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Throttle body differences?

1058 Views 5 Replies 3 Participants Last post by  aznnp77
Hi, don't know where else to post this but I have a question:

I recently blew my 2005 Civic coupe's d17a1, (spun rods, shrapnel in the oil pickup, bent crank, warped block etc) and found a good engine on marketplace. Only problem is it's a d17a2.

I tore down the VTEC engine and put a new head gasket in and decided to even put in the d17a1 intake on (it was cleaner). But I noticed that one of the sensors on the throttle bodies are different. One has 91 on it (the one from the a2) and the other has 90. Is there a difference? Engine runs no problem but auto transmission is a bit rough. Is this a VTEC specific sensor? Or a Transmission specific one? Any help would be appreciated!!!

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Maybe this will help.
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My best guess is the IAC valve. If so it adjusts idle speed and prevents fast rev drop stalling (dashpot).
I can't think of a way this would effect shifting right off.

You might consider changing to the ecu/harness from a d17a2 so you get the vtec solenoid working. The cam figure w/o it is very mild. ..I.e. big difference in mid and upper rev power with vtec working. If you did/do change it, I suggest using the A2 throttle body to keep everything matching.
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You might consider changing to the ecu/harness from a d17a2 so you get the vtec solenoid working. The cam figure w/o it is very mild. ..I.e. big difference in mid and upper rev power with vtec working.
Thanks for the info. Quick Google search of the part number confirms it's an iac valve. I changed it to the d17a2 throttle and notice idle is a bit smoother. Transmission is still doing weird things, but it's a honda auto transmission from 2005, so I guess its just on its way out. VTEC ecu and harness not worth it, probably just wait for this one to die and get an 8th gen civic instead
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Quick idea on the trans problem. I've had AT troubles when somebody had put in the wrong fluid type. It may very well be toasted though considering the crater the previous engine left.
I just changed my throttle body as well just a shot in the dark to see if the sensors were bad or something. I was running into the same question as you. That IAC valve has a different number for the last number. I wouldn't worry about it too much.

I got a used one off ebay, and I was checking the number on all of them. I did eventually find one that ended in a 0, but it was very hard to find. There was probably like 3 of them out of hundreds. I saw a lot of them that ended in 1, but I really don't think it matters. My car is an 01, and the throttle body came from an 03. Pretty sure they're pretty much interchangeable, especially if only the last number is different.

I've replaced my transmission 3 times already, so I've been through the slipping before. I've tried a lot of the transmission additives. Lucas stop slip actually killed my first transmission. Maybe I overfilled it or something, but it was completely done after I put that stuff in there. I did try again afterwards and it helped a little bit.

The weak spot of the transmission between 2nd and 3rd gear. Mine started flaring a few years back.

The thing that worked best for me was a fresh 3 quart drain and fill of Honda DW1 with 4oz of Lubegard red. It would actually make the car run pretty good for a couple of weeks. My friend has a GMC Yukon Denali, and he even put some in his transmission and it got rid of his transmission rumble even though it was the wrong type. I think domestics are suppose to use Lubegard platinum or something. Red is for Hondas.

But yeah, give that a try. Should be like 30 bucks for 3 quarts of ATF, and like $10 for the Lubegard red. It's $8.39 on ebay right now: Lubegard Red Ebay . I've bought from that seller before and he's fast.

I've also tried Seafoam Transmission treatment. I don't think it did anything. The one I disliked the most was Rislone Transmission Stop Slip. It made the car feel really heavy and the shifts were really lazy. It felt like it took forever to shift.
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Also, I hope you took off the IAC and cleaned it before you reinstalled it. Or at some point after you installed it. It does make the idle a smoother if you clean it out. The screws on it are pretty tight sometimes. I actually bought an impact screwdriver just for those screws. But it made the job so much easier.

Oh yeah, and don't clean the black film that goes around the throttle plate. I think it's intentionally put like that, so it's almost like a gasket for the throttle body. I cleaned mine spotless the first time, which was a mistake. I dunno if it mattered, but I did buy another throttle body because of it.
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