88 350 TBI timing

[PlayingWithTBI]

Your ECM doesn't know what your timing is set to (there's no feedback to it) so, It'll just run thinking it's at 0*. GM tuned these engines conservatively and it probably won't even see KCs with only 2*BTDC but, if it does, as mentioned above, it'll pull timing until it doesn't see KCs. Then you'll be a couple degrees retarded until the timing reduction decays back to normal. Really, it s/b set @ 0* and then get the EPROM tuned for better performance/MPGs etc.

 

[Postmech]

What he said. TBI heads are high swirl fast burn that don't need as much advance to make power. You may benefit with more timing using high octane gas but not with 87 octane.

 

[Erik the Awful]

There's no crank sensor on a TBI. It is entirely adjustable by turning it. The computer controls the advance, but it still runs off base timing. I'm running about 30* at 2000 rpm with a Holley Sniper, no ESC, and the computer still hooked to the ICM.

 

[Steven Petersen]

Well I warmed up the engine and checked timing again. TDC right on the mark. So evidently a cold engine is advanced 2 degrees.

 

[swb charlie]

I always set my SBC at 8 degrees advance, Most were with out a computer. But the last one I changed to that was a '95. Good Luck

 

[Gramps]

Stock tbi always Set them between6-8 degrees With good results.

Currently running 17* on the stock ecm/chip with a comp cam and vortec heads , made an honest 300hp and no ill effects.

 

[Childs]

I'm running an LT1 roller cam with 10:1 cr in my 95 5.7tbi with 93 octane. With the bigger cam i had to set base timing 2 degrees advanced or the engine would die. No detonation so far.

 

[HawkDsl]

Well I warmed up the engine and checked timing again. TDC right on the mark. So evidently a cold engine is advanced 2 degrees.

The computer has a cold start routine that it runs, IIRC, for 30 seconds at start up, and will run a higher RPM until some heat is in it. I remember at the time (having grown up with carbs), that it was the greatest
cold weather driver I've ever known.

Of course now'a days, no one even knows what an adventure it was like trying to start a car in the cold.. and having it stumbling around or cutting out for the first 30 minuts. My 89 was the first car i ever had you could start up and drive away with no issues regardless of the temp.

 

[HawkDsl]

To be clear to the OP. Bone stock 88 TBI, set you timing to zero (with engine @ regular warmed up temps).

 

[Steven Petersen]

The computer has a cold start routine that it runs, IIRC, for 30 seconds at start up, and will run a higher RPM until some heat is in it. I remember at the time (having grown up with carbs), that it was the greatest
cold weather driver I've ever known.

Of course now'a days, no one even knows what an adventure it was like trying to start a car in the cold.. and having it stumbling around or cutting out for the first 30 minuts. My 89 was the first car i ever had you could start up and drive away with no issues regardless of the temp.

You’re right. Kids now days have no idea. Pump the gas to prime and choke, but not too many or you flood and then gotta wait. Then bump it to kick off the fast idle. The 87 TBI was a whole new experience.