High mile TBI 350

[tRustyK5]

I've seen a few hints at advancing the base timing on TBI engines. I have two questions, which wire do I have to disconnect to get the correct base timing reading, and what is considered a safe ballpark for a TBI engine with a good amount of miles on it? 4 degress? 6? more? Leave it the hell alone? Will advancing it make a noticeable difference in power?

Also, I may have to ask this elsewhere, but the 700R-4 in this truck works. It's very apparent that it is tired as it shifts with no authority at all. I'm OK with that as long as all the gears work and stuff...but what it does do that I don't like is it shifts so damn early at part throttle. It'll drop into second at 8 mph and into thrid very shortly after that. With 3.08's and 31's it makes it kind of doggy unless i manually shift it.

Is this a TV cable adjustment thing? If so, can I safely adjust it without dooming the tranny to impending failure?

 

[brian wafer]

if i remember right theres a brown wire that sticks out off the main wiring harness on firewall helper side. and you unplug it to time.will check today at work if i,m correct! if i get it right the tv cable adjust line pressure for a firmer shift when you step on the gas hard,this is why when not ajusted right transmission may slip on w o t !

 

[dave w]

I've seen a few hints at advancing the base timing on TBI engines. I have two questions, which wire do I have to disconnect to get the correct base timing reading, and what is considered a safe ballpark for a TBI engine with a good amount of miles on it? 4 degress? 6? more? Leave it the hell alone? Will advancing it make a noticeable difference in power?

The tan wire with a black stripe with a connector near the ECM is what I use to set base timing. Sometime the tan wire with a black stripe has a connector under the hood near the distributor. When you set the timing, an error code will be set.

The ONLY REAL WAY to know if advancing the timing helps / hurts performance is to use Data Logging Software. Data Logging Software will show KNOCK COUNTS.

A stop watch to check accelerating from 0 to 60 MPH will show if advancing the timing helps?

If you can't Data Log, leave the timing the HELL ALONE!

I've not had any problems advancing timing 4 to 6 degrees, but I always CMA with Data Logging.

dave

 

[4X4HIGH]

The EST (Electronic Spark Timing) wire is located near the brake booster and is a brown or tan colored single wire connector.

 

[USSkoval]

Is the TV cable currently adjusted properly? If not, that might be the problem and leaving it that way can hurt the tranny.

Go ahead and bump the timing up to 6 degrees, even a tired tbi motor will like it.

 

[tRustyK5]

Yup, I 'set' the TV cable according to the instructions found in another thread here. Made a world of difference in how the truck shifts, crispness of the shift etc etc. i'm thinking the tranny is in decent shape now. It's not "shift kit" firm, but they're good shifts at the right time now.

As for the timing I may do that, although as it sits it has plenty of power. Nothing wrong with having more though. On wet pavement it'll break em loose at will at 20 mph. Considering it has 3.08's it pulls out pretty hard.

Rene