bought a pristine complete 1981 Imperial, may switch to carb

[70bigblockdodge]

from when the po was last driving it or new oil he put in to hide something

It's a 318 hard to break so I would not sweat that and don't hot rod a Imp. I like these cars and would buy one for right price and color combo, if all the parts are there I would figure out what is wrong, quality control was lacking in those years so the problem may be as simple as bad connections shorted wires. Check the simple stuff first, fuel, spark, and air.

 

[Carmine]

quality control was lacking in those years so the problem may be as simple as bad connections shorted wires. Check the simple stuff first, fuel, spark, and air.

That's just scatter-shot advice although I'd check electrical connections on any 30+ y/o car when troubleshooting. First of all, these cars received the highest (initial) quality ratings until problems with the EFI systems began to show themselves, largely brought on by alcohol in fuel and vacuum leaks. Component parts were actually "screened" with lesser-testing (but in-spec) parts set aside for Cordobas/Miradas. I've been around these cars for decades (and a member of the Imperial Mailing list back in the 90s), the main drivibilty issue has always been the system's inability to compensate for vacuum leaks, not "shorts".

However, mentioning that the car hasn't run in years (I now recall the ad myself) was a pretty relevant piece of info to omit from the first post that brings an entirely new set of issues.

 

[70bigblockdodge]

That's just scatter-shot advice although I'd check electrical connections on any 30+ y/o car when troubleshooting. First of all, these cars received the highest (initial) quality ratings until problems with the EFI systems began to show themselves, largely brought on by alcohol in fuel and vacuum leaks. Component parts were actually "screened" with lesser-testing (but in-spec) parts set aside for Cordobas/Miradas. I've been around these cars for decades (and a member of the Imperial Mailing list back in the 90s), the main drivibilty issue has always been the system's inability to compensate for vacuum leaks, not "shorts".

However, mentioning that the car hasn't run in years (I now recall the ad myself) was a pretty relevant piece of info to omit from the first post that brings an entirely new set of issues.

I am more or less saying instead of jumping to blaming the EFI, and making plans to ditch it before diagnoses, car needs to be checked just like any engine.
K.I.S.S.
All cars and companies were suffering from same quality problems. More vacuum lines more complicated wiring looms that were still just basically laying in a few fold over holders on the valve cover. That was okay in 50-60s with 3-4 wires in it taped up, when it became 10 wires and having twice as much mass rubbing in the old style holders will wear through.

 

[garyh]

If the EFI Runs I would leave it on there.
The IML has plenty of info on these Great Looking Cars !

 

[adam83]

Hi everybody thank you for the replies. Ive been to busy working on the car to take pics. I read everything on the imperial club website, and read through the EFI literature and the fsm that I got with the car. so, here's the deal

I took apart all the pieces of the HSA (control pump, fuel injection unit, etc) cleaned them and reinstalled. Took off the throttle body and cleaned the surfaces and gasket and used a little rtv to ensure no vacuum leaks. I replaced all vacuum lines with new. installed new autolite 65 plugs. Put 4 gallons of premium fuel and some seafoam in the tank. I installed the tophat/computer/Maf and turn the key. Engine turns beautifully but no start.

I checked and found Im getting spark, but not a drop of fuel. after some thinking, I turned the key again to on, no sound from tank pump or control pump. I took the connector off the asdm (automatic shut down module) and jumped the 2 #12 wires (blue and green). I turned the key to on, and the in tank pump started pumping immediately. Still, no start. I had my sister turn the key to on, then start while I looked at the fuel rails. Not a drop came out. With the asdm still bypassed, in the on position, the control pump was getting 6 volts.

The previous owner spliced in a T fitting in the fuel feed line from the tank pump to the control pump, and attached a hose with a valve on it. I opened the valve, turned the key to on, and fuel sprayed out. I closed the valve. I then removed the feed line from the control pump to the Fuel injection unit, turned the key to on, and a very low volume of fuel started pouring out. not a dribble, and not a spray, just a slow pour. I re-attached the line. I turned the key and the engine fired right up, ran so beautifully and smooth! It was the fuel that poured into the throttle body when I had the line off. then it shut off when it ran out of the small amount of gas it had. It was like being in hell and having an ice cream cone appear in your hand, only to disappear right before you could taste it.

I then removed the FI unit and took it apart. There are 2 needle and seat assemblies, they look like the ones you'd see in an edelbrock carb fuel bowl. The are spring loaded. I removed them, and opened them by hand easily, so they are not frozen or gummed up, and I sprayed carb cleaner through the now open bores of the FI unit, which in turn sprayed out of the fuel rails.

I kept the needle and seats out of the fi unit and re-installed it. The engine fired up. It was idling goofy and didnt feel right, but it ran and drove!

So, it looks like my problem is fuel pressure. there isnt enough to open the needle/seat valves in the fi unit. I need to get a fuel pressure tester and see what Im getting from the tank pump, and then from the control pump. I cannot confirm without actually testing with a gauge, but it looks like Im getting plenty of fuel from the tank pump and but Im not sure the control pump is actually working. I cant hear it running and the low pressure fuel coming out of it could be just the remaning fuel pressure after being pushed through the pump by the in tank pump. Or maybe I have a bad fuel sending unit. There could be a bunch of reasons why, but I need to verify my pressures first, then test the sending unit, and take it from there.

I really really want this car running. There seems to be zero issues with the trans and engine, and the car is so comfy and nice to drive.

Any advice or tips appreciated. I'll get some pics up soon. I've got another project going and dont want to spend a ton of time on the imperial, so if i cant get it figured out I'll either swap to carb or sell it. It's really frustrating because I think the problem is very simple I just dont know what it is yet. ok. calm down. buy fuel pressure tester.

 

[Carmine]

Hi everybody thank you for the replies. Ive been to busy working on the car to take pics. I read everything on the imperial club website, and read through the EFI literature and the fsm that I got with the car. so, here's the deal

I took apart all the pieces of the HSA (control pump, fuel injection unit, etc) cleaned them and reinstalled. Took off the throttle body and cleaned the surfaces and gasket and used a little rtv to ensure no vacuum leaks. I replaced all vacuum lines with new. installed new autolite 65 plugs. Put 4 gallons of premium fuel and some seafoam in the tank. I installed the tophat/computer/Maf and turn the key. Engine turns beautifully but no start.

I checked and found Im getting spark, but not a drop of fuel. after some thinking, I turned the key again to on, no sound from tank pump or control pump. I took the connector off the asdm (automatic shut down module) and jumped the 2 #12 wires (blue and green). I turned the key to on, and the in tank pump started pumping immediately. Still, no start. I had my sister turn the key to on, then start while I looked at the fuel rails. Not a drop came out. With the asdm still bypassed, in the on position, the control pump was getting 6 volts.

The previous owner spliced in a T fitting in the fuel feed line from the tank pump to the control pump, and attached a hose with a valve on it. I opened the valve, turned the key to on, and fuel sprayed out. I closed the valve. I then removed the feed line from the control pump to the Fuel injection unit, turned the key to on, and a very low volume of fuel started pouring out. not a dribble, and not a spray, just a slow pour. I re-attached the line. I turned the key and the engine fired right up, ran so beautifully and smooth! It was the fuel that poured into the throttle body when I had the line off. then it shut off when it ran out of the small amount of gas it had. It was like being in hell and having an ice cream cone appear in your hand, only to disappear right before you could taste it.

I then removed the FI unit and took it apart. There are 2 needle and seat assemblies, they look like the ones you'd see in an edelbrock carb fuel bowl. The are spring loaded. I removed them, and opened them by hand easily, so they are not frozen or gummed up, and I sprayed carb cleaner through the now open bores of the FI unit, which in turn sprayed out of the fuel rails.

I kept the needle and seats out of the fi unit and re-installed it. The engine fired up. It was idling goofy and didnt feel right, but it ran and drove!

So, it looks like my problem is fuel pressure. there isnt enough to open the needle/seat valves in the fi unit. I need to get a fuel pressure tester and see what Im getting from the tank pump, and then from the control pump. I cannot confirm without actually testing with a gauge, but it looks like Im getting plenty of fuel from the tank pump and but Im not sure the control pump is actually working. I cant hear it running and the low pressure fuel coming out of it could be just the remaning fuel pressure after being pushed through the pump by the in tank pump. Or maybe I have a bad fuel sending unit. There could be a bunch of reasons why, but I need to verify my pressures first, then test the sending unit, and take it from there.

I really really want this car running. There seems to be zero issues with the trans and engine, and the car is so comfy and nice to drive.

Any advice or tips appreciated. I'll get some pics up soon. I've got another project going and dont want to spend a ton of time on the imperial, so if i cant get it figured out I'll either swap to carb or sell it. It's really frustrating because I think the problem is very simple I just dont know what it is yet. ok. calm down. buy fuel pressure tester.

To be honest, it appears you're working through this as you should. You've found the IML resources (some of which you'll note came from me, although the best stuff came from Dick Benjamin, IIRC). It's been about 15 years since I've worked on one of these EFI units, but if the control pump won't run the car at idle, it certainly won't under a load. I dont know if you'll find a control pump, but I'd be looking into the electrical specs to see if another pump could do the job.

 

[BIGBARNEYCARS]

What I've been told from MY friendz in the Corporation at that time(Carmine, feel free to respond or rebut) is that the TSB that went out to ALL the dealers on the issues with the '81+'82+'83 Imperials(And I've read that TSB but it's been 35 years) went something like: The company will reimburse the dealers a total of X hours, (17 hours I think) at dealers labor cost, plus new 318 heads, intake, carburetor, fuel cell, fuel lines, and electronics as required in dash and engine compartment IF THE CUSTOMER CAN NOT BE PLACATED IN ANY OTHER WAY. (I guess if he screamed loud enough)And the few conversion kits I saw floating around back then were running around $2500.00 in '82 dollars. Kept me from buying one even if converted and I've always liked them especially with Ledo's sales pitch, Jer

 

[Carmine]

What I've been told from MY friendz in the Corporation at that time(Carmine, feel free to respond or rebut) is that the TSB that went out to ALL the dealers on the issues with the '81+'82+'83 Imperials(And I've read that TSB but it's been 35 years) went something like: The company will reimburse the dealers a total of X hours, (17 hours I think) at dealers labor cost, plus new 318 heads, intake, carburetor, fuel cell, fuel lines, and electronics as required in dash and engine compartment IF THE CUSTOMER CAN NOT BE PLACATED IN ANY OTHER WAY. (I guess if he screamed loud enough)And the few conversion kits I saw floating around back then were running around $2500.00 in '82 dollars. Kept me from buying one even if converted and I've always liked them especially with Ledo's sales pitch, Jer

There's nothing to refute, that's true. They did offer conversion kits.

And the last of them in Chrysler's pocession were destroyed at the Sherwood parts depot almost 25 years ago. Which isn't to say a dealer might have kept the pool-table sized crate somewhere, waiting for the right customer generations later. But you'd be better off hunting for the lost ark of the covenint.

One major factor in the conversions were that the dealer techs of the day had no experience with anything but carbs. The company pays for warranty time, so they were often paying for those guys to learn. Time is money.

Now we're decades into using voltmeters and other diagnostic tools. We have the internet to archive information and communicate. It's eaiser to diagnois those problems now, but the parts are much harder to find. We create work-arounds.

Just like all old cars.

 

[garyh]

Be sure the Air Cleaner cover has a Good Gasket and seals tight. This is Required for the Engine to run correctly.

 

[adam83]

yeah the more I look at this the more I feel its the control pump. It's getting voltage but doesnt make a sound. Does anyone know the range of the voltage that this pump is supposed to see? I want to feed it max voltage manually and see if it affects flow

 

[Carmine]

yeah the more I look at this the more I feel its the control pump. It's getting voltage but doesnt make a sound. Does anyone know the range of the voltage that this pump is supposed to see? I want to feed it max voltage manually and see if it affects flow

I'd be more interested in seeing if that pump/motor spins freely. Feeding more voltage into a seized pump just equals more chance to burn up the windings.

 

[adam83]

have you rebuilt one? is it pretty straight forward? Im going back to work on it now, Ill take it off and see if I can spin it

 

[commando1]

You guys have more balz than I do.
The wimp in me would have had me simply walk away at the beginning.
Nice troubleshooting.

 

[adam83]

Success, sort of. Taking both needle and seats out floods the car almost immediately. Putting them both in , I get no fuel at all. I took out the needle and seat for the rail with the small sprayers, and left in the needle and seat for the large sprayers.

Car fires right up and runs and drives. It's not as smooth obviously as it could be because the fuel is basically just pouring out of the fuel rail instead of a nice spray pattern. But it works and now it runs and drives. That is until it finally gets flooded then it stops and I have to wait for it to dry or plug the asdm back in and fire up the car and burn up all the fuel that's in the intake then unplug the asdm and bypass it again and then the car fires right back up and drives.. until it floods lol.

This is a decent mickey mouse fix until I can find the cause of my low fuel pressure. Or gather the intake and carb I need for the conversion.

I'm going to get the conversion parts anyways actually, just in case I cant find the parts I need for repairs to the efi.

I'll probably run a switch that connects the green and blue asdm wires and run the switch to the cabin so I can turn it turn off the bypass when I flood, then burn it off, then flip the switch and bypass it again and start it up and drive! It's a temporary mickey mouse fix but it is better than nothing. Taking the top hat lid off actually makes it idle high but that could prevent flooding a little longer. I need to find someone who can walk me through rebuilding my control pump or rebuild it for me. I'll update as things happen

 

[70bigblockdodge]

Good job keep up the good work you will sort it out.

 

[MarPar]

still munchin away I am...

I love to see this kind of troubleshooting...

You guys have more balz than I do.
The wimp in me would have had me simply walk away at the beginning.
Nice troubleshooting.

Btw Stan, is that hoffa in a Bus Driver's hat?

I didnt see it in @cantflip's thread as an option. lol

 

[commando1]

Btw Stan, is that hoffa in a Bus Driver's hat?

Yep. Hoffa in Chauffeur's Cap. Teamsters preferred chauffer to truck driver up to the fifties.

 

[adam83]

MY GOD, These cars are insane.

So, I settled with the fact that I would be driving it for a little while in the condition I described above. At peace with that fact, I start doing other things like putting the door panel back on, replacing the fuse for the horn, playing with the gauge cluster fuse (the gauge is fully digital, but looks all scrambled and weird, just another issue to deal with I guess). There is this hissing noise whenever you open the door and the gauge cluster lights up, and continues after the car starts. Well, take out the 4 amp gauge cluster fuse and the hissing goes away. Not sure what the hell that is, but I did notice at least 3 vacuum pods under the dash. So I also replaced the front passenger caliper which was rusted and locked up, bled the brake line, and finally put some under dash wire harness connectors back on their mounts (they were just hanging). I finally installed the under dash cover and now Im tired and I want to enjoy my labor and go for a cruise.. well, a cruise that involves the engine flooding every ten minutes, but whatever I know I just undo my jumper on the asdm and then crank the car and burn up the flooded gas, then re-jumper the asdm. Its worth it after a day of labor.


SO, I get in the car. Apparently an exhaust leak has begun somewhere, cause I can really hear it now. I take the car out from my coltesac, and give it some gas, it hesitates and BAM backfires through intake, so I just take it slow and easy. The driving characteristics begin to change. hard to explain, but it ends up with the car dying.

So I get out and take the jumper off the asdm and plug the asdm back in its connector as usual. I get in the car, turn the key and after a couple seconds it turns on and I sit and wait for it to die. But.... it doesnt die... it keeps running! I was mystified and scared at the same time. Could it really have solved itself??? I shut the hood, and go driving. peppy acceleration, doesnt run smooth but it runs. I drove it all over. It doesnt like hills, but does great on the flat roads.

So apparently the EFI decided its going to work again. I get home and get out to investigate exhaust leak. I opened the hood and within seconds my eyes are burning and crying, I backed up.. then looked under the car.. for a few seconds until my eyes begin to burn and cry again. It was running fatty fat pig rich. Must be because I took the needle and seat out, which was necessary at the time, but now is causing it to run super rich. I also had the o2 unplugged for same reason, to help it run better back when the asdm was shutting everything down, so I plug it back in. I turned the car off and called it a night.

Looks like I now have a running driving imperial with a fuel control computer that has decided it likes all the attention Ive been giving her and will now operate correctly when I turn her on.

So tomorrow, I re-install the needle/seat in the FI unit, and take a look at the exhaust. hopefully its just leaking at the connection points so I can solve the problem with some remflex gaskets and be done with it.

 

[commando1]

<Sighhhh.... >
Any enthusiasm I had for these Imps up to a couple of weeks ago has been completely sucked out of me.
Kudos for your persistence, tho.

 

[Duncan]

i don't know if this would be of any help but I will mention it just in case. I had a 78 LeBaron with the LeanBurn system. It ran really rough and rich, fouled the plugs in less than 10,000 miles, got horrible gas mileage, and I think I even remember backfiring through the carb a time or two, although I may be mistaken, etc. I found out the choke was set way too heavy and never fully disengaged. Once the choke was adjusted, it ran smooth as silk, got terrific gas mileage, had more power, everything. I really fell in love with the car after that. Don't know if it has anything to do with yours but it might. (The choke on mine was set so heavy, we literally turned the 'spring' mounted on the block at the end of the choke rod a quarter turn to make the adjustment)