rkthunder13

Hello everyone, I am new here to the forum and new to these types of cars all together so please hang with me here. Last week I bought a 1998 Civic EX with auto 4speed. It has 120,000 miles on it. The engine is a D16Y7, It drove fine for a few days but today it started idling very very low. It got so low when coming to a stop that the engine was shanking and started to almost knock before i revved it a bit. Ive done an oil change, new fuel filter, new air filter, new spark plugs. The distributor cap is factory so a new one is on its way now as well as the rotor. Im going to clean the IAC valve and throttlebody tonight, ive heard some people were able to solve the idle issue by turning the fuel up at the throttle body? Does anyone have any imput on this? It did throw a code for the cat on banks 1 and 2.(p0420) Also if anyone thinks of something to tell a new guy about these cars please do let me know! Any and all help is greatly appriciated.

mx5med

I would say along with the new cap and rotor you have coming, cleaning the throttle body and IACV should really help out. I've never heard of turning up the fuel, but maybe someone else has.

Maybe after you do the cleaning and get the new parts on, I would say to disconnect your battery if you dont have a code reader to reset the O2 codes and see if they come back. They could be getting poor readings from the engine not running well and not be bad themselves.

rkthunder13

I have cleaned the IAC and the throttlebody throughly. It really looks like the wrong TB gasket has been used on this car or the passages just under the idle screw are supposed to be covered up by the gasket? In any case the car has picked up in rpm but still isnt where it should be. Its acting alot better, the new cap and rotor should top help it even more I hope!

I did notice something fudged today after driving it. When the key is first cycled on no CEL lights up. I Can read codes fom ECU and TCM so i know its working. Is there any way to tell if someone just pulled the bulb? Thanks for your quick response mx5med

JRCivic1

If you get a CEL on the instrument cluster at any time... then the bulb is working. If you discovered the P0420 code simply by coincidence and no light came on, then there is a good possibility that the bulb is burned out or has been removed.

rkthunder13

JRcivic1 yes it was by coincidence that I found the code. The light never comes on nor have I seen it glow at all. Any advice on how to get at the bulb? Im still trying to track down a good service manual for this car so I dont know what it all looks like back there, thanks!

rkthunder13

Well after a little research....it looks like the ex should have a D16Y8 engine but this car has a Y7 block.
im going going to confirm which ecu the car has in it tomorrow....looks like I made a classic rookie mistake buying an engine swapped car and not knowing any better!!!

So if it still has a y8 ecu would it be advisable to get an auto y7 ecu? Also if I buy a used ecu on Ebag would I have to have it reprogrammed or anything like that? This may explain the idle issue and no mil. It may be looking for the VTEC?

Any advise is really appreciated!

chrysler kid

You just need to know what cylinder head is on the car. Vtec needs the y8 ecu

rkthunder13

The casting numbers on the head is 804220071 on the passenger side of the head and P2J-7 on the driver side/middle of the head I have the engine number as well thats under the D16Y7, is there a way to date the engine?

rkthunder13

rkthunder13

rkthunder13

Is this the spool valve in the photo indicating a y8 head? I have no way to tell the difference but when I google the vtec solenoid it shows something that looks just like the one in the pic.

Joey Mitchell

If this is a pic of your motor, then it is certainly a y8. The intake manifold is that of a y8, and that is a vtec sylenoid at the top left corner of your valve cover. What does the stamp on the block say? Could possibly be a y7 block with a y8 head/intake.

rkthunder13

Thanks alot for the verification on that!! I had no idea what im looking at haha The block is defenintly a Y7.
Is there anything I should keep an eye out for on a head swapped Honda engine?

Thanks again!

rkthunder13

rkthunder13

Just for my own knowledge how can you tell a D16Y7 manifold from a Y8?

Chrisfrom1986

iTrader: (1)

They are completely different. Google it

Joey Mitchell

It really sounds like you are having an issue with your iacv. Even if cleaned it still could be faulty, or possibly an issue with the power running to it. I'm having a very similar issue on my y7, shaking and jerking while under load at low rpm, and a surging idle. Mine all stems from a water pump leak that I've yet to fix. I can't keep the air pockets out of the cooling system until I fix my water pump thus making me have all types of issues with the iacv, and kinda domino effecting alot of other things. My advice would be to first see what the correct voltage running to the iacv is for when the motor is cold, and at operating temperttemperture and test the wires running to your iacv to make sure u are getting correct voltage. If you are then next I would look into how to test you iacv itself.

rkthunder13

Thank you for the advice I will certainly check that. Mines slightly different because it doesnt fluctuate it just gets very low...

After a reset on the computer I drove it and the idle is slightly higher. It's thowing a code for the transmission range sensor(?) P0705.

My idle also seems to fluctuate by about 100 rpm after I get off of the brake pedal.

Maybe I have a vacuum leak in the booster?? I've sprayed the manifold and vacuum lines hunting for a leak but haven't found anything. Do these boosters have a little valve in them that can leak?

Thanks again for all the responses.

rkthunder13

rkthunder13

Maintenance done on the car so far:
Oil change
Air filter
Trans change 5x with dw1
Fuel filter
Cap, wires and plugs
Iacv cleaned
Throttle body cleaned
Bg44k service
Honda type 2 antifreeze flush
Pcv and grommet
PS pump flush with Honda ps fluid
exhaust gaskets

After the pcv was changed and a new hose installed(since the old one was 95% blocked off) the biggest performance gain was felt and now I'm happy to report 100% no shake! The cap and new plugs helped alot also but after the pcv and exhaust gaskets it really feels opened up.

Thanks to everyone for their advice!

muellersfan

Is the engine running on a P2E or P2P ECU?

rkthunder13

It's the P2P ECU

muellersfan

I assume a knock sensor was installed on the Y7 block.

rkthunder13

Where would I look for the sensor? I've found a few fudged items when the PO put the y7 block in. I wouldn't be surprised if one wasn't installed. How do I check for it?

Joey Mitchell

I am having the exact same issue with my y7. A bad water pump leak that caused my iacv to have all sorts of issues. I've oreded a water pump kit and it's currently in shipping, but for time being I deleted my iacv hoping to solve the idle issues and the jerking at low rpm when under load. Although it fixed my surging idle, It still jerks under load at low rpms and seems really sluggish. Is this because I deleted my iacv and covered it with a metal plate or could this be something else. I was also told that the only reason that coolant passes through the iacv was to keep it from freezing in the winter, but that makes no sense considering that when you get an air pocket in those coolant passages the iacv starts acting up, whether it's freezing outside or not.