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ECMlink AFR Issues

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LarryJoe

10+ Year Contributor
364
9
Feb 10, 2012
Davisville, West_Virginia
The car I'm working on is an 89 Mirage running on E85. PTE 880cc injectors, Walbro 255 pump, and Aeromotive regulator. Fuel pressure set to 37psi. It's on a 16g on wastegate pressure currently. Don't have a boost gauge in it yet but since I just wired in my wideband I figured I could start tuning to calibrate my MAF and get my AFR's in line with how I set them in the DA tables. Problem is, no matter how many times I adjust the MAFcomp table based on the WBFactor in my logs, the car always goes lean in boost to the point I have to let out for fear of destroying the engine. Was hoping someone with a lot more tuning knowledge could take a look at my log and maybe point me in the right direction to whatever tuning or mechanical issue I have is. The log attached is 4th gear. I was trying to get a 3rd gear from 20mph but it's a little wet and traction is a big issue. Thanks in advance guys!
 

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  • log.2019.04.20-08.elg
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I understand what you're saying but I've got another issue here. 880's are plenty of fuel for a 16g on E85 on wastegate pressure. My airflow is off because I've kept raising the MAFcomp but even before, my duty cycles were in the low 70's so that's not what I'm looking at here.
 
I'll turn up my base pressure tomorrow but I still have a feeling I'm not running out of injector on 16g wastegate pressure and whatever creep comes with it is giving me.
 
You need to log fuel pressure. It should be going up 1:1 with boost. You can get a cheap pressure sensor with a signal output off of eBay and it works well enough to verify this. It threads right into the regulator.

Before you even do that though you need to verify what your boost is. You are shooting in the dark without it. A 16g with an aftermarket exhaust / downpipe can creep a ton. If I remember correctly I had trouble keeping mine under 20.

Also with e85 and 880s you are going to run out of injector. Fast. Because you need to flow a lot more volume of fluid to achieve a reasonable AFR. I had 880s and E85 before but I was definitely milking them.
 
If you look at my log, I start running lean long before my duty cycles even reach 60%. My airflow is even misreading terribly, you can see that because I start to show close to 50lb/m near the end of the pull which is not correct at all. I keep raising MAFComp to try and combat this lean tune with no results. I guess I can just wait until I have a boost gauge before looking into this further, but if you reference my pull at about 3300rpm, I'm already starting to run lean. I'm really thinking I haven't found the max these injectors can support already.
 
If you look at my log, I start running lean long before my duty cycles even reach 60%. My airflow is even misreading terribly, you can see that because I start to show close to 50lb/m near the end of the pull which is not correct at all. I keep raising MAFComp to try and combat this lean tune with no results. I guess I can just wait until I have a boost gauge before looking into this further, but if you reference my pull at about 3300rpm, I'm already starting to run lean. I'm really thinking I haven't found the max these injectors can support already.

Then you are looking at a fuel pressure issue. Buy a sensor like this and install it and see if fuel pressure is going up 1:1 with boost. But again, you are going to need a boost gauge installed to test it. Even if its temporary. I am not familiar with the fuel pump assembly on those cars but if the pump was installed incorrectly then it could be leaking into the tank hence bleeding off pressure.


https://www.ebay.com/itm/Pressure-t...0-psi-5V-for-oil-fuel-air-water-/261260635816
 
Was suspicious of a fuel pressure issue. Thanks for the ideas guys. I'm going to swap the know working regulator off my GSX and see if anything changes to rule that out. Hoping it's as simple as a regulator needing a new diaphram. Will also up my fuel pressure to 43.5psi while I'm in there and let you know how it goes. Unfortunately it won't quit raining here and doing pulls gets really sketchy haha.
 
Whats your global fuel and usec set at? It seems you have a tuning issue rather than injector.
Global is at -19.9%. deadtime is 420. I raised fuel pressure to 43.5psi today with no changes to the issue.
 
How does your AFRS look under boost, Also what brand injectors. Make sure your injector battery table in direct access is set to factory. How much boost are you running? I know you said wastegate, is yours at 10psi?
 
Don't have a boost gauge currently but I assume 10-11psi is the wastegate like on most 16gs with some creep I imagine. AFRs start off good in the mid 12s but just go leaner from there. Especially 4500rpm+. If you're able to look at my attached log in the original post you can see my wideband reading.
 
Don't have a boost gauge currently but I assume 10-11psi is the wastegate like on most 16gs with some creep I imagine. AFRs start off good in the mid 12s but just go leaner from there. Especially 4500rpm+. If you're able to look at my attached log in the original post you can see my wideband reading.
Hows your fuel filter. I Had a clogged one and when i replaced it my AFRs went from 13.1 to 10.6. Thats how bad it was and i was adding fuel across the board like crazy.
 
Hows your fuel filter. I Had a clogged one and when i replaced it my AFRs went from 13.1 to 10.6. Thats how bad it was and i was adding fuel across the board like crazy.
Brand new. Less than 200 miles on it.
 
I haven't tuned e85. My guess is you're close to the limit on injectors. I was high 90% on pump gas with 550s @21psi B16g. You need a boost gauge :beatentodeath:.

Don't know the reason but your loadfactor is literally off the charts.

E85 guys
His tartget AFR is 11.7ish, shouldn't that be leaner?
 
Little update. I swapped my good regulator off my GSX and the issue persists so I can rule that out. I know the 11.7 is pretty rich as far as E85 goes but I'm using that table as a good starting point to get everything in line before I start really tuning. I'm thinking I'm going to drop the tank today and pull the fuel pump and double check my install. Will probably rewire while I'm at it. I'll attach a log of another pull I just did with the new regulator and base pressure bumped to 43.5psi.
 

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  • log.2019.04.22-02.elg
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There's so much to e85.

Stoich on e85 is 9.8 so shouldn't you adjust maxoct table?
Everything Ive read is that to simplify things you want your wideband to keep reading as if you're running regular gas. I'm working on dropping this tank now, will update when I find something out.

UPDATE
Well I think I'm on the right track! The rubber line right off the hanger for the feed is almost completely pinched off, and the pump itself looks rough. I bought the car as an empty shell and never dropped the tank to check the pump out. Live and learn I guess. I'll update the thread whenever I get it all fixed and back together. Probably should go ahead and do -6an all the way to the filter.
 

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Last edited:
Solved! I replaced that rubber section that was pinched off with some 5/16" line I flared, rewired the fuel pump (NOT fun on a CSM btw), cleaned up the hanger and replaced the Walbro sock with a spare I had, and threw it all back together tonight and went out and did a pull without changing any settings in link and the car fell on it's face rich! Will zero my MAFcomp table back out and start fresh. Now I can finally start doing some tuning on this thing. Have a boost gauge on the way finally as well. Thanks for the help guys. I'm sure the fix was a combo of fixing that pinched line and supplying the pump with proper voltage.
 
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