Jason280ZX

So i just recently swapped my 280zx NA 83 thottle body (TB) to a 240sx 60mm TB. Ive asked once before about whether its okay to remove the Air regulator (AR), because doing the swap completely removes the availability to keep the Air Regulator. Also doing that also removes the idle adjuster, so im assuming that all the open vacuum lines that connect to anything with the Air regulator and Idle adjuster setup has to be capped with something. Same with the coolant line that sits above the intake manifold. There to is a senor i was told to remove without having serious changes or problems. So without the (AR) its okay ive been told. Ive placed a breather filter on the valve cover, that too is okay.

So my real concern about this is because ive blocked off almost everything on the intake manifold besides Fuel pressure regulator vacuum, carbon canister vacuum, and distributor vacuum. How can air properly pass through the throttle flap when its completely closed. Isnt that what the idle adj. must do? To be able to bypass air, and regulate into the intake without throttle opening. Now how can i do the same without choking the car of air? My car turns on but it idles VERY rough when the throttle is completely closed. When open it runs pretty good, struggles to pick up, but thats of still needing to fix distributor timing. The only vacuum line coming off the TB below it is for the distributor. Thats what really keeps a flow of air into the intake.

Also because of the swap i couldnt use the stock tube from AFM to TB anymore. I just bought a silicone 45 deg bent tube to replace it. Now ive tried adjusting the Throttle position by screwing the small bolt more upwards to keep the Throttle flap a bit open, but then my car shoots up idling super high to that i cant adjust the distributor enough to proper timing. I keep having misfiring even at, that i assume, proper BTDC.

Im trying to reach perfect medium with idle and timing. I really need help with this part of this swap, i didnt really know what to expect, i was hoping for only no need of going megasquirt of stand alone. Please help.

Jason280ZX

I should also add that im running a dual electric fan onto the new radiator. So that takes load off the engine. Ive heard that can effect the engine also by timing maybe or even idle. Both possibly but i need help for this part. I've done a lot of research about this and apparently its all okay on a stock ECU and for a non turbo.

Jason280ZX

So i just recently swapped my 280zx NA 83 thottle body (TB) to a 240sx 60mm TB. Ive asked once before about whether its okay to remove the Air regulator (AR), because doing the swap completely removes the availability to keep the Air Regulator. Also doing that also removes the idle adjuster, so im assuming that all the open vacuum lines that connect to anything with the Air regulator and Idle adjuster setup has to be capped with something. Same with the coolant line that sits above the intake manifold. There to is a senor i was told to remove without having serious changes or problems. So without the (AR) its okay ive been told. Ive placed a breather filter on the valve cover, that too is okay.

So my real concern about this is because ive blocked off almost everything on the intake manifold besides Fuel pressure regulator vacuum, carbon canister vacuum, and distributor vacuum. How can air properly pass through the throttle flap when its completely closed. Isnt that what the idle adj. must do? To be able to bypass air, and regulate into the intake without throttle opening. Now how can i do the same without choking the car of air? My car turns on but it idles VERY rough when the throttle is completely closed. When open it runs pretty good, struggles to pick up, but thats of still needing to fix distributor timing. The only vacuum line coming off the TB below it is for the distributor. Thats what really keeps a flow of air into the intake.

Also because of the swap i couldnt use the stock tube from AFM to TB anymore. I just bought a silicone 45 deg bent tube to replace it. Now ive tried adjusting the Throttle position by screwing the small bolt more upwards to keep the Throttle flap a bit open, but then my car shoots up idling super high to that i cant adjust the distributor enough to proper timing. I keep having misfiring even at, that i assume, proper BTDC.

I also did a dual electric fan kit with my new 3 row radiator. I've read before it should effect idle speed and possibly timing. So over view what ive done

-New Cardone Distributer
-240sx TB swap with 1'' spacer
-removed the AR, idle adj, and that small temp sensor that sits above the intake manifold but below the AR.

Can removing those really make a big impact to my car that i should worry about? Ive posted this on Zcar.com hoping someone there to can help also.

mrprofile

I don't think they have temp sensor on the intake manifold, you may have removed the cold start valve. post a picture of your setup so we can get an idea.

Jason280ZX

I do have the Cold start valve connector removed, but ive been told its unecessary. I live in Texas so cold weather isnt to much of a hassle. Your correct about the water temp not on the intake manifold, but its a sensor that as 2 connectors separate, you'll see it in the picture. It sits within the coolant passage that runs through above the stock TB, underneath the Air Regulator, then back to the heater hose where coolant runs into the water pump, but aside from that, im worried the fact that im using a custom TB setup from a 240sx. Meaning i had to remove the AR and all the other vacuum stuff around the intake manifold. Would i need to adjust the idle screw on the TB to make a small enough opening to allow air in? I got pictures below so you may see my setup.

mrprofile

opening the throttle plate a little bit to get air in the engine seems like a good idea, problem is the computer reads that slight opening of the throttle plate, as you pushing down the accelerator pedal, so it tells the injectors to give the engine more fuel, so your going to end up with a rich situation no matter how much you open that throttle, you have to find a way to surpass the throttle plate to let air in, which is where the idle adjustment screw comes in, problem is you took yours out, now you could put it in and have it get air from the outside but then you would be letting unfiltered air into your engine, never a good thing.

NismoPick

Some people have had luck getting the car to idle w/o the air regulator, and they are mostly using MegaSquirt.

I kept mine... just added a port to the TB spacer:

FricFrac

You could probably bypass the IAV but you are going to have different cold/hot idle speeds. Adjust the TB so it's partially opened.

The cold start valve is when the engine is cold - eg not at it's operating temperature of 90 deg C.

Mega Squirt is smart enough to take the air temp and adjust the fuel at the injectors - no need for a cold start valve. IIRC my warm up enrichment curve goes until around 75 deg C.

NismoPick beat me to it - add the valve to the spacer. One of the guys who made spacers had his machined for adding in the valve.

FricFrac

... and for all your work you won't be getting any performance gains with the 60mm TB on an NA car....

Jason280ZX

Yeah sadly to say most of this work wont get me much at all, but i really like the clean setup going. Im glad to hear ya'lls thoughts on this. I was hoping i wasnt doing anything wrong here. Well ima have to figure it out then. Thanks guys. I feel a lot more confident getting back to work onto it.