I have a 2000 crv. The timing belt broke and I had read that there is a 50% chance that the valves were not bent so I tried installing a new belt. I also replaced the crank seal, tensioner, and water pump.



The first attempt was off a tooth but the second attempt got everything lined up correctly. I adjusted the valve lash and closed everything back up. The car started and idled very smoothly. I took the car for a test drive and it drove great for about three blocks. Then it started to misfire. I headed for home and it got worse and worse barely made it back into my driveway.



I removed the valve cover and the timing still looked correct. The cam gear marks, the mark on the crank pulley, I even put a thin rod down the #1 spark plug hole and confirmed TDC. The timing seems correct.



I checked the compression (cranking the cold engine) and got good numbers. 185, 185, 190, 200. I did a leak down test and all cylinders were in the good range.



I realized that when I filled the radiator after changing the water pump that I did not burp the system. So I did that, although maybe it was to late.



I cleaned the spark plugs and the distributor contacts and charged the battery. The car started but soon began to misfire. When I reved it it grew worse and when I tried putting it in gear to roll back in the driveway it died.



Now it is not starting. It ranks but can not start. Also, the check engine light is on. Autozone loaned me their code reader and it said misfire in cylinder #2. Secondary DTCs were misfires in the other cylinders.



I am suspecting three things:

1. Weak coil. I am getting spark at the plugs but it is an orange spark. When I crank the engine and then remove the plugs they are wet with fuel.

2. Head gasket. The autozone computer suggested this based on the misfires. Since I drove it without burping I am worried. The car did not over heat and it did not use any of the reservoir. The oil is not milky at all. Also, should t the car still start run with a blown head gasket? Tomorrow I will borrow a coolant pressure tester and see how that goes.

3.Crank sensor: I read someplace that the crank sensor wire can rub against the timing belt and get broken pretty quickly. I don’t know if theirs is true. Is there a way to test the crank sensor signal at the computer or do I have to remove the crank pulley to test it.



Do any of these seem likely or unlikely? Is there anything else I can do to narrow down and confirm the problem?

 

I borrowed a cooling system pressure tester, hooked it up, and pumped it up to 18 psi. After 30 minutes it read exactly the same. I set the gauge to 0psi and cranked the engine and it remained at 0.

So so maybe I can rule out the head gasket?

To recap, after changing the timing belt the car ran well very briefly and now will not start. It has a orange spark at the plugs, not blue. It could be the coil, distributor, wires or plugs but I have a hard time believing that that any of those would fail at the same time as the timing belt. Also, wouldn’t a weak spark still ignite the fuel.

After cranking the engine, when I check the plugs, #s 1, 2, and 3 are wet with fuel. The #4 plug is carbon fouled.

 

I found these ignition coil test instructions in a post in the 92-2000 Civic section. I believe that it should be be the same as for my CRV. When I tested my coil I got these readings:
Between terminals A and B: 1.0 ohms
Between A and Secondary Winding 16370

The A and B reading is higher than the recommended range. I assume that this means that it should be replaced? Or are my readings close enough to say that this is not the cause of the misfiring? I appreciated any advice on this. I am trying to avoid throwing parts at the car until I know what the actual cause is.

 

This morning I put the two prongs on my multimeter together and it read .3 ohms. So I think that would mean that my primary coil is at .7 ohms and actually within spec. So I guess the coil is ok.

 

Yes, you have ruled out the ignition coil. Your compression numbers look fine as well. Usually a bad crank sensor will trigger a code.
Not much help, I know. Do rule out any wires, vacuum tubes were disturbed during the service.
If the belt broke at speed, I think the chances of valve damage is high.

 

Thanks. How can I rule out or confirm valve damage before removing the head? Don’t the high compression numbers and good leak down test and the fact that it drove well for three blocks mean that the valves are ok?

the belt broke (or actually the crank gear stripped the teeth off the belt) while my wife was pulling out of a parking lot. Probably going about 5-10 mph.

At this point I wouldn’t even mind if the valves were bent, I am just looking for some confirmation of the actual problem. This unknowing has me stuck.

 

I think bent valves should show up in the compression test, not sure though. And the coil is fine (new ones read outside that range across A/B). It can always be a vacuum leak, so double check all your hoses. To me, the best clue is the #2 misfire code. However, if it's a single cylinder misfiring or not firing at all, it should still start and run. You probably should measure the resistance of the spark plug wires which is pretty easy. Look closely at the cap and rotor and clean any corrosion from them. Look your fuel injector wiring over carefully for damage, I had a mouse eat mine once.

There are other tests that require the engine to be running. Listen to fuel injectors, swap #2 plug and injector with another cylinder and see if the code changes cylinders. Look for sparks between spark plug wires. etc. But it needs to run.

 

Triple check all your timing marks. Make sure all your keys are in if you took off the harmonic damper, etc.

 

(Thanks for your comments. I am seeing them just now after trying some other things and collecting some new clues. I will check the wires with an ohmmeter tomorrow. Since I am no longer getting a specific cylinder error code I am not sure if switching injectors will tell me anything now. Please read these new updates and I would appreciate any thoughts)

I rechecked the timing belt and it is definitely set correctly. I rechecked the valve lash and they are correct, I replaced the plugs, rotor and distributor cap. I checked the wires carefully visually and wit sorting water at night and gave the battery a full charge.

The car started and, like before, the idle sounded very good but eventually developed a misfire. I’ve been worried about a head gasket leak so I checked the radiator for combustion gasses with a test kit that I borrowed. It came out good, no gasses detected in the radiator.

The car was idling well for about ten minutes, then I took it for a test drive around the block. I almost made it around the block when I felt a couple slight misfires. I pulled into my driveway and it was misfiring more and so shut it off.

The next day I tried it again. It idled well in the very beginning but after about a minute it began to misfire. It now starts and will not stall but It misfires at low rpms and on quick acceleration it stumbles. At higher rpms under slower acceleration it is not noticeable.

I checked the timing with a light and it is just slightly behind the red line. Maybe a 1/16 of an inch. So I didn’t move the distributor because I would rather not introduce new variable. The car ran well before the timing belt broke.

I also bought a code reader. It showed the following:

When warmed up the idle fluctuates from about 800 down to 550 because of the misfiring.

At idle the spark advance fluctuates between 13 degrees and 19 degrees. Then revel the max advance is 38 degrees.

It registers a pending code of P1399 which is for misfiring.

I checked the spark after replacing the blush and distributor cap and rotor and it is still orange.

When I pulled the plugs after all of this idling all four plugs had white ground electrodes. Everything else on the plugs still looked new.

So what do you all think?

Would the cam sensor or would the crank sensor cause this? I have a hard time believing that an unrelated problem occurred simultaneously with the timing belt breaking so I still feel like that must have something to do with this. My best guess is the crank sensor was somehow damaged my my moving it. But does this sound like a crank sensor problem and would the crank sensor trigger a speciific engine code if it was failing?

Any help would be greatly appreciated. Thank you.

 

Very good detailed post and diagnostics, yet still mysterious. It seems you have eliminated the obvious spark and compression issues. All that remains are fuel issues.
What is your temperature gauge reading as you warm up? I had a bad thermostat cause random misfires whenever the engine warmed up, because the coolant was still cold. A bad coolant temp sensor can also cause this.
Might be time to figure out how to measure fuel pressure? You might have a plugged fuel filter, a failed pressure regulator, or a bad fuel pump, yet all those issues would exist when cold.

 

The Coolant temp sensor seems ok too, on the engine code reader tool it showed the correct temp before starting and then heated up to 200 and the fan turned on.

Nobody seems to be jumping onboard with my crankshaft sensor suspicion. Can that be ruled out by anything I have reported? If the crank sensor was malfunctioning and sending something different than the cam sensor then would the computer trigger an error code? If so then why didn’t it trigger a code when the belt broke and the two sensors were obviously off?

Is there any reasons why the misfires can’t be caused by the crank sensor?

I guess I should borrow a fuel pressure tester and rule that out next.

I recorded a video of the engine idling, near the end you can hear a high pitch ringing sound. I am not sure where that is coming from.

 

The Crankshaft Fluctuation Sensor (CKF) is used by OBD2 ECUs to detect variance in the crankshaft speed to determine whether or not the engine is misfiring. In these Hondas it is not used for spark or fueling. OBD1 engines do not even have them. And your engine will run fine without one, it will just throw the code. I can see where a failed one might indicate a misfire when none is present, but you seem to have an actual misfire.

I have a fuel pressure gauge on my civic. I just bought a $8 part on ebay and a 1/8 npt gauge. It's fairly easy to install. It's called a "Fuel Pressure Gauge Adapter 1/8"-27 NPT M12 x 1.25 Banjo Bolt Adapter For Honda". But to me it seems, big picture, like you are doing all this to eliminate the possibility of bent valves. So, if you exhaust all the possibilities of fuel and spark, I think you have to circle back to the valves. That has never happened to me, (I've been lucky a few times), so I don't know how you really know that or not, beyond a compression test, which you did.

 

Thanks, NukeNinja, but at are you 100% certain that the crank sensor does not affect the spark? Before reading your post I decided to pull the crank pulley and make sure the sensor looked ok. There was a high pitched squeal on the running engine and I was worried that the sensor might be rubbing on the pulley and heating up. It wasn’t, everything looked good.

I removed the sensor and tested the resistance and it was 2000 ohms. Does anyone know what the recommended resistance is on these. I assumed it was ok and put everything back together.

When I tried to start the engine it would not start. It cranks but does not catch and shakes and the timing feels off. When I pulled the plugs, plugs 1 and 2 were covered in fuel, 3 and 4 were carbon fouled. (Before, when it wouldn’t start, 1,2, and 3 were fuel flooded and 4 was carbon fouled.)

This seems to me like my messing with the crank sensor caused this. But reading your post, NukeNinja, and the cost of these sensors has me wary of ordering one on a hunch.

Does anyone have any ideas on this. Does the fact that the problem varies from no start to running with a misfire (like in the video) point to something electrical? Or could this still be caused by bent valves?

thanks.

 

Now it’s running again. I am trying to list all of the details without overdoing it and listing every little thing. But here are some more and some I left out.

between the time that it was last running and the time it stopped running what I did beside checking the crank sensor was the following:

• I removed the distributor cap and checked the rotor to see if it had any excessive movement. It was ok.
• I removed the #1 plug to check tor TDC
• I removed the spark plug wires and checked them for resistance with the multimeter. All were ok.
• I wiggled the wire connector to the distributor. That connector has some type of child proof latch that I can’t figure out, so I never got it separated.

That’s everything. Three times now the car has been unable to start for an extended period. The first time I just cleaned the plugs, cleaned the distributor contacts, and probably left the plugs out so the cylinders could dry out. Then the car started and ran with a misfire. After test driving the misfire grew worse and eventually the car stalled and would not restart.

Then after putting in new plugs, cap, and rotor, it started and ran with a misfire. The time I did bit test drive it but checked various things and it continued to start and run until today after checking the crank sensor and messing with the distributor cap.

Now today, after the car wouldn’t start and I wrote the previous post, I left the spark plugs out for a few hours. Removed the distributor cap and rechecked the resistance on the wires through the cap and wiggling the wires. They all looked good so I put them back in and the car started. It made a slight sound like it wasn’t going to catch and then started up and idled. I didn’t wait to hear the misfire but when I pressed the accelerator down quickly I could still feel it sputter.

————-

So that’s where things are at. How does that sound to you all? Are the electrical things just red herrings or is that the cause? Could the bent valves just cause the car to not start in certain cylinder positions and then once flooded remain unable to start? I think that during one period when it would not start I did jus try during the plugs and airing out the cylinders and it did not help. But I can’t be totally certain anymore.

Any ideas?

 

As you said, "I have a hard time believing that an unrelated problem occurred simultaneously with the timing belt breaking so I still feel like that must have something to do with this."

I have a theory that the valves are bent and the reason that the compression stays good is that they are still able to close and seal relatively well. They are just not able to open completely. So if the exhaust valves are bent, you may not be able to discharge the exhaust properly, and pressure remains in the cylinder during the exhaust stroke. Or you may not be able to get a good intake charge, and a vacuum remains in the cylinder after the intake stroke. The oil in the cylinders is from the valve stems no longer aligning with the seals and elongating them, opening up the seals, and allowing oil to be sucked into the cylinders, which may be a bigger problem than the valves opening and closing. It may be your only real problem. This is purely speculation.

Have you ever rebuilt a head? It's not that hard. All you need for parts is a head gasket, valve seals, and whatever valves are bent. You might want new valve cover gaskets and seals. For tools, a valve spring compressor tool, some valve lapping compound, and a suction cup tool.

 

You may be right, Nuke Ninja. The exhaust valves might not be opening. I don’t think that there is excessive oil in my cylinders so maybe you misread my post on that. The plugs do get wet with fuel when it doesn’t start but no signs of oil.

I would like like to confirm it somehow before I remove the head. Can you please consider these additional facts and let me know what you think?

Today I started the car. As usual it idled fine for about a minute or so before a misfire can be heard. It doesn’t stall. I drove it and was amble to make multiple trips around the block with no sign of the problem getting worse. When accelerating gradually and driving at a steady speed then you can not feel the misfire. Only when accelerating guickly do you feel the sputter. It’s probably worse when accelerating from a stop. When I stopped driving it continued to idle with an obvious misfire. Still only getting the code P1399.

Does all this still sound inline with the not fully opening valve theory?

Is there any way that I can confirm this theory? I suppose I could take the car to a mechanic that has a mini diagnostic camera. Is there any other way short of removing the head? Maybe removing the exhaust manifold and trying to look inside? Anything easier?

 

P1399 HONDA: Code Meaning, Causes, Symptoms, & Tech Notes (With Video) (engine-codes.com)

 

Oops, you said 'carbon fouled', I read 'oil-soaked', my bad.
Those borescopes are pretty cool. You might be able to see if a valve made contact with a piston. That would be the smoking gun. I think you can rent them at Ottozone or O'Reallies. Arbor Freight has one for eighty five bucks. I might do that myself, but then you are relying on yourself to make the call. Might be worth a call to a mechanic shop, if you know one you can trust.