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Pete, Cadillac Technician
Category: Cadillac
Satisfied Customers: 27883
Experience:  17 years Cadillac experience as a technician.
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Motor missing on #1 cylinder

Customer Question

motor missing on #1 cylinder
Submitted: 1 year ago.
Category: Cadillac
Expert:  Pete replied 1 year ago.

Hi my name is ***** ***** I will be happy to help with this today.I need a little more info to assist better.

Did you have a compression test done at all to see if #1 cylinder is lower on compression then the rest of the cylinders?

Let me know so we can continue,thanks Pete.

Customer: replied 1 year ago.
all were 150 psi
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Pete replied 1 year ago.

Is the #1 plug fouling with oil or fuel at all?

Customer: replied 1 year ago.
no oil on it but some gas .....have changed injector, with another , changed coil with another ...still missing on #1
Expert:  Pete replied 1 year ago.

How about #7 spark plug does it look like it has been burning engine oil at all?

Customer: replied 1 year ago.
no .......hooked to scanner went under miss fire data, only # ***** missing
Expert:  Pete replied 1 year ago.

There is a bulletin on a misfire on #1 and in some cases #7 cylinder.The bulletin number is ***** are two different causes:

Oil being pulled through the PCV system or oil spray that is discharged from the AFM pressure relief valve inside the crank case.If you inspect the build date on the drivers door sticker if it was built before February 1 2011 (02/01/11) an updated valve cover needs installed.If it was built after this date then the valve cover was already installed and does not need replaced.#1 is the old design and #2 is the new design should be the left drivers side valve cover.The pistons need cleaned with upper engine and fuel injector cleaner in each cylinder (there is a special procedure for this).Then the engine oil pan needs removed to install a shield on the AFM valve as seen here.Link one is original and link 2 is the updated shield installed on it., afm shield only needs installed if this is an aluminum block and not cast iron.

With all that has been done here already to try and locate and repair the fault here I would look into this as the cause as this can cause what you experience here and does affect #1 cylinder.If this was already done let me know so we can continue.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.Thanks Pete.

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