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Old 05-29-2008, 01:56 PM   #1
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Default Leaning out in 5th.

My setup:
Greddy Kit w/ custom Intercooler & Tony DP at stock boost
Bipes
Olderguy O2 Clamp
Narrowband O2 sensor

I installed the Tony DP and now I'm noticing that I'm leaning out in fifth under boost at lower RPM to the point that I'm pretty sure the thing is detonating at full throttle. Full boost is coming on as early as 3000rpm in 5th and I'm pretty sure that the reason I'm leaning out is because I had the Bipes on the most aggressive RPM map where it starts pulling timing at 3000 and ends at 4000. I haven't noticed an issue in 1st or 2nd, but the RPMs come up so quickly in those gears that I think I'm just missing seeing the lean condition. When I'm in 5th on the highway the car will hang around 3000rpm for a while at full boost as the revs come up so I think that is my issue, but I figured I would post up in case someone else thought something different.

Pretty sure I didn't have this issue before the Tony DP because boost didn't hit until 4000rpm or so with the stock DP.

I'm running 14 degrees pulling 8 and now I've altered the RPM map on the Bipes to start pulling timing at 2500 and end at 3800. Next down would be 2000-3600. I'll probably see if this fixes my issue before going to that setting.
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Old 05-29-2008, 02:22 PM   #2
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well open loop and closed loop are 2 different things. Just because you are lean in low-rpm /boost doesnt mean you are going to be lean in high-rpm/boost.

Do you have a wideband? If not, get one.
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Old 05-29-2008, 02:34 PM   #3
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Originally Posted by SloS13 View Post
well open loop and closed loop are 2 different things. Just because you are lean in low-rpm /boost doesnt mean you are going to be lean in high-rpm/boost.

Do you have a wideband? If not, get one.
You did get the part where I said I'm lean in low rpm/boost and not lean in high rpm/boost right? I never was lean in high rpm/boost.
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Old 05-29-2008, 02:38 PM   #4
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Originally Posted by Harv View Post
You did get the part where I said I'm lean in low rpm/boost and not lean in high rpm/boost right? I never was lean in high rpm/boost.
My bad, I saw 'full throttle' and I assumed high RPM. I dont know a whole lot about the 1.6's. Don't those have the on/off TPS's? Could it be possible that it's not telling the ECU that it's WOT and so it's staying in closed loop?
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Old 05-29-2008, 02:45 PM   #5
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I think any low-rpm/low-boost closed loop lean issue should be countered by the O2 clamp, assuming it is working correctly. I'm hoping it is just that I'm not pulling timing soon enough with the Bipes.
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Old 05-29-2008, 03:05 PM   #6
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your timing has little to do with the amount of fuel/air mixture....
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Old 05-29-2008, 03:33 PM   #7
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Im gonna assume your clamp isnt working, or your TPS isnt working.
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Old 05-29-2008, 05:19 PM   #8
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Quote:
Originally Posted by Braineack View Post
your timing has little to do with the amount of fuel/air mixture....
Yes, that would be true wouldn't it.

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Originally Posted by SloS13 View Post
Im gonna assume your clamp isnt working, or your TPS isnt working.
Not sure, but I don't think have a lean issue in lower gears, but then again I haven't given it a full examination on a dyno with a wideband as yet.

Could the O2 sensor be problematic at this point? It is probably the original and it's been repositioned closer to the turbo because of the new downpipe.

I'll probably need to verify that the clamp is working properly and maybe run it on a dyno to see what is going on exactly.
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Old 05-29-2008, 05:52 PM   #9
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It's possible that the O2 clamp is installed improperly. Could that be the reason why boost only hits 4psi? Did I possibly tap in at the wrong location?

Are the instructions for the O2 clamp online here? I'm pretty sure I have a copy somewhere from when I bought the clamp, but I just want to review.

The thing is I've not had a (noticeable) issue with lean tip-in in the lower gears.

Maybe I do have the O2 clamp installed properly, but I just need to tweak the settings on it a little bit? Eh, not really sure.

Last edited by Harv; 05-29-2008 at 06:20 PM.
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Old 05-29-2008, 07:10 PM   #10
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probably, the ONLY thing the o2 clamp does is prevent lean tip in....cant make more than 4psi, then you have a boost leak, loose wastegate or other issues.
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Old 05-29-2008, 07:26 PM   #11
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This might totally not relate, but... What injectors are you running? Maybe you're just outlfowing them?
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Old 05-29-2008, 09:13 PM   #12
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Are you reading lean off a WB O2 sensor as I did not see one in your sig? If no WB, then I take it you are running a gauge off the NB sensor? If so where is the gauge picking up?

If you are running only a NB sensor, then below 4k rpm and starting into boost, the o2 clamp will activate, and if you are tapping this signal it should show stoich/slightly lean so that the ecu will not pull fuel b/c rich while still in closed loop. Then, when the stock ECU goes into open loop around 4k rpm the fuel maps be on the richer side.

Unless the timing changes are drastic, it shouldn't really have any effect on NB/WB readings.
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Old 05-29-2008, 10:02 PM   #13
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I take back what I said, it's really leaning out at full boost is what is happening, but since I'm not really in full boost for very long in lower gears I was just not noticing it. At part throttle it shows in rich and then as I get into it and the boost goes above 1-2psi it tips over into full lean. So it's essentially lean all the time up at full boost, which I don't really understand how it got this way since it used to be rich up there. And yeah changing the Bipes settings obviously did nothing.

To answer some questions. I'm running the 1.6 injectors which I had rebuilt a couple of years ago and they are all flowing fine according to the report I got and I'm not pushing out more than 4psi at this point. I'm also running the 190HP fuel pump.

I'm not sure if I'm not making 5psi or if the gauge just isn't accurate at this level. It's a Flyin Miata boost guage that goes 30/30. When we put the turbo on we replaced all the vacuum lines so I don't think I have a vacuum leak. Since we put the turbo on it has basically maxed out at 4psi. I didn't really think much of it at the time as I thought possibly the IC was causing that? I admit, I'm not the brightest bulb when it comes to this stuff.

I'm running a narrow band sensor and the gauge is spliced off the wire in the engine compartment near the CAS. Pretty sure at that point it is spliced before the O2 clamp which is in the passenger compartment near the computer.

The thing is before it was running full rich in boost. Now when you get into full throttle and full boost it seems like it is bogging when it tips over to lean so I don't think I'm getting an incorrect reading off the gauge, I think it really is going lean.

One thing. I did go and power wash the engine compartment this past weekend using my little 1500psi electric washer. I covered up the intake and plugs and any wiring areas and the engine was cold, but it's possible that something got knocked around. I checked for loose connections on any vacuum hoses, but I did not notice anything.

Edit: The boost gauge is spliced off the vacuum line coming off the top of the Greddy AFPR, just FYI. I thought that was the right place to get a reading from.

Last edited by Harv; 05-29-2008 at 11:08 PM.
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Old 05-30-2008, 12:08 PM   #14
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So, if I'm leaning out at and losing power at WOT/full boost then is it a vacuum leak? I mean the FMU is relying on the manifold pressure to dump fuel into the system right?
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Old 05-30-2008, 01:48 PM   #15
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Just to be sure, make sure the O2 guage is getting the signal from the right place, if it's after the clamp, that's exactly what you'll see. Try turning on the car (power the guage), or even idle the car, but put pressure (with a mighty vac or something) into the O2 clamp and see if the gauge changes. Do this while sitting in your driveway, with no boost.

If it's working right, you will see the guage go rich as the car compensates (it might stall). If it's wrong, it'll go lean.

And I'm still wondering if you're getting enough fuel, though if it's happening at low RPM and 2 psi, I seriously doubt that's it.
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Old 05-30-2008, 02:04 PM   #16
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Check your fuel pressure, if you haven't done so already, to make sure your fuel pump/afpr are giving you adequate pressure in boost.
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Old 05-30-2008, 04:12 PM   #17
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Quote:
Originally Posted by AbeFM View Post
Just to be sure, make sure the O2 guage is getting the signal from the right place, if it's after the clamp, that's exactly what you'll see. Try turning on the car (power the guage), or even idle the car, but put pressure (with a mighty vac or something) into the O2 clamp and see if the gauge changes. Do this while sitting in your driveway, with no boost.

If it's working right, you will see the guage go rich as the car compensates (it might stall). If it's wrong, it'll go lean.

And I'm still wondering if you're getting enough fuel, though if it's happening at low RPM and 2 psi, I seriously doubt that's it.
I'm pretty sure it is not after the clamp as the clamp is spliced into the signal line inside the passenger compartment right before it goes into the computer. The gauge itself is spliced at the line inside the engine compartment.

I see what a mityvac is, but I don't have one of those. Not sure what I have that I can use to put pressure into the sensor.

Thing is it starts at around 2psi, but really gets into lean by 4psi. Remember, according to the gauge I'm only pushing out around 4-4.5psi max as it is. And the low rpm thing isn't really as much of a factor because with the new DP I'm getting full boost in high gears as low as 3000rpm.

Quote:
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Check your fuel pressure, if you haven't done so already, to make sure your fuel pump/afpr are giving you adequate pressure in boost.
The method in Braineack's DIY FAQ I assume is what I would use to do this.

Quote:
You’ll need to connect a fuel pressure gauge on your fuel lines to do this test. $20 at NAPA can get you what you need. Ask the counter clerk that you need a temporary fuel pressure gauge and length of 5/16” fuel hose, they can get you what you need. Attachment 3821

Turn your Miata to ON but do not start it. Open the diagnositics box and put a paperclip on F/P and GND. That will run your fuel pump. With a pair of pliers, squeeze the fuel line shut that connects the FPR to the original fuel pressure regulator. When squeezed shut, the pump will be forced to maximum output. Make sure the pressure available is consistent with your intentions. In all cases, the pressure must show, in this idle test, to be about 10 psi higher than the desired fuel pressure, as the available pressure under real load conditions will be less than that measured at idle. This test does not actually prove the pump to be adequate under boost, but if it doesn’t pass this test, it is certainly a waste of time to continue with the same pump.
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Old 05-30-2008, 07:08 PM   #18
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Yeah, you need to run a length of line from your fuel lines to an analog pressure gauge according to the instructions. Have enough fuel line to run the gauge up in front of your windshield so you can observe the change in fuel pressure under boost. You can use the pressure gauge to diagnose any number of issues associated with fuel delivery but in this case, you would use it to make sure that your fuel pressure is rising with boost in accordance with whatever rising rate you have your AFPR set for.
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Old 05-31-2008, 02:24 PM   #19
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Well, I'm not sure if this is the exact problem yet, but it can't be all that great. There is a crack in the coupler that connects the turbo to the intake. This is the one coupler that I didn't replace because I hadn't gotten one that was the right size. The crack was partly covered by the clamp, but when I took it off I noticed that it is all the way through. I dunno how much air was leaking out, but any after the air meter can't be good I would think.

Can anyone point me to the exact size I need for this coupler? I've been having a time trying to figure that out.
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Old 05-31-2008, 03:03 PM   #20
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Well, I found a coupler that fit well enough and put that on, but that didn't fix the problem. It's weird because sometimes it goes lean in full boost, but sometimes it doesn't. Seems like when I'm accelerating in first it doesn't go lean and if I shift to second immediately without losing revs it also doesn't go lean, but if I'm in second (or another gear) and accelerate from a slow speed it goes lean as it hits full boost.

I'll have to get the pressure gauge and see what is going on with the fuel pressure. I also am getting a BEGI AFPR unit at some point here to replace the Vortech.

If I want to run a fuel pressure gauge so that I can observe it while driving I assume I will I need to splice off one of the existing lines?
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