87' TBI timing question

[johns87]

Thanks guys for all the continued help trying to trouble shoot this thing. I did put in a new distributor, module, coil, wires, and plugs. The ECM path is something I have considered, and like I said a few lines up, I know the coil plugs are not clipping in anymore just really sitting in the coil. The pigtails should be here in a few days so here's hoping. Good idea on testing the timing light, its those little common sense things that seem to get lost when you are getting pissed off at these things.

 

[Jerry phillion]

I just set my timing on my 87 350 tbi this week. Runs great.
I don't think you are setting it right. You said you twisted dizzy
Clockwise and it's still a little advanced. Clockwise retards
Timing, not advances it. If it was too far advanced , it would
Try to kick back or you would have spark knock. Also you must
Snug dizzy down a little, so when you turn it ,it will stay where you put it. Also check your timing marks on balancer and timing
Cover. I set mine at 2 btdc. Good luck.

 

[Altemose]

Are you using a timing light? You can spend all day trying to fiddle with a TBI style distributor but the computer will offer a certain degree of curve adaptation if it is off. On a engine with a blown head gasket between cylinder 4 and 6, we retarded the timing back to 2 degrees BTDC with the timing advance connected (essentially 8 degrees After TDC base timing) to prevent spark knock. On the first start it would idle rough till it warmed up and then was fine aside from having little power. You need to set the timing at 0 degrees for a small block or 4 degrees for big block. Anything else and it will sputter and idle rough until it learns the timing curve. The carbureted ones could be timed by ear relatively easily, however the TBI ECMs rely on the appropriate timing being set.


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[bucket]

A healthy engine (no blown head gasket) will like more timing than what the factory calls for. A TBI small block will respond very well to setting the base timing at 8-12 degrees btdc.

 

[Jerry phillion]

Bucket, are you saying to advance tbi timing to 8--12 degrees btdc with The est wire unplugged or plugged together?

 

[bucket]

Bucket, are you saying to advance tbi timing to 8--12 degrees btdc with The est wire unplugged or plugged together?

Unplugged.

Some engines in some conditions may ping at 12 degrees. It's trial and error really. But advancing the base timing gives more ***** and a little better mpg too.

 

[Altemose]

Unplugged.

Some engines in some conditions may ping at 12 degrees. It's trial and error really. But advancing the base timing gives more ***** and a little better mpg too.

Wouldn't setting it that high make the timing at idle close to 20 or more degrees? I wonder why GM calls for 0 degrees then. I may try this on Silvy.

 

[74propu]

If you have a stock dizzy in it and it is old pull it out and inspect it they are known for the top shaft bushing wearing out and cracking the pickup . that will cause the timing to jump all over the place. that is why I have a dizzy behind the seat of my 86 it has a 95 tbi 454 in it

 

[Derick C.]

When I first put my 454 in my suburban it would detonate when towing, I retarded the timing a little bit and it got worse, so I advanced it and so far its seems to like 8 deg adv

 

[bucket]

Wouldn't setting it that high make the timing at idle close to 20 or more degrees? I wonder why GM calls for 0 degrees then. I may try this on Silvy.

Couldn't tell you honestly. I don't recall ever putting a light on a TBI motor with the connector plugged in. I always assumed GM did it for some emissions reason of some kind.

 

[Altemose]

Couldn't tell you honestly. I don't recall ever putting a light on a TBI motor with the connector plugged in. I always assumed GM did it for some emissions reason of some kind.

The most I ever went was two degrees base timing with the advance unplugged. I may have some tinkering to try once I get the EGR squared away on Silvy.

 

[74 Shortbed]

Couldn't tell you honestly. I don't recall ever putting a light on a TBI motor with the connector plugged in. I always assumed GM did it for some emissions reason of some kind.

That connector is in place of the vacuum advance, unplug the connector is like pulling the vacuum hose on the vacuum advance, the ECM is your vacuum advance, so I been told anyhow.

 

[bucket]

That connector is in place of the vacuum advance, unplug the connector is like pulling the vacuum hose on the vacuum advance, the ECM is your vacuum advance, so I been told anyhow.

Yep, and I've never doubted the ecm, so no need to double check the ecm advance.

 

[74 Shortbed]

Yep, and I've never doubted the ecm, so no need to double check the ecm advance.

Yeah, and you hope the ECM knows what it's doing, lol..

 

[Rylan]

Hey this is off the wall but I am am thinking about rebuilding a 350 TBI and I am 16 so I don't have any experience but i want to rebuild it as cheap as I can but I want power so what I am asking is, is what is the biggest cam I can put in and not have any trouble with my fuel injection system?