Exhaust burning eyes
Thread Starter
Teching In
Joined: Aug 2016
Posts: 20
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Exhaust burning eyes Exhaust is smelling very bad, I got a custom tune for my Holley Terminator X and it runs good but at idle it gets such a rich smell that even your eyes will burn.
I uploaded a datalog at idle to see what y'all think, thanks a bunch guys.
I uploaded a datalog at idle to see what y'all think, thanks a bunch guys.
Just run the engine and hook your laptop up and play with your Afr at idle and dial it in that way
TECH Fanatic
Joined: Jan 2018
Posts: 1,060
Likes: 198
It's probably from unburned fuel. The first thing to look at is the AFR, as you're probably running rich. (Like 91 Z28 said above.)
Also if your cam has much overlap you might have some fuel going out the exhaust port during the the time that both intake and exhaust values are open. Injecting slightly later in the cycle should help with that.
Also if your cam has much overlap you might have some fuel going out the exhaust port during the the time that both intake and exhaust values are open. Injecting slightly later in the cycle should help with that.
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Teching In
Joined: Aug 2016
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Looking at the log it's maintaining that 14.8 AFR pretty well and it has plenty of idle timing around 24-27 deg so the only thing left is injection timing. Also if you don't have cats even a 100% stock engine is going to smell.
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
It's probably from unburned fuel. The first thing to look at is the AFR, as you're probably running rich. (Like 91 Z28 said above.)
Also if your cam has much overlap you might have some fuel going out the exhaust port during the the time that both intake and exhaust values are open. Injecting slightly later in the cycle should help with that.
Also if your cam has much overlap you might have some fuel going out the exhaust port during the the time that both intake and exhaust values are open. Injecting slightly later in the cycle should help with that.
TECH Fanatic
Joined: Jan 2018
Posts: 1,060
Likes: 198
Assuming most tunes are set to inject before the intake valve closes (and definitely before the exhaust valve opens), did you mean "inject slightly earlier"? Or are you thinking of tunes that start the injection after the exhaust valve closes, in which case, yes, you can try injecting later?
But I'm only speculating on the root cause of the problem. Internet troubleshooting is hard.
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
FYI, the Holley EFI systems will auto-calculate the injector end angle after the user enters their cam's intake/exhaust opening/closing numbers. Some people on the Holley forums say they are good, others (of course) say they are not. They definitely are calculated to end the injection while the intake valve is still open and before the exhaust valve opens, especially with high-overlap cams.
Its seems that everyone who experiments with the injector end angle ends up with different preferences. What gives one guy the smoothest idle, gives someone else a rough idle and burning eyes. Seems that AFR and ignition timing all interplay with the injector end angle. No one "size" (or numbers) fits all.
Thanks for sharing. I suspect I've seen this before, but will check it out.
FYI, the Holley EFI systems will auto-calculate the injector end angle after the user enters their cam's intake/exhaust opening/closing numbers. Some people on the Holley forums say they are good, others (of course) say they are not. They definitely are calculated to end the injection while the intake valve is still open and before the exhaust valve opens, especially with high-overlap cams.
Its seems that everyone who experiments with the injector end angle ends up with different preferences. What gives one guy the smoothest idle, gives someone else a rough idle and burning eyes. Seems that AFR and ignition timing all interplay with the injector end angle. No one "size" (or numbers) fits all.
FYI, the Holley EFI systems will auto-calculate the injector end angle after the user enters their cam's intake/exhaust opening/closing numbers. Some people on the Holley forums say they are good, others (of course) say they are not. They definitely are calculated to end the injection while the intake valve is still open and before the exhaust valve opens, especially with high-overlap cams.
Its seems that everyone who experiments with the injector end angle ends up with different preferences. What gives one guy the smoothest idle, gives someone else a rough idle and burning eyes. Seems that AFR and ignition timing all interplay with the injector end angle. No one "size" (or numbers) fits all.
FYI, the Holley EFI systems will auto-calculate the injector end angle after the user enters their cam's intake/exhaust opening/closing numbers. Some people on the Holley forums say they are good, others (of course) say they are not. They definitely are calculated to end the injection while the intake valve is still open and before the exhaust valve opens, especially with high-overlap cams.
Agree 100% I dont recommend the built in one in holley at all.
Launching!
Joined: May 2023
Posts: 286
Likes: 94
From: AZ
close ur ****** eyes and send it 
or get someone who knows WTF they are doing to tune it. either way if u don't have cats that's apart of the game
I love the smell of burning gas and a lopey cam. give me joy to all those ******* driving teslas.
or get someone who knows WTF they are doing to tune it. either way if u don't have cats that's apart of the game
I love the smell of burning gas and a lopey cam. give me joy to all those ******* driving teslas.