marlim4lude

I have a 1997 Civic hatchback with a bone stock D16Y7 that I got from my brother. He had the car turbo'd for a couple of months and he recently decided to buy a s2k. Instead of selling the vehicle I decided to keep it as my daily driver. Current job situation changed my plan of doing the swap for now.

The problem is the erratic idle problems. The car pretty much sounds like it has high performance cams. Since the car doesn't have a tachometer. I am not able to tell the rpm range it bounce up to.

The cars idle jumps up and down and it stops once I disconnect the map sensor plug. Another thing I notice is that there are times that when I disconnect the map sensor plug while waiting for the engine to warm up and plug it back up. It idles normal until I turn off the motor and restart. I am hoping somebody here had experienced this problem and can give me a better idea if I should replace the map sensor. I just don't want to spend funds on something that is not broken. Thanks guys.

Duane_in_Japan

adjust the idle screw, do a search for idle problems, its called a vacuum leak but it could be a vacuum leak inside the throttle body not from the outside of the intake manifold, its called fuel cut strategy, the computer is doing what it is supposed to do in this scenario.

97civicdx

Try the IACV cleanout. Search for procedure.

97Ej6mike

Vaccum leak + IACv problems.

DO NOT UNPLUG YOUR MAP SENSOR!
You may think this solves the problem, but it in fact is hurting your motor by dumping excess amounts of fuel in, which when you drive, you can see its richness blow out in clouds of blacksmoke. This excess fuel will foul over your sparkplugs, foul up your 02 sensors, get you less than 100miles to a full tank, and burn out the insides of your catalytic converter, leaving you with a whole world of pain you do not want to deal with. Deal with the Loping idle for now, and look to have the IACv replaced and manifold checked for leaks


Modified by 97Ej6mike at 7:13 PM 10/8/2007

marlim4lude

Thanks guys. It appears removing the IACV for cleaning is tougher on the D16Y7. It is actually riveted instead of being bolted. I think I will have to see a mechanic for this. Thanks again.

confucioussae

iTrader: (1)

it could be possible that your TPS and MAP sensor plugs are mixed up.

They're the EXACT same plug, and if they're mixed up your car will run like ****. Give it a try, and swap them. If it still runs like ****, just put them back. You will not be running your car very long while doing this. Not long enough to damage it, anyway.

vrrodri

The IACV on a D16Y7 is on the front of the TB. You should not see rivets there but 8mm bolts...

EL Vap133

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vrrodri &raquo;</TD></TR><TR><TD CLASS="quote">The IACV on a D16Y7 is on the front of the TB. You should not see rivets there but 8mm bolts...
</TD></TR></TABLE>

Correct, I was able to unbolt mine. I hope you're not thinking about the TPS.

marlim4lude

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EL Vap133 &raquo;</TD></TR><TR><TD CLASS="quote">

Correct, I was able to unbolt mine. I hope you're not thinking about the TPS. </TD></TR></TABLE>

Yes I was thinking about the TPS. Whew! The darn thing was full of gunk I had to soak it with gun cleaner.

Update: The problem went away but came back after a couple of hours. I cleaned the IACV very good that it almost looked brand new. Any more suggestions as to where to look? I've checked all the hoses and no leaks.

Thanks everybody here has been very helpful so far.


Modified by marlim4lude at 12:25 AM 10/11/2007

vrrodri

test the ohms on the iacv terminals. if no resistance, then the iacv is bad, replace it.

Z3120

Try cleaning out the throttle body also.

EE_Chris

Was it always idling like this? Is the CEL on at all? Is the car still turboed?

Have you done a tune-up? Cap, rotor, plugs, wires, set valve lash, clean grounds, etc etc etc? Have you played with the idle screw or the TPS stop screw?

vrrodri

I'd say that before you do a major tune up, check the compression and condition of the engine, a leak down test, so that you are confident in spending the $$ on the tune up knowing that the engine does not have major problems that the tune up will not solve...also rule the IACV out as a culprit through the OHMS test.

marlim4lude

Update. I played with the throttle cable and TPS stop screw the idle problem went away but running a bit rough. I changed the spark plugs (burnt) distributor cap and rotor. Car is running much better now but the engine light is on. I tried to reset the ECU but the cell remained. I will need to have somebody check the code and go from there.

The car is not turbo'd anymore. Thanks guys.


Modified by marlim4lude at 9:41 AM 10/13/2007

vrrodri

Did you pull the code?

Duane_in_Japan

I will only guess but I will say you have a TPS code, the throttle stop screw is not for adjustment, that is what a throttlebody cleaning and an idle screw are for and an IAC cleaning if not cured by above cleaning. If the TPS has yellow paint on it, in some states during an emission test, this would be a failure due to tampering with the OEM settings, FYI. Your TPS now, may not be at the correct low voltage location that the ECU wants to see???

speedooo

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 97Ej6mike &raquo;</TD></TR><TR><TD CLASS="quote">Vaccum leak + IACv problems.

DO NOT UNPLUG YOUR MAP SENSOR!
You may think this solves the problem, but it in fact is hurting your motor by dumping excess amounts of fuel in, which when you drive, you can see its richness blow out in clouds of blacksmoke. This excess fuel will foul over your sparkplugs, foul up your 02 sensors, get you less than 100miles to a full tank, and burn out the insides of your catalytic converter, leaving you with a whole world of pain you do not want to deal with. Deal with the Loping idle for now, and look to have the IACv replaced and manifold checked for leaks


Modified by 97Ej6mike at 7:13 PM 10/8/2007</TD></TR></TABLE>


it didnt say that he was driving with it unplugged like you did for a month

marlim4lude

I have not had the chance to see my friend that has the code reader. I am now suspecting the TPS sensor. For some reason the throttle body gets stuck mildly open causing the erratic idle.

marlim4lude

"I will only guess but I will say you have a TPS code, the throttle stop screw is not for adjustment, that is what a throttlebody cleaning and an idle screw are for and an IAC cleaning if not cured by above cleaning. If the TPS has yellow paint on it, in some states during an emission test, this would be a failure due to tampering with the OEM settings, FYI. Your TPS now, may not be at the correct low voltage location that the ECU wants to see???"

I strongly agree with you on this. Appears the TPS is bad. It is riveted on the throttle body and a pain to replace. If I wasn't living in CA and the job situation permits I would have done the swap already. Thanks.

Duane_in_Japan

I didnt say it was bad, but yes it could be, I was saying since you touched the adjuster that is not supposed to be touched that it is out of adjustment now, open too far, giving the wrong voltage to the ECU and allowing too much air in the engine causing your eratic idle, can you close the idle screw more to compensate for the idle flux???

Can you tell us the voltage at idle from the TPS please, do you know the spec?

marlim4lude

Actually the erratic idle went away as soon as I opened it up a little. I tried playing with it without the intake box to see what is causing it. I noticed when I step on the throttle the throttle get stuck open just a tad bit causing the idle to fluctuate. When I removed the whole throttle assembly the throttle seemed to move freely without any issues. The problem went away when I opened up the TPS adjuster a tad bit but the engine check light still stayed on even with the ECU reset.

As far as the voltage at idle. I do not have a voltage tester and I will have to see if I can buy one today. Does anybody here know the actual spec? I really appreciate everybodys assistance on this. I am learning a lot in the process which is worth more than the money and time I spent working on this car.

EE_Chris

For OBD2, it needs to be less than .49v at idle.

Duane_in_Japan

Yes, adjust the throttle plate back where it was to get rid of the CEL, clean the throttle body if you didnt already do so and adjust the idle speed with the idle screw and the idle flux should go away and so should the CEL.

ywsek

From my own experience, the main reasons for idle fluctuations is due to the fact that there is a vacuum leak or you have a faulty IACV. I suggest
first find the CEL code
visually inspect all vacuum hoses
Make sure the throttle is closed all the way and then plug the lower hole with your thumb and let the motor almost die or shut off completely. If it doesn't do this, then you indeed have a vacuum leak, causing idle fluctuation.
If this is the case, then locate the leak with carb cleaner, which will shortly stabilize the idle.
As dumb as it sounds, make sure you have the correct throttle body gasket because part stores will sell what they claim to fit, but infact they leave an opening.
If this isn't the case, then I suggest you replace the IACV.
Even though you cleaned it, you haven't solved much do to the fact that it is still the same one.
Don't waste time on used units because they are probably being sold for the same reason. Go to the dealership.

MAP can shortly stabilize the idle but about most of the time it isn't the problem
MAP and TPS are simply sensors which send signals to your ECU then in turn alters the output signal. They tell the ECU what is happening. They don't control the system unlike the air intake, throttle plate position, and more importantly the idle air "control" valve.

Follow these steps before you mess with idle screw, TPS, MAP.


Modified by ywsek at 11:56 PM 10/17/2007

jdm91CrxSi

actually what year is the motor?