civicn33b

Well the car seems to be running rich. It failed emissions and I dont know if the readings will help or not, but on the 25/25 test the HC ppm read 235 with only 167 allowed. FAIL. CO % 1.95 with only 0.94 allowed. FAIL. On the 50/15 test the HC ppm read 233 with 173 allowed. FAIL. CO% read 2.03 with only 0.97 allowed. FAIL. NO ppm read 1437 with only 1372 allowed. FAIL.

Now... Ive tested the o2 sensor, MAP sensor, and the TPS sensor. The cap and rotor button didnt look particularly grimy. Air filter is straight. Replaced the plugs about 6 months ago, although upon checking them recently it appears it needs tube seals.

When I started reading about MAP sensor possibly causing this I got excited because I read it could cause a terrible sulfur odor (CHECK! although intermittent and sometimes doesnt show back up for months), MPG has dropped like 3-4mpg every tank as well. but the MAP turned out to be just fine when I applied manual vacuum and read it with a multimeter.

I don't want to replace the cat if I dont have to, but what would be causing the cat to fail if it was in fact the cat.... I dont just want to bandage a problem.

Does anyone have any ideas? I would greatly appreciate it.

Thanks,
Josh

NotARaCist

iTrader: (1)

Post a scan or picture of the sheet.

psychobear

iTrader: (1)

What d15 are you running?

lude-de

Running rich long enough will destroy a cat, but I'd try replacing the o2 sensor first. It's cheaper and it's easier. An old o2 sensor will make it run rich too.

I'd also try cap and rotor before replacing the cat for the same reason, it's cheaper and easier.

My understanding is that the sulfur smell is caused by a bad cat though... if the cat is bad, it's been caused by running too rich.

B serious

iTrader: (1)

Check that the map sensor port in the manifold is not clogged. Use throttle body cleaner (different from brake cleaner) and carefully poke thru with a paper clip.

Your cat may also be on the way out. Or your FPR diaphragm is torn. Or leaky injectors. Lots of things can cause this.

civicn33b

Stock motor, D15B7 I should also mention it only has 70k original dicumented miles... thats why I thought no way it could be the cat, but i've been noticing the lost mpg's for a while so maybe its been rich long enough to kill it.

Ill try replacing the cap and rotor button and the o2 first. Is an aftermarket ok with the cap and rotor assembly? I know people go OEMcrazy with ignition parts, but will MasterPro Beck/Arnley, Airtex work? I've done both installs on other vehicles before so I should be good.

As far as a torn FPR diaphragm, how would I know this, ive never pulled out a Fuel pressure reg, and some of this seems slightly above my paygrade lol.

Thanks again guys, lets get this bad boy sorted out... my wife needs her Accord i've been driving back

Josh

civicn33b

I should also mention the CEL has never been on. I tried the jumper wire and only got one long flash, long pause, long flash, long pause all the way to 14 before I stopped counting. That seemed to mean o2 sensor, but like I said, it tested out functional with the multimeter.

civicn33b

Also, checked for vacuum leaks and it doesn't seem apparent that there are any.

lude-de

As far as cap and rotor go, I just replaced mine (1995 Del Sol D15B7 136,000 miles) and I went ahead and bought Honda parts just so I was sure there would not be any issues. On my prelude (91 SI) though, I bought other brands. I'd just say make sure you get the same brand for both the cap and rotor.

An old o2 sensor usually doesn't cause a CEL.

As for the FPR, while possible, I'd say it's unlikely. Sounds like you've got a stock motor that you haven't been working on so it's not likely broken.

I always use NTK sensors, and stay away from Bosch. That experience comes from my Prelude though, which is a bit different.

I just went through emissions here is Delaware with my Del Sol. I failed HC at idle. I did the cap/rotor and put on new NGK wires. Afterwards, the car wouldn't start. Ended up being a bad coil, which I replaced. I wonder is the coil was weak, providing a weak spark at idle and allowing unburnt fuel out the exhaust (which will cause high HC) Hopefully you won't run into that.