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CarburetorsCarb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
Replace the bulb. It's a 194. Probably also original.
The pins to short are A & B. Should be the 2 at the top right of the connector.
No, you don't understand: at normal operation the SES light is illuminated and when I stick a wire in the top right connectors and turn the ignition to ON without starting, it just stays illuminated, no blinking.
Take a look at your ECM (pass side, metal box mabye 15 x 25 x 3 cm, right above the passenger's knees) and make sure the connectors are hooked up to it.
Take a look at your ECM (pass side, metal box mabye 15 x 25 x 3 cm, right above the passenger's knees) and make sure the connectors are hooked up to it.
Hmm... I think my ECM is as dead as a doorknob. I pulled it out of the car, disconnecting everything and the car still acts exactly the same: it runs (rich) and the SES light stays on. According to the service manual this means that 419 BRN/WHT is shorted...
Doesn't the car need the ECM to run? I mean: did anybody put the ECM out of the game on purpose and fiddled everything together to have it running without? Or is there a lack of power to the ECM and is the car running in limp mode?
the car will run without the ECM, just not very well... the carb will not be able to control the mixture and the dist will be stuck with the rudimentary ignition advance built into the Ignition Control Module.
you'll get crappy mileage and poor performance, but it will run and drive.
the ECM gets it power from a dedicated wire coming off of the positive battery cable that runs along the inner fender well towards the blower then passes through the right fender into the cabin. there's a fusible link on this wire that could be blown or it's simply disconnected. there's a little single wire connector on it maybe within a foot (1/3 meter) of the battery.
the car will run without the ECM, just not very well... the carb will not be able to control the mixture and the dist will be stuck with the rudimentary ignition advance built into the Ignition Control Module.
OMG, the previous owner drove the car like this for two years... No wonder the thing is crapping black sooth from it's tail pipes.
The crappy milage and overwhelming fuel smell is what put me on to this (and the SES light ofcourse). Could this mean engine damage as well? Or just (let somebody?) fix this and drive it happily ever after?
There must be something more wrong too, since SES light stays on even with the ECM out. That means wire 419 is shorted out somewhere.
I checked the orange wire powering the ECU at it's connector for 12volt which it did not have. It turned out to have a broken copper core near the black plastic "splice" on the black wire from battery +12v to alternator. I temporarily connected the orange wire to the red pole of the battery but it still isn't working. Also no error codes when connecting A and B on the ODB port. Is it some kind of special connection with that black wire or is it just an ordinary splice? In other words: will it suffice to connect the orange wire to the red pole of the battery?
I also noticed three loose connectors (two near the carb), might they have something to do with the ECM? Tomorrow I'll open up the ECM box and check that for power.
Also, these small hard plastic lines (air lines?) are melted through. You can see the one below the distributor is pulled to a thread and the other two lines are completely seperated.
BTW: can anybody tell me what that square metal plate is that is bolted to the intake manifold?
I'm beginning to think that removing all that stuff and putting a new Edelbrock & distributor would be the best way to continue...
Those 2 little plastic lines next to it there are related to it, and the object they are connected to is the EGR solenoid. The other one going toward the carb that's melted was the vacuum supply to the solenoid, and was originally part of the shorter one coming off of the solenoid. Trace that line to the nipple on the carb that it's hooked up to, get rid of the remains of the line, and put a rubber cap on the nipple. You can ditch the solenoid too for that matter; it's not doing anything anymore, and is now just dead weight your car has to haul around.
The 2 "loose connectors" nearer the carb are part of the AIR system, which has also been somewhat removed. The objects sitting up almost level with the air cleaner is a check valve for that system, whose purpose is to allow the air injection to force air into the exhaust while preventing exhaust from going the other way. They have rubber caps on the place where the air hoses used to go. The AIR pump is gone, as is the diverter valve, which controlled where the pump's output was directed to.
The green "loose connector" is the place you can hook up a dwell meter to check the carb's mixture control solenoid duty cycle. It's not normally connected to anything.
Whoever hacked the AIR pump and its brackets off didn't bother to put a bolt in the upper hole, which is the cause of the GIANT oil leak at the lower right front of the engine that's the cause of all that oil all over everything around there. Put a SHORT bolt (3/8"-16, maybe ¾" long at the most) with a flat washer behind the head and a drop of sealer on the threads, into this hole right here.
The reason it needs to be a SHORT bolt is because the fuel pump drive rod is in that passage you can see in this photo; and if you put a bolt that's too long in there, it (a) won't go in all the way, and (b) it will hit the FP rod and bind it up, and your FP won't work anymore, and the car won't run.
I note also that they didn't put a washer behind the tube spacer behind the alternator. That's why your alternator belt doesn't line up right. The AIR diverter valve had a bracket that went behind that spacer, which if it's gone, needs a washer or something there to replace it.
There's no filter element in the air cleaner. That should be corrected IMMEDIATELY, since dirt is a VERY fast-acting abrasive which will DESTROY the rings and bores.
I pulled the airfilter out to get the filter housing off, there is one in there now
I wonder where you noticed that alternator being misaligned? It isn't on any picture, was it?
So with this info:
- no AIR pump
- no EGR valve
- what's the condition of the ECM?
- do I have the correct distributor? (can't find the wire/connector that's going to the ECM)
- car has true double exhaust pipes (read somewhere that's also a problem for CC Qjets?)
- car is quite matching numbers...
- cost
...would my best option be to try and get the currect carb & ECM running like original, check all sensors (without AIR & EGR)? Or would it be more logical to delete most of it and throw in a new carb & ignition without all that complicated sensors and computer stuff?
Thanks! I thought I remembered there being 4 wires on the schematic, but I can't seem to see how many wires are here on the photo, I thought only two. I'll check tomorrow when I'm with my car.
That's not the ECM connector. It's the main "distributor" harness. It goes from the ign module inside the dist to the coil-in-cap: pink is ignition voltage, black is ground, brown is the coil/tach.
The connector that goes from the dist to the ECM is on the opposite side, in the back (toward the firewall) and has about 4 or 5 wires in it. It's a big flat wide Weatherpak type connector.
I wonder where you noticed that alternator being misaligned?
Because there's not a washer behind the alt spacer. I don't have to see the alt itself to know that it's misaligned.
what's the condition of the ECM?
Don't know; can't see it. They're rather rugged and only very rarely go bad. Most likely, once you get the wiring all sorted, it'll work fine. Assuming of course, that it's actually even still there. We don't even know that much about it yet.
do I have the correct distributor?
Correct enough. In the computer-controlled systems, the ECM does all the thinking. The dist is just a dumb pulse generator and a switch to route the spark to the right plug.
car has true double exhaust pipes (read somewhere that's also a problem for CC Qjets?)
That would be somewhat amazing. Not impossible, just, amazing. Stock, these cars have a Y-pipe, 1 catalytic converter, 1 I-pipe, 1 muffler, and 2 tailpipes. The Q-Jet and the ECM couldn't care less what it is though, as long as there's an O2 sensor.
car is quite matching numbers...
Not to be a jerk, butt, nobody cares about that, in a LG4 car. It's just ... not ... "that kind" of a car. Unless it is totally completely untouched unmolested original ALL ORIGINAL, with less than 100 miles on it; and even then, it's not likely to excite hardly anybody, except as a curiosity. Since it's got lots of miles and has been hacked on and repainted (at least the right fender and strut tower has, meaning it probably has been hit up there), it's now ... just another old car. Enjoy it for what it is and don't worry about that.
The carb is probably original, or close enough that it doesn't matter. The dist absolutely doesn't matter in any case. Yes you should get it running to the best of its ability. The photos show that some of the sensors have already been replaced; for example, it has the new style coolant temp sensor, with the oval connector, instead of the original one which had a sort of "coaxial" looking connector that was pure unvarnished unadulterated unalloyed DONKEY PLOP. The one that's on there now is MUCH better.
Last edited by sofakingdom; 10-07-2023 at 01:46 PM.
That's not the ECM connector. It's the main "distributor" harness. It goes from the ign module inside the dist to the coil-in-cap: pink is ignition voltage, black is ground, brown is the coil/tach.
Ah, just as I thought. I'll check the back if that connector is there to see how complete everything still is. If it's not there it's another step closer to new carb/dist and ditching the current setup.
Correct enough. In the computer-controlled systems, the ECM does all the thinking. The dist is just a dumb pulse generator and a switch to route the spark to the right plug.
It is, but isn't the ECM doing some adjusting of the timing based on the sensors and if so, isn't there a specific distributor needed that will work through that ECM connector? So I'll need a dist with that connector to profit from the ECM's commands?
Don't know; can't see it. They're rather rugged and only very rarely go bad. Most likely, once you get the wiring all sorted, it'll work fine. Assuming of course, that it's actually even still there. We don't even know that much about it yet.
ECM and the connecting wiring harnass under the dash is still there, not sure about all the rest of the sensors and wires/connectors going to it and problems with it. For instance: I had the ECM out of the car and the SES light was still on. According to the Shop manual that meant a short somewhere, since the ECM switches the SES light to ground...
That would be somewhat amazing. Not impossible, just, amazing. Stock, these cars have a Y-pipe, 1 catalytic converter, 1 I-pipe, 1 muffler, and 2 tailpipes. The Q-Jet and the ECM couldn't care less what it is though, as long as there's an O2 sensor.
Good to hear I know, it is amazing looking as well: a fully dual setup, but WITHOUT headers and also including a flattened piece of bend in it where it's in the way of the right front wheel I doubt if it has any catalytic converters so I'm looking forward to my emissions testing...
Not to be a jerk, butt, nobody cares about that, in a LG4 car. It's just ... not ... "that kind" of a car. Unless it is totally completely untouched unmolested original ALL ORIGINAL, with less than 100 miles on it; and even then, it's not likely to excite hardly anybody, except as a curiosity. Since it's got lots of miles and has been hacked on and repainted (at least the right fender and strut tower has, meaning it probably has been hit up there), it's now ... just another old car. Enjoy it for what it is and don't worry about that.
Over here in the Netherlands these kind of unmolested cars have some (financial) advantages, even for a standard run-of-the-mill Camaro, but OHO you're right: it's one of a gazillion produced, not like my Corvette that only has 700 or so built. I will take this into account.
The photos show that some of the sensors have already been replaced; for example, it has the new style coolant temp sensor, with the oval connector, instead of the original one which had a sort of "coaxial" looking connector that was pure unvarnished unadulterated unalloyed DONKEY PLOP. The one that's on there now is MUCH better.
I'm also very confused about this car. It is one of the best looking 3rd gen Camaro's I have ever seen. It was with one owner in the States from 1986 to 2011, after which it came over to Europe and has been restored around ten years ago. It looks like it's been in a cocoon. Paint, engine bay, interior, everything looks very good maintained and the guy I bought it from had replaced the coolant and window washer canisters because he didn't like them "yellow" and put in a new alternator because it had some "oxidation". He added Z28 mud flaps, new emblems, centercaps on the wheels and had parts repainted several times because of scratches. And how compulsive he was with the looks of the car, it's the opposite with the technical side. He told me the car ran perfectly, while he was driving with this crappy, half working carb/ECM setup for the past two years! When I drove home, I heard the wining of wheel & differential bearings (both worn and need replacing). The SES light was constantly on. Etc. Can't believe it...
BTW: I have seen photo's of the restoration and it was very thorough, engine and all wire harnesses were out of the car when it was repainted. That might have been the beginning of the problems with this ECM setup.
At this moment a relatively troublefree and simple, old fashioned carb&distributor setup seems more and more appealing
I had the ECM out of the car and the SES light was still on.
That's how it's supposed to work. There's a "lamp driver" module, buried in the wiring in the center console, kind of under / around the radio and HVAC controls. It's a light green color plastic box a little smaller than a pack of cigarettes. The module turns the light ON unless it receives the command from the ECM to turn the light OFF. Removing the ECM eliminates any possibility of the module receiving the OFF command, therefore the light stays on forever.
the ECM doing some adjusting of the timing based on the sensors
Precisely. The dist sends it a signal that says "I'm rotated to HERE now", and the ECM does all further processing after that. The dist is in no way responsible for the ignition timing beyond announcing that it has reached a certain point (1 of 8) in its rotation. Then of course it has the 1-pole 8-position high-voltage switch that sends the spark to whichever cyl's turn it is.
So I'll need a dist with that connector
Of course. Just like, the one you have.
Over here in the Netherlands
Haven't been there lately; not since the first of the year. I have relatives in the Leiden area. I've never seen any American cars at all whenever I've been there, so at the very least, they'd be a major curiosity. But that's not any kind of guarantee of "value". Just the same, enjoy what you've got.
a fully dual setup, but WITHOUT headers and also including a flattened piece of bend in it where it's in the way of the right front wheel I doubt if it has any catalytic converters
I'd be interested in seeing a photo of that. From underneath, looking up at it, if you can get that.
old fashioned carb&distributor setup seems more and more appealing
I'd STRONGLY suggest trying to repair what's there, first. The expense of back-dating the car to the 60s is likely greater than you anticipate, and the benefits FAR less, if any.
Incidentally, your dist looks something very much like this.
The 3-wire connector on the left is the one you can see in your photos; the other one, which clearly comes out the rear, is the one going to the ECM. Directly opposite the one you can see.
Note that the coil connection in the cap, which faces toward the driver's side, is at the top of this pic. Therefore the 3-wire harness that plugs into it, the one to the left, is to the front of the vehicle; while the ECM harness with the 4-pin Weatherpak, comes out the rear.
Last edited by sofakingdom; 10-07-2023 at 03:23 PM.
I think what's next is to try to get the ECM to work. First attempt at putting 12 volts to the orange wire did nothing... I might crack open that box and attack it with my scope, see if I have any signals. I'm going to collect some info on schematics and attached sensors and maybe I'll make a list of all important sensors and test them one by one (and see if they're even there?).
I found this in a pdf version of a Service Manual for the 1982-1992 Camaro, so that's going to help me. Also found a 1982-1992 repair guide as pdf, still looking for a 1986 only service manual because the 1982-1992 version has a lot of extra info on newer/older models that slows me down in finding the correct info.
The orange wire only supplies constant power for trouble code and "learned" calibration memory retention. The main ECM functions are powered by the Engine Control Fuse in the fuse block.
The orange wire only supplies constant power for trouble code and "learned" calibration memory retention. The main ECM functions are powered by the Engine Control Fuse in the fuse block.
I believe that specific fuse in my car also handles the ignition or something like that? So the car wouldn't start at all without that fuse I guess?
The feed to the distributor, that supplies the power for it to make sparks, has no fuse. Only the fusible link in the Big Red Wire that feeds that half of the ignition switch.
10-04-2023, 12:31 PM
No wonder the thing is crapping black sooth from it's tail pipes.
I know, it is amazing looking as well: a fully dual setup, but WITHOUT headers and also including a flattened piece of bend in it where it's in the way of the right front wheel 
