CEL in '95 del Sol
 

The CEL in my '95 del Sol came on, and I don't have a shop in town at which I can have it scanned. It is a recent engine swap, and it runs and drives fine. The idle is fumbling between 800 and 1200 rpm. Not quite sure what is causing it. The engine is a D16Z6.

Like I always say - best starting point is investing into a repair manual.
You can read error codes off ECM light. It may be in a different place on your car, but normally it is either underneath the pass side seat carpeting, or in the area where passenger has his feet. It has metal lid on it that when removed, shows blinking indicator.
You will need to jump 2 prong connector hidden underneath the pass side dashboard, right behind pillar A trim, about mid shin level sitting.
Then start engine and read error codes.
This should help:
https://www.tegger.com/hondafaq/misc/..._E_14JAN03.pdf
THen report error codes and we'll take you through this.
DO NOT replace any parts until you did so.
Wild guess - EGR is acting up, or idle speed air valve. But that's just guess.

Code 41 - O2 sensor. Which sucks because this one is brand new. Oh well... I will try to take it back. Thanks for your help.


Jon

Don't rush. I had O2 sensor fixed on wife's RX300 3 times, before we finally replaced it.
1. it is very common for cars to throw O2 sensor code when there's just something wrong with fuel system, like carbon build up.
2. not sure about Honda, but I know Toyota is very sensitive to parts specs, and if replaced with aftermarket ones, ECM may "not like it" and keep throwing the code.

So here's cheap suggestion for you. PLan for weekend, as it takes some time. Buy 2 cans of Seafoam. Suitable funnel, as you can not pour Seafom into tank straight, need to use funnel.
Fins a gas station somewhere close to a FWY. Run low on gas, then go to that gas station, pop fuel tank open, and pour Seafoam, both of them, into tank. Flush it down with about half tank of petrol. You have to flush it in, as filler pipes have elbow in them, and if not, fluid will just sit there.
What you need to do next, is to park somewhere on the side, pull ECM fuse out for about 15 minutes. Then reinsert it, ideally, code should be cleared, and then go on FWY and go for about 1.5 hr - 2hrs at FWy speeds.
What you do is you are blowing system clean with Seafom.
LIke I said, worked 3 times, about 15 000 miles apart, for wife's car.

Good thinking. I may try that as well.

Needing cans you might consider making your own seafoam.
Homebrew Sea Foam (SeaFoam) Motor Treatment Recipe

Interesting and yet not surprising. I knew Sea Foam wasn't some magical blessed brew, just a mixture of common petroleum distillates. It can be simplified to a mixture of diesel and gasoline (per the substitution section near the end -- note that the alcohol is likely already present in pump gas); so for use in the gas tank I see no need to mix it outside the car, just put a little diesel in and call it Sea Foam. Of course for top-end and crankcase usage you'd need to mix all components.

As an interesting tid-bit, when I replaced the HG on my VX the timing belt kit I got from Gates had the incorrect tensioner. The shop uses Napa as it's main parts supplier and to match the tensioner that came off of the vehicle NAPA sold them a tensioner from a D16Z6 model, IIRC; at least per their system.