[1982VetteGuy]

On my engine, if I unhook the EST connector, set my timing to 6 degrees BTDC, hook the EST connector back up and let the computer take over...and I hook a timing like back up to the engine....what should my timing read at that point?

It's a 1990-1992 Speed Density TPI set-up.

Thanks!

 

[RRT vette]

Set the timing at 6* BTDC with the EST disconnected. When you reconnect the EST and start the engine, the timing will be around 22-24* or about 12 o'clock on the HB. A scan tool will help confirm.

 

[driley]

:agree:

 

[1982VetteGuy]

I noticed that the setting for my chip should be around 17* BTDC after the est connector is hooked back up. I have stock 90-92 F-body settings...

But my engine is running lean right now (burns my eyes lol) so would advancing the base timing to say around 10* BTDC fix the problem?

It also surges at cruising speed at low throttle, will quit when I accelerate, but start again after I let off.

Everything in my ignition system is brand spanking new.....

I'm kinda new at this type of system so any help or ideas would be great :thumbsup:

 

[RRT vette]

Not sure why you have a chip that has a base timing of 17* BTDC. I believe you would have a ton of knock counts. Do you have the stock chip? I would set it at 6* BTDC and see if it makes a difference. The base timing is advanced in intervals of 2* mainly at a track. If you scan the engine you will be able to see where the knock counts start increasing and you should back off 2*.

The surging at cruising speeds sounds like an EGR problem.

 

[1982VetteGuy]

Not sure why you have a chip that has a base timing of 17* BTDC. I believe you would have a ton of knock counts. Do you have the stock chip? I would set it at 6* BTDC and see if it makes a difference. The base timing is advanced in intervals of 2* mainly at a track. If you scan the engine you will be able to see where the knock counts start increasing and you should back off 2*.

The surging at cruising speeds sounds like an EGR problem.

The base timing with the EST connector unhooked is 6* BTDC, timing after EST connector is hooked back up is around 17* BTDC when the computer takes over.

EGR is supposed to be fixed on the chip where I don't have to use it

I have a cable coming in (hopefully tomorrow) to attach my laptop to my ECM and get a better idea what's actually going on :thumbsup:

 

[RRT vette]

Understood! The EGR solenoid signal might be deleted out of the chip, but it has vac lines that run to it. I would check the vac line connections and apply vacuum to the EGR diaphram to make sure it's not leaking. You can advance the base timing if needed. I have mine set at 10* BTDC, but used a laptop and set based on knock counts.

 

[1982VetteGuy]

Understood! The EGR solenoid signal might be deleted out of the chip, but it has vac lines that run to it. I would check the vac line connections and apply vacuum to the EGR diaphram to make sure it's not leaking. You can advance the base timing if needed. I have mine set at 10* BTDC, but used a laptop and set based on knock counts.

No egr vacuum lines :thumbsup: It was fresh TPI installation and I never installed any egr related equipment. The egr valve location is blocked with a billet plate and the egr vacuum location under the TB is capped off.

I can't wait to hook my car to the laptop....I need to see what's going on.

 

[RRT vette]

Engine scanning gets adictive especially if you also erase/burn your own chips. It will show lots of info, you just have to understand what to do with the info given. After you get some scans going, you can post some of the info on here and we will look through it. Good luck. :thumbsup:

 

[1982VetteGuy]

Engine scanning gets adictive especially if you also erase/burn your own chips. It will show lots of info, you just have to understand what to do with the info given. After you get some scans going, you can post some of the info on here and we will look through it. Good luck. :thumbsup:

Thanks I appriciate that! I'm hoping to get into burning my own chips, it's kind of exciting to see exactly what your engine is doing and making changes to make it perform at it's peak.

I'll def post some figures because I have no idea what I will be looking at.:surprised