Maxx Alpha N issues

[craz azn]

Hey guys,

I am looking to get some opinions on the inconsistent behavior that my car has recently started to display within the last two weeks. I had the Alpha N controller reprogrammed earlier this year to be updated for the close loop wb02 setup, and everything seemed relatively fine, the car ran well as it always has with good AFRs (albeit I have not spidered the wb02 into the Maxx harness yet, so it is only a display for reference at the moment, and not a operational tuning tool). I drove the car twice, a few 100kms each drive, and while on my second test drive, I decided to connect with my laptop to try and richen the part throttle areas I felt the AFR could have been improved. Ever since plugging into the controller and trying to upload my updated map, the car has been totally undriveable, and extremely erratic in behavior, with anything past 5-10% throttle dropping to off the charts lean AFRs, and the car just pops and snorts. The car idles somewhat okay, but sometimes it decides to change on it own after idling for 20-30 secs, as referenced by the AFR changing to either extremely rich, or extremely lean, on its own. Just idling the car in 1st gear down the driveway results in extreme rich AFR conditions, like 10-11... of which it then goes pretty much fully lean as I tip into throttle.

I have done mechanical checks such as checking fuel pressure, measuring resistance of the throttle position sensor, and swapping to another known coolant temp sensor. No changes. I have resorted to thinking there is something seriously wrong in the background settings of my Alpha N file, but I cannot see anything obvious when looking at it in notepad.

I have emailed Martin at Maxx but have yet to receive a reply. I also did some searches online, and interestingly found another S14 member that had very much the same issues as I had, although if you read his various threads, I don't know what was the resolution to it. https://s14net.vbulletin.net/forum/s...uestions/page2

I have tried to put my original map back on, old maps from last year, and even the original base maps that come with the Maxx, and no changes either to the car's behavior. I've tried to set all the 02 corrections to 0 within the Maxx, in hopes it was somehow interfering and that was not successful either. Original narrow band 02 has never been plugged in since I've owned the car, so I doubt this has anything to do with it either. Yesterday in desperation, I tried to load maps in via the old version Maxx software, and that didn't work either.

I am open to any suggestions anyone has, as I am stumped on what to do next. Thank you guys!

[dllance]

I had a similar situation with my car. It started with not being about to adjust the idle but got to the point that the car would just go crazy rich. It would act totally different every time I’d start tat. Don Fields spent a long time trying to sort it out. It ended up being the Maxx system itself. It has been sent back to be fixed and have a loaner now.
Not sure you have an option of switch in a known good Maxx system from a car with very close specs to your.
I’m sure I would have pulled my hair out trying to figure it out.
After check everything possible Don ended up taking the Maxx system off and switch the car back to stock to figure it out.

[///Mavrikno13764]

Did you maybe activate or deactivate the Idle control valve?
That made my setup act crazy before I realized it was on. (I removed my ICV).

Also the software gets a little funky when dealing with maps with WB and non-WB.
When unconnected, I opened an older map that did NOT have WB option and the Maxx software did not have the option to turn it as well. So I made sure not to load it.

Good luck though. Hoping its an easy fix for you.

[craz azn]

Thanks for the replies guys.

I have all the options turned off at the moment, including ICV, and WB02. More on this in a moment.

To follow up, I wanted to post my findings, to date. Shortly after I wrote the original post, I got my hands on an S38 TPS (I believe it is 406? I cannot remember offhand) just for diagnostic purposes. Keep in mind, I had already checked my original TPS, and for the most part it seemed to display correct resistance readings when measured, but I figured why not try to swap since I had nothing to lose at this point. To my surprise, the car ran normally with the S38 sensor in place, albeit with incorrect AFRs across the board since it was probably measuring different resistances. I saved that exact Maxx AN file right on the spot, just so I had a baseline file to work with and hopefully go back to if needed. Last week I sourced a brand new Bosch 6 pin TPS 0 280 120 402, under the part number TH107 (reboxed by a different supplier) and I installed that.

In between that week of waiting for the new TPS sensor in the mail, I installed my new CF Airbox, and also deleted the ICV circuit, hoping to shed any potential problem issues. FWIW, one port on the CF airbox is going to the oil separator, but the second is capped off. Once the new TPS sensor arrived, I loaded my original AN file from the beginning of this year onto the Maxx, and to my dismay, the car was still acting erratically WITH the new sensor in place. BUT when I loaded my 'June' file that I'd used with the S38 sensor, the car actually ran, sort of. Super weird! However, I still do have issues, such as I notice the AFRs are VERY lean with sudden throttle movements aka sudden acceleration situations etc, and the car also momentarily goes VERY rich as I lift off throttle... It is like I traded one problem for another! I can live with the momentary rich off throttle situation, but I cannot have the lean spike at throttle tip in. Also, the car is unbelievably rich at idle, and low rpm/load areas, that I cannot seem to tune out.

Does anyone know if there is some sort of accelerator or throttle tip in enrichment that can be manipulated through the Maxx? I have also noticed that by playing with the idle contact stops on the Maxx, I can alleviate some of this issue, but that in turn gives me a car that does not idle, as I'd have to set the idle contact so low, that the car is always on throttle (thus my AFR always show some sort value, instead of going full lean when off throttle like it should)

I will try to mess around with it more this week and report back.

[mlytle]

"FWIW, one port on the CF airbox is going to the oil separator, but the second is capped off."
where is the intake air temp sensor? should be in one of those ports.

[france320isco]

Hey guys,

I am looking to get some opinions on the inconsistent behavior that my car has recently started to display within the last two weeks. I had the Alpha N controller reprogrammed earlier this year to be updated for the close loop wb02 setup, and everything seemed relatively fine, the car ran well as it always has with good AFRs (albeit I have not spidered the wb02 into the Maxx harness yet, so it is only a display for reference at the moment, and not a operational tuning tool). I drove the car twice, a few 100kms each drive, and while on my second test drive, I decided to connect with my laptop to try and richen the part throttle areas I felt the AFR could have been improved. Ever since plugging into the controller and trying to upload my updated map, the car has been totally undriveable, and extremely erratic in behavior, with anything past 5-10% throttle dropping to off the charts lean AFRs, and the car just pops and snorts. The car idles somewhat okay, but sometimes it decides to change on it own after idling for 20-30 secs, as referenced by the AFR changing to either extremely rich, or extremely lean, on its own. Just idling the car in 1st gear down the driveway results in extreme rich AFR conditions, like 10-11... of which it then goes pretty much fully lean as I tip into throttle.

I have done mechanical checks such as checking fuel pressure, measuring resistance of the throttle position sensor, and swapping to another known coolant temp sensor. No changes. I have resorted to thinking there is something seriously wrong in the background settings of my Alpha N file, but I cannot see anything obvious when looking at it in notepad.

I have emailed Martin at Maxx but have yet to receive a reply. I also did some searches online, and interestingly found another S14 member that had very much the same issues as I had, although if you read his various threads, I don't know what was the resolution to it. https://s14net.vbulletin.net/forum/s...uestions/page2

I have tried to put my original map back on, old maps from last year, and even the original base maps that come with the Maxx, and no changes either to the car's behavior. I've tried to set all the 02 corrections to 0 within the Maxx, in hopes it was somehow interfering and that was not successful either. Original narrow band 02 has never been plugged in since I've owned the car, so I doubt this has anything to do with it either. Yesterday in desperation, I tried to load maps in via the old version Maxx software, and that didn't work either.

I am open to any suggestions anyone has, as I am stumped on what to do next. Thank you guys!

It seems you "did" something to the sw settings. Did you took note or save the sw that worked before uploading your changes?

Take a chance to check the output voltage of all sensors (TPS, wb02...) and injectors also if you think they're working fine.

P.S.

Suggestion: install a knocking sensing. You are not running on stock motronic anymore, but a mix motronic+third party = check knocking.

[craz azn]

Mlytle - the Air Intake Temp sensor is in the front snorkel section, not in the airbox. It is a Markus S14shop airbox.

france320isco - I have looked through my files in notepad before and after, and I haven't seen any obvious differences. Can you explain what you mean by 'SW settings'? I am not sure what that is referring to. I actually did try to check the voltage of the original TPS while on the car as it was suggested to me by a friend not on the forums. I am 100% sure it seemed to display linearly and without dead spots while opening throttle through its range. I have not checked other sensors/items voltage though.

Good tip on the knock sensor! I have access to an old J&S knock sensor system that I can borrow to monitor... I just haven't gotten around to it yet :(

[france320isco]

Mlytle - the Air Intake Temp sensor is in the front snorkel section, not in the airbox. It is a Markus S14shop airbox.

france320isco - I have looked through my files in notepad before and after, and I haven't seen any obvious differences. Can you explain what you mean by 'SW settings'? I am not sure what that is referring to. I actually did try to check the voltage of the original TPS while on the car as it was suggested to me by a friend not on the forums. I am 100% sure it seemed to display linearly and without dead spots while opening throttle through its range. I have not checked other sensors/items voltage though.

Good tip on the knock sensor! I have access to an old J&S knock sensor system that I can borrow to monitor... I just haven't gotten around to it yet :(

Before any map update you should download the working file, copy it, and update the copy.
So if something goes wrong you can go back to the original. It seems you did that.

I don't know how the AN map management works, don't know if you can DL all the parameters at once and save them in a single file either.

Usually, stalling due to lean or rich mixture is related to the voltage of the TPS which is the base of the injection timing calculation on the load axis (when the map is not an issue).

In case of a feedback from a WBO2 it is also related to this feedback. Check the sensor voltage (if you have it). Check the WBO2 sensor settings in the AN mgmt.

From the description of the problem (TPS working) I'd say you missed something in your map update or your WBO2 is faulty. Rule of thumb.

Remotely, it could be the case of a major issue arising in coincidence with another mod but not related to. Check you alternator.

[HANDBLT]

Thanks for the replies guys.

I have all the options turned off at the moment, including ICV, and WB02. More on this in a moment.

To follow up, I wanted to post my findings, to date. Shortly after I wrote the original post, I got my hands on an S38 TPS (I believe it is 406? I cannot remember offhand) just for diagnostic purposes. Keep in mind, I had already checked my original TPS, and for the most part it seemed to display correct resistance readings when measured, but I figured why not try to swap since I had nothing to lose at this point. To my surprise, the car ran normally with the S38 sensor in place, albeit with incorrect AFRs across the board since it was probably measuring different resistances. I saved that exact Maxx AN file right on the spot, just so I had a baseline file to work with and hopefully go back to if needed. Last week I sourced a brand new Bosch 6 pin TPS 0 280 120 402, under the part number TH107 (reboxed by a different supplier) and I installed that.

In between that week of waiting for the new TPS sensor in the mail, I installed my new CF Airbox, and also deleted the ICV circuit, hoping to shed any potential problem issues. FWIW, one port on the CF airbox is going to the oil separator, but the second is capped off. Once the new TPS sensor arrived, I loaded my original AN file from the beginning of this year onto the Maxx, and to my dismay, the car was still acting erratically WITH the new sensor in place. BUT when I loaded my 'June' file that I'd used with the S38 sensor, the car actually ran, sort of. Super weird! However, I still do have issues, such as I notice the AFRs are VERY lean with sudden throttle movements aka sudden acceleration situations etc, and the car also momentarily goes VERY rich as I lift off throttle... It is like I traded one problem for another! I can live with the momentary rich off throttle situation, but I cannot have the lean spike at throttle tip in. Also, the car is unbelievably rich at idle, and low rpm/load areas, that I cannot seem to tune out.

Does anyone know if there is some sort of accelerator or throttle tip in enrichment that can be manipulated through the Maxx? I have also noticed that by playing with the idle contact stops on the Maxx, I can alleviate some of this issue, but that in turn gives me a car that does not idle, as I'd have to set the idle contact so low, that the car is always on throttle (thus my AFR always show some sort value, instead of going full lean when off throttle like it should)

I will try to mess around with it more this week and report back.

If you bought a 402 TPS and not a 406 TPS, it is backwards. The 402 is opposite the 406. Check and make sure you have the right 406 TPS and it is going through its range properly.

T

[craz azn]

If you bought a 402 TPS and not a 406 TPS, it is backwards. The 402 is opposite the 406. Check and make sure you have the right 406 TPS and it is going through its range properly.

T

I have to double check the part number on the e34 S38 sensor that I borrowed from my friend, but it is definitely not backwards. That one you're referring to is used on M30s I believe. 402 is what came on my car, and is what originally came with older versions of MAXX Alpha N systems. If you search the part number on this forum, there are more references to 402.

[JimK]

Backwards only means the wiring is opposite. I've never known of a TPS that was backwards. There is a procedure for determing the Vref, ground and signal terminals to give 0 volts at closed throttle and 5 volts at WOT.

[HANDBLT]

Backwards only means the wiring is opposite. I've never known of a TPS that was backwards. There is a procedure for determing the Vref, ground and signal terminals to give 0 volts at closed throttle and 5 volts at WOT.

its the 406 that is backwards, meaning that 0v is the opposite way, and 5v is the opposite. it's made for a TB that turns opposite of ours. I've ordered one and had to chunk it and order the 402.

T

[JimK]

its the 406 that is backwards, meaning that 0v is the opposite way, and 5v is the opposite. it's made for a TB that turns opposite of ours. I've ordered one and had to chunk it and order the 402.

T

Like I said it just needs terminal rewiring. Here is how to determine the terminal functions:

Label terminals A, B, and C.

1. With the TPS in the closed throttle position, measure the resistance of the following three positions A-B, A-C, and B-C.
2. With the TPS in the opened throttle position, measure the same three resistances. Two of the readings will have changed from Step 1, and one of the readings will be the same.
3. The +5V and Ground terminals are from the terminal pair whose resistance stayed the same between steps 1 and 2. The Ground terminal is from the pair whose resistance increased from Step 1 to Step 2.

[HANDBLT]

Like I said it just needs terminal rewiring. Here is how to determine the terminal functions:

Label terminals A, B, and C.

1. With the TPS in the closed throttle position, measure the resistance of the following three positions A-B, A-C, and B-C.
2. With the TPS in the opened throttle position, measure the same three resistances. Two of the readings will have changed from Step 1, and one of the readings will be the same.
3. The +5V and Ground terminals are from the terminal pair whose resistance stayed the same between steps 1 and 2. The Ground terminal is from the pair whose resistance increased from Step 1 to Step 2.

Its not the wiring from what I remember but this was 2002 lol, it the physical insides that are made for reversed use. From what I recall, If you install one on our TBs, it won't move because it is at WOT instead of idle. If it were as easy as changing the pin wiring I would have done that.

T

[JimK]

Its not the wiring from what I remember but this was 2002 lol, it the physical insides that are made for reversed use. From what I recall, If you install one on our TBs, it won't move because it is at WOT instead of idle. If it were as easy as changing the pin wiring I would have done that.

T

But you didn't say that was the issue. WOT and idle is a relative thing, If it strokes against the stops, then i agree its a physical issue, not a wiring issue.

I've done several custom works and have used Ford and Jeep products on BMWs including 2 S14s with non-OEM ecus., if they fit and stroke, they can be wired correctly for ~0 V and closed throttle and ~ 5 V at WOT.

[craz azn]

Just a quick post to follow up here.

So the part number of the S38B36 sensor ends in 404... and yes it DOES work with the S14 + MAXX setup. In my experience, the AFR was quite a bit off while using this sensor, but I have since found out that moving the throttle min and max points could possibly affect this drastically. I did not try to mess with this at the time because I did not know it would have affected it.

I ended up buying a brand new Bosch 402 sensor, and it DID NOT fix my issue. I have learned a few things since, while trying to diagnose this on my own. First things first, make sure the TPS is adjusted correctly. On my car, I could set it in a way (incorrectly) that even though it clicked off idle, there was still some movement in the throttle, and the car would not register it as revving, thus creating a lot of hesitation, flat spots, and just generally poor behaviour. Second thing, make sure the throttle settings in the MAXX for the min and max are set correctly to your car and your setup. I found that the car drove really smooth at slow speeds, but I had made the mistake of setting it so that the throttle was never registering as closed. A slightly higher idle was the culprit in this case, as well as my AFRs not going full lean off throttle as it should on a correctly set up engine. At this time, the minimum was set a hair above the actual physical TPS minimum setting. I set it one click below, but also had to readjust the TPS yet again to get them to jive, as just setting the min in the MAXX only created some odd AFR behaviours while driving. Also, since my car is predominately a track car, I found a post on S14power from John, that was relevant to my interests as a track car... in his notes, he mentioned that he'd set his WOT to activate at 70% TP, and this did wonders for my car... by coincidence it helped out my AFRs get to the exact spots I wanted them to be at, especially at critical points beyond 75% TP and higher rpm. I also read within his notes that a momentary split second of lean AFRs when major/heavy TP changes is a normal occurrence and will not hurt anything.

The actual problem I believe what happened to my car was something corrupt within the file of the MAXX. One random day, I started the car, and it again was sputtering and coughing when the throttle was pressed... even though the day before it had seemed to run somewhat okay. I hooked up the laptop to see the data live, and interestingly I found that the RPM reading was about half of what it was actually running. The trigger number is 116 as per default in the MAXX software... so I figured as a test to double this figure and see if the RPM would read correctly. It didn't do anything. If at all, it had become worse. I pressed on the cursor to move that number back down to 116, and voila! Car was running perfect. Strange, because in all my files that I've saved, the trigger number is all at 116, so it wouldn't appear to be an issue, yet changing that number back and forth on my existing file, live, seemed to do the trick for my car. It has not acted up since this happened.

I hope that this may help somebody down the road with their rough running MAXX Alpha N Plus supported car, since customer service/support for this product is lacking, especially once they have your money :(