This is my first post here, sorry it'* kind of long but I think it is a good topic.

I recently was having an issue with my 2001 Bonneville SSEi where it would seem to ‘shift’ gears oddly. Under acceleration it would seem to ‘upshift’ before kicking down and accelerating. I have a fresh engine and rebuilt transmission both with still less than 10K on them.

So here is the story, and my questions following.

I had my transmission rebuilt by a reputable mechanic who only does transmissions, he put a quaife LSD in my SHO years ago. I knew the tranny was good as well as the work but I still took the bonnie back to him to check it out. He drove with me shotgun and within a few minutes pinpointed my problem, most of it anyways.

When I though the car was ‘downshifting’ it was actually opening up my TCC (Torque Converter Clutch). He explained it as the car thinking it is going downhill so it stops locking up the torque converter, this reduces the stress on the transmission because it’* no longer slowing the car, the computer does this because brakes cost less than transmissions.

He showed me how to test for this if you think your car does it. When the RPM’* drop after the ‘downshift’ or ‘unlock’ use your left foot to tap the brake while still in the same position on the gas with your right. If it’* the TCC unlocking then tapping the brake locks the converter back up and your RPM’* will raise back up where they should be.

We drove the car back to his shop and he said I bet you have a K&N air filter, my response is ‘yea’. He told me to replace my Mass Airflow Sensor (MAF) and if it still acted up my Throttle position sensor(TPS). He explained that it’* not so much the K&N filter itself but the recharge oil used after cleaning the filter, as well as the oil that comes on the filter stock. He said it sucks into the intake and cooks these sensors.
So I replaced the two of them, both were burnt up pretty well (can post pics if you’d like).

Once I did that the problem almost instantly disappeared and a LOT of performance was gained back within a day or 2 (PCM had to relearn a few things I suppose).

So I just wanted to save a few people sensors if possible and ask if others have heard of this. I still use the K&N because I figure the oil is gone by now, the filter is a year old, I just won’t ‘recharge’ it only hose it off.

My questions are:
1.) Is my K&N still stopping dirt from entering my intake without that oil that burns up my expensive sensors?
2.) What is that 3rd sensor on the Throttle body, there is the TPS , the MAF, and another with I THINK 3 prongs?
3.) Have you ever heard of this K&N oil burning up sensors?

I think that 3rd sensor will completely solve the shifting problem, although it’* barely noticeable now anyways.
Thanks,
Jeremy

I'd like to see pics because an experiment was just done on this (not concluding the end result).

I've run K&N'* on all my rides for many years and have never experienced any problems. I do however; occasionally clean my MAF with a MAF cleaning spray on occasion.

Clean, then test before replacement. Some sensors can be expensive.

Also..Welcome to the Bonneville Forum!

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I think this is caused by adding too much oil to the filter. I think that if you apply a light coating and let it dry first you will be fine. I've been running mine for about a year now.

The actual cuase as JL said is overoiling. K&N directions are very specific about not overoiling.

The problem with the maf sensor occurs because the way a maf works is it heats a wire, then the sensor measures the amount of voltage required to keep that wire at a constant heat with air blowing over and cooling it. Oil on a hot sensor wire kills it.

The TPS is externally located and reads the TB shaft externally as well. A bad TPS can cause the pcm to have trouble shifting, but shouldn't be a cause of overoiling since the oil can not reach the externally located sensor.

Good information. Another good reason to keep things clean.

I'm out of town this weekend and slightly busy, however my brakes are due for a change and it'* supposed to be very nice weather in the 80'* up through Monday. So I'll take pictures of the old sensor and the intake as well Sunday or Monday. Also I'll take a picture of my mystery 3rd sensor which hasn't been changed yet. Thanks for the input.

Regards,
Professor Jeremy

If the third sensor is above the TPS, that'* the IAC or Idle Air Control. If it'* in your intake tubing it'* the IAT or Intake Air Temp.

Ive had my filter for about two years and have not had any problems. All you need is a light coat of oil and all will be good. If you are skeptical about using a light amount of oil you can look for a "pre-filter", they work good in dusty climates too. Pre-filters slide over your filter

Anyone reading this, keep in mind. It'* not the filter damaging the sensors. It'* the oil used when to much is used.