Waltk

I have a 2000 Civic Ex that is in very good condition and has run perfectly for the past two years. But I went to start it this morning and it tried to crank at first and then refused to start. I am an old-time hot-rodder so know how to work on cars but not so much after the carburator days so need some help. The engine turns over fine and tries to start a little, but it just won't crank off.

I plugged an OBD tester on it and got no codes.

I put a timing light on it and I get good regular spark. And this would also mean that the timing belt is OK, right? The previous owner told me that he had the timing belt replaced a couple of years ago so it should be good,

The gas gage is showing 1/2 full. I pulled the rear seat and can feel the fuel pump cut on when trying to start. But that doesn't mean it is getting gas.

What to check next????

California98Civ

You can test the distributor by pulling the cap off and with a test light checking the ignition control unit has power and that the coil is firing. ScannerDanner did a video that taught me how to do it:

California98Civ

And also, if you are getting fuel and no spark, then there should be a fuel smell on each of the spark plugs. Pull them to check.

Waltk

Actually its the other way around. My timing light test says I am getting spark, but I don't know how strong it is or if the engine is getting gas. I found the "no start diagnosis" in the troubleshooting section and will use that as a reference but may still need some help.

The biggest challenge is that my tool collection is oriented toward old carburated V-8 engines, not a fuel-injected 4 cylinder. So I am ordering some stuff to help with testing.

Waltk

Engine is running again! But lots of questions.

I disconnected the fuel line at the rail and confirmed good fuel flow when cranking.
I confirmed spark is very hot (shocked me through the wood handle of the screwdriver I was holding
I confirmed power to injectors using a probe

I began to get worried because fuel and hot spark means engine should do something. But it just would not start. So I tried some starter fluid sprayed into the intake. Still nothing, not even a sputter.

Here is the crazy part. I went back to my shed to get some paint to mark the timing notch on the crank pulley, was going to check base ignition timing to confirm that timing belt did not jump. Meanwhile my wife decided on her own to see if she could start the engine. I got back and the engine was running perfectly. She said it began threatening to start and then finally caught, made a lot of smoke at first and then smoothed out.

I test drove the car and the engine ran perfectly but the engine light came on. I read the code- P0131 Primary Heated Oxygen Sensor (Primary HO2S) (Sensor 1) Circuit Low Voltage. I reset the code and the engine light has not come back on, yet.

What happened? Maybe some water in the gas that I purged out testing the fuel pump? Or maybe it got flooded for some reason? Any thoughts out there?

And why the code now? Should I replace the sensor?

California98Civ

See if the O2 code comes back before replacing a sensor. Wait at least three driving cycles. Maybe the failed starts contaminated the sensor with unburnt fuel. Maybe the code won't come back. At any rate, such a code should not stop the car from starting, since the O2 sensor is for closed loop ECU governed AFR management. On startup, the car is in Open loop and the ECU manages it using preset fuel tables.

94CivicSi

iTrader: (1)

Check those grounds. Right side frame to top of tranny. Rad support to valve cover. Remove, clean, apply dialectric, reattach.

All my Hondas hate dirty grounds and they can cause really weird electrical behavior.

wunfstgsr

Sometimes when the O2 sensor harness sits on a hot surface like header heat shields it can damage the O2 sensor and cause a no start! it happened to my 2000 civic. The harness had a burned spot and wires got grounded or something but a new O2 got her running smooth again.

Waltk

Almost a year since I started this thread and the car has run perfect since then, until now. The O2 sensor code never came back, and it hasn't thrown any codes since.

But same problem, it does not always want to start but once started it runs perfectly. Only difference is back then it only happened once, now it has happened several times during the past week.

Harrymonk

You have fuel, spark, air and assuming the timing is correct. In my experience there are two sensors which could be the cause of the issue here. Throttle position sensor, but more likely, the map sensor. Are you able to get access to another map sensor to try? I don't want you to waste your money on buying one and it not fix the issue.
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Waltk

I haven't had any problems starting the car the past few days. I went ahead and disconnected grounds and cleaned them but all the connections looked very good. I went ahead and replaced the coolant temperature sensor since they are cheap and readily available. And I installed a fuel pressure gauge on top of the filter. It reads 32 psi running and 40 psi with the regulator vacuum hose disconnected so fuel pressure is in spec.

The no-start may never happen again but if it does I will confirm fuel pressure now that I have a gauge. Next step would be to try a new map sensor. Could the crank sensor also cause this?

fonkernuckle

iTrader: (5)

Yes the crank sensor can prevent a car from starting. It returns a signal to the ecu to go ahead and provide the pulse to the fuel injectors for them to fire in essence. Hence if the car is not starting and you want to rule out the crank sensor then I would use a noid light on an injector plug to see if it flashes or if no have then use a test light to confirm power to one wire and then the pulse on the other.