Low Compression after Injectors Cleaned and Reinstalled

rusty

rusty

Greenie N00B Member
Greenie Member
Was hoping someone has some insight into my issue. I removed my injectors to have them cleaned. I installed the injectors following the exact specification in the shop manual. After I was done I Immediately ran a compression test to check the seal. For some reason I'm only hitting about 50 psi per cylinder. Before I removed the injectors I was a solid 180 psi across the board. Do I have to run the car to set the injectors or something? I though they should seal right after I was done but maybe I'm wrong.
 
hey man,. quick question did you change the injector seal,. or installed one? corksport makes awesome ones. btw
 
Eroler1 said:
hey man,. quick question did you change the injector seal,. or installed one? corksport makes awesome ones. btw
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Replaced the seal with new OEM seals. My stock ones sealed perfectly fine after 80K miles so I went with those.
 
rusty said:
It's there but that shouldn't really matter since it's a cylinder compression test.
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true guess you gotta pull it all apart cause you're obivously missing someting if it's affecting all cylinders. Check if all the seels on the injectors were replaced/missing when cleaned
 
My compression tester checked out fine. I pulled the injectors again and verified their seating and sealing correctly. This might be an issue with my engine. Cylinders 1-3 are showing about 75 psi and 4 is showing 150 psi... I did a wet test on #1 and compression went up to 120 psi, still low but the rising makes me think my rings might be blown. Kind of crazy if this is the case. I literally tested my compression like 2 weeks ago and it was perfectly fine. I used a bore scope to inspect my cylinder walls they look great from what I can tell.

I also cleaned the intake valves while I was at it so maybe there is some kind of film or residue that's messing with the valve seal. My engine has also been off and cold for a couple of weeks so maybe that's a factor too. I'm going to button everything back up and get the car hot and retest.

Hopefully compression returns to normal if not I'll do a leak down and if that shows issues I'll start planning my rebuild.
 
If everything was good before this, there has to be a issue with either the injector seals or something else you had to pull off to get to them.

I have never pulled the intake manifold off yet. Have you attempted to start your engine? Can't see something going wrong internally on your engine...
 
Boom! Car stared right up and sounds great. Drove it around gingerly for 15 miles, then 5 miles with low boost then nailed the throttle on a canyon run for about 15 miles. Car is pulling like a freight train. I did a few logs and things are looking great and VD numbers are better than before. Compression test results are a perfect 180 across the board.

I guess it must have been some carbon debris blocking the valve seals. As much as I was looking forward to a Killah Built engine guess I'll stick with this one since it's still solid. Thanks everyone for your input.
 
I talk to you on Reddit sometimes, this thread had me nervous. How much flow imbalance was between the injectors?

Glad you have it sorted. Can you throw a log up sometime?
 
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mangosmoothie said:
I talk to you on Reddit sometimes, this thread had me nervous. How much flow imbalance was between the injectors?

Glad you have it sorted. Can you throw a log up sometime?
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The injectors were bad... The stock paper filters broke into pieces and were clogging the injectors. I have no idea what the flow numbers were before the cleaning because they didn't want to do test for fear of ruining the injectors. Luckily they were able to remove all the debris and replace the filters with a nicer metal mesh filter. The flow numbers after the cleaning were all within 2% of each other and spray patterns returned to normal. Definitely fixed my issue having them serviced. My car feels amazing now.

The logs I took yesterday weren't on my normal tune but I can do some once I feel these injectors are broken in enough. Still want to give them a little time before I turn up the Beaner.
 
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