Hi, i was wondering what may be comp controlled in my '82 LU5? The CFI has been removed, along with some of the cruise control and A/C compressor. ( I say some of the CC because the box is still there, but there is a steel cable that has been cut coming from it) The stock Dist. is still there, which I know I need to change at some point to a vac advance, but other than the dist, what else is the comp controlling?

 

Does anyone know? Maybe even some guesses? Any gauges? Trans shift points? Fuel delivery? Id like to make the car old school with as little electrical/computer control as possible (and would like to get rid of that annoying check engine light)

 

Gauges are completely separate from the ecm. Trans shift points are not computer-controlled, but if you have a 4 speed auto, the torque converter lockup is computer activated.

I'll list what I can off the top of my head:

Computer sensors (not controlled, but for ecm input, and can still be disconnected).
MAP sensor, TPS sensor, O2 sensor, temp sensor,

Computer controlled items (ecm output).
Fuel Injectors, distributor, AIR solenoids, EGR, Charcoal can purge solenoids, Fuel pump relay switch.


it's not a comprehensive list, but it's all I'm getting off the top of my head in 3 minutes.

BTW, the CC should have nothing to do with the ecm, and the AC should only have one connection somewhere that tells the ecm whether or not the AC is turned on. It will function the same. Also, you you don't need to change the distributor out at some point, you need to do it before you drive at all. the car will run without the ecm connected to the distributor, but it will run like absolute crap.

good luck

 

I don't think he even has a lot of those things listed on an 82. On my 83 the only thing the computer controls is the fuel mixture on the carb, emissions stuff and the timeing. There is an o2 sensor, temp sensor, tps sensor, egr solinoid, and an AIR solinoid. The only tricky thing is if you have an auto tranny cause of the tc lockup is computer controlled, otherwise get a non cc carb and distributer remove all the emissions stuff if you don't need it for inspection. If you get inspections at least make it look like it is hooked up for the inspection and wire in your fasten seatbelt light to a light bulb behind the check engine light so when you turn on the key it will light up making it look like the computer is still functional and it turns off when the car is started. (not exactly leagal but works if they check for that kind of thing) Sorry I can't help about the tc lockup but I'm sure someone could probely help on the engine swap or tranny boards.

 

Thanks for the replies. I really wish I knew more about what is going on under that hood in terms of what is connected and whats not. There are small vacuum? lines running from the Char can that are cut, but not all the lines going in/out are cut, some are still intact and connected to the solonoid. It looks like a mess under there. I dont know how long the car has been driven with the carb/OEM dist setup, I bought it with a 2bbl holley and just swapped it for a 4bbl edlebrock. I drove for the summer last year to and from work (a whole 2 miles) and seemed to run fine.

Black89ws6, if you dont mind, Id like to pick your brain a little more. What exactly does the AIR solonoid do? Ive heard it mentioned before but wasnt clear on what it was. Also with the removal of the FI, doesnt that eliminate the EGR too? The only hoses coming from the block are water and PCV. Ill try to take some pictures of some question areas in my engine bay and hopefully someone will be able to shed some clarity on things.

Thanks again for the help so far.

 

the A.I.R (Air Injection Reaction) system pumps air into the exhaust manifolds, or into the catalytic converter, depending on engine temperature, and other throttle positions. The AIR solenoids are how the ecm controls where/when the air flows.

Car's had EGR before there was FI, but I don't know how to regulate it without an ecm. I would just do without, but maybe someone else can offer helpful info here.

If you drove it, and it ran fine, are you sure it had a computer distributor in there? If it had a computer distributor without a computer, it would have no timing advance as rpm increases, and would run like a dog. Is there a vacuum line going to the distributor?

 

Crossfire injection. no carb.

 

No, I know it is computer controlled as there is no vacuum line running to it. The computer is still there right now, but Ive been told by others here that its in limp mode due to the removal of the FI. Are there any sure signs that the spark isnt advancing properly? (sputtering?, backfire?) The power band seems to drop off a bit around 3700-4000 rpms. Itll pull hard until that point but then levels off and stops pulling. I dont get any abnormalities other than that all the way to redline (except a squealing belt, but thats not related ) As far as AIR and EGR, I believe that both of those are gone now. I assume that the AIR had something to do with the large flange on the top of my drivers side exhuast manifold thats not connected to anything. I guess Im going to have to have another long sitdown session with my chiltons sometime in the future. Sometimes I really wish a mechanic hadnt been the previous owner, some things just seems so jerryrigged.

 

Put a non-computer distributor on it and it'll run a whole lot better.

 

Ok, after taking a good look under and inside the engine bay I determined that the EGR and AIR are both gone completely. Now as far as getting a non cc dist. will it help my idle at all? Here's the deal with it, in gear it idles around 600 or so, but out of gear it idles at 1000 - 1050 and diesels when I shut it off. If I set the idle screw to idle at 750 out of gear, it nearly stalls at a stop in gear. if I set in gear to 750, it idles at 1200-1300 out of gear and will stay running for a short while. Is the difference in idles more to do the dist advance or the carb? Ive resorted to staying in gear and shutting it down to prevent the dieseling as I cant imagine that its any good for the motor.

 

There isn't much point in even trying to diagnose what's wrong with a mismatched setup like that.

 

Unfortunatly, I have to diagnose whats wrong as I have 0 budget with only a single income and a household to support. This is what I have to work with and am trying to make the best of what is currently available to me. I realize that installing a non cc dist will help matters greatly, but I dont have one right now and cannot get one for at least another month or two.

 

Without proper timing advance when the engine is running, you're idle is probably set pretty far open to compensate. Getting a mechanical distributor will provide enough timing advance to allow you to slow down the idle. That should stop the dieseling.

I hear the single income thing. I'm in the same boat, as my wife's been out of work for a while due to health problems. One thing to consider, IF you are driving this car on a daily basis, putting in a distributor will actually save you money on gas. You can get them as cheap as $25 at some junk yards, and it wil make a tremendous improvement in your fuel mileage.

 

Ok, thank you very much. I hope it will bring the two idle speeds closer together (in other words, bring down the idle in park but not in drive at a stop) I thought maybe the new carb was dumping too much gas in all together. Also, once I can get the regestration renewed for the year (one week and counting!) I will be driving it daily, but its only 2 miles to work so its not a big deal in gas consumption (one tank every two weeks) Once again thanks for the info, hopefully I can track down a dist at a yard around here, or else Ill have to buy new which will be around the end of summer.