MAXX TPS problem

[Jake]

Just a word of caution when it comes to adjusting the cable or cable stop at the TB. The pedal stop (screwed into your firewall) is the primary stop. You should never contact the stop on the throttle body. You can generate some serious forces with your right foot. If you are contacting the TB stop then all that stress is going right into those little TB linkages. This is how throttle plates and spindles get bent.

Whenever you adjust your cable you are also changing how close you're coming to the stop on the TB. If you crank it all the way down you WILL contact the TB stop first and you may damage your TB's.

Just something to be aware of before you or someone else goes looking for that 10 free horsepower by adjusting your cable.

Jake

[Marco]

Adjust the throttle stop to get the required arc/throttle opening (see my earlier post)

[Reelizmpro]

Glad you solved the problem with the Maxx kit. Attach the throttle cable and make sure you're able to reach 93% with the gas pedal all the way down. Chances are it won't reach the same value as manually opening up the TBs by hand. Speaking of stretched cables I guess this is what happened to mine because I had to shim the end of the cable to effectively make it shorter.

[Mick]

I don't know about the voltages, but my TPS reads from 12.5 to 94.5

[UofOm3]

cable isn't attached... this was manually opening the throttles.

[Mdriver]

If your accelerator cable is 20 years old, you may want to buy a new one for $26. I was able to adjust my old one to only 85% at full WOT (it was too stretched). I bought a new one and was able to get 94%.

If your cable is still good, you should be able to adjust it to 93% at least.

- gabor

[UofOm3]

Alright guys... So it was indeed a wiring problem. I wired the three Gpot/Harness #7/D wire together instead of doing it properly.

I also ordered a new TPS yesterday and it got here today. Turns out, the old one was indeed causing problems. I now read this with the TPS instaled:

Idle = 12% throttle at .89volts
WOT= 89% throttle at about 4.49 volts

Does this sound appropriate or acceptable for the parameters? Someone previously mentioned it should go between about 12% and 96% so I am a little low on the top end but hopefully I can play with it a little bit and get it a little higher... I saw 93% earlier so hopefully I can achieve that again.

[M3 Adjuster]

Had the same problem here installing the Maxx system. Turned out, that the throttles were not opening up all the way with the accelerator down (no wonder!). After replacing the grommets and adjusting the cable, I was able to reach 96%.

Yes.. I am sure a lot of people have found that their throttles were not opening due to installing a MAXX set up. New grommets (if needed) are very inexpensive ($4-7), however most people simply need to use a pair
of open end wrenches to adjust the cables.

Jeff Krause (when he was in the Hoosier chapter) would come up to new members (that owned E30s) at BMW CCA meetings and ask if they would like 10 FREE horsepower. He would grab the 17 and 19 (iirc) wrenches from his trunk kit and then have them step on the accelerator and see if their throttle was opening up all the way... Whether or not one has a MAXX setup... if you don't KNOW that the throttle is opening up all the way, go to the garage and check it now! :cycle:

[Reelizmpro]

Had the same problem here installing the Maxx system. Turned out, that the throttles were not opening up all the way with the accelerator down (no wonder!). After replacing the grommets and adjusting the cable, I was able to reach 96%.

[1990m3]

The MAXX TPS is indeed bulky.... as per 1990 m3, mine is pretty tight against the fuel pressure regulator... you may need to make sure that the fuel pressure regulator is not preventing you from getting the needed clearance. Are you truly going ONLINE when checking the measurements on the Maxx? IIRC, the adjustment is done OFFLINE with the key in the vehicle ON, in position two (all the lights on the dash illuminated, but without starting the car) . FYI... the throttle percentages, never ZERO out.

in the idle position, mine reads about 12%, and with the throttle completely open, mine is at 94-95%.. Even though the thottle reads this way in the setup screen, i have seen 96% throttle while tuning and datalogging.

Mine is right on par with the 12%-96% range. I think it reads 12% at idle and 96-98% or so at WOT. It's been a few years since i played with mine though...haven't really messed with it since the dyno tune.

[Marco]

M3Adjuster,

Does your throttle open fully - just that the operator when mapping mine started at idle then worked up to WOT. He then couldn't get the WOT value, so I had to move the accelerator throttle stop ( a small nut which locks located to the left of the left side of the throttle bodies looking from the front ) to get WOT i.e more movement for TPS.

Cheers,

[M3 Adjuster]

The MAXX TPS is indeed bulky.... as per 1990 m3, mine is pretty tight against the fuel pressure regulator... you may need to make sure that the fuel pressure regulator is not preventing you from getting the needed clearance. Are you truly going ONLINE when checking the measurements on the Maxx? IIRC, the adjustment is done OFFLINE with the key in the vehicle ON, in position two (all the lights on the dash illuminated, but without starting the car) . FYI... the throttle percentages, never ZERO out.

in the idle position, mine reads about 12%, and with the throttle completely open, mine is at 94-95%.. Even though the thottle reads this way in the setup screen, i have seen 96% throttle while tuning and datalogging.

[1990m3]

definitely check your wires, it sounds like it could be an electrical problem. That TPS is pretty bulky and IIRC it butts right up to the fuel pressure regulator. Are you sure that you can't turn the TPS more when calibrating? On one of the cars I installed MAXX on the TPS was very tight up against the FPR and it was actually really hard to rotate it into the properly calibrated position. How's your clearance?

[UofOm3]

I'm going to double check the wiring right now. The ICV percentage in the perameters control is bouncing between 43-45% with the car off.

[jimmyC]

Disconnect the TPS output wire from the MAXX and check the output with a voltmeter. Sounds like it is wired incorrectly.
Is it mounted properly on the throttle shaft? Do the idle and WOT contacts function correctly?