Need Help With New Engine

[DanMcG]

Did you ever find out what the two ports on the underside of the manifold were for? and what did you do with them?

[Jon87V20]

Dan,

No I'm not sure what they would be used for. I just bought some tapered thread 3/4" plugs and plugged them up. I used some RTV on them and let it set for 24 hours. Unfortunately, I won't have any way to check on them other than watch for water on the dipstick and/or pull the manifold every few years or something. Seems pretty pointless to have those there.

I didn't see too much on the internet about those ports. No one else has really mentioned them. I put up a warning on Amazon in the reviews section to give others a heads-up about it.

[Stewart G Griffin]

You should be ok with the Jegs reman.


2) Is it fair to say, block the exhaust ports for power?  Unblock them for MPG?

Colder intake manifold = denser fuel+air mixture?

[Jon87V20]

Stewart,

These are just two holes in the bottom of the intake manifold where the coolant flows under the TBI. If left open, they just fill up the entire crankcase with coolant. I can't figure out what purpose they could serve or what you would thread into them. There's a photo of them above.

[Jon87V20]

What oil would you guys suggest I put in this thing after the break-in oil?

[Stewart G Griffin]

Stewart,

These are just two holes in the bottom of the intake manifold where the coolant flows under the TBI. If left open, they just fill up the entire crankcase with coolant. I can't figure out what purpose they could serve or what you would thread into them. There's a photo of them above.

i meant those metal plates for the intake manifold/manifold gaskets.

i would recommend mobil one synthetic  5W-30

[Jon87V20]

Oh okay I see what you mean now. Thanks.

[Stewart G Griffin]

i've run nothing but Mobil 1 syn in the 4.3 after breaking in with valvoline conventional.

Did you email 'Brock about the two holes?

[Jon87V20]

No. But I think I will. I'll post back with what they say.

[Jon87V20]

Had an issue with the TPS that I was able to sort out. Turned out I had ordered the wrong one. Everything is working great now. However, I noticed after the TBI rebuild, the injectors are very noisy now. They were audible before, but now they're loud enough to hear inside the cab. Should I be concerned about this? Does this mean there's an issue that could cause failure?

I changed out the o-rings, gaskets and fuel pressure regulator diaphragm as well as the little nylon washers that go on the fuel line fittings. I also changed the little screens that go over the injectors.

The first time I did the rebuild on it, I reassembled it incorrectly by having the injectors turned 90 degrees off from where they should be. I had to replace the o-rings and little screens again as they were slightly crushed.

The truck is running great. No issues performance wise. Just want to make sure this won't become a problem.