WaryDriver

D16Y7 Civic DX 98, NO MODS, factory intake manifold and everything is factory.

While driving, low in 2nd gear (15mph) twice then low in 4th gear (40mph) the engine light comes on. I keep disconnecting the battery after each time the light comes on. Have done that three times and keeps returning. P0170 (Fuel Trim Malfunction Bank 1) and P0172 (Bank 1 Too Rich/Fuel Trim) are the codes that Autozone read for me. Question: What is Bank 1?

I just changed timing belt, A/C compressor clutch assembly, and v belts everything myself right before this started happening. What could I have screwed up? Thought i might have knocked an intake hose loose causing a leak.

Things I've done to try and fix..

I carefully adjusted the valve clearances. All 16 are perfectly adjusted now. None were far off to begin with. Engine light came back on after driving across town.

Then, I checked for vacuum leaks using carb cleaner around the intake hose attachments. Engine sound never changed when doing this. Then hooked up vacuum gauge and pressure is steady at 21mmHg, indicating no vacuum leaks.

What should things should I do next?

EDIT/Note: Sometimes the car feels like it wants to die in Neutral, the puttering feeling like Im about to stall out. Then it did stall out once recently in Neutral shortly after cranking in a parking lot.

Former User

Bad gas mileage?

Measure the fuel pressure and test the FPR. Also check for a stuck open injector.

Are all 4 spark plugs black with soot?

WaryDriver

The next day after I posted, the light went away while I was driving.

I remembered something. I just did a timing belt change and was oiling some things over the exhaust manifold when putting everything back together. The motor oil dripped all on the exhaust manifold probably a handful of oil in total over the time I was doing that. Well, that is right where the O2 sensor is. Could this spillage have caused my check engine codes?

When I drove the first time after timing belt change my engine under hood smoked like crazy for 30 miles smelling like burning oil. Opened the hood in a parking lot and let the smoke out after driving. I knew it would just burn off if i kept driving and it did. Well, a day or two later I got the engine light. It stayed on for days driving. I disconnected battery three times total kept coming back after driving across town each time as mentioned in title. It went away by itself a week ago, then came back after two days. Then went away after a day or two. And now it hasnt been on at all in five days of driving interstate and all over town.

I didnt check spark plugs because the light went away the next day. Gas mileage is good. Coolant doesnt smell like gas. I tried feeling and listening to the fuel injectors to make sure they were clicking on and off. Could not hear any of them hear with a pole to them. Also could not feel any of them click.. should I be able to? If i buy a proper stethescope should i be able to hear them go on and off? I gentally tapped on all of them with something rubber so maybe that made on of them become unstuck. The light went away the next day lol.

Drzhope89

i finally understand this code trust me it has been driving me crazy the p0170 and the p0171 have you check the PCV valve because if your engine is not breathing so the air

Symptoms of a bad PCV valve

We see varied symptoms from a bad PCV valve, depending on the way it fails. For instance, a PCV valve that sticks open may cause a check engine light. The diagnostic trouble codes or DTC will normally not mention the PCV valve. Instead, the diagnostic trouble code P0171 and P0174 are common. These codes suggest a (lean-condition) in the engine. Other engines could set a mass-air-flow meter code or even an oxygen sensor code.

A failed PCV valve may also cause noise. Some will produce a whistle or whine and others can produce a low moaning noise. The easiest way to verify the problem is to temporarily block the vacuum source to the PCV valve and see if the noise changes or goes away.

Former User

OP, PM me if you wish this old thread to be re-opened.