Razorteez18

Hi there! New to this, and so here it goes. I own a 2001 Honda Accord 4-Cylinter 2.3 Liter ULEV (ultra low emission vehicle). The emission system on this vehicle is built to California spec and so it's a little different than other Honda Accord types. Anyhow, I've been hit with a couple problems recently with this vehicle, which are expected at this point . It has 230,000 miles! All my problems started with my fuel pump dying one morning. I was driving to work and my engine shut off without any Check Engine lights, warnings etc.. Symptom: After stranding me on side of road, engine would crank but would not start up anymore. So, not knowing what is wrong with car…. performed following tests to find the problem:
1) Fuel Pump Voltage test: Hooked up voltmeter strobes to fuel pump’s electrical wires and noted close to battery voltage when ignition in II Position. (This lead us to move onto other tests, since it was within range)

2) ECM Relay: Swapped the ECM relay with another one, and attempted to start. Cranked but no start still.
3) Spark test: Hooked up special cable to spark plug, and attempt to start car. Noted that spark plug testing bulb lit up successfully for each cylinder (tested all 4 cylinders 1 by 1)
4) Fuel Pressure test: Rented a fuel pressure test kit from AutoZone. Hooked up to fuel hose (hose that leads into fuel pressure regulator) , Then with gauge attached, switched ignition to cranking position. Noted VERY LOW fuel pressure. Supposed to be 47 to 54 Psi according to Service Manual, and I was getting only between 15 to 20 Psi.
5) Bought new Fuel Pump, and replaced. PROBLEM RESOLVED!

All was good for about 2 weeks, until I ran into a new issue: Check Engine light came on, Fuel Efficiency dropped signifcantly and engine is no longer performing well. Meaning, I'm seeing a sudden loss of performance and power, while attempting to rev/ accelerate from idle. Car shuts off when trying to increase RPM. Fuel efficiency is horrible now. The immediate codes thrown were:
P0170 Fuel Trim Malfunction (Bank 1)
P0171 System too lean (Bank 1)
Did following to narrow down without any luck:
1) Replaced downstream (secondary, after catalytic converter O2 Sensor since had not been changed and I've had car since 30,000 miles (now 230,000 miles). Cleared codes and rescanned. Codes did not go away after clearing, and actually two new codes came P1167 and P1166 (Air/Fuel Ratio Sensor 1 Heater Circuit Malfunction) Same performance problem: longer ignition turn before start, engine stutters and shuts off when pressing on the gas pedal to bring RPM above idle.
2) Then replaced upstream Primary O2 heated sensor (primary, exhaust manifold), cleared codes and rescanned. Noted same symptoms as above and observed that when engine warms up to idle RPM, it's choking and stuttering. It shuts off after struggling to stay on. So, symptom got worse. After rescanning the OBD codes, the previous codes disappeared and NEW code thrown: P1399-Random Cylinder Misfire Detected.
3) Did compression test on all four cylinders, and got 190 Psi reading for each of 4 cylinders. Visually inspected my spark plugs and looked fine also.
4) Did a random clear and rescan of codes after compression test, and threw P0108 (MAP Sensor faulty). So, then replaced MAP sensor that goes into air intake with a new one. Started up car and cleared codes, and rescanned. This time got same code P1399 and same performance issues. When idle and pressing on gas pedal car struggles to go up from 0.5 and shuts off. IDLE IS VERY ROUGH.
5) Next, thought it could be a sticky Throttle or bad Throttle Position Sensor. Removed the Throttle Body, cleaned with carb cleaner and mounted back on. (did NOT change the TPS sensor though) and same poor performance. This time though threw 7 OBD codes:
P0122, P0300, P0301, P0302, P0303, P0304, P1399

I have run out of ideas and put way too much time (and money) trying to figure out the cause of the poor performance problem. I am not sure I can trust the OBD codes anymore. Anyone have any ideas??? Again, the engine symptoms:
Check Engine Light ON
Idle is rough
When pressing gas to go up from idle RPM, enging struggles and popping noise can be heard
It appears as original OBD codes mentioned, System is running lean (too much fuel). I am out of ideas, please help me.

angrysmileyface

Is your fpr working? Also did you clean your tank of debris upon pump change?

Razorteez18

Hello angrysmileyface!
Yes, Fuel Pressure Regulator was changed during our troubleshooting process.
Fuel tank was inspected and free of debris .

bw77

You need to fix the P0122, tp sensor circuit low voltage.
Here is a good description of how to do that:

Part 1 -How To Test: P0122 OBD II Trouble Code (Honda 2.2L, 2.3L)

Are you sure the tps is plugged back in to the correct connector?

When you cleaned the throttle body, did you also clean the idle air control valve?

You wrote " System is running lean (too much fuel). "
Lean means not enough fuel. Rich is too much fuel.

Another possibility is a stuck open egr valve, but that might set a different code.
Does the engine run good at higher rpm?

Razorteez18

Hello bw77,
These are really good tips! All TPS connectors are plugged in correctly. I did not clean the idle air control valve however. I will definitely do that later this week. At this mileage (230,000 miles) it's probably long overdue.

I apologize, you are correct @bw77. One of the first set of codes I had received was P0171 and P0170. Weird they don't throw ever since I replaced the oxygen sensors (primary and secondary). A lean condition occurs when the engine either receives too little fuel or too much air. So, this might be the reason why my fuel mileage is terrible now? The computer thinks or detects very little fuel and is trying to compensate by letting more fuel in? I'm a little confused on this topic.

The engine (if able to rev to higher than idle RPM without engine choking/shutting off) does run good at higher RPM! If I get it up to 2000 or 3000 RPM and beyond, no problem and it runs just fine. It's the idle RPM and the instant you push gas pedal. As soon as my foot touches gas pedal, the car shuts off in most cases.

bw77

When you step on the gas and the throttle opens, the computer won't know it, because the tps is not working. So the computer won't add gas right away.
That would cause the near stalling.

If the tps was working before you cleaned the throttle body, you may have damaged it in the process.
Need to check the wiring and signals.

Less likely but easy to try - tap lightly on the egr valve at idle and see if it makes a difference.

Razorteez18

@bw77 That’s most likely it. I’ve ordered a new TPS sensor and waiting on arrival. Plan on replacing it later this week. Will update this thread with findings.

Razorteez18

*Bad news, I replaced my TPS sensor and it did not fix the problem. I crank, engine starts perfectly, when it's cold IDLEs just fine. When it warms up and RPM drops to the 0.5 mark, if I press down on gas pedal, car shuts off. I re-rented the Fuel Pressure kit from Auto Zone, and looks like we have low fuel pressure again. It's at 20 Psi, which is far below the minimum required of 36 to 48 Psi (Haynes Book). I'm going to recheck the Fuel Pump as "The Toecutter" mentioned up above. I bought the cheap Fuel Pump $50 bucks or so as opposed to the $120 something (Bosch) one from Autozone. Not sure if the pump is bad, or debris are caught in line. Either way after all the sensor replacements I've done so far, looks like issue is pointing back to a fuel problem again. GRRRR

Razorteez18

:D

I'm definitely keeping my fingers crossed on this one. I replaced/exchanged the original Auto Zone Fuel Pump (10 days since purchased from AutoZone) with another today. Problem has been resolved, and car no longer shuts off when I press on the gas pedal. Although, I am noticing some very weak and random hesitations. Definitely not like before where it wants to shut off. And the warmer the engine gets, the less it happens.

Wanted to thank everybody here for sharing all questions and their experience. This has been an interesting and at times challenging issue. I am hopeful that the issue doesn't come back again. I'm thinking of moving onto fuel injector cleaning. They haven't been cleaned once, since owning the car (30k) with now 232k miles.