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Discussion Starter #1
Hi guys need some advice. Today my 550 injectors crapped out. No idea what happened but 2 of the injectors ceased fire. I don't know if they're clogged but they're brand new. Less than 6 months old. I've never heard or seen this happen before but oh well. I had no choice but to put my old 440s in and I scrapped the stock afm so I still have the Lexus afm on the car. I haven't started her up yet, I wanted to know from you guys if this is going to work until I get the two injectors back in about 4-5 days because I'm having them rebuilt. I figured I'd increase the fuel pressure by about 25% to match the fuel output of the 550s. 440s are pretty large injectors themselves so I'm guessing this should work. Also took out the 6262 and put the 57 trim back till I get those injectors back to be on the safe side. Should this work?
 

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Discussion Starter #2
I need to drive the car tomorrow and for the next few days so responses here would be nice. I need the wise to teach me the ways.
 

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Joe -- I've ran the Lex MAF and 440s for a couple years with no issues. I have a wideband and never saw it run lean. You will be fine...
 

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Discussion Starter #4
Okay thanks you. I just don't want anything bad happening from the horror stories I've read about some people.
 

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I had the same issue a while back. I had them cleaned out and they been working ever since. I did change out my fuel filter as well. Not sure if that was the problem.
 

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Discussion Starter #6
I don't know what happened to those two. The 440s work fine, I don't know why tose two just decided to stop working. Well anyway I've been up for the past couple hours adjusting the fpr and adjustment screw and finally got afr's at ~12 at wot and around 10.7 regular driving. I figured wot and under boost is most important and the computer will do the rest of the adjustments.
 

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Adjusting the air bypass screw in the AFM could also help. Just drill a hole in the cover and pry it off for access. Might want to also disconnect the battery for 15 minutes to reset the system for a relearn (pulling the EFI fuse might work also, can't remember). Count how many turns you adjust it so you can return it to factory specs if needed in the future.

-edit- Oops, just reread that you did tweak the adjustment screw. An ECU reset might help though still.
 

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Discussion Starter #8
Today before driving to school a couple hours prior I took the car out and adjusted all that to make sure I wasn't running lean anywhere. I just wanted to know if this was safe for now. I was trying to read up on it last night and I mean I read that many people have blown this damn thing up. It got me kinda worried so I wanted some help from you experienced members. I don't know what they were trying to do, boosting 20psi on stock fuel system and what not with the Lexus. Ridiculous. I'll reset the ecu tomorrow morning morning. Thanks guys.
 

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Well the fact that you are now leaner under boost than when you're just driving around shows you that the Lexus AFM with stock injectors isn't a good combo. People that do damage most likely have no fpr or wideband to make adjustments and keep an eye on things. They just crank the boost up as high as it'll go and...
 

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Discussion Starter #10
. I set the fpr to 42psi, have the afm adjustment screw about 90% open and am running 16lbs of boost. WOT I'm at ~12.5 Regular driving about 11. I tried adjusting some more and that's the best I can get
 

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have you checked the resistor box on the lh side of engine bay by the fuse box i had one crap out on me and cause 2 injectors to be dead, another 2 to be halfway dead and 2 to be fine... just a thought but now re reading the post probable not
 

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Discussion Starter #13
which injectors went bad (i.e. which cylinders)?
6 and 2. And to answer the other guy the 440s work fine so that should be fine. I really don't know what happened I just sent them to my friend out in Cali to have them rebuilt. I know a guy so he's doing it for minimal cost. I really don't know what happened.
 

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6 and 2. And to answer the other guy the 440s work fine so that should be fine. I really don't know what happened I just sent them to my friend out in Cali to have them rebuilt. I know a guy so he's doing it for minimal cost. I really don't know what happened.
2/6 is the same channel from the ecu, your problem isn't likely the injectors, rather it is your ecu or wiring.
 

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Judging by your AFRs, they aren't. You should be around 14.4:1 while cruising. At 10:1 you are wasting a ton of fuel and seriously diluting your oil. Keep it up and rod bearing issues will be right around the corner.
 

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Discussion Starter #17
Judging by your AFRs, they aren't. You should be around 14.4:1 while cruising. At 10:1 you are wasting a ton of fuel and seriously diluting your oil. Keep it up and rod bearing issues will be right around the corner.
Oh okay I understand. I didn't understand what you were saying before but I get it now. Thank you.
 

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Discussion Starter #19
So I thought about what you said and my wiring harness looks as if it saw better days. I got a used wiring harness from a friend of mine for the 7m that looked in much better condition than my current one and completely swapped them. I also put the stock afm in and put the fuel pressure back to stock which is I believe 30psi( correct me if I'm wrong). Went out for a test drive and afr's now while driving normally and at idle are dead on 14.8-14.9. During boost they completely plummet to 10 immediately. This is at 12psi now bc any more I'd hit fuel cut. After seeing that all is well, I put the Lexus one back on and have the screw wide open and also upped the pressure to 40psi on the afpr. Now I'm getting a 14.2 idle/ cruise and 11.3 under 15psi boost.
 

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Did you reset the ECU for a relearn?

Before swapping the harness I would have pulled the injector clips on 2 and then 6, while the car is idling, to see if idle is affected at all. No change means something is up. You can still do this though, to see if maybe it's your resistor box, or ECU, etc. Or use a mechanics stethoscope ($15) to verify that the injectors are indeed 'clicking' (while the car is running), something I would have done before pulling the 550's.
 
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