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light throttle hesistations with lean symptoms

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Old 07-14-10, 01:24 AM
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what brand fuel filter are you running?
Old 07-15-10, 08:39 PM
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CA i made it

I used some Fittings from McFadden dale Hardware with a union in the middle and punched out some 5/8 circles of 60 Stainless Screen material and put them inside. I used 8 of them and I think i'm gonna take a couple out.
Old 07-15-10, 08:48 PM
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have you ran a fuel pressure test yet? to see if your pressure is dropping when it goes into limp mode, and a max pressure test. mine problem is gone.
Old 07-15-10, 08:54 PM
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Originally Posted by lastphaseofthis
have you ran a fuel pressure test yet? to see if your pressure is dropping when it goes into limp mode, and a max pressure test. mine problem is gone.
I haven't yet but I did do some logging with my rtek 2.1 today. I recently replaced my 02 sensor because it was shooting a code and when I ran the diagnostics again today it said my 02 sensor was bad...I'm guessing this is directly coorelated to the lean problem because while datalogging my 02 sensor it wasn't responding to anything, just showed 0 volts.

BTW, how'd you fix yours?
Old 07-15-10, 10:20 PM
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well.. after the replacing my fuel pump with the 3rd gen pump, it did it very lightly about 3 more times getting less harsh each time, and then went away. then i went to an rtek 2.1, and it came back for a few times and went away, then came back again when the battery was disconnected and then after afew times it didn't do it anymore. i can't explain why it matters but.. i had a fuel pump that tested bad(only on max pressure test, good on the rest) and a problem that is now fix'd, got me. i'm not saying go buy a new fuel pump, i'm just saying do the max pump pressure test, watch the pressure while watching the wideband.
Old 07-16-10, 03:58 AM
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Originally Posted by lastphaseofthis
well.. after the replacing my fuel pump with the 3rd gen pump, it did it very lightly about 3 more times getting less harsh each time, and then went away. then i went to an rtek 2.1, and it came back for a few times and went away, then came back again when the battery was disconnected and then after afew times it didn't do it anymore. i can't explain why it matters but.. i had a fuel pump that tested bad(only on max pressure test, good on the rest) and a problem that is now fix'd, got me. i'm not saying go buy a new fuel pump, i'm just saying do the max pump pressure test, watch the pressure while watching the wideband.
hmm, maybe you're on to something cuz I've heard of a couple guys who had FPR's and when they increased the fuel pressure the problem slowly phased out . I doubt mine is bad, I'm thinking though that possibly it's just getting erroneous information from the ECU, which is causing it to whimper up possibly?
Old 07-16-10, 02:33 PM
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Any ideas what would cause the 02 sensor to constantly shoot a code?
Old 07-23-10, 10:19 AM
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For anybody who was watching this thread, the problem (at the moment) is fixed. After running a clean wire from my LC-1 narrowband simulator to my ECU and rewireing my fuel pump for 12v all the time the problem went away. I only get a slight stutter while the car is warming up but even still it will blip into the 16's whereas before it would register 22's..I'd say thats an improvement

If problem comes back, I will let you know
Old 07-23-10, 11:58 AM
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what kind of wire did you use? was it shielded?
Old 07-23-10, 01:20 PM
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Originally Posted by gxl90rx7
what kind of wire did you use? was it shielded?
Nah, it was a 14-16 standard wire. I ran it on the outside of the ECU harness until about the last 6 inches from the ECU to help in reducing any noise. It was just going to be a temporary thing since i saw that my original 02 sensor wire had been spliced in several places by the PO, but probably won't be touching it for awhile now.
Old 05-31-14, 12:12 AM
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Bumb.

Having the same issues.
S4 turbo, rtek 2.1 with 4 rc 750's.
Nothing have been changed in the ecu besides the starting map and selecting the injector size.

Happens really bad in first gear. All the way up to 18afrs. Only under very light throttle, if it starts going lean I can give it more throttle and then it will richer up and accelerate just fine. Otherwise it will just stumble and hesitate.

I did it repeatedly in a parking lot to simulate the issue, I stopped and unplugged my 02 sensor thinking that it was the issue and I did more testing. The afrs were even worse with it disconnected! Almost undrivable. So I reconnected it.


Cruising closed loop has been fine and I have been driving on this setup for over a year and never have had an issue till recently.

I am going to check my range on my tps tomorrow and also disconnect the boost sensor and see if it changes anything.


Other than this it drives fine, boosts great, afrs are nice and clean besides this issue.

Anyone found out there solutions or permanent fixes?
Old 05-31-14, 12:14 AM
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Also here is a screen shot of a recent log i did. It was just at idle and my 02 sensor is registering 0.0X volts and it dosent change.

Can any tell me what that means?
Attached Thumbnails light throttle hesistations with lean symptoms-forumrunner_20140530_221433.png  
Old 05-31-14, 06:10 AM
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I honestly think a lot of the hesitation problems are coded in the rtek. I was able to reduce the stuttering when I rewired the fuel pump to have full 12v all the time but it never ran as smooth as when i went to a Power FC.
Old 05-31-14, 10:53 AM
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Man that really sucks. I will try reseting the ecu as well and reinstall my rtek 1.8 and see what happens.

I noticed that trend in this thread, that most the people with the issues have a rtek of some sort...
Old 06-17-14, 12:29 PM
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Originally Posted by rx7 SE
For anybody who was watching this thread, the problem (at the moment) is fixed. After running a clean wire from my LC-1 narrowband simulator to my ECU and rewireing my fuel pump for 12v all the time the problem went away. I only get a slight stutter while the car is warming up but even still it will blip into the 16's whereas before it would register 22's..I'd say thats an improvement

If problem comes back, I will let you know
What do you mean, "narrowband simulator"? Did you remove and cap your O2 sensor?

Is this the practice of using an external input at ATP or VarRes?
Old 06-18-14, 06:38 AM
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I replaced my factory O2 sensor with the new sensor that comes with my Lc-1 wideband kit. There are 5 wires instead of 1 for that sensor, 1 of which draws a narrowband voltage similar to a stock o2 sensor so that you can run that to the ECU and make it think that you're still running a stock o2 sensor.

I can't quite remember the ATP/VarRes wiring so hopefully someone else can chime in there.
Old 06-18-14, 06:51 AM
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Ah, ok. Thank you! My autometer wideband has a "datalogger signal wire" for hooking it up to your ecu. I believe I can do that with my rtek...
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