Help installing fuel injectors

[dkmcgowan]

So I got some 746 fuel injectors for my 89 4.0L.  I removed everything and cleaned up the fuel rail with some cleaner and I'm ready to start installing.  My question is do people normally try and clean the block fuel injector holes?  They seem really dirty and gummed up, but I'm scared I will just push crude into the cylinders?

 

Also, I had not driven the vehicle in probably 24 hours, but there was no pressure on the fuel rail to relieve when I pushed on the valve, should there have still been some?  Wondering if this is a sign of an issue.  I am replacing the pressure regulator while I have it apart with an OEM replacement.

 

Also a few of the injectors were really hard to get out, seemed normal, but a couple of them in the rear came out super easy.  I assume this could have been a vacuum leak and the cause of some of my idle issues, they should take some force to remove right?

 

I also had a bunch of fuel come out when I removed the injector in the rear, but no fuel when I removed the others, it could just be that it sits at an angle and all fuel goes to the rear.

 

Here is a picture of the injector hole?

 

[Marine1Texas]

Looks like carbon build up. you can always remove the manifold and clean it out. Or get a small tip vacuum head and suck it out.  From the look of it, it is on the manifold side. Pressure over time drops in the rail and lines as it sits, that is why when you start it up you hear the fuel pump prime to get it up to the 31PSI. Good thing to replace the regulator at when you put new injectors in.  Just make sure you have a snug fit when you put new ones in. I have had some really easy to pull out and some where the rubber ring was so hard it was really hard to come out. Just make sure not to tear any of the new orings!

[dkmcgowan]

I spilled a decent amount of fuel in the rear with one of the injectors and some got on the manifold.  If I let it sit overnight and finish tomorrow will it be fine to crank?

 

I don't want to catch anything on fire.

[dkmcgowan]

I just put all the injectors into the rail and the regulator, got it all ready to reinstall.  I went out and took a look at the manifold holes again.  I decided to just get a small screwdriver and try to scrape the crude towards the manifold and clean it out.  This worked for the most part.  I got most of the crude scraped out and then twisted up some shop towel and twisted it into the holes.

 

I only did two of them because some of the crude definitely fell back into the cylinder.  Not much, I bet I scraped 70% of it out and little pieces fell back into the cylinder.

 

I plan to fire up the vacuum cleaner tomorrow and see if that will help, but don't think it will help much with the hole being so small.

 

Will a few small specs of carbon buildup hurt the cylinders?  Isn't it most likely already in there as well or at least will just burn up next time it ignites?

 

I felt I had to clean it at least a little or it wouldn't seal correctly, otherwise I would have left it alone.

[Knucklehead97]

I've had complete injector Orings fall into the cylinders with no problems. Just burnt them away during combustion from what I can tell. I wouldn't be worried about the small specks of carbon. I have 746's as well, great injectors!

[Crash]

Run some seafoam or Berrymans B12 through the intake after you fire it up. The destructions are on the bottle. 

[dkmcgowan]

Got it all installed today, seems like no leaks and a success!