spartan_chaz

So i just installed headers on my 88 HF. At low RPM getting the car going in first it will bog down unless i rev the engine up pretty high and doesnt like to idle consistently. I have be reading up and found a few things stating that with the new headers the exhaust cant heat the sensor enough, being farther back than it original location. Is this correct? if so am i able to wire in a universal 4 wire o2 sensor into this car, it being OBD0?

spartan_chaz

Can anyone provide some incite on this? I am just looking to get something to make the stock engine run fine for a little while while i get my stuff in order for my B16 swap.

sacermors

Trust me the headers get hot enough. you may have a leak where the manifold bolts to the motor. an imperfection in the part or the gasket or it could be tightened down unevenly or too tight.

extra air will mess with your o2 sensor.

sacermors

Hot enough to barbeque your flesh from bumping into one

spartan_chaz

THe sensor is not in the header it was relocated to the back of the motor right before where the cat would be. THe manifold bolts are torqued to spec. and from my experiance if you gasket was leaking or you had some kind leak, you would hear a distinct ticking sound and i do not hear anything out of ordinary when running. Also it run fin once it is past 1800 RPM like nothing is wrong.

Now i could be wrong but, i know the OBD0 sensors arent heated, so they are located close to the head to get the heated up to run correctly.

acmoc

The o2 sensor is fine before the cat, it needs to read off all four cylinders in order to provide correct air fuel ratio.
The thing is your crx might have a clutch from another mode and the hf is no torque monster

sacermors

well i was thinking about moving mine back there on my header but now i see what your saying. Your header didnt come with an o2 bung on the #4 cylinder tube? closest to distributor. Got a picture of it? What did you do to relocate the o2 sensor?

spartan_chaz

I feel i need to clarify. Before i installed the header and exhaust the car ran perfect. And as for the clutch, im not sure how relevant it would be to my issue, but i worked at a Honda dealership and the clutch kit and flywheel was ordered correctly, by myself, for an HF. And the clutch job was done over a year ago and the header and exhaust was done maybe a month ago.

spartan_chaz

It does have a bung on the #4. I put it near the cat location because the fan shroud was in the way i at the time i knew i could have cut it for the spaced be decided not too. And to locate the sensor back there all i did was take the connector and bend it back off of its bracket and it reached the rear location without any cutting.

I am considering just cutting the shroud and placing the sensor in the $4 bung to see if it fixes it. if it does then im cool with that until i get stuff to do my b16 swap

sacermors

yeah the owner before me cut the fan shroud but im thinking if it only reads from one cylinder that isnt correct either. im thinking about going to a stock manifold that has the o2 right where all four tubes connect because i havent found an aftermarket one that does. its either way back under the motor or just on the cylinder 4 tube.

sacermors

ill try moving my sensor to your location tomorrow and see what happens to verify.

spartan_chaz

and im going to try and relocate to the #4 bung just to see. Since im not getting a whole lot of answers here. Worst case i just drive my SRT-10 Ram to work from here on out lol

sacermors

well ill tell you mine runs with it at #4 but it was rnning very lean when i checked the plugs. cant say for sure if thats the issue as i bought the car with the header already and its hasnt ran right yet.

sacermors

Yep everywhere ive looked has said using that bung for a 1 wire o2 will cause issues. It makes sense the more i read. It needs to be atleast within 12 inches of the motor to heat properly. Im thinking for obd0 its best to stick with the stock mani or wire up a obd1 sensor with internal heater to switched power and ground so you can place it where you need it.

acmoc

Dc sports header has it in the back and they ship with an extension plug.

Get an ebay header and just undo the wire loom and the o2 sensor wire easily reaches. Zip tie it somewhere secure

This is mine, U undid the loom and the o2 sensor hanges near the driver axle, it plugs in right before the cat

acmoc

What might be your issue is your coolant temp sensor, the one underneath the distributor, it has two prongs.
This is what reads the temperature and accordingly gives fuel based on engine temp.

If you use water or have used water in coolant system, it corodes this sensor.
They're like 20.00 bucks.


Change it on a cold engine and thread the new one in until it stops leaking coolant, then do 1/4 turn more or so for safe measure.
Then top off the radiator, let the car idle with the heat **** on "HOT", without the radiator cap until the fan turns on.
Turn the car off and let it cool, then top it off and reinstall the cap.

Buy 1 gallon of distilled water at target or walmart and 1 gallon antifreeze.
Mix your own 50/50 for way cheaper

sacermors

so your still using the obd0 one wire o2 sensor plugged in right before the cat at the collector and no issues?

acmoc

Yea, dc sports made it that way. Why not?

sacermors

Just most people say theyve atleast gotten an o2 code from the sensor not being able to heat up properly as its no longer close enough to the motor. But then again there hasnt been a clear answer in all my searching. Some say they get a code, some say it runs poorly and some like you say its fine. I guess theres only one way to find out XD Ill take your word for it and give it a go tomorrow. I may try the ect change too. Would one from say advance auto work alright or do i need to go oem?

acmoc

Go with OEM or Napa autoparts only
Napa parts are made by the same oem suppliers
Whereas stores like autozone, oreilly and advance no longer stock oem brand products

acmoc

You have to realize these are 20+ year old cars and an o2 sensor doesn't indicate a bad o2 really. It means there is an imbalance in the air/fuel ratio.

I threw an o2 code once and it was a bad fuel pressure regulator that was only putting 26 psi at vacuum where it's suppose to be 38-40 I believe

spartan_chaz

well as for the o2 sensor it is a new bosch sensor. and i was able to pull the connector on the harness side enough to get the sensor in and not have any issues with fitment. as for the temp sensor i thought it was located on the back on the block close to where the temp switch is? I could be wrong so please tell me if i am lol. but i may give that a shot.

I also looked at the #4 bung location and i wont be able to fit my sensor in that one. The passenger fan shroud is plastic and i dont know if im comfortable with cutting plastic off. But, sadly i have to figure out whats wrong with this thing because i can drive my gas guzzling truck all the time lol.

acmoc

sounds like a bad ect. It could not be reading the heat and dumping fuel for a cold engine.
The sensors at the back of the block are for the fan temperature switch (two spades) and the oil pressure.
UNder the distributor is the temp gauge sender, one small nipple. And the ect, a two prong plug.

Remember, they don't thread in all the way to make a good leak free seal. Just thread it in by hand and until it doesn't leak.

The one is red signals your cluster. Has no other effect.
The one to the right is connected to your ecu and controls fuel and is the one that will be the possible culprit of a cel

acmoc

And just for referance get a slim radiator fan and zip tie it to your radiator.
More clearance and cleans up the engine bay nicely.

I'll get a pic of mine tommorrow if you like.
Mishimoto fans are good

spartan_chaz

I appriciate the pics. And idk if i explaind my issue in detail but the car runs fine when cold its when it gets warmed up with it feels like it bogs down as i start to get in gear. The only way to get it to run smooth is to rev the hell out of it, to about 2k-2500 rpm. At that points its smooth and while crusing on the highway its smooth but you can feel a hesitation every now and then. I just ordered a temp sensor now. Im willing to try anything right now to get this thing running right...also there is no code being thrown