Skip the auto shop - Our mechanics make house calls

Q: Generally speaking, would a cracked crank shaft pulley be replaced during a full engine rebuild?

asked by on

We had our engine rebuilt and when we brought it home the mechanic said we needed to replace the crank shaft sensor. We did so and about a month and a half later the Jeep wouldn't start and idle. After testing found that cylinder 2 was dead and the rest had low compression. After this the computer ended up shorting out and then they blamed that on an "improperly seated crank shaft sensor". When we pulled the engine and all of that a part, we found the crank shaft pulley was cracked along the inside and that cylinder 2 was bright and sparkly silver color while the rest were all black. According to the shop that rebuilt the motor, this happened to the cylinder because gas was let in there from a faulty sensor. So I don't know if this is possible or true but my theory is much different.

My car has 209000 miles.
My car has an automatic transmission.

A: Hello there, this seems like a rather compl...

Hello there, this seems like a rather complex situation with everything that has happened. I will answer this the best I can with the information given. The crankshaft sensor could cause the vehicle to not start, but if it does, it would idle erratically. The ECU uses the information from the crankshaft and camshaft sensors to fire the proper cylinder and the proper time. The computer may become damaged if there is a short in the wiring such as with the crankshaft sensor. If a cylinder is not firing but the fuel injector is still spraying fuel into the cylinder, it can cause what we call a fuel wash. The fuel in this case is unburned and will clean the cylinder resulting in the clean cylinder you have noticed. Either the cracked crankshaft pulley or the crank sensor or the computer could of caused this misfire among other issues. It sounds like a few different issues contributed to the engine failing. With everything going on, you may want to have a professional inspect the car firsthand to verify what happened and advise on how to proceed in this situation.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: turns over but win't start I can pop the clutch and it'll run fine till I shut it off then sometimes it will start others it won't

I can understand your frustration with your vehicle's starting issues. Since you are able to get the vehicle to start and run just fine when you "pop" the clutch, it is likely that you are having issues with your starter....

Q: Misfires of several cylinders on highway drive

Hello - this is a known issue, and BMW has a technical service bulletin out to address this (#385317). A software upgrade to the engine management computer is the repair for this. You should check with your BMW dealer's service...

Q: What type of unloaded fuel is recommended for citroen c3 1.4i 2002?

You can start with the lowest octane rating available and see how well the vehicle performs. If the vehicle performs well without hesitation and has decent fuel economy, then you can stick with that octane rating. If you begin to...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.