Fuel Issues

[MazdaS3JIM]

Hello! I am new to the website and wanted to say thank you for the help!.... In advance.

I have been fighting some issues with my 08 Mazdaspeed3 and wanted to know if someone could help. i am located in Wyoming and from my knowledge there are no dealers/shops that are capable of helping me. i will start with the list of mods that i have done to the car or have looked over and know it is aftermarket** Below is three data logs #33 is a cold start, #35 is 1st gear through 6th gear pull (not redline pulls). Then #36 is casual 1st through 6th.

*HPFP Internals
*COBB Intake
*SURE TURBO INLET
*FULL Exhaust*
*COBB AP
*STAGE 1 + SF INTAKE TUNE


I bought an AP after the purchase of the car. I referenced my data to research on the web (before i found the forum). I noticed my LTFT were too lean. I was seeing -12 on the AP. After buying the HPFP internals, DS O2 sensor, COBB intake, And Cleaning the MAF. nothing changed. I checked my Spark Plugs and noticed they were foul. I replaced them. still no change. I even gave that CRC Valve And Turbo cleaner a chance, and it did nothing. Just two days ago I took my Intake apart, I left my Turbo Inlet on. Took my TMIC off, and took the Throttle body off, and cleaned everything. After putting everything back together, and reflashed the tune, its been running rich. My LTFT's are now at +12-+17%. It has been back firing, or after firing.....Whatever you call it, and running like poop. I've double checked all connections for leaks, and there are none. Something i did changed how it runs and its not right. I did get a CEL for running lean at idle. Which my LTFT were at -3%. then at part throttle, and full throttle it jumps straight to +12-+17%. I checked my O2 sensor connection, which is fine. But while i was down there i noticed 2 bolts missing from the TBE.....So i may have an exhaust leak. but i dont think that would do anything to my LTFT's. Any help is appreciated!

[Jeff23spl]

you cannot visually see a leak, you need to put it under pressure to hear it and if the fuel trim move after working on the car, it is likely a leak or a problem with your maf install/position. i hope you did install new gaskets ?
btw the gunk won,t be on the intake or tb but in the head around the intake valves...it is harder to clean...

have you gaped your new spark plugs ? these cars need a tight gap. I think many use 0.024''

[Vansquish]

I haven't looked at your logs, but...

It really sounds like you have a boost leak. At idle, and under vacuum, unmetered air would be entering the system, causing it to run lean-ish. Under boost, metered air would be exiting the system and causing the system to run rich.

So, since you messed with the TMIC and the throttle body, I would be willing to bet that you have a boost tube that is not properly attached and/or some hose clamps that are not properly secured.

[MSMS3]

He’s only hitting 12 psi with high 13 AFR, almost stoich AFRs. Very low g/s.

[Vansquish]

Originally Posted by MSMS3 He’s only hitting 12 psi with high 13 AFR, almost stoich AFRs. Very low g/s.

Holy knocking knockity knock too.

Also...my bad, I hadn't had my coffee yet this morning. @MazdaS3JIM;, if your LTFTs are negative, that means your car is running rich, and the ECU is trying to pull fuel out of the mixture. If your LTFTs are positive, that means your car is running lean and the ECU is trying to put more fuel into the mixture.

Basically, your assumptions about what's going on were completely backwards (and I was too sleepy this morning to recognize this fact).

I would still encourage you to check each and every hose, boost tube, and hose clamp that you touched. Check for cracks in the hoses and boost tubes, check to make sure none of the hoses and tubes is pinched, make sure that the hose clamps are properly secured as well. Don't forget that you have a recirculation tube as part of the turbo inlet pipe as well. If that's not properly secured, you could have AFR control issues (among other things).

If you have a full exhaust (including an aftermarket downpipe), then you are also running the wrong tune.

The OTS Stage 1 maps are not calibrated for an aftermarket exhaust (including downpipe). Please make sure you read the map notes before using a map. Using the wrong map for your car is dangerous for the engine. Note also that the parts don't have to be brand specific with the exception of the intake. MAF housing diameter determines the MAF calibration and diameters vary between manufacturers.

Stage 2 map notes:

Engine Management: COBB Accessport
Air Induction: COBB Turbo Inlet Hose
Intercooler: Stock Intercooler
Fuel Pump: COBB Fuel Pump Internals
Downpipe: COBB Downpipe(s)
Intake: COBB SF Intake
Cat-back: COBB Cat-Back

https://www.cobbtuning.com/maps/2007...dm-stage-2-map

Compare the above with the Stage 1 + SF map notes:

Engine Management: COBB Accessport
Intercooler: Stock Intercooler
Fuel Pump: Stock Cam Driven Fuel Pump
Cat-back: Stock Exhaust , COBB Cat-Back - If you have a full exhaust (that includes an aftermarket downpipe), then this category is not satisfied by the Stage 1 + SF map, and you cannot safely run this tune on your car.
Intake: COBB SF Intake
Air Induction: COBB Turbo Inlet Hose

[MazdaS3JIM]

Thank you for the reply. I was curious about the knock as well. There is no noise. I was wondering if it could be the motor shifting from bad mm or rmm?? i do have a VVT kit ready to install, maybe that could be the issue?

I have made sure that everything is tightened and secured. the only difference is i cleaned everything.. it doesnt hurt to be sure and i will one more time today. but could the exhaust leak have anything to do with LTFT? maybe gases are escaping from it and the DS O2 sensor isnt reading properly? I will change tunes after checking clamps and hoses. again thanks for the reply.

[Vansquish]

Once you have checked all those hoses and clamps and switched to the correct map (you can also use a safe tune for testing purposes), please try and take a datalog in 3rd gear from 3000rpm to 6000rpm at WOT if you can. When we only have 1000rpm bursts of acceleration in a given gear (and not at WOT), it is hard to determine whether the car is achieving the targets set in the ecu map.

The knocking *could* be from a bad motor mount, but it isn't occurring when you are shifting, and it is sustained for a full 1000rpm at a time. This indicates that it is either a mechanical problem with the engine, you have bad fuel, or something is loose in the engine bay.

Additionally, it might be useful to know how you "cleaned everything." What did you use to clean the various parts and which parts did you clean? Did you physically touch any of the very fragile sensors?

Finally, yes. It is possible for your fuel trims to be affected by an exhaust leak. If the leak is before one or both of the O2 sensors, then the O2 sensors may not be correctly determining the exhaust gas constituents. This could cause the car to apply short and long-term fuel trims to try and get closer to spec.

[MazdaS3JIM]

Originally Posted by Jeff23spl you cannot visually see a leak, you need to put it under pressure to hear it and if the fuel trim move after working on the car, it is likely a leak or a problem with your maf install/position. i hope you did install new gaskets ? btw the gunk won,t be on the intake or tb but in the head around the intake valves...it is harder to clean... have you gaped your new spark plugs ? these cars need a tight gap. I think many use 0.024''

I gaped the plugs at 0.028. That is what they were at before. I used carb cleaner to inspect for leaks. I also installed everything back the way it was. There was no need for new gaskets. they were good. There were only 2 gaskets, one for the throttle body, then one for the BPV. Back when i used crc valve cleaner, I just followed the instructions on the can.
I also dont think its a bad exhaust leak but i will get the two missing studs for it. I know i could take the others out and bring it to the store for a reference but woukd you happen to know what bolt specs they are?

[MazdaS3JIM]

Originally Posted by Vansquish Once you have checked all those hoses and clamps and switched to the correct map (you can also use a safe tune for testing purposes), please try and take a datalog in 3rd gear from 3000rpm to 6000rpm at WOT if you can. When we only have 1000rpm bursts of acceleration in a given gear (and not at WOT), it is hard to determine whether the car is achieving the targets set in the ecu map. The knocking *could* be from a bad motor mount, but it isn't occurring when you are shifting, and it is sustained for a full 1000rpm at a time. This indicates that it is either a mechanical problem with the engine, you have bad fuel, or something is loose in the engine bay. Additionally, it might be useful to know how you "cleaned everything." What did you use to clean the various parts and which parts did you clean? Did you physically touch any of the very fragile sensors? Finally, yes. It is possible for your fuel trims to be affected by an exhaust leak. If the leak is before one or both of the O2 sensors, then the O2 sensors may not be correctly determining the exhaust gas constituents. This could cause the car to apply short and long-term fuel trims to try and get closer to spec.

I broke the parts down, removing the intake first through to the throttle body. I removed all electrical connections that were in the way. and put them off into safe areas. i removed all Two gaskets and put them in a safe area. then started cleaning partially inside of my intake Mani, moving to my throttle body then all the couplers, and TMIC. before reinstall i lubed the couplers, then cleaned the wiring with MAF sensor cleaner. i only disconnected Two wires which were for the MAF and the throttle body.

[MazdaS3JIM]

I am sorry I havent updated yet. I've been busy with some personal matters.

I retraced my steps and found where I fucked up lol. The hose that goes from the bpv back into the intake wasnt connected all the way. I'm glad i caught it in time. Call me a dumb ass Haha.

It turns out I did all this for no reason, being my fuel trims went back to what they were. I did put the correct tune on, and did a 3rd gear pull but my computer crashed so I'm not able to post it. I am seeing -3% at idle and -12% at partial throttle. At wot I am seeing -0.16%. Thank you for all the help!

[Vansquish]

Originally Posted by MazdaS3JIM I am sorry I havent updated yet. I've been busy with some personal matters. I retraced my steps and found where I fucked up lol. The hose that goes from the bpv back into the intake wasnt connected all the way. I'm glad i caught it in time. Call me a dumb ass Haha. It turns out I did all this for no reason, being my fuel trims went back to what they were. I did put the correct tune on, and did a 3rd gear pull but my computer crashed so I'm not able to post it. I am seeing -3% at idle and -12% at partial throttle. At wot I am seeing -0.16%. Thank you for all the help!

Just so you know, -0.16 at WOT is normal, as the car enters open loop and does not provide LTFTs under those conditions. -12% is still pretty rich at partial throttle, but it should be safe, and it's within the range that the ECU can handle.

[Jeff23spl]

Originally Posted by MazdaS3JIM I retraced my steps and found where I fucked up lol. The hose that goes from the bpv back into the intake wasnt connected all the way. I'm glad i caught it in time. Call me a dumb ass Haha.

Checking the leaks with your carb cleaner wouldn't point this out but pressurize the intake path would have shown it on the first seconds...

re-using old gaskets could work if you are lucky, some re paint them too but it is suppose to be a 1 time use gasket....

[MazdaS3JIM]

Originally Posted by Vansquish Just so you know, -0.16 at WOT is normal, as the car enters open loop and does not provide LTFTs under those conditions. -12% is still pretty rich at partial throttle, but it should be safe, and it's within the range that the ECU can handle.

When at WOT, should I watch my STFT's? Also has anyone heard or done, a pcv bypass to your exhaust? I've been reading up on it. I mean for the money I'd go with an OCC but I was just curious..

Originally Posted by Jeff23spl Checking the leaks with your carb cleaner wouldn't point this out but pressurize the intake path would have shown it on the first seconds... re-using old gaskets could work if you are lucky, some re paint them too but it is suppose to be a 1 time use gasket....

They were in good shape. I believe the previous owner modded the car, then before selling, went back to stock.

[Vansquish]

I wouldn't bother "watching" your STFTs. The refresh rate on the screen is too slow to provide you with meaningful information, and you can't do anything about it on-the-fly anyway. I would datalog instead.

[MazdaS3JIM]

Originally Posted by Vansquish I wouldn't bother "watching" your STFTs. The refresh rate on the screen is too slow to provide you with meaningful information, and you can't do anything about it on-the-fly anyway. I would datalog instead.

Okay. I was just curious what I should be watching at WOT. I've been avoiding it because of the knock. It doesn't record any knock if I'm just casually driving. Also my computer broke so I cant upload any data logs hah. I have a Google Chromebook but I cant download accessmanager.