Symptoms:

The car runs normal for about 30 Km, after that it started losing power, It looks like there is not enough fuel going into the engine even thou the gas pedal was pressed to the floor,(fuel gauge showed half a tank) the tachometer showed droping in rpm and the speed drop to 80 Km/hr and gradually dropping to 20 Km/hr and the tach showed 2000 rpm and before it reached my driveway it dropped below 1000 rpm, it runs 10 Km/hr.max only.

The ECU indicates 1 flash which is the oxygen content, I replaced the O2 sensor with a new one and cleared the ECU memory but the car still can not go higher than 2000 rpm, it looks like the ECU is controlling the flow of the fuel into the injector?, the idle seems to be normal, better than before, is it possible that the ECU needs more running time to detect the new O2 sensor?

I replaced with a new gas tank, fuel pump and a new fuel filter 2 years ago and a new ignitor, new coil, distributor cap as well and also fixed the main relay(resolder the hair line crack) recently, check the air filter still clean

I hope there are experience Honda mechanic or expertised hobyist in Honda civic that can give me some clue where to look

 

Check the mechanical timing. The timing belt may have skipped a tooth out of time.

A clogged fuel filter or failing fuel pump is another possibility, so you next should check the fuel pressure.

A clogged cat is also possible.

 

The catalytic converter was replaced last year in November, the fuel pump was replaced a couple years ago when I replaced the fuel tank at the same time, also the timing belt was replaced 2 years ago by my mechanic when I got this car.
How do you check for fuel pressure? and do I need to remove the timing belt cover to check for ignition timing?

 

Note that even a new cat can be melted very quickly if the engine is running rich.

Checking mechanical timing:



Measuring fuel pressure:

 

I replaced the fuel filter and check the fuel pump by loosen the bold at the filter and turn the ign key to II position and the pump works fine, it squirts a lot of fuel

I tried to start the engine and it turns but will not start, some cylinder hesitate but not fired, I suspect like you mentioned before the ignition timing might jump a few notch.

In the olden days, normally I loosen a few bolts on the distributor and turn either way to adjust the ign. timing but on this Honda, I saw three bolts and there is no way I can turn this distributor, did I missed anything?

 

You loosen all 3. But that's not going to change by itself on you-- should the timing belt skip the cam will be out of sync with the crank, and you can't fix that by turning the distributor.

 

You might be right MK378, but I am still puzzled what caused the gradual lost of power while driving? just for the last 10 Km before I reached home, it can go only 10 Km/hr speed and the rpm dropped below 1000 rpm.

I have an older Nissan pick up truck and never had any problem with the engine it starts every time, it uses timing chain except the body and chassis rusted very badly.

 

Thank you RonJ and MK378.

I found the problem of the gradual losing power on my Honda Civic '91, it was the Catalytic Converter, the cat was completely clogged, just to prove it, I removed the O2 sensor so that the engine can breath a little bit and the enigne start and run normnal. and now the whole thing make sense.

One can not trrust the ECU completely, it indicates code #1 which is the O2 sensor which I replaced and also code#16 which indicated the fuel injectors and the actual problem was at the main relay which has two hair line cracks which I resolder and fixed the intermittent "can not start at the pump".

At first I thought the timing belt jumped a tooth and my mechanic estimated just to replace the belt it cost about $ 600, assuming all the valves are still good. which to me is not worthed for an old car, and he suggested like RonJ said to check the Cat.

I hope this write up is useful to some of the reader who own Honda Civic.