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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29522
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I have a 2008 5.3 with dod had no running comp on number 1

Customer Question

I have a 2008 5.3 with dod had no running comp on number 1 cylinderand lifters replaced ran fine for 25 miles back to no compression on number 1 cylinder but only the intake valve rocker disengages
Submitted: 1 year ago.
Category: Chevy
Expert:  Gary replied 1 year ago.

I am sorry your having this problem

it was fine for 25 miles and then just the intake lifter is unlocked at idle or when cranking it over ? and the cam shaft lobes where fine ?

are there any codes set in the computer ?

Customer: replied 1 year ago.
the rocker works fine just cranking unlocks when engine starts
Customer: replied 1 year ago.
140 pounds compression static 0 running
Customer: replied 1 year ago.
Miss fire code on 1
Customer: replied 1 year ago.
Just intake same as before switched 1 and 7 cylinoide No change
Expert:  Gary replied 1 year ago.

ok that is running at idle correct ?

if so and the lifter is brand new then this issue will be a defective lifter OR the solenoid or DOD assembly being bad or even one of the DOD seals leaking

the DOD system is NOT supposed to come into play at idle or very slow speeds when this happens at the slower speeds its usually one of what i said causing this issue and if it boils down to the DOD system then either replace the DOD assembly complete all one piece OR they do sell a kit to eliminate the DOD system with regular lifters

Expert:  Gary replied 1 year ago.

you can always get me back for FREE through this post with any follow up anytime with this question

if you have any questions please ask as i do not get credit for my work until you rate me here

Customer: replied 1 year ago.
shouldn't that disengage both lifters on number one cylinder if it was in the solenoid
Expert:  Gary replied 1 year ago.

yes but if the seal is bad or the solenoid it can just unlock one lifter

i personally am leaning towards a defective lifter that unlocked and physically can not lock back

Customer: replied 1 year ago.
switched 1 + 7 solenoids in problem stay that one didn't move to 7
Expert:  Gary replied 1 year ago.

ok if it did not move that would leave the lifter being defective

if the cam lobe is perfectly fine then the lifter is defective

Customer: replied 1 year ago.
Same thing we started with same valve
Expert:  GM Tech (Cam) replied 1 year ago.

Hi there, I am Cam.

I have a question. How did you change the solenoids over? The valve lifter manifold assembly is exactly that, an assembly.

As for parts, what source did you get the parts from? Were there any signs of debris in the system?

Customer: replied 1 year ago.
They were new lifters my mechanic said he swapped the one and seven silinoids
Customer: replied 1 year ago.
Lifter were from carquest
Customer: replied 1 year ago.
He said that screens were dirty
Expert:  GM Tech (Cam) replied 1 year ago.

Ok so that likely means the lifter needs to be replaced again. The solenoids are not controlling each lifter, rather each cylinder so if its turned off #1, then oil flows to that portion of the block which triggers the #1 lifters (both at once). For only the intake to be triggered means its internal fault in the lifter. Not using AC Delco lifters may mean that the updated design is not being used by aftermarket suppliers and having evidence of debris in the system is concerning. I would be changing out the filter for the oil manifold assembly at the same time. But the bot***** *****ne here is the lifter in #1 is faulty again and needs to be changed.