Fuel Injector Analysis

[Lobo]

I have the intake manifold off of my truck and I was looking at the injector tips, they all look fine except #5 which isn't shiny and actually seems to have a different shape. 5 of the 6 are rounded and shiny (in the hole on the bottom side of the intake manifold) but the #5 tip is more dull, flattened and cylindrical. Does anyone know why that would be the case? Was it maybe replaced once with a different type, or has the rounded part fallen out? Let me know if you have any insight. Thanks!

 

[SteveVB]

Possible the cap fell off, but they seem to be attached well (or were in my case). Could be it was replaced with a different one, but all that I have seen have the plastic dome like cap. Can you see the pintle? Is there some type of cap around it that is different or is there no cap at all? Has it got carbon on it from an oil leak maybe?

When I pulled my intake off I could see all of the injector tips, but they had carbon around the holes- some more than others. May want to pull the injectors and clean the manifold.

Sorry looks like I havent been so helpful.

 

[Lobo]

#5 clean, next problem

Thanks for the response! It tuns out that the injector was very carbonized. I soaked it in seafoam and it came out looking good as new. Just for others infomation make sure that you insert the injectors back into the fuel rail before reassembling into the intake manifold. If you have the intake manifold and fuel rail off I would suggest assembling them before you put the intake manifold back in (i.e. insert them back in already together). It cost me a couple of frustrating hours because the injectors were leaking. Anyone know why I am still getting an incredible vibration at 1700 RPM. I thought it might be the engine but it only happens at about 35MPH and 60 MPH. If I put it in drive (vs. OD) and keep the RPMs above 1700 it runs great. Let me know if you heard of or experienced this. Thanks!