RocHatchDX

I have a 1999 honda civic DX hatch, mt, D16Y7 1.6L non-vtec. Now beofre purchasing the car off of a friend the car ran perfectly fine, then the intake manifold was pulled off and a skunk2 intake manifold was installed, this caused issues to the car. I had another thread about the intake manifold and trying to make it work but I ditched all of that because I just wanted to go back to the stock intake manifold for the car.

Now with the skunk 2 manifold the car would jump idle horribly from 1000-2000 rpm's, running from open to close loop on the scanner, sometimes it would eventually level; out and idle normal. . From what was being discussed in theory putting the stock intake manifold should take care of the issue...or so we thought.

I have installed the stock intake manifold and the issue is worse. Start the car and the car will shoot quickly to just above 3 grand then drop down and start jumping idle from 1000-2000 rpm's uncontrollably. I get two codes, p0505 for iac system failure, and a p1457 for an evap leak. The evap leak code was opn before the issue started. I used to get a code for iac malfunction but since the swap back to the stock manifold it now gives me p0505.

I have replaced the ECT, no change. I have checked, re checked, and checked again for any leaks and I have found none. The TB and all the sensors including the iacv are brand new, were installed along with the skunk 2 intake manifold. Now the issue happened before the new TB and thats why it was replaced because it may have been the issue with no change. I have heard of new parts not functioning correctly. So I have been suspect of the TB for some time now.

new TPS sensor, no change. Now while the car is running and jumping idle I covered the hole in the TB for the iac and the car immediately stopped jumping and idled just under 1500 rpm's which is high but it was a big difference. While plugging the hole I was able to adjust the idle speed. For ***** I j-b welded the hole shut and set the idle screw to "closed". when I would start the car it would jump immediately to 1500 rpm and idle normal. but after driving for about 5-10 min the car will start jumping idle again, after witnessing this I took the j-b weld off the hole.

To recap: New tb, new tps, new ect, correct gaskets, and no leaks in the system. Im mainly at a loss. I dont want to throw parts at the problem but I fear at this point I may have to. I cant for the life of me figure out what is happening. If anyone has any information on what to try, test, replace let me know. Thanks in advanced.

P.S. I have also made sure there are no air bubbles in the coolant system.

silkypillows

ensure your o2 sensors are responding well and adjust your idle using this:

--im not reading it in these particular diagrams, but other procedures i've followed have stated to remove the "back up/radio 7.5a" fuse from the under hood fuse box for 10 seconds after idle is set with car off, to reset the PCM.




-silky

Former User

Did you voltage calibrate the TPS when you replaced it?

RocHatchDX

I have been religiously reading through the Honda service manual lately to get more ideas on what to try, thanks for posting that.

No Ron I did not voltage calibrate the TPS when it was replaced, The TPS that was on there was new but I do not put 100% faith in a part because it is "new" so got another one and put it in. On the scanner they both registered a little above 10% while running at idle.

What I did notice today is that the throttle does not shut 100% properly. It gets very very close, but yet it is slightly open but a hair, when I grab it and hold it fully shut myself it helps the idle slightly. I believe I have another TB coming to me this weekend to test the theory I have about the TB not functioning correctly.

Former User

Make sure the throttle cable has some slack. If it's too tight, the idle speed will be too high because the throttle plate cannot properly close. Also clean the throttle body if it's dirty.

After replacing the TPS, voltage calibrating it is crucial. Adjust its output to 0.5V at closed throttle. Then check at WOT. It should read approximately 4.5V.

B_Swapped93

You have to calibrate it properly you can't just "eye ball" it. agree with Ron on the adequite slack on the cable

RocHatchDX

I had the throttle body off and cleaned it in and out the other day. I made sure I had adequate slack in the cable when I put it on, then double checked it as well. I'll take one more look at it tomorrow.

Also tomorrow I will voltage calibrate the TPS to the specs you listed, thanks guys. I will see what happens tomorrow.

RocHatchDX

So here is an update on what is happening. New throttle body, new tps (also voltage calibrated), new iac, no leaks. Still have the bouncing idle. Also there is another thing my car does as well.

If I am sitting at and idle in neutral or in gear with the clutch in and i go to take of, when the rpms are rising it is almost like the rpm's hit a wall and the car jerks and shutters violently. I then have to turn the car on and off and it will stop untill it does it again. This is a video I took of me slowly pressing the gas.
I still have code p0505 and have gone through all the trouble shooting steps for the whole iac system and everything seems to be in working order. Also I have code p1457 for an evap leak somewhere.

I have tested continuity for the connector that plugs into the iac, both wires from the ecu and one from the pgm-fi relay behind the glove box. I everything checked out so no breaks in the circuit.

Anyone have any ideas?

RocHatchDX

Since I do not want to rule anything out yet im all about rechecking things. Instead of putting my finger over the hole in the throttle body that feeds air to the iac, I instead blocked off the throttle body with my hand, the idle dropped only a tiny bit but the engine did not choke out. The other tests for leaks I have done show indicate that there are no leaks present, but after doing this could there be a Possible leak?

grumblemarc

iTrader: (4)

Sounds like a vacuum leak to me. Did you check the IM manifold gasket?

RocHatchDX

To test for leaks I was spraying everything with carb cleaner. Found a leak on one of the air hoses, put a new clamp on and fixed that. where the iac screws into the throttle body was one big leak, I took off the iac and siliconed around the edge and put it back on and took care of that. I sprayed the manifold and i had no change in the rpm's but then again I can really spray the bottom of the manifold so there is a possibility.

The other thing I did to test for leaks was to plug the hole in the tb and see if the rpm's would change. I plug the hole with my finger and the rpms dropped and the bouncing idle stops and levels out. Which is suppose to indicate there are no leaks.

Yet when I plug the tb it should choke the engine out, yet it doesnt.

nub

If you're blocking off the tb and the engine doesn't die you have a vacuum leak somewhere. The bouncing idle is a tell tale sign.

Two things I can point out since you've been replacing parts.

For the P0505, where did you get the replacement IACV. The auto and manual versions are different. Using an auto version with a manual ecu or vice versa will throw this code.

What did you use for the tb gasket? Most parts stores list all civics as the same and they're not. Y7's have their own specific tb gasket. If you use one for a Y8 for example the whole side of the tb under the IACV will be one huge vacuum leak. 16176-P2A-004, $2 at any dealership.

RocHatchDX

The Iac and the gasket are both correct. The iac is for a manual, and the gasket for the tb is for a manual y7.

I may end up tearing down the whole set up again and redoing the manifold to make sure there is no possibility of leaks after I do some more testing. Thanks for the help

nub

I'm not trying to be argumentative but HOW do you KNOW they are correct?

Where did you get the parts and what are the part numbers?

If the IACV isn't OEM I wouldn't trust it. If it is what color is the sticker on it?

RocHatchDX

This is a link to the exact gasket I have been buying from advanced

http://shop.advanceautoparts.com/web...le+body+gasket

Also for the iacv it is a blue and silver sticker, says "denso" on top, "52" on the side
and number 136800-0520

Trust me no arguing here, just been frustrated with the issue. Lots of time invested in this and I hate not being able to solve an issue.

d_boi_swag

Make sure you don't have the tps and map switched sounds dumb but happens a lot

nub

That gasket is for a tb with the IACV on the back of the manifold not the three wire on the tb. If it's actually cut correct you'd want the 61065 that has that extra tab of material on one edge.

If you can, get it from the dealership so you know it's correct.

You're good on the IACV.

RocHatchDX

The TPS and the MAP I made sure were not switched. Just for the heck of it I switched them myself to see the difference, and the difference is huge. I can see why they are easy to mistake but how one makes the car act it's simple to tell when they are switched, imo.

Thanks nub. Ill try to run up to the dealer tomorrow and check out the gasket, considering it takes me about 5 minutes to switch one out now its worth a shot to see if there is any change.

I'll update after I do this on whether it is corrected

nub

That other gasket from Advanced (61065) may work if the dealer is closed Sunday (if that's what you mean by tomorrow).

You can't alway trust those photo's companies use online.

On the inside diameter cut in the gasket for the "bore" there's the "tounge"cut into one side at an angle...opposite that side (180*) one gasket has a extra "tab" of material and the other doesn't.

That "tab" is for the three wire tb under the IACV.

RocHatchDX

Ah Alright Ic what you are saying. Yeah I forgot tomorrow (technically today) they may not be open, I would just wait until Monday because I would like to make sure everything is correct.

I know what you mean about not trusting the photos. I have had a hell of a time with advanced on the gaskets I was buying. They are the only parts place that would have them, they never update the inventory so stores that had them would not have them when I called. Also one advanced the lady working told me that a gasket does not go there. After an argument where I explained why a gasket is there and always had been, plus showing her the gasket I originally removed she still told me one does not exist there. I just walked out

RocHatchDX

So out of curiosity I took a spare gasket and put it on my spare Y7 throttle body. I believe the portion I have circled is what you were referring to nub, the gasket I need should have an extended lip on it to cover that area or else it is just one large leak. Correct?

nub

I was going to mention if you flip the tb over and lay the gasket on you'd see it.

You are correct sir.

RocHatchDX

The little things you dont always pay attention to. This makes a lot of sense. Hopefully upon getting a new gasket and installing it that it will take care of the issue. Ill update when i get that all done

RocHatchDX

I would like to start of by saying thank you to everyone for giving out your ideas and such for me to try to resolve my issue.

I would like to give a special thank you to nub, you figured out the issue I have been fighting with for months. It was instant once I turned the car on that I could tell the difference. Thank you again.

Too many times I have searched threads where no one states if the issue was resolved or not. So I wanted to make sure I posted it. This issue is fixed

Now on to the next one.

Flipperhead

i had the same problem it was the TB gasket . i neeeded the gaket from my original mani. i chased it for hours . i thought my brake bosster had a leak . damn gasket missing the tab letting the iacv ports leak . ihad switched around iacvs from both cleaned yada , BTW the iacv from the tb on the ex had 54 in purple and the air port was slightly larger than the 52 in blue) stoopid gasket forgot to say thanks to the members for following this through and posting