank.

Mods:
- BBK Long Tubes
- No cats
- No rear o2's

(No wideband atm)
Image

In my tune I have changed the following:
Image

Should I increase my o2 transport delay? Force open loop at idle / below a load %?

Any help or advice will be appreciated :)

ChsReb
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Re: Effect of long tubes, and general questions

Post by ChsReb » Tue May 04, 2021 6:52 am

I'm not acquainted with your tuning software, but going back to the days of Carbs and Headers, I can say for sure Headers will lean things out. You made no mention of Removing the EGR, but it really confuses the computer unless you tell the computer it is no longer there.

Bottom line: I'd say your MAF curve is way off. Lots of discussion here on changing one. I've got several videos on YouTube as to how I adjusted mine. I'd spend lots of time fixing that. Now if your graphics are accurate, you're extremely lean down below and improving as load increases.
95 GT, CBAZA with U4P0 Base, EEC 56k 1 Bank, 408 Windsor with Trick Flow intake, BBK 75mm throttle body, Ford 47 LB injectors, AFR 185 Heads, Custom Comp Cams Cam, Moates QH v1.6, BE 5.122, with Sailor Bob Strategy upgrade, AODE w/SatNightSpl and full TCI Rebuild. 4" Gen 1 Slot MAF with 4" K&N Filter in custom cold air enclosure.

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cgrey8
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Re: Effect of long tubes, and general questions

Post by cgrey8 » Tue May 04, 2021 7:05 am

The best piece of advice I can give you is...umm get a wideband.

It appears you do have BE and EA so the next thing you could take a peek at is if your Injector Parameters look reasonable based on your datalogs. There's a writeup somewhere (possibly in the tech docs section) that talks about how to analyze your datalogs and tweak your Injector parameters. While it is possible to do this without a wideband, the results are far better and quicker with a wideband.

Once they are "close enough" then tweak the MAF curve to get it whipped into shape. However there's only so much you can do here without a wideband...but even more-so for MAF tuning than with Injector parameter tuning.

With those two dialed in, you shouldn't have rich problems.

Now to your point about long-tubes. What they do is accentuate scavenging of the exhaust from the cylinders at moderate to high loads. Combine them with a heavy-overlap cam and you could get scenarios where your exhaust appears lean to sensors due to unburned air getting into the exhaust, but shows black smoke out the tailpipe thus suggesting things are much richer than they otherwise would appear from datalogs. When using HEGOs, any significant unburned air getting into the exhaust will present as a lean condition causing your computer to adjust rich (during closed loop modes). Based on your KAMRFs adjusting for a detected-rich condition, I'd suspect this is NOT the problem you are fighting even if this problem actually exists. I suspect there's other problems with the tune right now that are worse than the affects of blow-thru due to a heavy overlap cam and long-tubes.

Here's where having a quality Wideband comes in. What QUALITY wideband controllers can do is tell you the ratio of air and fuel in your exhaust (burned and unburned). If the wideband controller is quality, it can compensate for the unburned air by also sampling the unburned fuel and reporting the ratio of what the air-to-fuel is in the exhaust. This is one of those areas where cheap wideband controllers are inadequate. Cheap widebands work fine for a mildly built engine where the vast majority of what's in the exhaust is burned air and fuel where the excess being measured is either an excess of oxygen and very little fuel (lean burn) OR an excess of fuel with very little oxygen (rich burn). But when you start introducing a significant portion of both unburned air and fuel, this is where they start not working well and their accuracy is questionable to down-right unreliable. So depending on how crazy your build is will dictate whether <$180 WB will be fine or whether you should not skimp and budget for a quality ~$400 WB controller.

This of course also assumes you don't have exhaust leaks. Exhaust leaks introduce oxygen into the tubes that did NOT go through the engine. So exhaust leaks will cause a leaner-than-actual measurements under conditions where the headers are creating a vacuum in the exhaust and literally are sucking in outside air past the leak. So if you have exhaust leaks, you do not have useful data from your exhaust sensors.

Those are my thoughts....
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

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034v
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Re: Effect of long tubes, and general questions

Post by 034v » Tue May 04, 2021 1:58 pm

HEGO Delay or FN1351

This is a delay in revs from the O2 sensor that the engine fueling will see that change.

For long tube headers and some turbo applications, these numbers should be raised.

Table is at 0x12B8E in CDAN4
Created the XDF's below in my spare time. More to come as time allows. Let me know if you need one.
CDBA4 - DONE
CDAN4 - DONE
CMBA0/CMAI3/6/7/9 - DONE
CZAJL - DONE
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GSALI - DONE
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serfma
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Re: Effect of long tubes, and general questions

Post by serfma » Tue Jun 01, 2021 4:56 pm

034v wrote: Tue May 04, 2021 1:58 pm HEGO Delay or FN1351

This is a delay in revs from the O2 sensor that the engine fueling will see that change.

For long tube headers and some turbo applications, these numbers should be raised.

Table is at 0x12B8E in CDAN4
When you say these numbers should be raised, I have no concept or baseline of what would be too high or too low of a change. Some reading around seems like people generally blanket 20% - 25% raise it across the board. My next question is, with it being raised, what am I looking for in terms of changes in KAMRFs (or elsewhere) to indicate whether it was a good or bad increase?

With the exhaust leaks fixed, I am seeing around a 14% idle lean condition on the passenger bank which I am unsure if this is normal due to LT's or another exhaust leak somewhere, or possibly bad O2? As for my driver side bank I had a leak at the two small EGR tube vacuum lines that caused it to reach 25% lean, to which I've since plugged the lines and idled around 10 minutes and had it drop to 20% but am unsure if I need to go ahead and reset KAMRFs on that or if the ECU will with some time adjust down.

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skunk
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Re: Effect of long tubes, and general questions

Post by skunk » Wed Jun 02, 2021 3:15 pm

I would leave the delay alone for now...it just makes the HEGOs a bit sluggish to respond.

As stated...you need a wideband to know how much error you have between what the computer thinks is stoic and actual WB results otherwise you are flying blind.

If you wish to do what you can without a wideband....reset KAMs with every change you make and get your fuel close by adjusting injector parameters first then attack the MAF for fine tuning.

John
1987 Turbocoupe.
A3M1/A9L, BE/EA, Tweecer RT.
306,Single Turbo, Ported E7's, Ported Stock Intake, 42lb Matched Green Tops, PMAS 3" Blow-Thru Protube (42# supercharger calibrated),T5z, 3.73 gears
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serfma
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Re: Effect of long tubes, and general questions

Post by serfma » Wed Jun 02, 2021 6:21 pm

skunk wrote: Wed Jun 02, 2021 3:15 pm I would leave the delay alone for now...it just makes the HEGOs a bit sluggish to respond.

As stated...you need a wideband to know how much error you have between what the computer thinks is stoic and actual WB results otherwise you are flying blind.

If you wish to do what you can without a wideband....reset KAMs with every change you make and get your fuel close by adjusting injector parameters first then attack the MAF for fine tuning.

John
Hmm.. Yeah getting a wideband ASAP. I just wanted to rule out any possible issues before starting to tune anything. With driver side having a much higher % of leanness, could this be possibly a symptom of a faulty injector or two?

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skunk
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Re: Effect of long tubes, and general questions

Post by skunk » Thu Jun 03, 2021 6:52 am

Once you have ruled out all possible intake and exhaust leaks, I would verify that your base mechanical idle is set correctly. If the throttle blade is open too much or too little the ISC routines will only be able to compensate so much. You are basically stock and the tune should be close as is. The black smoke could be due to the stored closed loop enrichment carrying into open loop.

A suggestion if its available in your strategy....turn off adaptive learning (Kamrf) and tune via LAMBSE in CL. It will speed up the process by giving you the instantaneous correction. Make sure KAMs are cleared when you do this or they will stay in the mix. Just remember, if LAMBSE is commanding lean you are rich by that percentage and vice versa.

John
1987 Turbocoupe.
A3M1/A9L, BE/EA, Tweecer RT.
306,Single Turbo, Ported E7's, Ported Stock Intake, 42lb Matched Green Tops, PMAS 3" Blow-Thru Protube (42# supercharger calibrated),T5z, 3.73 gears
..... Nothin Fancy.......Just something to keep me from the honey-do list.........

assasinator
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Re: Effect of long tubes, and general questions

Post by assasinator » Thu Jun 03, 2021 6:16 pm

yes adaptive can be turned off in cdan4. you must do it for sanity until its close.

plug up all egr in ur headers. turn off egr in your toon.

you cant toon it with exhaust leaks. the pcm will wander endlessly. either get a pair of widebands, or take it to a dyno and get them into the tailpipes. aftermarket adjustable FPR and a gauge to see it.

have you cleaned you IMRCs? are they working? as others have said, you need to get your injector slopes to match your new conditions, then adjust the transfer function. if its mild you could just toon the maf.

you also need to take care with the load and the borderline spark table to avoid hurting it. if you have IMRCs then stocking timing is close, if they are gone, timing is not close.

nothing is simple with our early 4Vs.

serfma
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Re: Effect of long tubes, and general questions

Post by serfma » Tue Jun 08, 2021 10:21 am

assasinator wrote: Thu Jun 03, 2021 6:16 pm yes adaptive can be turned off in cdan4. you must do it for sanity until its close.

plug up all egr in ur headers. turn off egr in your toon.

you cant toon it with exhaust leaks. the pcm will wander endlessly. either get a pair of widebands, or take it to a dyno and get them into the tailpipes. aftermarket adjustable FPR and a gauge to see it.

have you cleaned you IMRCs? are they working? as others have said, you need to get your injector slopes to match your new conditions, then adjust the transfer function. if its mild you could just toon the maf.

you also need to take care with the load and the borderline spark table to avoid hurting it. if you have IMRCs then stocking timing is close, if they are gone, timing is not close.

nothing is simple with our early 4Vs.
IMRCs are clean and working.

Thank you for all of the info thus far, it is very helpful. At the moment, bank 2 is showing more lean than bank 1 by roughly 6%, I assume this indicates a leak is still present and it needs to be almost identical to bank 1 or is there something I am unaware of that could cause uneven banks?

Was going to attach log but it's too large (5.4MB) to attach, so here's a link to it: https://onedrive.live.com/view.aspx?res ... -rIIbihOG4

I have everything capped off driver side, just had my exhaust welded up and all of the pinholes covered up from the last shop's shoddy job, reset kamrfs and this was a short idle log while I was in a drive thru already up to op temp. The tune differences compared to stock are the following:
Image

To disable EGR, COT since at WOT a ton of fuel being dumped and I have zero cats, no rear o2's, and I hadn't reverted changes back to stock for HEGO transport delay as I've not had time to get to tuning and I wanted to make sure the differences between banks was or wasn't a big deal so I didn't waste hours into tuning just to find out I have to narrow down more exhaust leaks lol

Planned on getting a wideband, but now I'm wondering if I need to go ahead and get a second to cover both banks as I seen a lot of people using or recommending one.

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