I can put new into old I am not worried about that and that cats are not an issue because the 85 has cats. I was just wondering if the wiring and such would be easier if the 90 EFI was emissions free. They do not do an under the hood inspection all they do is sniff the tailpipe.

 

...and don't forget EMISSIONS. Since EFI is constantly self-tuning itself for optimum economy and emissions, they tend to run cleaner without the owner having to do anything about it. In the past, most people didn't take the time to properly tune their vehicle for changing conditions, and that is a big reason older carbureted vehicles were considered "dirty."

Your splitting hairs here, Chief. I think you knew what I meant. But yes, you are correct if you want to get 100% technical about it.

I don't think EFI is really all that "scary." Between my wife and I, we have four vehicles between us and only my F150 is carbureted. I would never switch out a perfectly good EFI system in favor of a carburetor. What I have learned is that with the right tuning, a carbureted vehicle can run just as good as any modern vehicle, PROVIDED you understand what a carburetor can and can't do without input from YOU.

Swapping gears in a rear axle is nowhere NEAR as easy as wiring up an aftermarket tach! Properly changing gears is an art all by itself; it is very easy to ruin expensive gear sets if not set properly, not to mention the labor involved is much more than wiring up an aftermarket tach. There are a lot of old timers who cut their teeth on carburetors who can wire up an aftermarket tach all day long, but scratch their heads when it comes to modern electronic fuel injection.

Changing the subject a little...
Since it sounds as if you have been around a lot longer than I have, and was driving vehicles before I was old enough to know, what was/is your opinion of the once state-of-the-art "feedback" carburetors that shared characteristics of carburetors AND electronic fuel injection that were common in the mid 1980s, and that was once on my own 1985 F150?

 

When running closed-loop, there is no need to re-tune modern EFI systems. They run closed loop 99% of the time, outside of competition scenarios.

This 99% scenario is where a carburetor will have to be retuned; there is some adaptability via the air-bleeds and other systems, but nowhere near as much as EFI.



Why did you post about being forced to take your car to a technician then? There are plenty of EFI solutions that are easily troubleshooted by the home mechanic.

I don't disagree with this.

I never said that wiring an aftermarket tach and changing a gear-set were equivalent abilities. I said if one was capable of doing both, they should have the capability to maintain an EFI system. Probably more apt to say that if you have the ability to wire a tach and change a headgasket, as keeping EFI running is nowhere near as difficult as swapping a gearset.


I did own an 80 Corvette for a short period of time with the Rochester CCC q-jet. (Computer Command Control, I believe. and I may have been mistaken on the model of carb my 78 'vette has, it was most likely an M4MC. My memory coming back is telling me the E4MC was the CCC q-jet...)

Anyhow.

I think feedback carburetors were a decent "bridge" design between carburetion and injection, but were limited by the technology of the time and also still had many of the limitations presented by carburetors. (obviously)

The CCC was basically a regular Quadrajet with computer controlled primary jets. The secondary operation was completely mechanical. I never had an opportunity to drive the 80 'vette to elevation but I'd bet it would have had slightly better off-idle response.

The biggest issue with carbs is the fact that mixture flow depends primarily on vacuum signal from the motor and no other input factors.

 

The engine wiring harness on a '90 is almost completely seperate from the rest of the vehicle.. the exceptions are power and ground and the check engine light, and since you have a donor vehicle right there this won't be too hard and should not cost you anything. The '90 also has a much simpler fuel system than your '85.. just a high pressure pump in the tank and two lines up to the motor.. no selector valve or booster pump on the frame, so I'd also suggest you move that over. The emissions system(air injection)on this motor does not affect engine operation so most of it can be deleted, that includes the air pump and all the plumbing and valves on top of the motor and those that run down to the exhaust. To avoid computer codes you just need to retain the TAB and TAD solenoids mounted next to the coil and keep them electrically connected. I'd also suggest you ditch the complete stock exhaust system and install shorty headers and an aftermarket Y pipe, doing so will really wake the motor up.

 

Thanks Conanski if I have any questions when I go to try and install this on my truck can I PM you for some help?