I have an 84' with stock computer and the ccc q-jet (q-jet is brand new) This car originally had a LG4 in it but a L69 was swaped at some point. I was wondering if the H.O L69 computer was any different than an LG4.

My problem right now is that I've been getting a code 14 and I replaced the coolant sensor and double checked all wiring and still get the code about 2 min after the cars been running. I've also been getting a code 32 sometimes. I'm figuring the computer may be on it's way out and thought I would go and get another from the bone yard and try it. I was gonna grab an H.O computer.

 

I believe one difference is, that in 84 the lg4 did not have a knock sensor where the H.O. did. I could be totally off here, someone correct me if I’m wrong.

 

Yeah, 84 LG-4s did not have a knock sensor (they got one in 85 when the LG-4s compression was raised to 9.5:1, same as the HO had been all along).

Aside from that difference, the LG-4 always, in all years, had a very mild "tune" in the chip. Really weak spark advance curve, primarily. 2 different things you can do to help it:

1. For cheap, set your base timing around 10* BTDC. Stock on the LG-4 was 0*. Stock on the L-69 was 6*. This'll often make a pretty big seat-of-the-pants improvement.

2. Any old aftermarket "Stage 1" chip for your year of LG-4 will have a much more aggressive timing curve than stock. Pick one up for reasonably money, pop it in and away you go. You will probably end up backing the intial timing down to about 4-6* again if you use an aftermarket chip.