Main relay can cause odd problems. You can get a good idea by how hot it gets or if there is corrosion at the solder joints. Not too hard to get another one and try it out. What I actually did was cleaned and resoldered mine.

 

The OP originally said it died in addition to having starting problems which is why i pointed to main relay.

 

Well I am back and I thought I had repaired the issue. I replaced both "O" rings on the Vtec solenoid and this fixed most of the oil leaks. Oil appears to be leaking around the wire that exits the bottom of the solenoid. Since my last post I have replaced the Main Relay with a new unit and replaced the ignition switch as these appeared to me two major issues. I replaced the ground wire on the battery with an genuine Honda Part. The connector that attaches to the transmission appeared to have frayed wire and corrosion. I checked the alternator output and it is 14.2 volts. I removed and cleaned the IAC Valve. I replaced the seal with a genuine Honda seal. I removed, disassembled, cleaned and reinstalled the Cold Idle Valve (mechanical). I removed the EGR valve cleaned it and the passages and replaced using a new Genuine Honda Gasket. I removed the injectors and removed the cover to the EGR ports on the intake manifold. All were totally full of carbon and many of the passages in the cover were plugged. I cleaned and cleared all the blocked passages and reassembled with a Genuine Honda gasket. I reninstalled the injectors with new Genuine Honda injector rings (gaskets). I checked the fuel pressure with the vacuum line connected to the pressure regulator and with it removed and pinched closed. All reading were nominal per the Helm manual. I replaced the fuel filter as it had not been changed for 90K + miles. I rechecked the fuel pressure and both pressure readings were the same as before the filter change. I replaced the thermostat and gasket (kit), the "O" ring between the thermostat housing and the head and the "O" ring between the pipe and the thermostat housing. I refilled and bled the cooling system. I replaced both thermo switches, (one on the thermostat housing and one on the radiator hose to head adapter, during the summer. I have not replaced the thermo switches on the end of the head (below the distro). I replaced the PCV valve hose as the original hose collapsed. The only items I have not replaced in the ignition system are the spark plug wires and the cam position sensor in the distro. I checked the spark at the cap and at each spark plug wire end with a test light. Great spark from both points and all four positions.

The strange thing is the car runs well and starts well. It runs on fast idle when it is cold and idles down to about 750 rpm per the car's tach. The car runs well for about two or three short trips from the house. The vehicle will occasionally die at a stop sign or traffic light. It usually restarts on the first attempt and rarely dies again. More recently it died and would not restart after four of five attempts. I was a short distance from the house and decided to walk home of a meter and LED tester I made to check ECU signal back to the distro. I waited about five to ten minutes and decided to attempt one more restart. The car started and did not die. A few times I noticed a brief cutout when I was running WOT on the highway. The worst issue is there are no fault codes stored or pending fault codes stored. None of the stalls set a check engine light. I attempted to simulate a shutdown by pulling the connector off the MAP sensor. Each time the engine died immediately, no codes were set and the engine restarted as soon as I plugged the MAP sensor in and hit the key. All the idiot lights remain illuminated when the engine dies. I suppose the ECU might be failing intermittently. I hope to find a used ECU at our local pull apart. My last time there was unsuccessful as this is a VTEC engine with automatic transmission and I could not find a Honda of my vintage to remove the ECU. I removed the ECU from the car and then removed both covers to visually inspect the unit. Neither side of the PC board showed any sign of burns or burnt components. The circuit board appears to be the same as the day it was installed below the front passenger's kick plate.

I have five items that I want to check with a volt meter and/or ohm meter and one item with a pressure gauge.

1. MAP sensor
2. Throttle position sensor 5V+ supply, 5V-ground and .4V to 4.7V signal
3. TDC and crank position sensor (vibration dampener end attached to the block)
4. Cam position sensor in the distributor and signal to the distro from ECU
5. Fuel pressure at the time the engine dies
6. The two thermo sensors on the end of the head (below distro) to check their function


My old code reader does not show real time values from the various sensors. I may need to update my code reader. My digital voltmeter (sears cheap, but decent, unit) does not have a true RMS voltage display capability to check the crank/cam sensors.
I do not have an oscilloscope to check the various outputs from the sensors.

I suppose I might have a bad ignitor, however, the replacement was new and I attached it to the mounting block with a thin film of silver heat sink compound. It has better thermal contact than the original heat sink.

I am usually decent in finding, diagnosing and locating failing components. This has me totally baffled. Please let me know if you have any ideas or if you see an item I have overlooked.

Thank you in advance for your time, talent and consideration. I hope I have simply overlooked a very simple item that is easy to repair and does not cost and arm and a leg to repair the problems.

 

I had a similar problem for a long time on my 94EX, which I eventually traced to "sticking fuel pump". It happened at random and mimiced Main Fuel Relay at times. I finally proved w/ "tell-tale" wire to the fuel pump power lead. When I confirmed power to the fuel pump and no fuel pump, I replaced fuel pump to permanently fix.

Wire is rigged from trunk through opening in rear seat to front seat where driver can monitor light condition while driving.

good luck

 

Thank you for your prompt and kind reply. My biggest frustration is no trouble codes are set and, yet, the vehicle dies. I had not thought of an intermittent fuel pump issue. It is too bad the engineers at Honda did not include a fuel pressure sensor that is tied into the ECU. My scanner is an older unit that simply reads and resets codes. The unit will not allow me to monitor data in real time. It might be past time for an updated/more expensive OBDII reader and a volt meter that reads true root mean squared alternating current values. This would allow me to properly test the condition of the crank position/TDC sensors. ...... I digress to much....... back to the topic at hand...... the fuel pump.

I have a question about fuel pump replacements. I did some research on Airtex fuel pumps and I was impressed. They are manufactured in the United States of America and are backed by a limited lifetime warranty. Both are important to me personally. I stopped by the O'Reily's yesterday as they stock Airtex parts. The person at the counter told me they have noticed a higher return rate from Airtex than other brands. He suggested the Import Direct brand and he checked to confirm that it is also made in the USA. There is no warranty information on the website or in the box. The website indicates to check with the local O'reily's store. I did not have this information with me as I had only reviewed two possible choices: Airtex and Delphi. The Delphi unit did not list the warranty information. I decided to go with Airtex as it included the lifetime warranty. The store was out of the Airtex fuel pump and I had located one, in stock, at a nearby store. I don't know if he was simply adding to his daily sales total or if he was leveling with me on the higher return rate for the Airtex units.

I am interested in your thoughts. The vehicle has 177K and I hope to trade it off in about two years. I want something that is reliable and that I will not have to replace in a few months. The labor is not a big deal as I am doing the work myself. I simply do not want the headache of replacing the fuel pump in the middle of winter.

Thank you in advance for your time and sharing your expertise.

Sincerely,

Brían S. Du Bois
Evansville, IN

ps I am interested in the thoughts and opinions of anyone/everyone on this forum. I simply addressed this reply to latest responded to my thread.

 

We infrequently see fuel pump failures, so most brands are likely reliable. I have no opinion or info on Airtex vs other brands.

Did you perform the diagnostic w/ tell-tale light to confirm intermittent fuel pump w/ power but no fuel pump run?

If not, fuel pump replacement is a lot of work to "hope for a fix". I did not see in the thread that Main Fuel Relay has been replaced or tested. MFR is more likely the problem than fuel pump, however the tell-tale light will indicate when no power is getting to the fuel pump from MFR, so both systems MFR and fuel pump are evaluated.

good luck

 

I have two threads going on the same topic (different sites) and I forgot to include some info on this site.

I replaced the ignition switch, main relay, negative (ground) wire on the battery, plugs, rebuilt the distro (ignitor, coil, inner seal and outer "O" ring, cap and rotor), removed and cleaned the EGR valve, removed the injector rail and injector (as a unit) and removed and cleaned the EGR ports and cover, replaced the two "O" rings on the VTEC solenoid, replaced the thermostat and two "O" rings and the upstream Oxygen sensor (I replaced the downstream sensor about 2 years ago due to bad heater error). I removed, disassembled, cleaned and reinstalled the cold idle valve. I replaced all three "O" rings. I removed and cleaned the Idle Air Control Valve and reinstalled with a new "O" ring. I removed the ECU and looked for burnt spots, bulging caps, burnt resistors, etc and found nothing glaringly obvious.

I checked the fuel pressure with a rented gauge. The pressure was about 35 psi with the vacuum hose connected to the fuel pressure regulator and 46 psi with the rubber hose removed and clamped off. There was no evidence of fuel leakage at the rubber hose and the pressure drops to 35 psi when the hose is reconnected.

This is running me bat **** crazy... I don't have that far to go! The engine starts and the car runs great. A few times it has cut out at WOT on the highway. Several times it has died on me and then restarted immediately. Three or four times it has died and will not restart for several minutes. There is no rhyme or reason. The unit does not set a check engine light, code or pending code.

I checked the MAP sensor for 5v+ and a good ground. Both are good. I started to remove the MAP, apply a vacuum and check for voltage change. It started to rain and I did not complete the test.

I plan to check the MAP sensor, throttle position sensor, air temperature sensor, cam position sensor in the distro and the crankshaft position/TDC sensors on the front of the engine.

I am considering removal of the fuel rail and injectors as a unit. I would like to place each injector in an empty water bottle, disconnect the distro to prevent spark, and see how each injector is working. The disconnected distro may prevent the injectors from firing. I don't like the idea of an active spark with the injectors removed from the intake manifold.

I am concerned the car will eventually strand my wife and family. I am usually decent in finding and fixing issues with any of the automobiles we have owned.

Thank you in advance for your kind consideration.

Sincerely,

Brían S. Du Bois
Evansville, IN

ps I have not taken time to run the wire to the fuel pump, however, I can hear the fuel pump running. It turns on for about 2 to 3 seconds and then stops until the engine starts. I purchased some wire and two different colored LED with built in resistor. I plan to run a wire to the yellow/green wire on the distro and the another wire to the fuel pump supply wire. This will hopefully tell me if the spark or the fuel pump is dropping out. I suppose the fuel injection might be loosing pulse and this should be the only other item if the distro and fuel pump are both receiving voltage at the same time.

 

Hard fact is that diagnostics on an intermittent condition are unhelpful if the condition (no-start) is not present. This may be at the heart of your problem.

Since car runs/starts well at times a fuel injector problem seems unlikely. The intermittent fuel pump seems more likely given history of parts already replaced. Again the tell-tale light is easiest way to know since it wiil provide an indicator of problem when problem is presented (engine stoppage, no start).

good luck

 

I have a bit of an update. Today it warmed up to the low 60's and it was much easier to troubleshoot the Accord. I checked the MAP sensor and I appears to be functioning correctly (removed from the intake manifold, attached vacuum pump and t pinned the control wire). The initial voltage was 2.8 V at atmospheric pressure. The voltage dropped to approximately 0.4 V as a vacuum was pulled via the hand pump. The voltage increased back to the initial voltage as the vacuum was released. I next tested the throttle position sensor. I t pinned the control line and attached a digital voltmeter. The voltage reading was approximately 0.5 V with the throttle closed and 4.5 V with WOT. The voltage returned to the initial voltage once the throttle was gently released. The voltage varied smoothly as I changed throttle positions. I gently tapped the TPS body with a small screwdriver and changed throttle positions. There were no voltage drop off or abrupt voltage changes. The carbon brush does not appear to be bouncing due to vibration. I may run a line from the TPS control line to the inside of the car and attach it to my DVM. It would be nice to have voltage changes while I am driving. My Son will read the meter while I drive. This will allow me to check the voltage output of the TPS under real driving conditions. I will test the engine water temperature sensor (2 pin connector on the end of the head) to make certain resistance (and the resulting voltage) varies as engine water temperature changes. I will also check the intake manifold temperature sensor (if I can get a t pin or probe on the terminal(s) due to the location of the sensor). This should rule out error from all the sensor input devices [or it will identify the faulty unit(s)]. I also want to run a line inside from yellow - green strip wire on the distro and attach it to the negative terminal on an LED and a positive supply wire from the battery. This will provide a visual flash of the LED as it is driven by a signal from the ECU. I will run another set of wires from the power connector on the fuel pump to another LED inside the car. I hope this will help me determine if I am loosing signal to the ignitor or the fuel pump. If no signals are lost .... then, I may have an intermittent fuel pressure/volume drop. The pressure regulator tested good. The coil and ignitor are relatively new. The fuel pump might not be delivering enough pressure and/or volume. I despise the thought of dropping the fuel tank, replacing the pump and re-installing the fuel tank. I am certain I can change the fuel pump ... should it be defective. A BIG THANK YOU to everyone who took time to respond and offer suggestions to address my issues. I will continue to update until the car is repaired .... or until I go completely BAT $hit Crazy

 

I am back on the Accord now that the weather is more tolerable outside.

I have good news and, I thought, excellent news..... and then it went to $hit. I decided to replace the fuel pump as I thought it would be relatively easy from the various YouTube videos I had watched. The 1997 Accord has a plastic cover below the fuel tank. It has about 11 fasteners that hold it to the frame. Several are difficult to reach because of the heat guard on the exhaust system. I finally removed the plastic cover and I was able to remove the fuel tank and replace the fuel pump. I found six rusty and/or unusable metal clamps. I ordered new clamps from the dealer and installed the clamps. I reassembled everything except the plastic cover (I might have to drop the tank later). I drove the car that evening and it was like new. Quick starts (following the initial priming), great acceleration, excellent idling and I was about 60% certain it was fixed. I have been down this road before. I drove the vehicle tonight (two days later) and it was the same. Excellent acceleration, quick starts and no stalling at stop signs. I was ready to move my degree of certainty of repair up to 80% and thank TexasHonda for his suggestion to replace the fuel pump. We live off of a "cow path" and I was going around a 90º left hand turn and it happened. The car stalled without warning. I quickly dropped the auto transmission into neutral and hit the starter. The engine restarted immediately and did not stop again. I did not have time to check many items on the dash as I was too busy trying to make the turn without power steering. I am glad I was on a road with a 25 MPH speed limit.

The following is a list of the repair/replacements/tests I have performed in an attempt to solve the mystery of the stalling engine on the 4 cylinder VTec engine:
I rebuilt the distro (igniter, coil, outer "O" ring, inner oil seal, cap and rotor. I replaced the negative battery cable as it appeared to be corroded near the end that attaches to the trans. I replaced the ignition switch and the main relay. I removed an cleaned the idle air control valve and the cold start valve. I removed and clean the EGR valve. I removed the intake manifold port cover and cleaned the carbon out of all the ports and the cover. I tested the throttle position sensor and it was in spec. I checked the MAP sensor and it was in spec. I don't know if the hard left hand turn is a major clue or not. Perhaps this is applying a strain to a part of the wiring harness and I am loosing connection. My next test is to t-pin the yellow wire w/green strip and connect it to an LED. This will provide a visual reference of the signal from the ECU to the ICU. I started to run two wires to the fuel pump connector and decided it was unnecessary. I should have gone with my gut feeling. I may send the ECU for rebuild/repair. It will be worth the money to make certain it is not the issue. I suppose it could be the crank sensor (two sensors on the front of the engine between the oil pump and timing belt). Do these sensors fail often? Is there a similar LED test (that I used on the hall sensor on the distro) for both of the crank sensors? If so, which wires and which connector?

I forgot to mention that I changed the fuel filter with a Genuine Honda filter last fall. The filter had approximately 100,000 miles. I think the manual calls for 60,000. I was concerned the filter replacement might have been beyond my ability because I don't have a lift. I found a excellent YouTube video that demonstrates how to change the filter. Changing the filter did not fix the stall issue.

Have I overlooked something? Any suggestions (other than the scrap yard)? This is the most difficult issue I have attempted to troubleshoot. I am self taught and I learned most of what I know watching my Dad as he worked on his vehicles. The Helm manual helps, however, I am nearly out of ideas.

Thank you in advance for any suggestions, criticisms, comments or jokes that might assist in determining the root cause of the stall issue. It either has to be lack of spark, lack of fuel or an obstruction in either the air intake or exhaust. I would think an obstruction would not clear quickly or easily and the engine would have not restarted immediately.

Thank you for taking the time to "wade" through my mess with me. The items listed are not necessarily in the order preformed. The main item that does not make sense is how well the engine runs most of the time.

ps I cleaned the fuel tank prior to installation. I added five gallons of 93 octane gasoline to the tank. I did not want to add too much in the event I had to drop the tank again. I hoped the higher octane gasoline would help to clean any remaining gunk out of the system. I ran a can of B12 through the system prior to the fuel filter change.