A_Rotary_Guy

My girlfriend's 97 Civic DX MTX is throwing a code for the IACV, but I finally realized that it's not the IACV causing the issue. It's actually the TPS causing the problem. When the car is idling without your foot on the gas it's reading 11.4% throttle and idling at 1000 RPM's, meaning the TPS is reading incorrectly. Is there any way you can adjust the TPS or do you just have to replace it? Is it even a replaceable part?

overspooled

just replace it. they are pretty cheap

A_Rotary_Guy

I just wasn't sure if it was a replaceable part because Honda doesn't sell it seperately. Also, when I looked at the throttle body it didn't look like it was removeable, but I now see that you have to use a flathead screwer and put two slits into the bolts to remove them.

So, where can I buy another TPS and is there a specific brand I should go with? And where can I get a gasket for the new TPS?

wernhersey

I think that the only thing u can do is repace it with a used one. GL

turbo-2nr

you can replace it with a aftermarket omni power,blox, ext look in ebay. honda only sells the whole throtle body, but try and ajust the on you have first because your going to have to ajust the new one any way

A_Rotary_Guy

Yea, I figured I could try and adjust the one on the car before I go trying to get a new one. It could be just that the stock one is out of adjustment. Good to know if I need a new one I can get one off eBay. Now I just need to find the specs for adjustment.

A_Rotary_Guy

I was able to find this thread that lists the specs the TPS is supposed to have.

https://honda-tech.com/zerothread?id=2193100

How exactly do you go about adjusting it? Do you just loosen those two screws and then slide it around until you get the correct values and have it reading 0% throttle when you're not touching the gas?

The_Honda_Guy

Well, I got a chance to check out the issue with the TPS and IACV. The car was throwing a code for the IACV, but it seemed to be functioning correctly. The car was idling high at 1000 RPM's but the fast idle was working correctly. Also, the car would very intermiddently throw a CEL for the IACV but the car would still function correctly.

Well, I checked the TPS according to the Hayne's manual. It has .5 volts at closed throttle and 4.5 fully open. Also, when opening the throttle the voltage smoothly climbs from .5 volts to 4.5 volts. Also, the TPS is getting the correct reference voltage (equal to battery voltage). So it seems to check out correctly.

Nextly, I started checking the IACV. While the vehicle was running at operating temperature I unplugged the IACV connector and the idle increased. It says in the Hayne's manual that the D16Y7 engines should increase in idle speed when disconnecting it, so it checked correctly there. Next I checked to see if it was getting a reference voltage and it was. Finally I checked the resistance between the connectors. The Hayne's manual said there should be 16 to 28 ohms resistance between the middle terminal and the two outside terminals. I found there was 0 ohms of resistance between the terminals. So, now where do I go from here? It just says that if the IACV tests correctly on the resistance test to check the PCM and circuit for the IACV, but doesn't say what to do in the case if it tests bad. I'm guessing that I'm supposed to replace the IACV? I already tried cleaning it and it didn't fix the problem, so I'm guessing my next option is to replace it.

The_Honda_Guy

Around have any ideas on this one?

The_Honda_Guy

No ideas anyone?

2redstars

did you try cleaning out the tb? worth a try.

The_Honda_Guy

Yea, I de-carbed the TB and IACV. I'm pretty sure the IACV itself is defective and needs to be replaced. As a last resort I'm going to try and adjust the idle using the screw on the TB to see if that does any good.

The_Honda_Guy

Well, I got a scan tool and started checking out some more stuff on the car. I started by checking all the sensors associated with the intake. The TPS is reading 11% throttle at idle and all the wiring and voltages are correct. The MAP sensor is reading the correct vacuum and voltages too. The distributor advances and retards the timing correctly while adjusting it and while changing throttle positions. The IAT sensor is reading the correct ambient temperature. All seem to be working correctly.

Nextly I tried to adjust the idle using the set screw on the TB. I was able to adjust it down 25 RPM's before the screw bottomed out and I couldn't adjust it down any further. I then thought maybe the distributor timing could be advanced and throwing the idle off, but it's reading 12 degrees at BDC like the manual says. After that I started checking for vacuum leaks but couldn't hear any and all the vacuum hoses are good with no cracks.

My last resort is to replace the IACV. What do you guys think it could be?

The_Honda_Guy

Any ideas guys?