secondary throttle plate reinstallation
 

ok, this past week i did some work on the t2 and decided to remove the secondary throttle plate while everything was apart....after everything was put together, took it for a drive and found the under 3k hesistation to be VERY annoying....i miss the responsiveness of the old setup....is it possible to put the plates back?...i only removed the plates and left the rotating shaft still attached

also....could this hesistation be caused by too much fuel?.....cleaned 550/750 with a walbro 255.....

btw.....pickup after 3k is alot faster.....however i do 90% of my driving in the 2-4krpm range....yes..i know its a 7...but no point in driving like an idiot in normal traffic

you left the shaft in but you took out the plates? are you positive you didn't take anything else out? I removed my plates and shaft and found no problems afterwards, i find your situation kind of strange.

Odd that you have less responsive after removing the plates, i had better response.

I would think that you can put them back in just like you took them off, screw the plates back on.

yeah...before i did the mod i read up on it and found that not too many people had problems with the mod....but i guess it might be because my O2 readings is weird and makes the comp run in open loop constantly.....

putting them (plates) back on is going to be a bitch if you know what i mean. were the 4 screws completely stripped after you removed the plates? they are like aluminum foil screws, i just drilled them out. i even tried soaking them in PB for a good hour, but they are loctite'd in.

Make sure you use Loctite on the screws. You don't want your engine to eat them. I've seen lawnmowers eat throttle butterfly screws and it ain't pretty

you know the plates are only active when the car is warming up rite? so this cant be your problem.

Wrong. That's only on NA's, On Turbos the upstream plates operate in tandem with the downstream ones, but their motion is damped to prevent bucking if you open the throttle too quickly.

torean, the problem is your driving style. Mazda put this system in because of people just like you. ;) If you train youself to open the throttles a little slower below 3000rpm you won't have a problem, and the throttle response will still be better than with the system working.

yes i kno..but its easier to change the car setting than my driving style.....its just anal to drive with the plates off thats all....its like a different car now plus it stumbles alot with the way i drive.....i know my O2 is busted...would that cause the hesistation to be worse?....running in open loop and dumping more fuel than i need?

I would disagree, but that's because I drilled the screws out...

Then your driving style must be really bad, because most people don't have that much of a problem with it. There's no point in driving like that, all you're doing is using more fuel without getting any more performance. Consider this an opportunity to teach yourself to drive a little better. Finesse is always better than ham-fistedness. ;)

Another possibility is that you've done something wrong and the TB is not working properly. Make sure the plates open smoothly as put pull the throttle cable, without any binding or sticking in the mechanism. You impiled that you only removed the plates but not the shaft, which is not recommended since the plates stop the shaft from moving sideways, which could jam the linkages.

No, the O2 sensor is only used during light-load, constant-speed cruise and the reduction in fuel used isn't that much. You can't tell the difference between a good sensor and a bad one (or none) from the drivers seat.

Make sure your TPS is working properly and is adjusted. When you remove the double throttle on the t2 it will become much more dependant on the 'accelerator pump' enrichment which should occur when the ecu detects major positive throttle movement. I don't know exactly how the stock ECU operates this mechanism, if it uses the AFM or TPS exclusively to detect this condition, or a mix of the two... I would assume the TPS is the primary input for the accelerator pump enrichment, but the stock setup is a bit odd. The double throttle when it is present will dampen this transient requiring less accelerator pump enrichment during abrupt throttle movement, but the problem is when you have the stock ECU, the enrichment configuration will be for a stock throttle with the damper present.

This mod on stock ecu cars works best on NA's, T2's are more sensitive to it, if you go standalone or have a way to tweak the accelerator pump enrichment on the stock ecu it can be made perfect.

The fact that they do not have this on the NA's but do on the T2's makes me suspect it depends on the AFM for the enrichment, the increased latency of the T2 AFM due to the intercooler and turbocharger between the throttle and AFM are probably why it needs a damper vs. the NA. If this is the case, it's bad news for doing this mod on stock ecu'd T2's in my opinion... go standalone.

I used an impact tool on the screws and they popped right out in mint condition :D

Then I used some loctite and put set screws back into the plates. I reccomend it.

nope...i used a screw driver and they came right off :)