My Z28 runs very well, and has the usual bolt ons plus a baby 501 cam. My best gas mileage, city and 75% highway is only 19mpg. When I drive like I usually do, it is only 15.5mpg. Since I just barely pass smog with high HC, I am thinking that maybe my noisy valvetrain may be stealing away some ignition timing. I have the LT4 knock module, but my valetrain may still be overcoming it. The lifter adjustment is one full turn past zero, so it cannot be made quieter. With a live data tool ( you tell me what to get ) I can at least see that I do or don't have enough ignition lead.Also, give me an indicater of what kinds of advance I should be getting at idle, part throttle, mild and heavy loads. Thanks guys , edman-out

 

I have a snapon mt2500 that should read live data from it if your even in the san diego area


any shops w/ a mt2500 should also be able to tell you current timing, knock retart - traction abuse retard, o2 numbers, tp , etc... just dont know what they will charge

i know it reads from 96+ (obd2) i do have the obd1 cables and software for it - just never used it on an obd1 car

 

Do you have stock RR or aftermarket? 1 full turn is way too much for aftermarket RR. 1/4-1/2 turn is all you need.

Any shop with a Tech2 can read if you have knock retard. The LT1 Scanmaster can tell you that as well.

 

I'd say get a data cable and some software like TunerCat so you can not only see where you're getting spark retard, but you can tune it accordingly for a noisy valvetrain.

 

I bought a datacable for obd2 off ebay about $35 bucks...then hook it up to your laptop and download scanmaster.

 

Scanmaster is a hardwired real time display (hardware). The OBD-I software scanning systems are:

TTS DataMaster
http://www.ttspowersystems.com/

FreeScan:
http://www.andywhittaker.com/

EFILiveV4
http://store.efilive.com/overview_obdi.aspx

Then use this to interpret the data:
http://members.aol.com/InjuneerZZ/ScanMast.htm

 

Tunercat is not diagnostic software-just programming.

 

Yup those that injuneer said and there is one other called pcm communicator