Anyone ever get a P1171/Lean with GMSC, 2.5 pulley? - Boost Forum

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Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Sunday, August 31, 2008 5:55 PM
I did a search and couldn't find any useful info. Anyway, 01 Z24 with GM charger with a 2.5 pulley on it, auto.

I get a P1171 code under 1/2-to-WOT throttle at various times depending on what gear it is in, etc. Now, it won't throw a check engine light for this code, only the trac off light comes on until you restart/cycle the ignition. I used a tech 2 to diagnose this and the injectors are maxed out. As far as I know they are the injectors that came with the kit (the car is navycav3's old car). I was curious as to if any one else has had this problem?

Now, I have been looking into getting some Cobalt SS/SC injectors but am reading conflicting stories on what will work with a quad 4 fuel rail/engine, some say they do and other say they don't. Then again, I am not sure if 370cc's will be enough when it has 310cc injectors in it now. Also, will the stock computer be able to compensate or lean it out enough at idle with 370cc injectors? Or what is the max cc injectors I can throw on it with the stock ecu being able to control them? Trying to get some opinions to as to what works and what people have had good and bad luck with. I am in Colorado and the elevation is 4,900-5,000ft above sea level where I am at. Thanks.





Re: Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Sunday, August 31, 2008 8:00 PM
Your AFRs have to be in the 13.5+ range at WOT.

BAD.

Mine are 13.0-13.5 with the stock 310cc injectors and the 2.6. Injector duty cycle at 93% in first gear (typically substantially higher in higher gears but that's all I logged). The Cobalt SS/SC 378cc injectors are great for your setup. You must change the injector constant with HPTuners, and then it should run far better, but you REALLY need a tune.

You just can't be throwing more air in without adding fuel! I'm not sure where people get the notion they can just toss on smaller pulleys and other flow mods and think it'll run perfectly safe and have far more power. TUNING is essential. FUEL is essential.

Yes, the 378cc injectors work, it's not that difficult. I don't know where the hell you're getting people saying they don't work. You slot the fuel rail bolt holes so the rail sits lower. Plug in the injectors. Change the injector constant so the VCM knows what size injectors are in there and opens them the correct amount of time. Then you drive. Done. Simple.



Re: Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Sunday, August 31, 2008 9:35 PM
If you searched, you would have easily found and learned that the 310s are damn near inadequate for the 2.6" pulley, let alone anything smaller than that. I'm actually surprised you haven't poked any holes in pistons, or worse. Not sure who you've been talking to, but I've never heard anyone say the LSJ injectors won't work.




14.330 @ 96.37mph
Re: Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Sunday, August 31, 2008 9:40 PM
Currently you have a time bomb. Get some 36# injectors, meth, and a good tune and it could be a rocket....



P&P Tuning
420.5whp / 359.8wtq

Re: Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Sunday, August 31, 2008 9:54 PM
I know the injectors are running at 100% duty cycle. I also want to say that the afr was around 13 but I never felt you could trust it through a scanner unless you had a true wideband. My buddy that got me the tech 2 is a tech at a chevy dealer and we were monitoring it one night out driving around. He was the one that did the reflash on it for the guy that had it before me. I bought the car the way it is right now. The car had some wiring issues and it always had a check engine light. I have been getting all the bugs out of it and this is what I am down to now. One thing we also noticed was the engine load said 30-35% load at idle with out the a/c on. Not sure if that is normal for a s/c quad or not.
This is why I am asking about this as I want it done right. I had a boosted 96 Z a couple of years ago before HPTuners came out with the program and I was sick of fighting the bastard 96 ecu's. I am re-learning the boosted J scene as things have changed. Thanks for the input C2!




Re: Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Sunday, August 31, 2008 10:16 PM
Yep, no problem. Get yourself an AEM UEGO and get to know HPTuners and do a little VE tuning, it'll work wonders. The 310cc injectors are maxed out on the stock pulley, and yours are definitely far over 100% IDC; they're trying to stay open longer than is possible which will lead to catastrophic failure. Stay out of boost until you get some larger injectors in there, and even better, some tuning for the added air modifications. Good luck.



Re: Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Monday, September 01, 2008 5:46 AM
Get lsj injectors, slot fuel rail bolt holes about 1/4", and change injector constant with hpt or if you must get an afpr. They plug right up so no splicing.

When I had my 310cc's I know my afr was well in the 13's and injector duty cycle was well over 100% on the 2.6 pulley. Put in the 378cc lsj's and afr is around 11.8-12.1 at wot and IDC is only about 80%. Just wondering, how much boost you seeing with the 2.5 pulley? Your iat's must be pretty damn high too lol



Re: Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Monday, September 01, 2008 7:52 AM
I can also say Cobalt SS injectors will work. I had them on my 01 Z24. You just have to do a little bit of modifing on the fuel rail to get it to sit lower (because they are shorter). With a dremel it should take about 15 minutes.



FU Tuning



Re: Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Monday, September 01, 2008 9:51 AM
I have seen the modification needed for the fuel rail but there may be many who have not. I know there is a pic of modified 2.4 fuel rail floating around somewhere. Could someone please post it.



FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!

Re: Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Monday, September 01, 2008 10:03 AM
What size fuel injectors would you say to use. If you look here you can see that you can get injectors up to 70#.http://www.wbodystore.com/grandprix/fuel-injectors-free-flowmatching-p-185.html

I am going to be running a GMSC kit on my car and its a 99. Whats the difference between the 99 and 00? If it makes it easier can I just run cobalt injectors??


http://www.overkillengineeringmotorsports.com/

Re: Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Monday, September 01, 2008 11:04 AM
Here ya go wade...


The venom still works like a stock rail, just flows more volume. Im not sure if the lsj's would work in a pre 99 due to the injectors being different.



Re: Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Monday, September 01, 2008 11:46 AM
You can use high impedance injectors on an originally low-impedance setup, just not vice versa.

(Various people have done it, Kinsler fuel injection has affirmed this fact as well)



Re: Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Monday, September 01, 2008 10:57 PM
[ion wrote:

C2]You can use high impedance injectors on an originally low-impedance setup, just not vice versa.

(Various people have done it, Kinsler fuel injection has affirmed this fact as well)


I still have my old Ford brown top injectors from when my old car was boosted. I was actually thinking about looking for a resister box to run them on my 01.




Re: Anyone ever get a P1171/Lean with GMSC, 2.5 pulley?
Tuesday, September 02, 2008 7:43 AM
Finally a post about the ol blue Z . The car meth on it for a while. But when brian had his little fire issue he took it back off. Good luck figuring it out ryan. If anyone can its you and skyler



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