Tobin22

I recently bought a car with a bad timing belt, I replaced the timing belt, water pump and tensioner. Since I already had it apart I felt it prudent to replace the camshaft sensor and the crankshaft sensor at the same time. I also removed the intake manifold and cleaned out the EGR channel.
I am getting the following codes:
P0336 crankshaft position "A" circuit range/performance.
P0300 random/multiple misfire
P0301 misfire cylinder 1
P0302 misfire cylinder 2
P0303 misfire cylinder 3
P0304 misfire cylinder 4
When the RPM's reach 3500 the engine will lurch and buck until you let off the pedal, would this mean the New crankshaft sensor is bad or could it be something else?

mac25

did everything run normal at first? What do you mean by a bad timing belt, old?

A new sensor being bad is possible, but I'd bet on bad timing.

Recheck your timing.

Did you change anything else like spark plugs?

Tobin22

It ran rough so changed the plugs and it ran better but had sputtering and shudder so suspected it was out of timing, it was found to be 1 tooth out of timing. Belt was old and was missing several teeth, timing was checked 4 times before reassembly since I wanted to be very sure, didn't figure it would jump time with all new parts and sensors.

ezone

Did correcting the timing fix all the problems?


The connector for the CKP sometimes get water entering it past the seals and that causes corrosion of the wire terminals, that causes poor electrical connections.

Same sensor may sometimes not make good contact after being unplugged for any reason, I never disconnect the wires when doing a timing belt job.

Tobin22

Going to check the timing today, the problems didn't occur until after we did the timing kit and put in new crank and cam sensors. If the valves got bent when the engine slipped time would it cause the CKP sensor and All cylinder misfire? It doesn't act up at all until you reach 3500 RPM then it starts chugging and throws All of the misfire and CKP code. The first time it threw the codes it also threw a Camshaft sensor no signal code, but when I cleaned out the EGR channels it ran 70@ 3500 RPM fine, then yesterday getting it up to 70@3500 RPM, it threw the codes for the CKP and All cylinders like it did before the channel cleaning.

mac25

So ever since you got it, it has had poblems above 3500rpm?

Is it a vtec engine?

anyway the vtec solenoid is not plugged in all the way?

Any way the original owner changed the ECU for a non-vtec, if vtec, or vice versa?

ezone

But OP did not list a VTEC fault code.


I wonder if the original CKP was never faulty, parts got replaced just because it was in the area, and a brand new faulty discount part is causing more hair pulling.

Tobin22

Yes it is a Vtec
checked the timing and it is still correct and dead on
checked all connectors and they were tight
Did a compression test: (#1) 195 (#2) 200 (#3) 200 (#4) 195
Haven't gotten the tool to do a leakdown test yet
Still no change, runs fine and only codes the P0140 until it is driven, then when reach 3500 RPM starts sputtering and jerking, drive it back home and check the codes and it throws all of the ones I originally posted.

Tobin22

I don't know if it had the problem above 3500 RPM before I got it, it wouldn't go above 2000 RPM because of the rough running problem.

It is a vtec, but everything is plugged in firmly, I'm pretty sure it's all original, the girl didn't even know what the vtec meant when I asked if it had a vtec engine.

ezone

But there is no fault code for it.


Not the connector shell, it's the terminals inside the connector that are important.
Compression seems great, no reason for leakdown check.


Hmmm



Since I already had it apart I felt it prudent to replace the camshaft sensor and the crankshaft sensor at the same time.

So there was probably nothing wrong with the original sensors,......reinstall the originals and see if it still acts up.

I suspect flaky aftermarket crank sensor..... maybe air gap issue or weak magnet/inductive pickup.

ezone

What year is the car?

Tobin22

It's a 2001 civic EX
I wish I could put the original back in but it must have got thrown away when we picked up rags and stuff, they said I can bring the sensor back for refund, what is a good brand to buy?

Tobin22

So you figure a faulty Crank sensor could make it throw those codes only when it reaches 3500 RPM? perhaps the magnet craps out at that specific point?

ezone

Or a flaky code reader that is not telling you the truth. Grab a different brand reader and double check see if code retrieved is different?

An incorrect air gap or a weak magnet might cause a signal waveform of low amplitude, and the faster the crank spins the weaker the generated electrical signal gets, then the computer gets confused.
It was just a wild guess.

Did the crank gear get dropped on the floor? A damaged reluctor tooth (the little nubs that stick out to trigger the sensor) might cause this issue

I work at a dealer, I trust genuine Honda parts.

Tobin22

Tried different reader, the only code it gives is the p0336 crankshaft sensor range/performance code. Have a new denso sensor on order. No the reluctor did not get dropped or damaged.
I discovered something else while tinkering, I had noticed when setting at idle and I would let off the pedal the idle would fluctuate before returning to normal (700 rpm) so I reved the engine, then out of curiosity decided to push it to 3500 rpm's, did it a few times, the engine surges and rpm fluctuates but won't go above 3500 as if it's hitting a Rev limit which would explain the lurching while driving. Would the crankshaft sensor cause that or something else?

ezone

Been thinking....tried new sensor yet?

What if you go under and push/pull/hold the connector for the CKP sensor while you have someone operate the throttle, could you either reproduce a poor connection or correct a poor connection while it's running at 3500+ RPM? If stressing the connector causes any change in how it runs, that may indicate poor contacts within the connection area.

Tobin22

Actually put the new sensor in last night, revved to 4000 rpm a few times, took it out on the road and drove aggressively and responded fine, so guess it might have been the cheapo after market CKP sensor. So far so good, hope that was the problem.

ezone