dmwracing42

iTrader: (3)

So I'm doing a 305 to 350 swap on my '84 T/A. I don't have to go through emissions anymore, so all of that stuff is going away. I'm trying to decide if I want to lose the computer, or if I could hook it back in to the 350. Anyone have any idea what the computer actually controls (I'm not using the CCC on the 350)?

An older tranny is going in, so lockout won't be an issue. Is the fan ECM controlled? And would the fuel pump in the gas tank be as well (I'm pretty sure I have one, as my car is H.O.)? Is there anything else I should consider with removing the computer, or would my life be easier just sticking with it. And if I do that, how do I go about using it for the 350?

Ronny

iTrader: (1)

CCC I believe uses an 02 sensor although I never owned one. Fact of an 02 sensor allows the engine to run at stoich and improves emissions. Since it has no idea what the CID is it may work on a 350. However if the carb is jetted for a 305 that would be a problem for WOT or high load/demand. Spark I believe is not computer controlled IMO. Check the stickies for more info.

Most would say remove ECU and carb and use a modern carb.

dmwracing42

iTrader: (3)

Yeah, I'm dropping the current carb and getting a 650 Holley Double Pumper. I've heard differeing stories about the fuel pump, if there is on in the gas tank. I have an H.O. and some say there is one, others say there are. And if there is, some say the mechanical can pump through it, and others say it can't, so I'm not sure. I'm getting a vacuum advance distributor, so that won't be an issue.

Any ideas on the fan, if it's computer controlled?

Ronny

iTrader: (1)

My 84 EFI car has the radiator fan controlled by a sensor in head not he ECU. so I believe yours is not ECU controlled. Some would put in a switch to allow manual control.

james1227

Hey guys. totally new to the ecm thing and this is my first restore. 86 yr i think it has an ecm in it i see a small box under the dash with a interface conection on it. the original motor was removed and there is a 305 in it right now from a 85 truck. not sure if im going to rebuild the 305 or go bigger as this is my first project. the car has ac. what does or what did the ecm control on theses cars? it was a carb motor from what ive found out. do i need to run the ecm or can i by pass it and go old school. im in the process of finding out what the emission regulations are here in Houston. thanks for your help and recommendations.

dmwracing42

iTrader: (3)

If you go to a carb you will definitely need a vacuum advance distributor, a carb that's got a manual choke (Holley double pumpers are good), need to drop the gas tank and remove the helper pump in it (for this some would replace the helper pump with a line and filter sock, others would just get a whole pickup assembly), and if you have a lockout torque converter, a kit sold to make this lockout. The torque converter lockout isn't required, but helpful if you have it.

1986 305 RS

From the short research about out right removal it sound unfortunately bad cause i want to remove mine also. Ive heard about reverse lights not working, lock up, fans not working, alt not charging, speedo not working ect. If anybody has removed theirs with little to no issues please let us know and what you did to bypass the issues you encountered.

rusty vango

why create problems for yourself ?? the old one applys here "if it aint broke ,don't fix it". personally it breaks my heart to see a otherwise nice 3rd gen with a bunch of mis matched parts and worse parts cut off. and it makes it hard to sell should you choose to

1986 305 RS

Im making it clean looking. Some people like crap everywhere in their car some don't. Im knocking it down to only what I need. Head and tail lights, horn wipers and sprayer, radio and wiring to make it run ect. I ripped out the old stinky red interior and entertaining the thought of a roll bar before I go with new black interior the list goes on. Its being well taken care of my mechanic/race car builder has had it at his place for a over a month so pics will be comming some time.

dmwracing42

iTrader: (3)

Rusty Vango, some would argue that the ECM makes things messier. All the wiring and other emissions controls under the hood ruins (IMO) the look of the engine. With my engine swap, I want a nice clean look under the hood with only the essentials. And it's only mismatched if not done right. If it's done cohesively, you can make anything you do look factory.

1986, the biggest issues from my research and peoples' experiences would be lockout, timing advance, fans, and possibly the in tank fuel pump. Your sig says you have a T-5, so lockout is a non-issue for you. (Unless you have another car your doing this on thats auto, in which case they sell kits where you can hit a switch to engage lockout). Timing advance is easily remedied with a vacuum advance distributor. Fans I'm less sure of. My particular year has a switch/sensor in the head that controls it. And the in tank fuel pump (again in my year) runs off of the ECM for 2 seconds before the oil pressure switch takes it from there. You may not even have one, you'd have to go under the car and see how many electrical wires run to the gas tank. If only two, you don't have one, if 3 then you do. So for me, the only real issue is a new distributor, since I'm installing a TH-400 and torque converter that won't have lockout.

1986 305 RS

Wow ty dmw I will have my mechanic read this tomorrow it was very helpful. All my emissions stuff is gone all my a/c stuff is gone etc so with the way the wires are laid we just have to extend the alt ground wire and fire it up and if I recall there's 2 plugs going to the ecm so you know....unplug 1 and watch listen drive ect pull the 2nd etc. So I guess the ultimate question is what does the ecm run/control because there's alot of wires going to those plugs.....START PULLIN! geeeennnntttlllyy

1986 305 RS

totally off subject but how do you change your name on here. With a little research I discovered that my car is a sport coupe not a rally sport I love this site.

dmwracing42

iTrader: (3)

Haha no problem. Basically, to abbreviate it, the ECM controls (to my knowledge):
1. Torque Converter Lockout (again, manuals don't have a torque converter and therefore no lockout)
2. In tank Fuel Pump (If you have one). In my year that was only for 2 seconds then the oil pressure sensor controls it. I'm not sure for 1986, you'd have to talk to someone who knows more about '86's.
3. Emissions crap. You don't have it, so no worries.
4. Timing Advance. You need the vacuum advance distributor. If you're already running a carb, you may already have one.

As for the rest of your worries: Reverse lights aren't ECM. Fans are potentially. Not in my year, but potentially in yours. Alternator is not as best I'm aware. All the alternator does is create a current to recharge the battery. ECM shouldn't control that, but someone correct me if I'm wrong.

Not sure about changing your name. I'd guess somewhere in your profile you can edit it.

1986 305 RS

Whew busy productive day chasing wires and what not. Discovered that the ecm is needed for the eci but at this point nothing else. Tomorrow everything should be done and back on the road but if not no biggie its been on my mechanics lift for a month and a half whats another week. These cars are fun to work on.

TA Daddy

How did it turn out removing your ecm?? I have an 87 TA and want to put a 406 in with a Super T10 out of an 76 TA. So I am looking for any input I can find out. I was planning on keeping my ecm and have Sean Murphy build an computer control quadrajet which Sean thinks I should scrap the ecm and put a new dist. and regular quadrajet in.

1986 305 RS

everything turned out extremely well I couldn't tell you exactly how my mechanic did it but the only thing that needed to be bypassed was a wire to the transmission switch so the reverse lights would light up that that was the only issue and for him it was very simplistic. if I could run everything that off the top of my head that has been done to the car it would take me like 5 minutes and it still far from finished. it might not even be finished by this time next year I sure hope it is.

1986 305 RS

Items replaced ....rear end fluid and gasket, all rubber gas and brake lines, upgraded to iroc sway bars, front brakes and calipers, polyurethane sway bar brackets, non ac dash, ac delete box ripped out every unnecessary wire, timing gear set, timing cover gasket, edelbrock valve covers and air cleaner, chrome dip stick, plugs, wires, tranny, tires, dash pad, oil pump, oil pan gasket, shocks and struts, msd ignition, all crankshaft bearings, wipers, window fluid sprayer motor, 670 cfm holley, k&n filter, all new gaskets except rear main, whew and im sure im forgetting more.....

Ronny

iTrader: (1)

Consider a single plane manifold LS throttle body with Edelbrock TB adapter with EFI port fuel? Check out dynamicEFI.com (port fuel). If you want computer contol of
A/F closed loop that is the way to go.

ajastinger33

Not sure on the year, but I did a swap in my 89 rs and I'm running a mechanical pump, just remember to unplug the pump relay.

ibmtech

iTrader: (1)

I think you have to have ask the one of senior webmasters to change your name...