General E85 tuning and the dreaded breakup or misfire

[gimmie11s]

Im am posting this only as a reference for some who may be fighting the same issue i was which is finally fixed tonight.

Forgive me if some of this is obvious to some but ive been out of DSMs for about 5 years and came accross a 92 awd laser for an attractive price so im back.

Anyway... The car's setup is extremely basic at this point as i bought it 100% bone stock.

-3" turbo back exhaust
-RC 1200s
-EVO MAF (awesome)
-SAFC2
-AFPR
-sleeper billet 6 blade td06h-20g in FP 8cm housing
-old school Digital Tuning pocket logger that i kept around

My issue was getting a clean pull out of the car on e85. It would run all day long on 91 octane gas and pull cleanly to redline. I would get minimal counts of knock at 19 psi.

I made the switch to e85 and made the necessary fuel adjustments and it would break up badly from 5000 rpm to 7k. I swore it was fuel or ignition related. Things i did to combat this:

-buy brand new BR7ES plugs
-gap them to .018
-adjust base fuel pressure everywhere from 25 psi to 50 psi
-adjust global AFC high setting from -25 to +25 and everywhere in between.
-swap plug wires for known good set
-swap factory coil pack for known good one

To make a long story short--EVERYTHING i did with regards to ignition and fuel did absolutey nothing to clean up this misfire. Plug reading showed some white spatter/speckling on the plugs so i knew it was preigniting (UNGOOD) but the logger read ZERO knock. I read all day long on this forum searching for a solution hoping to clean it up before i blew holes in the poor 166k factory longblock. Well i came to the conclusion that my base timing may be too high.

I got home, grounded out the timing/idle wire and put a light on it. Bummer.. it reads 5 btdc (which i thought would be fine). The CAS was adjusted roughly dead center of its adjustment.

Nonetheless i retarded the base timing to ~2 BTDC and took her for a spin. PERFECT. No break up, no misfire, the ol girl runs like a scalded ass ape cleanly all the way to redline. I was stoked.

Got back from test run and pulled plugs (they looked great--no speckling), pulled gap back out to .028 and set timing closer to 0 (TDC). This gave me a fantastic idle, absolutely 0 knock, and a car that overall runs fantastic.


Moral of my E85 story:

-Turn the timing down!
-Read your plugs and believe what they are telling you!


Hope this helps someone fighting the same battle before their motor goes BOOM... I know mine was close.

 

[clipto]

I dunno about you but I love lot's of timing especially on e85. Plugs gaped to .020 and boosting 30psi no knock a/f of 12.1-12.5. Then again every car is different and with your setup am not fan run old school palm loggers or smc afc's. But glad it's running good for you.

 

[phunny]

You should not have to pull timing on e85 and your plug gap should be tighter. Sounds like you put a bandaid on the real issue.

 

[crash89]

Perhaps a lot has to do with trying to deal with 1200s on an AFC..

 

[SonySlave]

Everything you've done confuses the hell out of me. We'll start with your initial setup for E85. I'm going only based on the terribly vague info you gave.

First, what are you logging true AFR with? Doubt that pocketlogger has wideband capabilities. How do you know what AFR you're running?

Second, why was your AFPR initially set for a base fuel pressure of 25psi when stock 1G fuel pressure is 37psi? (May as well set to 43psi as that's the pressure injector flowrates are based on) And why did you go up all the way up to 50psi after your issues?

Third, why was your 'Hi' setting set to -25 when your base 'Lo' and 'Hi' maps should have been set to around -44% based on 1200s at 43psi base pressure before before any tuning was ever started? ECMTuning has a great resource available.
baseinjectordata [ECMTuning - wiki]

Even if you turned base fuel pressure down to 25psi to make the 1200s "smaller" so the AFC would be easier to tune, setting your 'Hi' and 'Lo' maps to -25 wouldn't be correct.

Fourth, why didn't you make pulls to figure out where in the RPM range you needed to add/remove fuel? All you claim to have done is set the lowest RPM point on the AFC to -25 and the highest RPM point to +25 and just made it smoothly transition between them. Not good.

I could go on but there's really no point.


To make my long story short, nothing you did was really effective in the end. You have no idea what your AFRs are and you compensated for the MASSIVE timing advance that you S-AFC was causing by retarding base timing. Sure it worked but you're still left with an insanely crappy tune. As well, pulling the spark plug gap back to .028" was a mistake as well. Adjusting to .018" was about the only correct thing you did during this whole process. There's no reason at all that you have higher than a plug gap of .020" with E85. All you're doing is asking for misfiring under load.

Nothing personal to the OP but the true moral of the story to help everyone else out there: Get a wideband so you can track proper AFR and get a real tuning device like Link, AEM, Jackal, etc.

 

[thecman02]

I will agree with the guy above you should really get a wideband. Your not knocking with plug confirmation which is good, but there is still room for doubt that your tune is safe. I've seen cars that ran pretty clean with 13.5AFR WOT right up to the point where the valve and pistons melted.

 

[donniekak]

No wideband, and tuning 1200's with an safc. Is this a how to on how to blow up a car?

 

[gimmie11s]

Wow this forum sure has changed. A guy posts what hes done to make the car work and gets 6 responses of ridicule?

Amazing.

I have no wideband at this point to get a real AFR but would it matter if if AFR on a gas WB read 12.5 when it was misfiring and now reads 11.1 and runs clean? No it wouldnt. But ill give you that.... its really not wise tuning a strange setup like this (1200s and an afc) with no WB and isnt recommended... but i did what i had to until mine arrives.


More to come! And i welcome your positive responses when the car puts down 400+ on my junk afc and 1200s

I will agree with the guy above you should really get a wideband. Your not knocking with plug confirmation which is good, but there is still room for doubt that your tune is safe. I've seen cars that ran pretty clean with 13.5AFR WOT right up to the point where the valve and pistons melted.

Noted and agree. However with 1200s and a small turbo i guarantee its not running out of fuel.

Everything you've done confuses the hell out of me. We'll start with your initial setup for E85. I'm going only based on the terribly vague info you gave.

First, what are you logging true AFR with? Doubt that pocketlogger has wideband capabilities. How do you know what AFR you're running?

Second, why was your AFPR initially set for a base fuel pressure of 25psi when stock 1G fuel pressure is 37psi? (May as well set to 43psi as that's the pressure injector flowrates are based on) And why did you go up all the way up to 50psi after your issues?

Third, why was your 'Hi' setting set to -25 when your base 'Lo' and 'Hi' maps should have been set to around -44% based on 1200s at 43psi base pressure before before any tuning was ever started? ECMTuning has a great resource available.
baseinjectordata [ECMTuning - wiki]

Even if you turned base fuel pressure down to 25psi to make the 1200s "smaller" so the AFC would be easier to tune, setting your 'Hi' and 'Lo' maps to -25 wouldn't be correct.

Fourth, why didn't you make pulls to figure out where in the RPM range you needed to add/remove fuel? All you claim to have done is set the lowest RPM point on the AFC to -25 and the highest RPM point to +25 and just made it smoothly transition between them. Not good.

I could go on but there's really no point.


To make my long story short, nothing you did was really effective in the end. You have no idea what your AFRs are and you compensated for the MASSIVE timing advance that you S-AFC was causing by retarding base timing. Sure it worked but you're still left with an insanely crappy tune. As well, pulling the spark plug gap back to .028" was a mistake as well. Adjusting to .018" was about the only correct thing you did during this whole process. There's no reason at all that you have higher than a plug gap of .020" with E85. All you're doing is asking for misfiring under load.

Nothing personal to the OP but the true moral of the story to help everyone else out there: Get a wideband so you can track proper AFR and get a real tuning device like Link, AEM, Jackal, etc.

Take the time read again what i wrote. The AFC wasnt set at -25 the entire time. I made "global" adjustments to the entire curve from -25 to +25 and everywhere in between in attempts to combat the issue.

Now that the car runs clean my high setting is at -2% accross the board so the factory timing map is being used.... actually its the factory map minus the 5* i took out of base.

 

[SonySlave]

Your initial information was very poorly worded so I made my comments based on my interpretation. Your comment about the wideband is true, it wouldn't matter if your gas AFR was 12.5 and sputtered and didn't at 11.1. My point was that you don't have a clue what it is at all right now. Maybe once you get a wideband you'll find that you tuned the AFR perfectly. Who knows? So, my point being, based on what you've said and done so far, you're telling people that even if you have no idea what your AFR is, as long as you pull enough timing and you aren't sputtering, you'll be ok. You and I obviously have different opinions on what a properly tuned car means.

I not trying to ridicule you, but I don't feel you've given people very good tuning information and I'm trying to let others be aware of that fact. If I was in your shoes, I'd be giving the community advice to not be going WOT until I had all of the proper tuning tools installed.

 

[eclipsegsx1736]

Using an SAFC at ALL is a bad idea, using one without a wideband is a terrible idea, using an SAFC with 1200cc injectors is a REALLY terrible idea. The SAFC "works" by modifying the airflow signal, and in your case reporting too low of an airflow which causes a reduction in fueling, and a significant increase in ignition timing. With 1200s, on gasoline, this would happen so much so that I'm amazed the engine is still in one piece. Then, when you switch to E85, you have to add fuel trim to the SAFC, causing an increase in airflow seen by the ECU, causing a reduction in ignition timing, which is the opposite of what you want when switching to E85, assuming it was tuned properly on pump gas (which it clearly wasn't).

I'm betting you didn't have any misfires on pump gas because the engine was knocking enough to allow the ECU to pull timing and miraculously hold the engine together. On E85, you'll likely soar right past MBT before the knock sensor picks anything up, but luckily the combustion was poor enough to alert you of a problem.

Beau

 

[WES_393]

I not trying to ridicule you, but I don't feel you've given people very good tuning information and I'm trying to let others be aware of that fact. If I was in your shoes, I'd be giving the community advice to not be going WOT until I had all of the proper tuning tools installed.

+1 to this and what Beau said.

With my Small 16g, 1150's, and DSMLink I ran nearly 30psi, 12:1 AFR's, and 17-18* timing from 3k to redline. I never had misfire or knock issues. Ever.

 

[gimmie11s]

Your initial information was very poorly worded so I made my comments based on my interpretation. Your comment about the wideband is true, it wouldn't matter if your gas AFR was 12.5 and sputtered and didn't at 11.1. My point was that you don't have a clue what it is at all right now. Maybe once you get a wideband you'll find that you tuned the AFR perfectly. Who knows? So, my point being, based on what you've said and done so far, you're telling people that even if you have no idea what your AFR is, as long as you pull enough timing and you aren't sputtering, you'll be ok. You and I obviously have different opinions on what a properly tuned car means.

I not trying to ridicule you, but I don't feel you've given people very good tuning information and I'm trying to let others be aware of that fact. If I was in your shoes, I'd be giving the community advice to not be going WOT until I had all of the proper tuning tools installed.

Fair enough... i should have stated a WB is a must when attempting something as outside the box as I am. You are correct.

FWIW in my past life in DSMs my old car was in fact tuned via WB but to be honest.. like i already stated-- the car either runs or it doesnt. All a WB is going to do is show you how quick its going ot blow (lean) or how much of a pus you are (rich)... Im exagerating but you get the point.

Using an SAFC at ALL is a bad idea, using one without a wideband is a terrible idea, using an SAFC with 1200cc injectors is a REALLY terrible idea. The SAFC "works" by modifying the airflow signal, and in your case reporting too low of an airflow which causes a reduction in fueling, and a significant increase in ignition timing. With 1200s, on gasoline, this would happen so much so that I'm amazed the engine is still in one piece. Then, when you switch to E85, you have to add fuel trim to the SAFC, causing an increase in airflow seen by the ECU, causing a reduction in ignition timing, which is the opposite of what you want when switching to E85, assuming it was tuned properly on pump gas (which it clearly wasn't).

I'm betting you didn't have any misfires on pump gas because the engine was knocking enough to allow the ECU to pull timing and miraculously hold the engine together. On E85, you'll likely soar right past MBT before the knock sensor picks anything up, but luckily the combustion was poor enough to alert you of a problem.

Beau

Really? I have taken fuel OUT of the AFC-- NOT added as you point out. Read again. You obviously have 0 experience with AFC --- because its so crappy.


Guys... Im not telling everyone how wonderful the AFC is... im merely stating what works on my worked ass 166k $1000 dsm... thats it. If she blows.. so be it. Ill be the first to report back and tell everyone what NOT to do.

BTW.. ill be at RRE tonight if you want to stop by and see how well my POS AFC 1200s laser idles and drives.

+1 to this and what Beau said.

With my Small 16g, 1150's, and DSMLink I ran nearly 30psi, 12:1 AFR's, and 17-18* timing from 3k to redline. I never had misfire or knock issues. Ever.

Understand that but you have to undersatnd the 1g timing map is MUCH more agressive than that.

You all are correct... the car was running so far past MBT that it literally broke up and wouldnt run. Im surprised i dont have 4 bent rods (maybe i do? ). With no way to control timing in my case, im merely showing others who may be attmepting the same thing how to accomplish it.

I forgot to add that the EVO maf (which almost no one runs) makes the car run EXTREMELY lean. So much so that it wont even drive with stock 450s in place. The 1200s and EVO maf compliment each other nicely. I have an idle video i could post if i knew how...


Ive been out of these cars for a while but im by no means a complete moron.

 

[thecman02]

I have no wideband at this point to get a real AFR but would it matter if if AFR on a gas WB read 12.5 when it was misfiring and now reads 11.1 and runs clean? No it wouldnt. But ill give you that.... its really not wise tuning a strange setup like this (1200s and an afc) with no WB and isnt recommended... but i did what i had to until mine arrives.

Noted and agree. However with 1200s and a small turbo i guarantee its not running out of fuel.

I'm not really talking about running out of fuel as much as trying to say you could have your car tuned lean, but wouldn't know it without a wideband or EGT. If you stay out of boost you should be fine until you can verify your afr's. I've been in e85 cars with horrible tunes that still pulled clean with unsafe AFR's. I hope I'm not coming off as someone trying to ridicule you.

On a side note I noticed you don't have an aftermarket fuel pump listed. I'd be weary of not enough fuel getting to the injector.

 

[eclipsegsx1736]

Really? I have taken fuel OUT of the AFC-- NOT added as you point out. Read again. You obviously have 0 experience with AFC --- because its so crappy.

....Read MY post again. You will have to add fuel to your SAFC when you go from 91 to E85. I didn't say the trim value on the SAFC would be positive. I said you have to ADD fuel, meaning a likely a less negative value with your large injectors.

I've been tuning for 9 years and have tuned (quite possibly) the majority of DSMs and a decent amount of Evos in the SoCal area. I first touched an AFC in 2003 (the one with the knobs), and have done every subsequent SAFC after that. They're all a crappy way to tune. The units themselves I suppose are decent, as they're dead reliable and I've never had a "problem" with them. I think I have a pretty good idea of how to use them

 

[gimmie11s]

Again.. No one said the AFC is the end all be all because it is NOT. (im having déjà vu)...