Fuel running rich/trim malfunction

I have a 98 Prelude, and my check engine light is on for those 2 codes, and I've got like 3 different people telling me different things!! Ahh! I've been told 02 sensor, which I replaced, and I've been told Fuel Pressure Regulator, and also that the timing could be off. Has anyone else experianced these codes? I know the EGR valve hass been replaed previously, and I checked the pressure on it and it's fine..... ??????

What code is it. And how are you determining that you are running too rich.

You know, off the top of my head the code p0172 sticks out, and that was the "fuel trim malfunction" And a code very close to taht one was the "fule to rich" maybe p0173 or 4 ? It's at the mechanic, $350 later and they still don't know whats wrong with it. I'm ready to sell the damn thing!

Ahhh don't say that. You just have not found the right person to take the time out to really look at it.

Your EGR (Exhaust Gas Recirculation) SHOULD basically only comes into play when the vehicle is in a certain drive cycle; Cruising at a high way speed. It opens to allow some exhaust gas to enter the combustion chamber to take place of the air fuel mixture. Less air fuel mixture, less explosion, less explosion, less heat. So it is really there to cool the combustion. EGR is best checked with scan tool or scope

O2 Sensor senses how much O2 is in the exhaust. O2 may be fine but giving a reading like .83v because you are getting too much fuel. In that case I would like to look at the ECU’s fuel Trim Values.

A Five Gas Analyzer would be nice to have as well so we could check the Co2 % (efficiency of Combustion) and the PPM (Parts Per Million) of Hc (Hydro Carbons or Fuel) lets hope the Cat is working properly for this test.

I’m telling you this stuff so you can look it up for a more in-depth diagnosis. And so you can mention some of this stuff to the Technicians to see if they are really trying to fix your problem.

If EGR is opening when it is not supposed to you will normally get an EGR Code and maybe a rough running condition.

If the fuel Pressure Regulator is allowing too much fuel to enter the Combustion Chamber then your O2 may pick it up as a Rich condition.

And why would your timing be off. Have you been playing? Maybe the timing chain got loose and it jumped time. Yeah like that could happen: Can you say timing BELT

But Many thing can cause your problems, you just need someone to take their time and check it out. Do a visual inspection. Check all vacuum routings. Check plug condition.

Ok, so here's the update. This BUM mechanic is telling me the voltage is incorrect on the EGR valve. 5volts going in and no more than 1.25 coming out....and mine is putting out 1.76volts. Could this cause my car to have this "fuel trim malfunction" and give me a shitty idle? If the car isn't warm, it stalls, when I give it gas, sometimes it feels really laggy. I just don't know if this guy knows what the hell he's talking about. Anyone ever had to replace the EGR valve on their Prelude? I've got about 93kmi, is this normal??

Those CEL codes don't exist. Check it again for a real MIL code:
http://hondaprelude.to/articles/maintenance/check_engine.html

Go to Autozone or do it yourself. You really need to be more specific on the symptoms of your car. Are the revs bouncing up and down? During idle? During drive? Both? Is your car running rich? Is there black smoke? Are you experiencing knock?

I can't really tell you anything unless you are more specific about it.

Hey just read about it. see if you can find out how this stuff works. The answer he gave you is pretty shitty I wouldn't think he knows what he is talking about.

Maybe is has toned it down for you or he just wants to shut you up.

YOu need another tech looking at your car. ask him to explain it to you.

Well, it definately does have a rough idle. If the car isn't warmed up, it tends to stall while I'm coming to a stop. Not like it sputters down to a stall, the RPM's literally fly to zero. Then I also notice a loss of power, and sometimes when I go to give it gas, it doesn't accelerate right off, very "laggy" feeling. In my very unprofessional opinion, it feels like a gas problem, but what do I know??? I went to Autozone, and they are the ones who said Fuel Pressure Regualtor, which I have had replaced now, and it didn't fix anything. SO, I am about to run those codes myself to see what happens, and check the EGR again. Does that help at all?

A while back, we had a guy who also had a problem with hesitation when he hit the gas. It would bog down in the mid range RPMs like it was losing horsepower, but never completely cutting out. Unfortunately, we were never able to pinpoint his problem.

Some things that could be wrong that is causing the hesitation are fouled spark plugs, dizzy cap/rotors, wires, and the distributor itself. It could be something as simple as an old fuel filter as well. Rough idle is a separate symptom with an unfortunately equally wide amount of causes as well. Vacuum leaks are typically the culprit, one of the non-fluid hoses are not secure. An EGR system failure could also cause bouncing RPMs *and* hesitation, so perhaps this is your answer?

I don't want to lead you on with an endless amount of possible causes, so it is essential that you check the CEL codes your car is reporting if you want to find the real answer. Use the link I gave above and it will help you pinpoint your problem.

There are many other causes to these symptoms that I haven't mentioned yet, but these are the main ones. Keep us posted, this bothered the heck out of me last time because we never found the cause.

Feel bothered no more, I believe I have found the problem! I did the CEL code, and it was a 45, which was "fuel running rich" (surprise surprise..) And under the possibilities was o2 sensor, which I've replaced, contaminated fuel, valve clearance and something else, can't remember. So we're now thinking valve clearance because I did have a valve job done earlier this year. Well, while taking the cover off, we decided to look at the timing belt too. I know belts can't jump on their own, har har......but I did have it replaced, and I really think it's off by a tooth. So, that would be a cause off all of this, and we're going to fix it later this week. So, it's not my car that's a piece of shit!!! It's my mechanic!!! I will be very relieved if this is what's wrong. Here I'm thinking I bought a lemon!