88 350 TBI timing

[Steven Petersen]

I finally got a timing light and checked the timing on my 88 350 TBI. It's 2 degrees advanced. Yes, I unhooked the brown timing advance wire. What effect will 2 degrees advanced have on this engine? I need to buy a distributor wrench so I can set it to zero. I haven't messed with these in about 20 years. I seem to remember advancing a couple degrees they ran better. Opinions?

 

[man-a-fre]

Curious myself on this,as long as it doesnt get knock counts from too much timing it should help. Octane would play a big roll in this also.

 

[Steven Petersen]

Curious myself on this,as long as it doesnt get knock counts from too much timing it should help. Octane would play a big roll in this also.

I agree. I remember I used to play with until it knocked, then I knew it was too much.

 

[kenh]

I thought the computer took care of the timing? Or can you slue the total timing range? Example, total range is 20 degrees. You advance the base from zero to +5 so now your range is +5 to +25. Am I wrong or right? Asking 'cause I don't know.

Ken

 

[thinger2]

I finally got a timing light and checked the timing on my 88 350 TBI. It's 2 degrees advanced. Yes, I unhooked the brown timing advance wire. What effect will 2 degrees advanced have on this engine? I need to buy a distributor wrench so I can set it to zero. I haven't messed with these in about 20 years. I seem to remember advancing a couple degrees they ran better. Opinions?

Im kinda curious about this myself. I always set them to 0 tdc but ive also had people tell me that 2 degrees helps.
My only issue with that is ive never seen any real data to back that up.
Did it run better because the valves had never been adjusted and it was carbon loaded and had major blow by and running ethylated gas with fouled plugs while driving at 8,000 feet?
Im wondering about this because we have hacks at the state capitol who really want to increase the corn juice in our gas from 10 percent to 20 percent.
Yep, that will be pretty well fatal for a lot of vehicles.
Hopefully, one of the many tech guys on this forum will chime in before I start hoarding gas in the hot tub.

 

[smdk2500]

Years ago I had a fbody with tbi 5.0 then a tbi 5.7. I ran both engines at 2tdc with no ill effects. The 5.7 had 15-20k on it when I rolled the car over and bent up the subframe. I don't have any hard data on it just my experience.

 

[Nad_Yvalhosert]

As far as I've seen, TBI engines act more like carb'd engines with regards to timing. A couple degrees doesnt hurt.
Multiport engines, no. The PCM uses the cam and crank sensor inputs and adjusts by it's own tuned algorithm

 

[HawkDsl]

Hmm... Well, your 1988 chevy TBI computer is expecting it to be set to 0... and that's exactly where you should put it. A degree here or there is only making your computer think your nuts. As primitive as these first computers were, the Chevy engineers worked this all out on slide rules and fingers and toes. Setting it + or - wont matter much, as the computer will run what the Chevy boys told it to do way back in the day... including adjusting out your silly attempt to fool it.

Setting it a couple here or there is what is known as an old wife's tale. Any gain you think your getting is a placebo effect. You can however go outside what your old man computer can compensate for.. and while your blasting Quiet Riot on your six by nines, your pistons and heads are making neat dots in the metal. Oh sure, she don't have a reluctor wheel to know for sure what you set it at... but it's going to use it's knock sensor, and AFR readings from the Ox sensor, and it's gonna expect certain numbers to be true.

Set it to Zero.

 

[DerekTheGreat]

Yeah, the computer expects and acts like it's set where it's supposed to be. So when it goes to do what it was programmed to do and finds knock via the knock sensor, it'll pull timing out, probably more than ideal to compensate for it. I was young once and played around- never noticed anything and didn't look at counts because at the time I didn't have a scan tool. Now I just set to zero in every case with my TBI stuff and we've got a bit, '89 Fireturd, my '89 K1500 and her '92 C1500

 

[Steven Petersen]

I need to recheck it today with the engine warmed up to operating temperature. I haven’t checked timing on anything in probably 15 years and forgot that it needed to be warmed up.