What are the signs of bad injectors and or intake manifold?

Hi,

What you described can be caused by several things. When you say, "... then dir wait a few..." does the engine stall, and then is difficult to restart?

I ask because a failing crankshaft position can cause issues when the engine is warm. It can cause the engine to stall and then restart after it cools off.

On the other hand, if you have to hold the throttle to the floor to make it start, that tells me it is flooding. When you hold the pedal to the floor, it shuts down the injectors when cranking. Are you sure the fuel pressure is within specification and not too high?

Also, if you have a live data scanner, check the coolant temperature sensor signal before starting the engine for the day. It should be close to ambient temperature. Additionally, let me know what the short-term fuel trims are at idle, operating temperature, and the vehicle parked.

Do me a favor. Take a look through this link and let me know if it seems to mirror what you experienced:

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

Also, let me know if there is any dark gray or black smoke coming from the exhaust.
As far as an injector or intake issue is concerned, either of the two can cause a misfire. Further damage to the catalytic converter can occur if there are leaking injectors.

Let me know.

Joe

Hi,

If it was related to a cam sensor, you would have a diagnostic trouble code to go by. When it stalls, how long does it take to restart? If it has a delayed restart, check for spark to the plugs when it won't start.

Here is a link that explains how:

https://www.2carpros.com/articles/how-to-check-for-ignition-spark

If there is spark, try holding the throttle to the floor when cranking to see if it starts faster.

Let me know.

Joe

Hi,

The cylinder issue would cause a misfire, but it shouldn't shut the engine down. How long does it take to restart after it shuts down? Also, have you had a chance to look through the crankshaft position sensor link I listed above? If so, does it mirror what you are experiencing?

Also, if you have 0 compression in cylinder 4, you should disconnect the injector. Otherwise, it will continue supplying fuel that isn't being burned. Check to make sure the engine oil isn't polluted with fuel.

Let me know.

Joe

Hi,

Are you able to move the push rod (see pic below)? Also, no that is not normal. Either we have a bent/damaged pushrod or something is broken on the rocker arm. It's hard for me to see it.

If the pushrod is can be moved, inspect the valve to make sure it isn't stuck down.
Let me know.

Joe

See pic below.

Hi,

If the valve spring is collapsed and tight, it sounds like a bent valve. Let me know what you find.

Joe