El Camino Central Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
196 Posts
Discussion Starter #1
i'm trying to adjust the timing on my 87 and know I have to disconnect the electronic timing connector. Where do you diconnect it? If it is the plug behind the distributor, how do you get to it? It seems to be right up against the firewall.

Jim
 

·
Registered
Joined
·
532 Posts
it will be a tan wire with a black stripe somewhere between the esc module and the firewall, a single wire plug,disconnect to set base timing, reconnect once you are done,(don't forget to unhook the batt for a few minutes once you have plugged it back in to clear the code)
 

·
Registered
Joined
·
555 Posts
i'm trying to adjust the timing on my 87 and know I have to disconnect the electronic timing connector. Where do you diconnect it? If it is the plug behind the distributor, how do you get to it? It seems to be right up against the firewall.

Jim
Please excuse my ignorance.

Why do you have to disconnect something in order to adjust the timing on your engine?
 

·
Registered
Joined
·
532 Posts
Please excuse my ignorance.

Why do you have to disconnect something in order to adjust the timing on your engine?
With computer controlled timing it is necessary to set the base timing so the computer knows where to start adding timing,you disconnect the bypass connector in order to stop the computer from adding timing while you are setting the base,
 

·
Registered
Joined
·
196 Posts
Discussion Starter #5
it will be a tan wire with a black stripe somewhere between the esc module and the firewall, a single wire plug,disconnect to set base timing, reconnect once you are done,(don't forget to unhook the batt for a few minutes once you have plugged it back in to clear the code)
In the area of the MAP and ECS on the wheel well, I have three muti plug connections but none with a tan/black wire. Are there any pictures of this anywhere?

Jim
 

·
Registered
Joined
·
555 Posts
With computer controlled timing it is necessary to set the base timing so the computer knows where to start adding timing,you disconnect the bypass connector in order to stop the computer from adding timing while you are setting the base,
Oh, that makes sense. Thank you
 

·
Registered
Joined
·
532 Posts


this came from alldata, couldn't find any pics though (yet) im not positive, but inboard of bulkhead could be in between the ecm and the firewall, connecter will be black/single wire and wire will be tan/black.
 

·
Registered
Joined
·
532 Posts
there is no easy way to explain without pics, but coming out of your distributor there is a four wire plug and a two wire plug(a little late to ask but this is a tbi motor right?)on the four wire plug pin b is a tan/black wire, this is the esc bypass. the connector will be somewhere in this wire between the distributor and pin d5 on your ecm. thanks to gm every vehicle has the timing bypass in a different spot, some are under the glove box, or against the firewall or even right out of the distributor, but it is usually by itself taped to the outside of the loom.

this diagram is for a 1990 g series van, but most of the colors/pinouts are the same
 

·
Registered
Joined
·
196 Posts
Discussion Starter #10
there is no easy way to explain without pics, but coming out of your distributor there is a four wire plug and a two wire plug(a little late to ask but this is a tbi motor right?)on the four wire plug pin b is a tan/black wire, this is the esc bypass. the connector will be somewhere in this wire between the distributor and pin d5 on your ecm. thanks to gm every vehicle has the timing bypass in a different spot, some are under the glove box, or against the firewall or even right out of the distributor, but it is usually by itself taped to the outside of the loom.

this diagram is for a 1990 g series van, but most of the colors/pinouts are the same
http://i385.photobucket.com/albums/oo299/skandolis/ELky/wireTBI-1990b.gif
When I plug an OBD 1 scanner in with the motor running, the ECM goes into some other mode. Can I advance the timing when its in this mode without disconnecting anything, or is just wishful thinking?

Jim
 

·
Registered
Joined
·
532 Posts
i honestly don't know, but i dont think so. if you were very careful (and comfortable with doing so)you could unpin pin b at the distributor,set your timing, then put the pin back in(would be the same thing as the bypass connector,just in a different spot)
 

·
Registered
Joined
·
196 Posts
Discussion Starter #12
there is no easy way to explain without pics, but coming out of your distributor there is a four wire plug and a two wire plug(a little late to ask but this is a tbi motor right?)on the four wire plug pin b is a tan/black wire, this is the esc bypass. the connector will be somewhere in this wire between the distributor and pin d5 on your ecm. thanks to gm every vehicle has the timing bypass in a different spot, some are under the glove box, or against the firewall or even right out of the distributor, but it is usually by itself taped to the outside of the loom.

this diagram is for a 1990 g series van, but most of the colors/pinouts are the same
http://i385.photobucket.com/albums/oo299/skandolis/ELky/wireTBI-1990b.gif
Its a CC Quadrajet motor. I just had a 350/ 290 crate motor with a cam from the 350/ 330 HO put in it. Its not running very well at 45 mph and above. A couple of people that burn chips said I could compensate for the miss matched ECM and prom by advancing the timing a couple of degrees. The blank proms for this motor are not being made anymore. If the timing advance doesn't help, I'm going to try to get a blank and have one of these guys make me a custom prom.
Is it possible to advance this timing a little without disconnecting the ESC?

Jim
 

·
Registered
Joined
·
532 Posts
Its a CC Quadrajet motor. I just had a 350/ 290 crate motor with a cam from the 350/ 330 HO put in it. Its not running very well at 45 mph and above. A couple of people that burn chips said I could compensate for the miss matched ECM and prom by advancing the timing a couple of degrees. The blank proms for this motor are not being made anymore. If the timing advance doesn't help, I'm going to try to get a blank and have one of these guys make me a custom prom.
Is it possible to advance this timing a little without disconnecting the ESC?

Jim
i didn't know they still made ccc motors in 87, i could be wrong, but i believe you can just unplug the four wire plug at the distributer, that takes the ecm out of the pic, the most that can happen is it won't run unplugged,but it will definately not advance timing that is how you set base on the 2.8 with est, i believe it will work with the v8 as well. the tbi engines wont run like that, but the ccc ones should., the problem with adding timing to compensate is if the computer detects a knock it will actually retard the timing more than it needs to to get rid of the knock,so you end up with less advance than you had to begin with.
you would probably be better off using an adjustable map sensor to compensate for the cam.
and yes, you can advance the dizzy without disabling esc, but it is impossible to know exactly how much you are advancing it,
 

·
Registered
Joined
·
196 Posts
Discussion Starter #14
i didn't know they still made ccc motors in 87, i could be wrong, but i believe you can just unplug the four wire plug at the distributer, that takes the ecm out of the pic, the most that can happen is it won't run unplugged,but it will definately not advance timing that is how you set base on the 2.8 with est, i believe it will work with the v8 as well. the tbi engines wont run like that, but the ccc ones should., the problem with adding timing to compensate is if the computer detects a knock it will actually retard the timing more than it needs to to get rid of the knock,so you end up with less advance than you had to begin with.
you would probably be better off using an adjustable map sensor to compensate for the cam.
and yes, you can advance the dizzy without disabling esc, but it is impossible to know exactly how much you are advancing it,
Thank you, I think the plug at the distributor is where I have to unplug it. Its so close to the firewall I was thinking there might be another site.
The adjustable map sensor sounds interesting. How would that work?

Jim
 

·
Registered
Joined
·
2,102 Posts
it is the 4 wire plug at the dist . if yours has a disconnect it will usually be under the glove box or i have seen them laying on the intake harness near the alt. some were a 2 wire disconnect. but the 4 wire plug at the dist will do the same thing.
 

·
Premium Member
Joined
·
846 Posts
X2 on under the glove box.....blk conn. with tan wire.....but as staed above disc the 4-wire at dist., same result...
 

·
Registered
Joined
·
196 Posts
Discussion Starter #17
X2 on under the glove box.....blk conn. with tan wire.....but as staed above disc the 4-wire at dist., same result...
Thank you both, I got in some road repair congestion Sunday night and the temperature on the new motor went up to 210 degrees. I am taking it back to the dealership that installed it next Monday. I am going to let them set the timing...I'll be watching closely. I think retarded timing could be causing both the miss and the overheating. Since it has a 2 yr. 50,000 mile warrenty, I'd like them to see it just the way it is, before I touch it anyway. I took it back to them Friday and they brushed off the miss as carb adjustment. I told them about a 5 degree rise in temperature when I turned on the AC, and they just said that was normal. I just hope this engine's problems in the first 500 miles hasn't hurt it.

Thanks again, I appreciate it and I'm learning a lot about this motor and my EC.

Jim
 
1 - 17 of 17 Posts
Top