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Help me identify what's Missing from my head

Posted: Nov 24, 2021 9:03 PM
by Rocketflip
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Hello. It seems like something is missing from my head, I'm am experiencing some strange idle issues after installing my new head gasket , in wondering if maybe I lost a part, and that might be the issue.

There are these 3 bolt studs with a port of some kind, what is supposed to go here?

https://imgur.com/a/oVcFzgD

Re: Help me identify what's Missing from my head

Posted: Nov 25, 2021 6:23 AM
by RobertRO
In my opinion, nothing is missing.
That's where the mechanical fuel pump was installed, on pre-injection M30 engines. Even after the carburetor was dropped, the M30 heads continued to have the fuel pump location machined and related bolts fitted in, bar the hole for the fuel pump arm. Kind of like the human appendix.
AFAIK, it was eliminated only in the last release of M30 heads (B35 casting# 1708843 and B30 casting# 1708497).

Re: Help me identify what's Missing from my head

Posted: Nov 25, 2021 8:32 AM
by Federico
RobertRO wrote: Nov 25, 2021 6:23 AM In my opinion, nothing is missing.
That's where the mechanical fuel pump was installed, on pre-injection M30 engines (...)
Also, the L-jets (525i, 528i...) carried the air slide valve in that location.

As for the idle issues, I would start by checking for vacuum leaks. A hardened injector seal can cause issues when removed & reinstalled.
A classic mistake is to install one or more intake gaskets rotated or upside down. Did that on a Renault Alpine engine and it drove me nuts.

Re: Help me identify what's Missing from my head

Posted: Nov 25, 2021 11:29 AM
by Rocketflip
I think it's a fuel Injector problem myself, as I've inspected and remedied every possible vacuum.

I just ordered some rebuilt fuel injectors off eBay, altho they have 4 tiny holes in pintle rather than the 1.

When I was reassembling the car after I switched the head gasket , I actually installed the Ford injectors that are recommended all over this forum, and I assumed that is what made it run poorly, but those are also 4 pintled.