I have 93 Del sol si. Every since I added headers and a new O2 sensor it's been running weird, hesitation, fouling spark plugs, and horrible gas mileage- about 24 miles a gallon. I suspected an up line air leak before the O2 sensor. I had the mech recheck the gasket. No leak. I checked it myself. No leak. So I just now unplugged the O2 sensor- idle smoothed out. Drove it, now back to its old self.
Of course, the CEL is on. I'll run it for a tankful, see what the gas mileage is.
Is this a fixable problem, or just get used to a pretty little yellow light?

Ps
I had put in a new O2 sensor matching OEM stats.

John

 

Remove that aftermarket O2 sensor and install a Genuine Honda one. Aftermarket O2 always have issues on Hondas/Acuras. They never seem to read correctly.

 

It was a Denso. Is that not Honda genuine?

 

Did you get it from the H0nda dealership? IF not, it's not GENUINE Honda. No auto parts stores carry Genuine Honda parts. OEM is NOT factory Honda.

 

Of course, the next logical step would be to pull the CEL code(s) and post it.

 

A denso sensor will be fine, I've used them 100's of times. Was this one you bought plug and play or was it universal? Question though is where did the new header place the 02? Post a pic if you can and like Ron said post the code.

 

Thank you.
The O2 is Denso and it was installed in the only open hole (near where original was)in the
Headers.
The car ran great all day yesterday with CEL light on.
Then this AM it died twice on the way to Post Office. So, I re-connected the O2 sensor.
The CEL went out immediately. Now back to surging,running rough, and I'm sure bad gas mileage BUT it runs from A to B. I can't see there would be a diff CEL code but....so I'll
Check when I can.
FYI, after reading this forum, I cleaned the throttle and intake manifold, Fitv, iacv and ran Seafoam through the whole system. Helped a little. I replaced nearly every part under the hood except the starter, including a new dizzy. Seriously, it ran real nice with the O2
Sensor unplugged, until this AM.

 

Some headers only have the 02 bung onone tube not where they meet all together. So was the 02 plug and play?

 

Why not hook up a code reader or jump the service connector to pull the code? There's more than one type of O2 sensor code, and you might even be surprised to find that it's not an O2 sensor code.

 

First of all, check the CEL and post. Then, you need to post pictures of what you have been doing. We're not magicians or psychics.

 

Sorry, no access to car right now, went out of town with medical issue. Get back Monday, will try to take pics, CEL, etc. Please be patient. Thanks
cpf777

 

Did you have to pin the connector? If so its probably pinned wrong. It's easy to de pin and repin tho

 

Sorry for the delay.
The cheap Chinese alternator,bought off eBay, quit after 4 months. I had the car towed to the dealer. Took 8 days, over 4th of July to get a new one. Then, next day, the cheap Chinese distributor went out!!! Put old oil leaking OEM Honda one back in. It runs.
I have not checked for Codes yet, although the CEL is not on. It still runs horrible, as before. I thought it was the fuel pump for moment. So did the dealer until they tested the the pressure at 46 lbs.
What is 'pin the connector?'
I'll try to post pics, but always have probs
John

 

Just got under car to pull CEL codes. I have 1993 Del Sol. Pulled the carpet back and there is the ECR and a green rubber jumper plug with 4 wires in 2 separate plugs. What to do now. The left side seems to be blue and green/grey stripe. The right hand ride seems to have a brown wire and green/grey stripe. Do you pry the connector out of the green rubber plug? I assume so. OK,you use the Brown and Green/White (grey now) connector for the CEL code light. I'll try that. But whats the other for? Good luck to me

 

FAQs. All this can be found there.

 

Ok, did it by removing plug from green rubber harness. Jumped plug with paper clip.
Turned car on to Accessory #II. All lights including, CEL came on. CEL never went off or started to blink ( I was dissappointed, but I knew it wasnt throwing a code before this).
I checked it 3 times. Same result.
So let's try other things... Pin the connector, ??? Maybe O2 sensor?
Clean the IACV or FITV? I'll try anything. Only other thing is that the mech who put in the water pump with a new timing belt said, " that's the best I can do" That has me concerned.....hmmmmmmm