I just bought a Actron scantool from autozonel. I'm very impressed. It was cheap and works superb. It gives me everything i need. I have a few questions here about some specs i'm reading off....
1- IAC counts?? where should that be for setting it? what's setting procedure?
2- MAT temp is stuck at 98F!!! NOT GOOD. it's been at that for a whole day now.
3-ECS knock counts, how many is normal....when should i see them??

 

1) It's gonna fluxuate anywhere from 0 to 150. A good target to shoot for with car warmed up, etc is around 10-20 counts, but really anything under 40 should suffice. Anything over 100 at idle and you probably need to adjust your minimum air rate screw. Odd problems will usually set the IAC to go full open (something over 150 counts, maybe right at 150, I can't remember these days). Doesn't mean a problem with the IAC though. It's kinda cool to watch the IAC and as it goes full open, you can start to hear a whistling/whoosing sound.

2) When car has been sitting overnight, turn the key on and scan the MAT and the CTS. They should be dead even, or at least +/- 1-2 deg C. CTS is going to increase at a faster rate than MAT (generally). I have a feeling that if you go for a drive vs have your car idle in one spot, you will see your MAT values changing from each condition to the next. Air rushing over the sensor inside the plenum will keep it cooler, but at the same time, if you have no air circulation under the manifold, the upper plenum is going to be a heat sink. Note: This is why some people move the MAT to the air filter effectively making it an IAT instead of a MAT. GM knew what they were doing on this one. Remember, gains in HP by moving the sensor doesn't always mean that a correct improvement has been made.

3) You are almost always going to have some knock counts. GM had a self-test routine for the ESC system that forced knock. I honestly don't know what is normal. On my car, I really don't have many at all, ever. I am also running cast iron heads and haven't advanced my timing too much yet.

As you scan more and more, you will start to grasp that it isn't so much "what should these values be" but "Ok, these are the ambient conditions, this is the type of hell I am putting my car through today, do I notice anything out of the ordinary???"

Believe me, that's what will turn you from a good tuner into a great one. I struggled with BLMs for such a long time. All my parameters were correct. After looking and looking, everything still looked correct. I posted up my VE table cause it didn't look quite right, I got some prompting from some helpful folks on the forum, and upon further investigation, I realized that my canister purge system was not operating correctly. I know I fixed it, but I don't know exactly what I had fixed.:lol:

Ok, I'm done rambling. I just had a normal night where customers were right, I was wrong, I don't know squat about cars, and since they can't get their fuel filter off because it has been on there for 9 years and was never removed, I need to tell them other ways to fix their fuel delivery problems. It's good to talk tuning every once in a while :D

 

thank you so much for the tech. rambling is good. I like to hear everything i can. you seem to know a lot. next Q for ya.... 1- my MAT is relocated in the air box using a LS1/LT1 sensor (fast response) and it's still stuck at 98F. wiring or sensor bad i feel. next.... i have a high idle problem.... i have a few mods, headers, bolts ons...custom chip by jesse on here... and that idle sits right at 1,000RPM in P/N and then after a while will go to 1,500rpm. i set it using the 500RPM in gear after pushing the IAC out...and then hook it up, readjust the TPS to .55V. 2 new TPS's, and 3 new IAC's. What is the BLM?? I have no idea. also.... is the TPS supposed to be "slow response"?? thanks.

 

forgot.... What's the best procedure to set a good idle??

 

I think I still agree with the majority of my novel in this post.
http://forums.corvetteforum.com/zerothread?id=201164

It was too long for me to read all of it over again, but I still agree with (haven't found a reason to dispute) everything besides my last post, which is where I got tired of reading my own posting ;)

If you have a stock setup, or your cam is mild/stock and your PROM is mild/stock, you should be able to use the link to the tech tips that Pete posted. Good luck. -85Y



[Modified by HighHopes85, 9:17 AM 3/20/2003]

 

well, like i think i've said... my problem is a HIGH idle. 1,000 and then when its hot it goes to 1,500rpm. pulls hard. I've replaced the IAC. I'm seeing about 20 IAC counts at idle 1,000rpm right now. Bad IAC?? Also my MAT sensor and ECT this morning were both 95F.... after sitting all night and it's 74F outside...weird. HOW the heck can it be 95F. what is BLM??
-Jason 89 Auto Coupe
Low 13's