Help diagnosing negative fuel trims/ P2178 / P2188 Rich off/at idle codes

[Mike117]

I have an 08 speed3 with corksport hpfp internals, short ram intake/tip, and just a cobb OTS stage 1+ tune. I just fixed a low fuel pressure issue by cleaning the spill valve on the HPFP. A few weeks later I now have codes P2178 (fuel system too rich at off idle), and P2188 (Fuel system too rich at idle).

I have cleaned the MAF sensor and am getting voltage from 1 to 3.4... and airflow 1.99-124.98 g/s (probably both would be higher but didn't hit full throttle position/boost) The only thing that is off is that my LTFTs are in the -20.88 to -0.16 range. Range of STFT is -11 to 8.42. From research I am seeing next possibilities being O2 sensors or purge valve? My AFRs are normal and fuel pressures are great, hitting near 1800+ at times. On the V3 accessport I don't see any parameters/voltage from the O2 sensors besides the AFR which is from the upstream sensor correct? So if I have normal AFR readings, the problem shouldn't be the upstream O2 sensor correct? The car is running great but I need to try to find and correct the issue for the car to pass inspection as soon as I can (check engine light). Is -20% extreme considering the car runs well and I haven't noticed any change in gas mileage?...meaning does that sound like a false reading? Is there any other tests I can do or parameters to look at that can help point to the issue?
Since I had a low pressure issue for a long time, (car running with what appeared to be in tank pressure of 60psi) could the car have learned to run with the injectors open too long? Would I just disconnect the battery to make the car re learn or how would I make it re learn? thanks for any help

 

[The_big_dill]

I have an 08 speed3 with corksport hpfp internals, short ram intake/tip, and just a cobb OTS stage 1+ tune. I just fixed a low fuel pressure issue by cleaning the spill valve on the HPFP. A few weeks later I now have codes P2178 (fuel system too rich at off idle), and P2188 (Fuel system too rich at idle).

I have cleaned the MAF sensor and am getting voltage from 1 to 3.4... and airflow 1.99-124.98 g/s (probably both would be higher but didn't hit full throttle position/boost) The only thing that is off is that my LTFTs are in the -20.88 to -0.16 range. Range of STFT is -11 to 8.42. From research I am seeing next possibilities being O2 sensors or purge valve? My AFRs are normal and fuel pressures are great, hitting near 1800+ at times. On the V3 accessport I don't see any parameters/voltage from the O2 sensors besides the AFR which is from the upstream sensor correct? So if I have normal AFR readings, the problem shouldn't be the upstream O2 sensor correct? The car is running great but I need to try to find and correct the issue for the car to pass inspection as soon as I can (check engine light). Is -20% extreme considering the car runs well and I haven't noticed any change in gas mileage?...meaning does that sound like a false reading? Is there any other tests I can do or parameters to look at that can help point to the issue?
Since I had a low pressure issue for a long time, (car running with what appeared to be in tank pressure of 60psi) could the car have learned to run with the injectors open too long? Would I just disconnect the battery to make the car re learn or how would I make it re learn? thanks for any help

Upstream O2 sensor is used for reading AFR.

You have an aftermarket CAI and/or TIP running OTS. -20 trims is too much, Did you calibrate the MAF table?

If you did not calibrate the MAF, this needs to be done first. This can be done through a tuner or you can get ATR through COBB and modify it yourself. Alternatively, put the OEM intake back on.

 

[Mike117]

Upstream O2 sensor is used for reading AFR.

You have an aftermarket CAI and/or TIP running OTS. -20 trims is too much, Did you calibrate the MAF table?

If you did not calibrate the MAF, this needs to be done first. This can be done through a tuner or you can get ATR through COBB and modify it yourself. Alternatively, put the OEM intake back on.

I installed the corksport short ram intake and TIP over 3 years ago and have run that ots tune for that time with normal fuel trims. Since the AFRs are normal, does this point to the MAF needing to be recalibrated? It seems like this issue came about after I had a low fuel pressure issue for several months where my fuel pressure read 60-70 but was still driveable somehow other than an occasional misfire/stumble

 

[The_big_dill]

I installed the corksport short ram intake and TIP over 3 years ago and have run that ots tune for that time with normal fuel trims. Since the AFRs are normal, does this point to the MAF needing to be recalibrated? It seems like this issue came about after I had a low fuel pressure issue for several months where my fuel pressure read 60-70 but was still driveable somehow other than an occasional misfire/stumble

Please post a log.

The ECU reads MAF voltage, this voltage is then referenced on a table. This table has a corresponding air mass (g/s) for a specific voltage. If you change the dynamics of the airflow through pipe size, material or shape, this table is no longer appropriate for your set up - even if you didn't see problems before. That being said, it may be a small enough deviation that you have acceptable fuel trims. What fuel trims were you seeing prior to this, when it was "normal"?

 

[Mike117]

Please post a log.

The ECU reads MAF voltage, this voltage is then referenced on a table. This table has a corresponding air mass (g/s) for a specific voltage. If you change the dynamics of the airflow through pipe size, material or shape, this table is no longer appropriate for your set up - even if you didn't see problems before. That being said, it may be a small enough deviation that you have acceptable fuel trims. What fuel trims were you seeing prior to this, when it was "normal"?

Thanks much for the help. I for some reason can't find a high speed micro USB even though my prior two phones used them so il have to pick one up tomorrow to post a new log. I don't believe I have any logs prior to the low pressure issue I had, but I uploaded a log taken while I had the low pressure issue. I reviewed these logs and the LTFT varied but still in the negatives. -7 on some logs and -14 on others. I have been told that I should get a pro tune as OTS tunes the fuel trims would be off. I found a table with the values for specific intakes. Can I use those values to modify my OTS stage 1+ tune so the trims will at least be closer? Do you think these trims (anything greater than say -10 would likely cause the check engine light/rich codes? Seems to make sense

 

[JohnnyTightlips]

https://www.revisionsrus.com/logs/1653

Log looks pretty normal to me. Trims are a little high but nothing that I would be alarmed about. Time to start looking for leaks if it is throwing codes. My trims have been around this off and on and it seems to be mafcal and weather related. I have not tracked down any leaks and the car runs fine. You generally have a BAD problem when trims peg at +20 or -20 which is when it can't control them anymore and is doing the max it can.

Pre-turbo = + trims, air added or sucked in
turbo to TP = - trims, air lost or pushed out
post TP = + trims, air added or sucked in

 

[The_big_dill]

Thanks much for the help. I for some reason can't find a high speed micro USB even though my prior two phones used them so il have to pick one up tomorrow to post a new log. I don't believe I have any logs prior to the low pressure issue I had, but I uploaded a log taken while I had the low pressure issue. I reviewed these logs and the LTFT varied but still in the negatives. -7 on some logs and -14 on others. I have been told that I should get a pro tune as OTS tunes the fuel trims would be off. I found a table with the values for specific intakes. Can I use those values to modify my OTS stage 1+ tune so the trims will at least be closer? Do you think these trims (anything greater than say -10 would likely cause the check engine light/rich codes? Seems to make sense

-7 is not a terrible fuel trim. Even -10 can be acceptable, it is why your ECU has the power to compensate for it without adverse effects to your performance. Codes usually come up when your system would like to apply a trim that is larger than its limits (+/-25).

I think there is a lot of push against the OTS tunes. They are not ideal, but they work, you just have to be conservative and ensure your car isn't exceeding any limits with those tunes. (easier said than done). I used OTS tunes as a baseline and modified it to match my set up.

If you have access to ATR, you can just use COBBs guide to calibrate the MAF cal. I found that when I upgraded to a larger intake, the OTS MAF cal was closer to what the MAF cal should have been than those tables that you found. This is likely due to the variation in MAF sensors, ECUs and physical condition of the intakes.

This is why every individual car benefits from a MAF cal, a very sensitive system with many variables at play.

Looking at your log, everything looks good, even the fuel trims could be improved, but they are nothing to be alarmed about. Can you post a driving log?

 

[Mike117]

https://www.revisionsrus.com/logs/1653

Log looks pretty normal to me. Trims are a little high but nothing that I would be alarmed about. Time to start looking for leaks if it is throwing codes. My trims have been around this off and on and it seems to be mafcal and weather related. I have not tracked down any leaks and the car runs fine. You generally have a BAD problem when trims peg at +20 or -20 which is when it can't control them anymore and is doing the max it can.

Pre-turbo = + trims, air added or sucked in
turbo to TP = - trims, air lost or pushed out
post TP = + trims, air added or sucked in

-7 is not a terrible fuel trim. Even -10 can be acceptable, it is why your ECU has the power to compensate for it without adverse effects to your performance. Codes usually come up when your system would like to apply a trim that is larger than its limits (+/-25).

I think there is a lot of push against the OTS tunes. They are not ideal, but they work, you just have to be conservative and ensure your car isn't exceeding any limits with those tunes. (easier said than done). I used OTS tunes as a baseline and modified it to match my set up.

If you have access to ATR, you can just use COBBs guide to calibrate the MAF cal. I found that when I upgraded to a larger intake, the OTS MAF cal was closer to what the MAF cal should have been than those tables that you found. This is likely due to the variation in MAF sensors, ECUs and physical condition of the intakes.

This is why every individual car benefits from a MAF cal, a very sensitive system with many variables at play.

Looking at your log, everything looks good, even the fuel trims could be improved, but they are nothing to be alarmed about. Can you post a driving log?

Thank you both for taking the time to help. I'm sorry but yesterday I didn't have a transfer cable to upload my logs so I just put a log from a few weeks ago when I had the extreme low fuel pressure issue which was very odd for the car to be drivable like that with what appeared to be the in tank fuel pump pressure.

I posted 2 logs. The first it looks like i'm in neutral cruising, and at idle the LTFT sits at the most negative (-20.44). The second log I am cruising and then get into a little boost, which during, the fuel trims come closer to 0. The codes, P2178 and P2188 read rich at idle/off idle, which again is when they are the most negative. Would that point to a calibration issue? I checked hose connections and didn't see any obvious leaks but didn't do a legit boost leak test as I don't have the fitting made up. A boost leak would not be as much of an issue at idle though I assume? I do not have ATR and have never tuned. As much as i'd like to figure out how to adjust the calibration if that may be the issue, if ATR costs money, i'm tempted to just say maybe go for an OTS freek tune so the tune is better for my specific (corksport) short ram intake and TIP, also since that includes one revision. Maybe my trims were off when I first put the intake on but I just didn't monitor them. Thanks again for the help and advice. -Mike

 

[The_big_dill]

Thank you both for taking the time to help. I'm sorry but yesterday I didn't have a transfer cable to upload my logs so I just put a log from a few weeks ago when I had the extreme low fuel pressure issue which was very odd for the car to be drivable like that with what appeared to be the in tank fuel pump pressure.

I posted 2 logs. The first it looks like i'm in neutral cruising, and at idle the LTFT sits at the most negative (-20.44). The second log I am cruising and then get into a little boost, which during, the fuel trims come closer to 0. The codes, P2178 and P2188 read rich at idle/off idle, which again is when they are the most negative. Would that point to a calibration issue? I checked hose connections and didn't see any obvious leaks but didn't do a legit boost leak test as I don't have the fitting made up. A boost leak would not be as much of an issue at idle though I assume? I do not have ATR and have never tuned. As much as i'd like to figure out how to adjust the calibration if that may be the issue, if ATR costs money, i'm tempted to just say maybe go for an OTS freek tune so the tune is better for my specific (corksport) short ram intake and TIP, also since that includes one revision. Maybe my trims were off when I first put the intake on but I just didn't monitor them. Thanks again for the help and advice. -Mike

When you get into boost, your car goes into "open loop" fueling, your car no longer uses fuel trimming to compensate. It will look for Knock Retard(KR) and if present, will add fuel based on the KR tables. So 0 LTFT and STFT under boost is expected.

People call it a boost leak because you pressurize the system and look for leaks. The ideas is you are looking for areas for air to get in and/or out of your intake system.

If you don't have ATR, you cannot modify the tunes. It isn't expensive if you already have AP, but there is a learning curve. IF you don't care to have full access to the software or don't want to invest the time to learn, you can get a remote tune. Just remember, if you ever want to modify the car, you would need to adjust the tune if you want it to run well.

It looks like your car is able to use the fuel trims to compensate for the condition, and it learned where it needs to be without changing. This is another sign that you may not have a vacuum leak. Are you sure your fuel trims weren't this bad when you originally installed the CAI?

Vacuum leaks can be VERY difficult to find. but I think you should leave that as a last resort. Do you still have the OEM intake for your car OR do you have a spare MAF sensor? If yes, try them, reset the battery and let the car relearn the trims.

 

[Mike117]

When you get into boost, your car goes into "open loop" fueling, your car no longer uses fuel trimming to compensate. It will look for Knock Retard(KR) and if present, will add fuel based on the KR tables. So 0 LTFT and STFT under boost is expected.

People call it a boost leak because you pressurize the system and look for leaks. The ideas is you are looking for areas for air to get in and/or out of your intake system.

If you don't have ATR, you cannot modify the tunes. It isn't expensive if you already have AP, but there is a learning curve. IF you don't care to have full access to the software or don't want to invest the time to learn, you can get a remote tune. Just remember, if you ever want to modify the car, you would need to adjust the tune if you want it to run well.

It looks like your car is able to use the fuel trims to compensate for the condition, and it learned where it needs to be without changing. This is another sign that you may not have a vacuum leak. Are you sure your fuel trims weren't this bad when you originally installed the CAI?

Vacuum leaks can be VERY difficult to find. but I think you should leave that as a last resort. Do you still have the OEM intake for your car OR do you have a spare MAF sensor? If yes, try them, reset the battery and let the car relearn the trims.

I am not sure what the fuel trims were when I installed the corksport short ram intake/TIP. One thing notable is that when I fixed the low pressure fuel issue by cleaning the spill valve (I also put a new pressure relief valve on) and just a day or two is when I got the rich at/off idle codes. I could only see that having any effect if there is now a constant higher pressure in the fuel rail and it takes the car an extremely long time to adjust. I have stock intake burried up in attic. I do not have an extra MAF but may be able to borrow someones I know. I got my accessport used and it has quite a few OTS tunes on it, it turns out, for my 2008 speed3 with corksport short ram intake and TIP, and hpfp internals...the map that has been on my car for years with these mods is the Stage 1+ 91 map with the description: Stage1+ 91 - Intended for an otherwise stock 2007-2008 MAZDASPEED3 vehicle with a stock or cat-back exhaust, a COBB Tuning SF Intake System with TIH, and a stock CDFP only. 91 or 92 octane fuel. Boost Targets: ~16.5psi peak boost pressure tapering down to ~16.5psi by the 6700 RPM redline, +/- 1.5psi. PURE Pressure-Based Boost Tuning. FFS, LC and Load Scaling enabled.)

The only similar map I see on the Cobb website is the Stage 1+ SF map. Another map on my accessport is: Stage1+CS+TIH 91 v231 - Intended for otherwise stock 2011-2013 MAZDASPEED3 vehicle with a stock or cat-back exhaust, a Corksport SRI with TIH, and an upgraded CDFP only. 91 or 92 octane fuel. Boost Targets: ~17psi peak boost pressure tapering down to ~16.5psi by the 6700 RPM redline, +/- 1.5psi. PURE Pressure-Based Boost Tuning. FFS, LC and Load Scaling enabled.

Those are my exact mods, but it says 2011-2013 speed3. Do you know if I could still use this map or would it not allow me to? I tried to email Freektune just inquiring about the issue and getting an OTS freektune but no reply yet and also on the freektune website I do not see the option for speed3s anymore under tuning. OTS and custom tunes do come up when you use the search on the website. hmm odd. I updated the firmware on my AP and am going to try to reflash the map (of different map) and see if it makes any difference.

Johnnytightlips what is turbo to TP/post TP....what is TP? or TB throttle body?

 

[JohnnyTightlips]

TP is throttle plate so yes throttle body.

 

[Mike117]

TP is throttle plate so yes throttle body.

Negative trims from turbo to throttle plate...only thing is my negative trims and check engine light is for rich at idle. -20.44 at idle. At idle since youre under vacuum, if there is a leak anywhere (after maf), youd have excess air and be lean so trims should be positive. Im not sure if i should get a new MAF or not. So far i haven't gotten a reply from a few well known tuners as I metnioned the issue and said I was interested in an OTS tune just so they could calibrate the MAF

 

[Mauro_Penguin]

I dont have time to look at your logs right now, but does your HPFP begin to drop pressure if you got WOT? Regardless of whatever internals you have.

Does your engine oil smell like gasoline?

 

[atorres]

I have this same code with corksport hpfp, JBR Sri and turbo smart dual port bov but difference is I am tuned by freektune and that my car would die almost instantly after turned on. I seen some people say they’re purge valve or the o2 was the problem. Would this be the case in my instance. Or would it have to do something with calibrating the maf

Upstream O2 sensor is used for reading AFR.

You have an aftermarket CAI and/or TIP running OTS. -20 trims is too much, Did you calibrate the MAF table?

If you did not calibrate the MAF, this needs to be done first. This can be done through a tuner or you can get ATR through COBB and modify it yourself. Alternatively, put the OEM intake back on.

 

[The_big_dill]

I have this same code with corksport hpfp, JBR Sri and turbo smart dual port bov but difference is I am tuned by freektune and that my car would die almost instantly after turned on. I seen some people say they’re purge valve or the o2 was the problem. Would this be the case in my instance. Or would it have to do something with calibrating the maf

You calibrate the MAF to eliminate that as a possibility. If you have a pro tune, it was running fine, and now it can't stay running, then you have something failing on your car.

 

[atorres]

Yeah I assumed something in the car was failing. Any suggestions on where to look first after I see all hoses are on and tight ?

You calibrate the MAF to eliminate that as a possibility. If you have a pro tune, it was running fine, and now it can't stay running, then you have something failing on your car.

 

[Awafrican]

Yup check all your hoses, even the MAF sensor gasket. Here's an idea of where to look

Pre-turbo = + trims, air added or sucked in
turbo to TP = - trims, air lost or pushed out
post TP = + trims, air added or sucked in

+5 or -5 is ideal
+7 or - 7 not crazy might want to look into it
+10 or -10 look into it , you got a leak
+20 or -20 shits broke yo

 

[atorres]

I redid everything and double checked all of my hoses and clamps. I even replaced the the purge valve and the bypass hose. Here are my data logs one of them I'm on idle. the other one I was on the road. I noticed that sometimes I would get Knock Retard when go into boost. I on a base map so I am be on low boost. I also noticed forgot to mention to my tuner that I did corksport hpfp. He has yet to respond. Im not sure if this would in any way affect the check engine light problem i was having.

Yup check all your hoses, even the MAF sensor gasket. Here's an idea of where to look

 

[Mike117]

My oil does not smell of gas. I assume if injectors were leaking there would be other symptoms like hard to start or smoke at startup. Fuel trims are staying around -15 to -20.44. Check engine light/ codes p2177 p2188 are intermittent, on the verge of coming on and off.

 

[atorres]

I dont have time to look at your logs right now, but does your HPFP begin to drop pressure if you got WOT? Regardless of whatever internals you have.

Does your engine oil smell like gasoline?

If my engine oil were to smell a little like gas what exactly would that mean?