Unsure of how to move forward with 81 EFI Imperial

[70bigblockdodge]

Start a thread.

I will, literally picked it up yesterday afternoon. She's a dead dog. I have to empty the car out just to make it #1000 lighter to push.

 

[70bigblockdodge]

I bought a 81 Imperial a few months back and it's made a mighty fine lawn ornament, but now that I get even a hint of sunshine, I want to work on it and get it all prettied up for summer, but here's my problem: I'm not sure if I should switch to Carb or not.

Currently, vehicle does not run unless gas is dribbled in from the top, elderly woman who previously owned it had the gas tank pierced by something and it sat in her garage for 30 odd years. It's all electronically fuel injected and fired right up no problem even after sitting for such a long time, also no ticking or odd noises, but just that issue with the fuel tank. I was told a fuel pump and fuel cell could be iffy due to the "specific" nature of early electronic fuel injection. So now I'm at the crossroads - would it be wise to switch to carb to circumvent problems? or could I actually have a fuel cell hooked up and it won't be an issue? any advice appreciated, apologies if I cannot answer questions and whatnot, this is the first vehicle I've owned that's over 20 years old.

I will say that in some of my quick reading and research the fuel pressure is supposed to be around 36psi. As luck would have it my son has a 90s Jeep Comanche has a extra fuel pump that runs at 31 psi so I'm going to build a fuel system (my tank is shot) if it works great I'll see how it runs on EFI. Once I run into having to buy some weird parts I'm out and 2 bbl and intake goes on. I need it mobile to not become a permanent shop obstacle.
Another point about stock tank. It is exactly the same as any F,M,J body except it apparently has a big bump on the top (mine is not out yet), there is one that popped up on goggle search $460+ dollars, nope. Stock Aspen tank is $90 on rock auto. So if someone really wanted to go down the EFI road there are options other than a almost $500 tank.

 

[CHARLES374]

I'm leaving both. Refresh on the trans, because it's never been apart and seals are I'm sure very hard and not pliable. Rear end is 7.25 with im told 2.21 ratio. Works out to around 2200rpm at 70 mph with 215/70R15 tires or in that ballpark. That should be about perfect for 20+ mpg highway with A/C blowing ice cold.
Trans is a 999 so has the 2.77 first gear, and I believe lock up converter.
Doing math 2.77x2.21=6.122
2.45x2.94=7.203
So unless your running a 3.23 or better (more than that is terrible on highway) your pulling out gear from red light is hardly worse.
IMHO anything 3.23 and above needs overdrive to run 70+ mph all day long, that's a different argument.

I think they came with 8.25 rear.

 

[70bigblockdodge]

I think they came with 8.25 rear.

No it's definitely a 7.25".
7.25 cover is oval
8.25 cover is round with bolt dead center on bottom of bolt circle.
9.25 is shaped like a stop sign and has two bolts even with one another across the bottom.
That's the easy identification just by sticking your head under the bumper.
I've been under enough Darts and Dusters to know a 7.25 by quick glance.
It will be fine. If I drop a 5.9 magnum in that came out of one of those late nineties PU it might not be happy.
If I put the 5.7 in it I will have to change because that will accompany a matching 545 trans. For now stock drive line just not EFI long term.

 

[commando1]

I left two 7-1/4's scattered like shrapnel on US1 back in the 70's. And that was with a 273!
I'd use a light foot with those.

 

[marko]

i feel it needs to be be pointed out that fwiw an 81-83 imperial is not a c body, c bodies were 1965 to 78 full size cars.
not sure what the appropriate forum this should be under

 

[bronze turbine]

It's a J body.

 

[70bigblockdodge]

i feel it needs to be be pointed out that fwiw an 81-83 imperial is not a c body, c bodies were 1965 to 78 full size cars.
not sure what the appropriate forum this should be under

In Imperial section. 67-68 Imperials are not exactly a C body either. Technically a D body, lot of similarities with a C body, but some oddities under there.

 

[DeltaV]

Just a random comment about the efi. Well, nix the comment, see this:

1981-1983 Imperial EFI General Information

 

[david hill]

What do you guys think of this.
Plug n play conversion?


Pro-Flo 4 EFI Traditional 4150-Style Kit #35900 For Chrysler SB 318-360 CID

View attachment 642958

I don't know the costs to install, It appears like a very doable alternative. TV hook up would have to be fabricated. I would consider it.

 

[marko]

In Imperial section. 67-68 Imperials are not exactly a C body either. Technically a D body, lot of similarities with a C body, but some oddities under there.

no, not a D body. the last D body was the 66 Imperial which was a body on frame car

 

[70bigblockdodge]

Been down this road before. Whatever you want call a 10 year old chassis design that they suddenly decided to give a designation after the development of the A body 1960, B body in1962, and C body in 1965, D body 1955? Ebody in 1970, F body in 1977. But hey they are all Imperials so all good.

 

[300K Man]

I bought a 81 Imperial a few months back and it's made a mighty fine lawn ornament, but now that I get even a hint of sunshine, I want to work on it and get it all prettied up for summer, but here's my problem: I'm not sure if I should switch to Carb or not.

Currently, vehicle does not run unless gas is dribbled in from the top, elderly woman who previously owned it had the gas tank pierced by something and it sat in her garage for 30 odd years. It's all electronically fuel injected and fired right up no problem even after sitting for such a long time, also no ticking or odd noises, but just that issue with the fuel tank. I was told a fuel pump and fuel cell could be iffy due to the "specific" nature of early electronic fuel injection. So now I'm at the crossroads - would it be wise to switch to carb to circumvent problems? or could I actually have a fuel cell hooked up and it won't be an issue? any advice appreciated, apologies if I cannot answer questions and whatnot, this is the first vehicle I've owned that's over 20 years old.

It’s a retired Chrysler Mechanic I can tell you we had quite a time fixing them , when they we’d new

I bought a 81 Imperial a few months back and it's made a mighty fine lawn ornament, but now that I get even a hint of sunshine, I want to work on it and get it all prettied up for summer, but here's my problem: I'm not sure if I should switch to Carb or not.

Currently, vehicle does not run unless gas is dribbled in from the top, elderly woman who previously owned it had the gas tank pierced by something and it sat in her garage for 30 odd years. It's all electronically fuel injected and fired right up no problem even after sitting for such a long time, also no ticking or odd noises, but just that issue with the fuel tank. I was told a fuel pump and fuel cell could be iffy due to the "specific" nature of early electronic fuel injection. So now I'm at the crossroads - would it be wise to switch to carb to circumvent problems? or could I actually have a fuel cell hooked up and it won't be an issue? any advice appreciated, apologies if I cannot answer questions and whatnot, this is the first vehicle I've owned that's over 20 years old.

as a retired

I bought a 81 Imperial a few months back and it's made a mighty fine lawn ornament, but now that I get even a hint of sunshine, I want to work on it and get it all prettied up for summer, but here's my problem: I'm not sure if I should switch to Carb or not.

Currently, vehicle does not run unless gas is dribbled in from the top, elderly woman who previously owned it had the gas tank pierced by something and it sat in her garage for 30 odd years. It's all electronically fuel injected and fired right up no problem even after sitting for such a long time, also no ticking or odd noises, but just that issue with the fuel tank. I was told a fuel pump and fuel cell could be iffy due to the "specific" nature of early electronic fuel injection. So now I'm at the crossroads - would it be wise to switch to carb to circumvent problems? or could I actually have a fuel cell hooked up and it won't be an issue? any advice appreciated, apologies if I cannot answer questions and whatnot, this is the first vehicle I've owned that's over 20 years old.

fuel pump there was a faulty batch of them as a Chrysler mechanic they gave us fits till we finally discovered it was the fuel pumps were bad they show pressure till after a minute then the pressure and volume drops off

 

[Northcoast300h]

As others have said. This EFI system is a closed loop system. Any tiny leak of air will make it run like crap. Misaligned seals on the air filter cover was the main culprit. Way before the internet, almost all mechanics didn't know that. Mechanics would try to start it with the air filter off and of course it would die right after starting.

I always wanted to buy one, but always leary of that EFI. Still, I'd mess around with the EFI and see if I could get it running correctly. If you want to change it to carb or better EFI, you'll have to change out:

1) the carb/EFI of course
2) fuel pump to match new EFI or carb system
3) Ignition control box
4) Electronic distributor
5) possibly the gas tank
6) possibly the intake or an intake adapter.
7) Wiring harness
8) Instrument cluster. (I read the gas gauge, mpg indicator and trip gauge will be wrong).

The mpg indicator will probably state "99 miles per gallon", so I guess that a good selling point...hee.hee!

 

[Northcoast300h]

Beautiful car but the resale values are pretty scary, so I wouldn't put much money into it.

This $50K invested white imperial has a 401 stroker with 16,000 original miles. Owner said he won't take less than $15,900??? This posting was in 2020. It looks like he was trying to sell it for 3 yrs prior to that.

 

[polara71]

Beautiful car but the resale values are pretty scary, so I wouldn't put much money into it.

This $50K invested white imperial has a 401 stroker with 16,000 original miles. Owner said he won't take less than $15,900??? This posting was in 2020. It looks like he was trying to sell it for 3 yrs prior to that.
View attachment 643527

If the original wheels were on it without that rake he may have gotten his asking.

 

[DeltaV]

 

[Clover]

I bought a 81 Imperial a few months back and it's made a mighty fine lawn ornament, but now that I get even a hint of sunshine, I want to work on it and get it all prettied up for summer, but here's my problem: I'm not sure if I should switch to Carb or not.

Currently, vehicle does not run unless gas is dribbled in from the top, elderly woman who previously owned it had the gas tank pierced by something and it sat in her garage for 30 odd years. It's all electronically fuel injected and fired right up no problem even after sitting for such a long time, also no ticking or odd noises, but just that issue with the fuel tank. I was told a fuel pump and fuel cell could be iffy due to the "specific" nature of early electronic fuel injection. So now I'm at the crossroads - would it be wise to switch to carb to circumvent problems? or could I actually have a fuel cell hooked up and it won't be an issue? any advice appreciated, apologies if I cannot answer questions and whatnot, this is the first vehicle I've owned that's over 20 years old.

My take on the OPs post is that the EFI works fine but there is a hole in the gas tank. Weld up the hole and run it.

 

[polara71]

View attachment 643552

.
So he took less

 

[Mr C]

I left two 7-1/4's scattered like shrapnel on US1 back in the 70's. And that was with a 273!
I'd use a light foot with those.

A 7.25 will live forever behind an 80's 318 2 bbl. It's only if you add performance that you need to swap it out. Sounds like this will be a 5th Ave kind of drivetrain...stone axe reliable but not exciting in the stop light derby.