Ok...last spring I was putting my turbo setup together...And the question came up of what size injectors to use. Based on what I had posted on the org...15-20psi boost and what not, there were about a dozen people that said I need 550cc injectors. So I ordered them from car customs, and started on my project.
Well its now sept. and my motor is built and everything is in and I cannot get it to run decent. Problem being injectors are too big. I have a safc to tune them down but it still wont run decent. Now I know its my fault cause I bought the injectors but when I asked the same question last week about injectors...everyone said 550's were way too much fuel. So for everyone that relies on this forum to make big decisions I would just keep it in mind but dont listen to everything that is said. There are a lot of people on here that think they know what they are saying but in fact they are guessing!!!
I have now spent over $5000.00 in just my motor and still my car sits in the garage because it doesn't run. So on that same note....on my safc according to the manual and what not...on the lo and hi settings the positive side would be adding fuel by a theoretical percent and vice versa for the negative side correct???
I left everything at zeros and it runs extremely rich(due to the injector size). moved to the negative side and it wont even start or run (wtf). Moved to the positive side and its starts and runs and my wideband showed decent ratios but it still ran rough and black smoke out the pipe. All in all, I got it to run its best at:
1000rpms= +7%
2000rpms= +5%
3000rpms= +4%
4000rpms= +4%
5000rpms= +4%
Honestly...does that make any sense to anyone??? I have huge injectors so I would think I need to take away fuel...which would be on the negative side...but when I do that it wont even start or run. Anyone have any idea what is going on??? I triple checked my safc install to make sure I have every wire right. WTF???
"Spent way too much to give up now!!!"
Sorry for the long thread above but I have been so pissed off at myself for not being able to get this thing to run decent so any ideas would be appreciated greatly.
here is some more info on my setup...fuel pressure is at 40psi, and really when I adjusted that it didn't run any different except lower than 30 it shuts off but that cause the injectors wont even open that low. So i dont know why that is either. And I do have the secret exhaust cam but that shouldn't matter that much should it? Anyway I just need some advice on tuning it ...let me know what you think either way...thanks a bunch.
"Spent way too much to give up now!!!"
First do not get mad at people. You act like it was the ORG that made you spend 5k, when you made the choice. The injectors do not cost no where near 5k. You can always get your money out of them. If you really are going to run up to 20psi, the 550's you will need.
Yes at idel and off boost they will dump a lot of fuel. You need a AFPR to turn down fuel pressure at idle. The use your FMU and S-AFC to get your fuel under boost. I also notice you have a Cartech FMU. I have not worked with that unit, but I thought it also adjust fuel pressure off boost as well. You might have a problem with your AFPR, and FMU. I know the S-AFC has only so many adjustments, so save those for in boost.
Also to everyone always make sure you do plenty of research before jumping into modding. If you want to play, you have to pay.
FU Tuning
Quote:
fuel pressure is at 40psi, and really when I adjusted that it didn't run any different except lower than 30 it shuts off but that cause the injectors wont even open that low.
Fuel pressure doesn't open up your injectors, voltage pulsed from your computer opens them up. Turning down the fuel pressure means you can apply more voltage and they should open up more. If your injectors are that big, you are going to need to run low fuel pressure at idle and bring it back up with your FMU like John Higgins stated.
Cardomain|
Myspace
You will need 550s to run 20 psi of boost. In my opinion your problem is the limmitations in your fuel management system.
If you are planning to run 20psi you should have considered an e-manage or a megasquirt efi system. To run that kind of boost you would benifit from propper fuel management. If your system was flexible enough to create a propper fuel map you'd be better off.
Otherwise, get smaller injectors and limmit yourself to about 12 psi.
"Go Before Show Yo."
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Pimpfire wrote:You will need 550s to run 20 psi of boost. In my opinion your problem is the limmitations in your fuel management system.
If you are planning to run 20psi you should have considered an e-manage or a megasquirt efi system. To run that kind of boost you would benifit from propper fuel management. If your system was flexible enough to create a propper fuel map you'd be better off.
Otherwise, get smaller injectors and limmit yourself to about 12 psi.
You are right. I still think his problem, is he is trying to use the S-AFC to take fuel away, and not the FMU, and AFPR.
FU Tuning
Well i had 525CC injectors, and i was only running low amount of boost (like 4psi), but i got it tuned (decently) by disconnecting my FMU and tuning it down with the S-AFC. At idle it was at like -40%, and under load around -50. As you can see theres not much room left for improvement on that, but i did get it tuned and running. All in all i got tired of dealing with them so i got some 38 lb injectors instead. I'm not planning on running 15 to 20 PSI like you, but for you i think they'll be needed. For idle tho your going to need the AFPR i beleive, just because its a boat load of fuel at that pressure, so you need to lower it. the S-AFC is just going to tune back or up your fuel amount, it doesnt take away fuel pressure. Unless the Cartech FMU can reduce fuel pressure, im not familiar with the unit.
I will try to turn down the base fuel pressure even more. But even so...on my safc when I put the settings at any less than -2% it wouldn't even start or run... thats the part that doesn't make any sense to me.
Quote:
Well i had 525CC injectors, and i was only running low amount of boost (like 4psi), but i got it tuned (decently) by disconnecting my FMU and tuning it down with the S-AFC. At idle it was at like -40%, and under load around -50.
The above quote makes a little sense...why mine wont even start or run with anything less than -2% doesn't make any logic to me at all....does anyone have any ideas on that??? I am out of reasons why that would be. And why would you have to disconnect the fmu???I thought that only increases fuel pressure under boost...so at idle or slightly revving it it shouldn't matter right?
And I haven't even been able to get it running good enough to go out and test drive under boost. Right now I am concerned with getting it to start and idle and rev decent.
"Spent way too much to give up now!!!"
todd are you going megasquirt now?
R.I.P. Brian Klocke, you will never be forgotten
turboz24 wrote:I will try to turn down the base fuel pressure even more. But even so...on my safc when I put the settings at any less than -2% it wouldn't even start or run... thats the part that doesn't make any sense to me.
Quote:
Well i had 525CC injectors, and i was only running low amount of boost (like 4psi), but i got it tuned (decently) by disconnecting my FMU and tuning it down with the S-AFC. At idle it was at like -40%, and under load around -50.
The above quote makes a little sense...why mine wont even start or run with anything less than -2% doesn't make any logic to me at all....does anyone have any ideas on that??? I am out of reasons why that would be. And why would you have to disconnect the fmu???I thought that only increases fuel pressure under boost...so at idle or slightly revving it it shouldn't matter right?
And I haven't even been able to get it running good enough to go out and test drive under boost. Right now I am concerned with getting it to start and idle and rev decent.
Double check all the wires is the only suggestion I can think of. Sorry i can't be more helpful. Also, check the wiring on the injectors, maybe there's a short, or loose wire, and they aren't getting the voltage needed to open them. The car should run at low fuel pressure, and not cut off like u said either.
turboz24 wrote:I will try to turn down the base fuel pressure even more. But even so...on my safc when I put the settings at any less than -2% it wouldn't even start or run... thats the part that doesn't make any sense to me.
Quote:
Well i had 525CC injectors, and i was only running low amount of boost (like 4psi), but i got it tuned (decently) by disconnecting my FMU and tuning it down with the S-AFC. At idle it was at like -40%, and under load around -50.
The above quote makes a little sense...why mine wont even start or run with anything less than -2% doesn't make any logic to me at all....does anyone have any ideas on that??? I am out of reasons why that would be. And why would you have to disconnect the fmu???I thought that only increases fuel pressure under boost...so at idle or slightly revving it it shouldn't matter right?
And I haven't even been able to get it running good enough to go out and test drive under boost. Right now I am concerned with getting it to start and idle and rev decent.
I only have a little bit of knowledge with the S-AFC. From ym understanding the adjustments it makes, it will cut the signal the ECU gets (can anyone verify this?). If that is the case, when you adjust so much out you could be reducing the signal soo much it will not run.
For idle purposes the AFPR should be able to get the fuel pressure down enough to idle. You might not have a idle like stock, but enough to run fine. Keep in mind bigger injectors will put more fuel at the same pressure as stock injecotrs. That is why less fuel pressure is needed.
Yes you want the FMU hooked up. You can always disconnect it to see if the car runs any different (better), when no hooked up. If it does, then your problem is with the FMU.
I said earier I belive your FMU also controls idle pressure as well. I think thereis 2 adjustments on your FMU. One is for under boost, and one for idle. You could be adjusting that wrong.
What kind of air/fuel are you getting at idle?
FU Tuning
Well at idle when the safc is at zeros across the board my wideband says around10-11 and sometimes just says rich. But when i adjusted the safc to +7% at 1000 and +5% at 2000 it brought it back to around the 14-15 area. that doesn't make any sense to me what so ever. I will quadrouple check all the wires AGAIN.
As for the idle fuel pressure I forgot the my fmu does base pressure also...which would explain why i cant drop it past a certain point...(because i was adjusting the afpr but the fmu was still keeping it up) that makes sense to me now. Thanks for the reminder. Please keep the ideas coming in as far as my safc. I am stumped. Thanks again.
"Spent way too much to give up now!!!"
No, I'm going to a FASTsetup. Lot more money, but alot simpler and it has been tried and tested more so than the MS.
so, does the afc raise fuel with the positive adjustments and lower it with the negative adjustments, or is it the other way around?
It's because the do-hickey wasn't installed on the right what-cha-ma-call-it, and now the round thing is borked. The oblong thing is probably FUBAR now and will need to be replaced with a square widget.
turboz24 wrote:Well at idle when the safc is at zeros across the board my wideband says around10-11 and sometimes just says rich. But when i adjusted the safc to +7% at 1000 and +5% at 2000 it brought it back to around the 14-15 area. that doesn't make any sense to me what so ever. I will quadrouple check all the wires AGAIN.
As for the idle fuel pressure I forgot the my fmu does base pressure also...which would explain why i cant drop it past a certain point...(because i was adjusting the afpr but the fmu was still keeping it up) that makes sense to me now. Thanks for the reminder. Please keep the ideas coming in as far as my safc. I am stumped. Thanks again.
Ok question when you had a air/fuel of 14-15, what was wrong with that? Actually that might be just a little lean for idle. I understand where you said the adjustments were, and that seems weird, but if it gets the job done it does.
Yes, play with you FMU and AFPR. Put, or turn the S-AFC off and do it. See if you can get tour idle down right. Let us know how it goes.
FU Tuning
not to try and change the subject, but will a stock ecu (ecotec) run 440cc injectors without flooding or having problems? i have a fmu and fuel pump. and 320cc injectors now.. im waiting for either the GM ecotec reflash or HP tuners to help with my 440s. just wondering if a safc is needed with 440s or if i could be fine with a fmu and fuel pump.. i dont mind having a rough idle or running a lil too rich at idle, as long as iv got enough fuel. aiming for 15-16psi
i have the e-manage and i am having a similar problem but mine's running. It has a tendency to stall, at idle and when starting in 1st gear, sometimes i can get around it but i have to be really aggressive with the clutch. But mine doesnt have much tuning done yet. Oh and im 440cc injectors. So if anybody running the e-manage can help me out it would be appreciated.
According to my calculations, for 20psi boost on a 2.2 you would need 440cc (42lb) injectors. Much more than that and tuning a decent idle and off boost response would be nearly impossible. If I ever get to the point where I need larger that 440cc injectors, I'll go staged injectors to keep a good idle.
Kevin Johnson
Jbody Club of Alberta
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