you are right I forgot they were 2 seperate things. I guess I was talking about the throttle opener then the one with the vacuum line by the tps.

you are wrong about the car idling down in any other way than the IACV. that is the only way it can idle down, it will close up the IACV until it gets to 650 rpm no matter what. as I said earlier you have not turned the idle screw far enough, all you did was go to 1000, and ecu told IACV to go down 1 setting and you get 650 again. what you need to do is keep turning it and give it a few minutes to adjust again and you will find that when the IACV is in the lowest position it cannot go down any more and you will be able to set an idle that the ecu cannot lower anymore (since its in the lowest position, but the ecu can raise it still for cold start etc..)

so try turning it a few more times and then find a way to get the tps in range. might need to slot it out or something I am not sure or maybe we need to make an adapter plate that allows the tps to turn back more. I can think that cutting the plastic edges around the tps hole would give you a little more adjustment if you use a washer or something but I haven't done anything like that.

The dashpot under the throttle cable side is just there to not let the throttle plate snap closed too fast. this has a worse affect on manuals which is why the rod is set out at a higher rpm. it just softens the closing of the throttle body it shouldn't be used for setting the base idle.

no matter what you do increase the idle screw or tighten down on the throttle cable to open up the throttle blade (or even if maxing out the dashpot will hold it open more), its going to be turning the tps still cause the tps sits on the throttle blade, so you haven't gotten around the problem at all by setting the idle amount somewhere else than the screw. what you need is to turn the idle screw more and find a way to get the tps back in range, but the slots on the tps are only so big. maybe if we made some kind of adapter that would let us turn the tps further it would solve the problem. like a thin piece of metal with 4 mounting screws or something.

or maybe the arms inside that turn the tps can be clocked back a few mm. then it would be like turning the tps but instead turning the arms. it would probably take a bit of modification to that piece not sure that would be feasible though.

The q45 throttle body because of the adapter you can place the tps in any position so it makes it much easier, but I have found with the q45 throttle body it lets in so much more air faster than before that if you go from cruise to accelerating too fast it will lean out for a second. didn;t used to do that before with the stock stuff so the FFIM and larger throttle body is sort of pushing the stock tune a bit, but for everything else its still working pretty good.

Why is the car cutting out though can you take a video of it. mine used to idle at 650 and sure it would dip occasionally but it wouldn't ever shut off.

 

I'm not really trying to change the idle, i want it to run like stock. It idles smooth at 650, but when the car revs down it just dips to far like its not coming down soft it goes down hard and stumbles to survive and come up. I've had the screw as far down as the top of the nut but didn't want to push it any further. That's why i was thinking one of the two things would help my problem. i think you are correct about the tps not going far enough but its not something i really want to play with. Its such a small weird problem that just kills normal driving. I could probably take a video if my description sucks. But when i looked up ppl talking about the dashpot it sounded just like what I'm experiencing

 

well you could always max out the dashpot and see if that helps, it does let it not snap closed but once it closes you will still have the issue possibly. I have never really adjusted one let us know how it goes and if it helps.
The q45 throttle body I have on now has literally none of those things. its just a big throttle plate and a tps, I kind of dig the simplicity but wonder how they got away with that.

 

Yeah i'm pretty skeptical, especially since no one else seemed to have this problem. Which just adds to the mystery of obd2.

I'll look at the throttle tomorrow morning but I won't be bale to do anything until Saturday.

 

So, has anyone figured out how to wire up the TT ecu trans? I have a complete TT transmission and drive shaft ready to go in, but I'm a bit concerned to tackle this by myself as it does not seem to be a matter of just running a few wires between the ecu and the transmission harness. I can't seem to make any sense of the pinouts I've looked at so far. However a manual swap is not an option, so sooner or later The TT transmission will be going in.

 

I would open your throttle past where you idle at 1000rpm on cold start. I idle at 1200rpm on cold start up and then it settles down to 1000rpm when warm. There is a point where it physically can't idle down further. I also have the issue where the engine will stall after a hard pull when I let off because the engine doesn't catch itself. I just give the throttle a light tap as the rpms fall. If you get used to this then it won't bother you.

 

The whole idea of the mod was for it to run like stock for me, which is asking alot apparently. I have the same thing but im usually up shifting so it won't have the 3-4 seconds to stall. I could get a new screw to force the idle even further down i suppose but I want to give these two things a shot first.

They are both adjustable I checked today, but im not sure which one would be the most helpful. The "dashpot" seems like it does almost nothing, so I was thinking if I increase the way the throttle opener slows down the revving it will keep the plate open a bit longer and stop it from being really rich as the engine revs down. But the real problem is the bounce down on idle which would be the dashpot. So it almost seems like you have to change both, but I think Ill start with the opener.

 

Yeah it seems like we all get some form of the dip when it wants to idle at 650 rpm's.
it doesn't seem to be map sensor or maf specific, but the stalling after a hard pull is definitely BOV and MAF related. if you had a map sensor it wouldn't do that nearly as bad. you could always use a map ecu or a vpc/safc combo, or try and get a stiffer BOV.

normally the gte guys use a map ecu or a safc/vpc where the vpc will make it map sensor to get rid of the bov issues, but now I am wondering how the stock bov gets away with it then. maybe it lets very little pressure out compared to aftermarket ones.. hard to figure it out without seeing it.

 

Yea I figured it's because my BOV vents to atmosphere.

Quick update; I finally switch over to a 6 speed ecu and I am getting some codes after 20 or so miles of driving.

I don't remember the exact codes(I cleared them without writing them down like an idiot) but 1 is for "wastegate control circuit" and the other is the same "EGR Insufficient flow" that I had with the auto tt ecu.

Anyone have these, or a fix for these? My tags expire this month so I am down to the wire getting past emissions.

 

you really have to let it go or try to come to a stop right out of boost to get it to stall fast, which never really happens because you should always be in gear or going to a gear before it stalls. I don't think the bov makes any difference because I tried it both ways and it made no difference with my existing issue other than not making cool noises anymore .

Just curious, what do your afr's do when u rev it (3-4k) up in neutral and let it drop back down to idle?

 

the waste gate one is a resistor fix, and the 02 you can do a couple different things. I have an 02 spacer on mine and its hit or miss but I haven't been able to run my car super long.

I know I still have one to fix which is pin 60, it might be the same code.

 

My AFRs will spike rich then lean then right back to normal all within like a second. Always between like 13.0 and 16.0 give or take a few tenths Which I would assume is correct.

 

Guess this makes road racing and autocross difficult for us lol

 

I'll have to take a video of my afr's and everything this weekend. Right now i think drifting is the only thing that would work if u hold it in 3rd gear forever. My afr's go really rich on the rev down to idle, which seems like the opposite of what I would expect.

 

Hey guys I have a few questions. Is the wiring harness pinout the same for a 93 GS300 and the SC300? Because I cannot seem to find pinout on the non vvti GS300. Second what is the absolute lowest number of sensors I need to run the engine so I can pull them out of the harness. Mind you I have a 94 gs300 na-t in a 1989 Chrysler Conquest with full stand alone...R-154...I won't be needing emission stuff. I am pulling the stand alone out for another project and want to put the tt ecu on this engine. A few things I know I will need to change out already is I have low-z 1600cc injectors, GM 3 bar map, gm coolant sensor, ford tps and throttle body, gm IAT, ford IACV, msd 6a ignition and coil. I do have and already use the distributor and the two Toyota knock sensors. I was hoping to be able to pull everything out of the GS300 harness and leave only the minimal engine running wires.