High Mileage Fuel Injectors and IDC's

[BuddySpeed3]

Does anyone have any insight about the possibility of old high mileage injectors causing an increase in Injector Duty Cycle, ultimately reducing fueling headroom? I mean it makes sense, that as injectors get dirty over time, their ability to flow efficiently would decrease. I'm thinking of trying out some injector cleaner in the gas tank to see of it brings my IDC's down a bit. Does anyone know if this will work?

[Fstrnyou]

If your injectors are having to spray more to overcome clogging or whatever, it would show up as positive fuel trims.

[BuddySpeed3]

Originally Posted by Fstrnyou If your injectors are having to spray more to overcome clogging or whatever, it would show up as positive fuel trims.

That makes sense, but wouldn't the injectors get dirty over a long period of time? Which would make for a very slow shift to a positive fuel trim nearly undetectable?

I mean I've been doing a lot of maf cals since I've had the car from upgrading parts, intakes, tuning, etc. So right now my latest closed loop and open loop maf cal is dialed in for the current state of my injectors and setup.

I would think that the only way to truly find out if they are dirty and impeding flow is to do some sort of flow testing with special equipment, and comparing the results to new injectors.

I've read that some people have sent out their injectors to be cleaned, but didn't find out if it helped very much.

I'm hoping that using a fuel injector cleaner might help slightly, and maybe a negligible amount of fueling headroom can be regained, but who knows. Maybe I'm just in denial that I'm already nearly maxed out lol

[Fstrnyou]

That is correct, a MAFCAL would erase any trace of trims due to dirty injectors.

What duty cycle are you seeing?

Also, why so many MAFCALs? Once you install an intake and finish the MAFCAL, you should never have to go back and do another CAL...unless you change your intake pipes.

[BuddySpeed3]

Originally Posted by Fstrnyou That is correct, a MAFCAL would erase any trace of trims due to dirty injectors. What duty cycle are you seeing? Also, why so many MAFCALs? Once you install an intake and finish the MAFCAL, you should never have to go back and do another CAL...unless you change your intake pipes.

I wouldn't call my IDC's abnormally high but I was just curious if anyone had noticed any reduction in IDC's after cleaning the injectors. I'm not sure I want to give the Injector latency multiplier a try.

With 2 gallons of in tank meth I'm seeing about 95% IDC at 22 psi at redline at 11.5 or so AFR so I would imagine it is pretty average.

My plan come spring time is to make a decent amount of power with IDC's as low as possible to promote the best possible atomization of the air fuel mixture. I'm hoping that upgrading the intake and exhaust manifolds, along with going catless will allow me to make more power with a lower alcohol mix in essence increasing fueling headroom.

[GroceryGtr]

high mileage, possibly dirty injectors, and numerous mods is a formula for zzb. The problem isn't so much compensating, its that dirty/clogged injectors don't function consistently. Sometimes you'll get a good spray pattern, sometimes you wont. Thats not what you want for a high boost application, especially if you're on stock internals. Precision will give you a before and after report on your injectors so you'll have a decent idea of how bad they actually were. Fuel injector cleaner won't do much for ya. You can try running it super concentrated in like 4-5 gallons of gas, but don't expect it to put them back to showroom condition by a long shot. If you're going to have the intake manifold off anyways pull the injectors and spend the $100 to make sure they are in peak shape.

[Fstrnyou]

Cold Canada air and 22psi, 95% doesn't appear strange to me. I'm at 18psi in warmer climate and seeing DC's in the 80's, and my injectors are clean.

[BuddySpeed3]

Originally Posted by GroceryGtr high mileage, possibly dirty injectors, and numerous mods is a formula for zzb. The problem isn't so much compensating, its that dirty/clogged injectors don't function consistently. Sometimes you'll get a good spray pattern, sometimes you wont. Thats not what you want for a high boost application, especially if you're on stock internals. Precision will give you a before and after report on your injectors so you'll have a decent idea of how bad they actually were. Fuel injector cleaner won't do much for ya. You can try running it super concentrated in like 4-5 gallons of gas, but don't expect it to put them back to showroom condition by a long shot. If you're going to have the intake manifold off anyways pull the injectors and spend the $100 to make sure they are in peak shape.

I just looked up Precision and it seems like they're the guys for injector cleaning. I found some good info in this thread:

DI Fuel Injector Service at 2000 PSI!

Thanks for the help

Originally Posted by Fstrnyou Cold Canada air and 22psi, 95% doesn't appear strange to me. I'm at 18psi in warmer climate and seeing DC's in the 80's, and my injectors are clean.

Right on, did you get your injectors cleaned?

[Fstrnyou]

Originally Posted by BuddySpeed3 Right on, did you get your injectors cleaned?

I used InjectorRX in TX. They test at regular pressures, but it doesn't matter as long as they flow equally.

[BuddySpeed3]

Originally Posted by Fstrnyou I used InjectorRX in TX. They test at regular pressures, but it doesn't matter as long as they flow equally.

Nice, I wonder if running an E-mix or M-mix in the tank helps keep them clean or makes them worse. What do you think?

Also did you notice regained fueling headroom or performance after getting the injectors cleaned?

[Fstrnyou]

I run an E20 mix.

My fuel trims did not change with clean injectors. Didn't compare DC's. I did it more as a preventive maintenance.

[BuddySpeed3]

Originally Posted by Fstrnyou I run an E20 mix. My fuel trims did not change with clean injectors. Didn't compare DC's. I did it more as a preventive maintenance.

Ok awesome! I'd like to start running lower boost with less alchy in the tank, in order to run the lowest possible IDC's, and use conservative timing to make my power. I don't really see a point in over working the injectors as this may cause poor air to fuel atomization. What I really need is aux fuel lol.

[Fstrnyou]

You mean less boost, less alky, and AGRESSIVE timing.

[BuddySpeed3]

Originally Posted by Fstrnyou You mean less boost, less alky, and AGRESSIVE timing.

Yeah exactly! If I can get my peak IDC's with WMI turned off to about 85% I'll be happy to use timing to make some decent power. Then with the WMI turned on I should hopefully be below 80% IDC. We'll see, I'll have to do some testing when it gets warmer. With the upgraded manifolds pumping losses should be reduced. I'm hoping to make 350 whp consistently with IDC's below 80% but we shall see.