Another Conversion

[53 Catalina 292]

I think the 4.3 is 262 c.i., so your system has the capacity to fuel an engine 12 cubic inches bigger than the 250. Sounds close enough to me, in my vast ignorance. And the 305 c.i. system I have can supply 13 cubic inches bigger than my 292 (although mine is bored .060, giving a total of 298 or 299, I think - haven't done the math.) Also sounds close enough to me, in my vast ignorance. Your PROM, being from a 6 cylinder, seems to be what I would need to replace my 8 cylinder one with, though I don't even know if the PROM cares how many cylinders it's running, maybe just the displacement matters to it, and the distributor reports the number of cylinders. Know anything about that? Is there a number on your PROM that you can see, without much trouble?

[r.e.c.enthusiasts]

Hmm. Yea. Kinda feel retarded making that previous statement. But. Thats why im here as well. So as for the prom im not sure. But i will look at it when i get home Wednesday. Its still very accessible. (Uts the removable chip right? Lol)

[53 Catalina 292]

Hey, just being ignorant, that is, not in possession of all the facts, doesn't mean we're stupid, does it? Sir Winston Churchill, British Prime Minister, said to America, prior to its entry into World War II, "Give us the tools, and we'll finish the job." The tool we need is accurate pertinent information, which I'm confident the EFI GearHeads have. Somewhere. The answer to the question, "How do you eat an elephant?" being "One bite at a time.", I guess we make progress (learn) one question at a time. The PROM (for Programmable Read Only Memory, I believe) chip is the removable chip inside the PCM (Powertrain Control Module) a.k.a. ECM (Electronic etc.) ECU (...Unit) and "the aluminum box in a hard to access location inside the car that all the wires plug into." And I think when I read about "Calpak" it means the PROM. I welcome correction and clarification.

[r.e.c.enthusiasts]

Awesome. Yea the ecm has not been mounted yet so it will be easy to get to. Ill post that later today.

[53 Catalina 292]

Great, thanks - but enough about me. Or "Moi", as Miss Piggy puts it. Do you have a wiring diagram for the donor 91 Astro, to help you answer your wiring questions? (I'm thinking about your inquiry about anyone having pictures of their wiring installation on a 250.) No responses to that request, yet? I'm wondering if there is enough similarity between the harnesses of your 91 Astro donor and my 89 Caprice donor to be of any use. Manufacturers have been known to goof up and do things the same way for a couple of years.

[r.e.c.enthusiasts]

I do not have a book per say. but I do have the downloaded wiring diagrams for the 91 Chev Astro 4.3l auto. I do not know if the oil press switch is looking for the same pressure as what my l6 original pump puts out.
Also the prom is Delco AUMJ 1278 underneath it has
JT8(G)/J6/P
LFIVN960
AE03

[53 Catalina 292]

Thanks for the information - that's a lot to put on a small part. I think oil pressure should be about the same for the 250 and the 4.3. So oil light on at idle causes can be, besides actual low oil pressure from engine wear - oil pressure not getting to switch, due to passage obstruction, switch failure, oil too thin from gas dilution, and idle speed too low. Any of those possible? Does the light go out as engine speed increases? Are the valves noisy?