on my 91 vette my timing is 12 btdc. a year ago when i had tpis headers installed my mechnic checked the timing and it was the same. so we put it back to 6 btdc now today i checked it and it's back to 12btdc. ?? ski-down-it did my chip and said the total was 32 but i wouldn't think that would have anything to do with it. what the hell is going on a bad damper?????? i have 80,000 miles.

 

Are you disconnecting the ESC to check it? The "total" you were given, is what is burned into the chip plus your base timing. Is it based on 6*, 12*, or ? Are you checking the base (ESC disconnected) at the same temps and rpms as before? Rev the engine a couple of times and see if it settles down to a consistent reading. Do the readings jump around, at all?

RACE ON!!!

 

no i didn't disconnect it and the timing isn't jumping around. it's based on 6btdc. thanks

 

Any timing reading you get with the ESC connected is virtually meaningless. It you read EITHER 6* or 12* with the ESC connected, at idle, your timing is severly retarded.

RACE ON!!!

 

okay well it reads 12 at idle connected?????????????

 

as CFI-EFI said, forget what it reads when the ESC wire is connected.....go back out, DISCONNECT it, then read the timing.

Don't forget to disconnect the battery for about 30 secs. afterward, to clear the code.

 

what kind of timing light are you using ?

if your using a light with a advance **** make sure its on " 0 " degrees

good luck

 

6spd,

Give me your real name and I will be able to look to see exactly what it should be at idle, with the ESC connected.

We all need to step back and get on the same page. Here are the guidelines that some are confusing. With a 91 bin the following apply.

Base timing of 6* - this is what you set with the ESC unplugged.

With the ESC plugged in you should be ~20-25* timing at idle, ~800-1000 RPM. WHen you give me your name, I will be able to check it for sure.

Suppose its 20* for idle at operating temp etc. What this mean on a 91 bin is the following.

You have a base of 6*, then the ECM is adding an additional 14* to achieve the total 20* that you should now see if you have a timing light that you can dial up till it reads 0* on the balancer.

Base 6* + 14* ECM = 20* total at idle.

Hope we all are on the same page now.

Now let me say if you increase the base timing to 8*, then you will have

base 6*+ additional 2*+14* ECM = 22* total now. BUT THE ECM WILL ONLY THINK ITS 20* and report that out on the laptop!!!! That is due to the parameter referred to as "initial base timing". In other words with the intial base timing your telling the ECM what your setting the base timing to. If you deviate from that, then you must add or substract the amount you deviate to your programmed timing.

So, looking at what you have supplied here for data, I would say the following. Regardless of your balancer is off or not. If you infact set it to 6* base with the ESC unplugged, when you plug it in you should see a min of 14* added to that base. Otherwise your ESC is not working properly and your not getting the advance that you should be. It *MAY* be adding more but I highly doubt less than 14*. When you get me your real name, which is what I file the bins under, I will be able to determine a much closer number it should be adding.

But from what I am reading, if you are setting the base to 6*, then plugging in the ESC, and your only getting a total of 12*, then something is definately NOT right with the ESC/ECM.

Few things to be sure of:

1. verify that your setting the base timing at BTDC and not ATDC. Cause that would put you close to what your seeing.

6* ATDC + 14* advance would be ~8* BTDC If I have the advance at idle set to ~25* you would be at 13*

2. That your getting the same readings with a different light.

3. That your for sure on #1 wire.

4. Not sure how to figure this out, think you should still get the same additional advance of about 12* even if your distributer is in wrong. That is too much thought to figure out.

Well that is about all I can think of now. But the "Advance" when you plug in the ESC should be about 14* min. Maybe more depending on where I have the base timing set.

My guess is that you have it at 6* ATDC, then the ECM is adding about 19* advance which is then putting you at 12* BTDC. That is the exactly scenerio you would have if I have the timing at idle set to 25*.

Can you see the markings on the pointer? Are you sure its on right?

Get back to us.

 

You should be with regards to the timing map Jim, roughly around 26* at a 800-1000 rpm idle speed.

So with a base timing of 6* you should be seeing a 20* incremental increase with the ESC plugged in. IF your not, then your ESC or ECM is NOT reading correctly. Be sure to check the light also to rule that out. You have to attack the problem systematically or you will miss something. DO NOT ASSUME anything is right.

How is the car running other than this variable? Do it feel better if you increase the base up to say 12* (take it easy testing it), or does it feel better back at 0* base?

Anyways you should see that increase with the pluggin in of the ESC.

Can you take a digital picture of the timing pointer/indicator for us. Show us where your lining up the marks.

 

i will try to take a pic and post tomorrow. the car rides and runs mint but i just want to make sure.

 

okay heres whats happening i started the car and checked timing with est connected the timing mark showed a little past 12 btdc as the car warmed up my operating temp is 160 thats when the fans come on the timing mark moved right on 12 btdc. then i removed the est wire idle dropped down and timing mark is dead on 8btdc steady. so how does this look. thanks

 

Bad. Reread Jesses's posts.

RACE ON!!!

 

i'm still not understanding what is bad?? i new with this timing thing so bare with me.

 

CFE-EFI---
You leave your EST wiring disconnected all the time, correct?

So how does that affect your timing?

 

i disconnected it to check my timing it's at 8 btdc

 

No! The only thing I have unplugged is my knock sensor.

RACE ON!!!

 

and where do you do that?

 

CFE-EFI you said it's bad so what is bad about it???

 

6spd,

You need to go back and read and re-read my post that I explain what *should* happen.

You are NOT getting the right amount of timing added to by the ECM. Why, I can't be sure of.

If you have the base set at 6* and you plug in the ESC, clear the code with unplugging the battery, restart the car, it should add about 19* more timing!!!!! 19 Degrees not 6 degrees like your reporting.

What happens if you rev the motor a little with while reading the timing mark?

Its very tough for us /me to conclude exactly what might be wrong.

Perhaps if you go point by point listing like 1., 2. 3. and so on in VERY GOOD detail what your going when you read the timing - we can conclude what exactly is happening.

I still think your setting the timing to 6* After TDC and then when you plug it in, you are getting the full amount of timing, but it lands you at around 12 to 13* depending on RPM.

Is the 12* your reading at idle with ESC plugged in the SAME side as the 6* base? Or is it on the other side of the pointer? It it the upper side or the lower side of the pointer?

 

the base is set at 8btdc i never touched the timing thats what it said when i looked at the timing tab btdc. like i said i am in the dark when it comes to this could it be a bad ecm??