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Discussion Starter · #1 ·
M buddy owns a 99 civic si with the b16a2 motor. the only mods are DC sports header, high flo cat, magnaflo cat back and a AEM v2 intake.

He tried to install a skunk2 intake manifold and a skunk 2 throttle body. The problem is after installation is when the car is started it revs to 7500 rpm then drops to idle and jumps to 4200rpm and goes back down and goes right back up, We checked all the vacum lines and all and cant figure out why this is happening. No codes. Any help would be great
 

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Did he disconnect the battery before doing the work, particularly plugging/unplugging electrical connections?

Is the TPS properly calibrated on the new throttle body?

Also, you might have the vacuum lines correctly installed, but that doesn't mean there's no vacuum leak somewhere. Like if the intake gasket was reused (a no-no), or if it wasn't scraped off entirely from the head for a clean surface. Or the intake bolts perhaps aren't properly torqued or were torqued out of sequence. Or perhaps you have all the lines connected but there is another port that is open with nothing attached to it causing a leak.
 

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Discussion Starter · #3 ·
I wasnt the was one who put it on so I have no idea if the battery was disconnected. The gasket was replaced, i know that much. The stock intake and TB were reinstalled.

I went to the honda dealer with him to buy a new TPS and they told us the TPS should have never been removed and that the only was to get a nw one was with a new TB and that costs $600.
 

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It is true that you can't buy a TPS new from the dealer by itself, but you can buy new ones from Ebay. And you can remove it from the stock t/b and put it on the new t/b. It just has to be calibrated with a voltmeter before tightening it all the way down. I made a little jumper harness I can connect the voltmeter to to calibrate them. It's really fairly easy and there are instructions for it somewhere on this site as well as elsewhere on the web.

Removing it from the old t/b is also fairly easy.
 

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Setting the TPS

You have to use a voltmeter to set the Throttle Position Sensor, the TPS sends a voltage signal to the computer to tell it how far open the throttle is. If it isn't set properly then the TPS will send the wrong voltage to the ECU when the throttle is closed, creating a bad idle.

To fix this you need it sending the right voltage when the throttle is closed.
There will be three wires going to the TPS.

The Green one is a ground
The yellow one is constant 5V
The red one fluctuates between 0 and 5V depending on how open or closed the throttle is.

You need to connect the voltmeter to the ground wire and the other one to the fluctuating wire by exposing some of the wires. Loosen the screws and shift the TPS around until it gives a voltage of 0.45 Volts when the throttle is CLOSED. It doesn't matter what it says at open throttle.

The harness must be plugged into the TPS which must be attached to the TB, therefore it is much easier to do this with the TB removed.

If you need to adjust the TPS, loosen the two small bolts holding it on and turn it either way until it gives the correct voltage. Some TPS's are attached with rivets instead, in this case you will need to use a Dremel tool or similar to remove it. If there are rivets holding it it is most likely still set from the factory and will not need setting.

If you need to adjust you idle, turn the idle adjustment screw with a flat blade screwdriver. If the screw is loose you may need some silicon to hold it still like I have.




After doing this I noticed my idle wasn't quite right. The Honda manual I have says 0.45V but when I measure my stock TPS which was still set from the factory it was 0.32V so that is what I have mine set to. Once I had it set to 0.32 the idle was fine.

If you know someone with the same car you could measure their closed throttle voltage to see what their car has but try setting to 0.45V first. I suggest you measure your stock TPS setting before moving it so you can at least revert back to the original setting. There may be other Hondas which have settings other than 0.45 volts, you can ask someone on www.**********.com who may have the same car.
 

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If the original/stock throttle body was re-installed, then I doubt it is an issue with the tps. It is most likely a vacuum leak or he may have gotten the map and tps sensor plugs mixed up.

Here is a little write-up on the tps : http://www.superhonda.com/forum/showthread.php?t=239633

Also did your friend replace the intake manifold gasket or did he try to reuse the original one? Have you checked all around the intake manifold to make sure that all of the ports/fittings have a line connected? Also, did he remember to re-adjust the throttle cable when he installed the new manifold?
 

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Discussion Starter · #8 ·
Well the TPS and MAP was removed from the stock TB inorder to use on the other one. I dont know what was done to it or anything. The vacum hoses were all replaced and the gasket was replaced for a 2nd time and still no luck, Im goin to try that volt thing too. If not Ill just stick a match in his gas tank :bash
 

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ah, so the original throttle body was *not* re-installed. If the tps was removed, then it needs to be recalibrated. However he still needs to check the tension on the throttle cable. My idle shot up to 5k rpms when I installed my edelbrock IM. Problem was it moved the throttle body and the extra tension on the throttle cable caused the throttle to be partially open even at idle.
 

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Discussion Starter · #11 ·
new

We unplugged the idel motor on the back of the manifold. Itll hold a idel at about 1500rmp but its real rough. if you plug it back in and start the car back up itll go to 7600rpm..but if you keep it unplugged and re-start the car itll hold at real rough idel :bash :bash :bash :bash
 
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