I have a 1989 GTA 350 TPi.....when attempting to set the timming I disconect the EST wire, attempt to start the car....it cranks but doesn't turn over......cant figure this out for the life of me.....anyone who knows about this please help me. Thanks.

Keith
GTA350FNC@AOL.COM

 

PS.... Runs with the EST connected.

 

What exactly are you disconnecting?

 

I'm disconnecting the tan wire w/ black stripe by the accumulator.

The EST Connector. I unplug it.....crank......but no start.....I plug it back in....it will crank and start and die a couple of times....but will eventually run normal. But if it is disconnected it does not run at all.

 

Wow. Strange, thats the right one. I'll have to think about this one. I've never seen this before. Can you start the car with est connected & then disconnect it & have the car still run? I have seen the idle dip very low during est bypass, maybe it just won't start without a little throttle.

 

If I disconnect the wire while it is running it will die instantly.....even if I open the throttle all the way.....it just dies

 

Not much comes to mind. You say instantly. Like turning off ignition? Is it possible base timing is way too low & when you bypass the timing is way retarded? I would be leaning towards ign module, do you have a spare?

 

No....I dont have a spare....the one I have is stock.....but I was looking into a MSD one.....I have a MSD 6AL......stock distributor....but coil cap and rotor are all MSD components. Any way I can test my module with a multi meter??

 

Sorry, I don't know of a test using a meter. I'll run it by some people at work & get back to you.

 

Have you thrown any codes? 42...43? Other than what's already been said about your base timing possibly being too far off, I'm clueless. Maybe check all the harnesses coming off the ignition module to make sure you're getting a good connection.

If the module was bad, I don't think it would run at all. Under 400 rpm the car runs off of base timing and the little bit of advance built into the module. Over 400 rpm, the ECM takes over timing advance/retard and tells the module what to do. This is what I read when I was diagnosing my code 42 I had the other day.

Does the car run well when the EST bypass is connected? What about when you increase the rpms? Do you have a scanner? Maybe you should check to make sure the ECM isn't in limp home mode.

 

By the way, most auto pats stores will be able to check the ignition module to see if it's good or bad.

 

If the dist is super-retarded, that will cause what you're describing. Engine will run, albeit poorly, with EST connected because the ECM dials in more advance.

Have a buddy crank the engine w/ EST disconnected, use your timing light to see where where the timing is set while the engine's cranking.

 

Steve91....I occasionally throw a code 33.....but it does not keep the MiL lit at all times.....it will light up on start up and then turn off. I have a snap on scanner and when I scanned it it said no codes present. All my grounds are good.....all wires commng off IGN MOD good....(Connected to MSD 6AL). Do you think it could be my MSD? I havent tried disconnecting it.....but It was connected when I originally set the timing and it worked with ESC bypass connector unplugged. So I'm not sure what it coud be. Maybee if I unplug the EST.....loosen the Distributor.....have some one crank it while I move the distributor around and see if it starts......as far as the base timing being to retarded??

 

It will work better if you use your timing light. Really simple, just hook up the timing light, disconnect EST, have a helper crank the car while you "shoot" the timing tab. You'll see exactly where the dist is set, and can adjust it as necessary.

You do have a timing light...right?

 

Mine did the same thing after I installed an after market high performance ignition module. Ran fine with the ESC wire connected but I couldn't disconnect it to set the timing. Installed a new ac-delco module and no more problems.

 

Just out of curiosity, was this a running car that you decided to set the timing on, or is it something you put the dist & MSD in and then tried to start?

 

Yes this was a running vehicle. It was running a lil rough....so I decided to check the timimg and thats when it all hit the fan. It worked fine for a year after I installed the motor. I'm gonna try the timming light w/ the EST disconected....just to see where its at.

 

Since this was a running engine for a year & the timing was set before, I can't see base timing being way off unless the dist loosened up & turned. If it was my car, I would unhook the MSD & try it, if problem is still there, I would replace module. They really aren't too expensive & its good to have a spare.

 

Eureka! I got it. The timming was too far retarded. I made the necessary adjustments.....now the car runs with the EST bypass disconnected. I set the timming and evrything is perfect now. Thanks all for your help.

Keith

 

Congrats!

 

I am going to revive this thread.

I went out to try and set my timing and with the EST Wire disconnected, my car does not start just like the guy that started the thread. I can crank it but no start. Has anyone came to any conclusions as why this may be other than the base timing is way off? Any help would be appreciated. Thanks.

John

 

GTA350VORTEC...what adjustments did you have to make in order for your car to run with the EST in bypass mode? I need to get this figured out, so I can make necessary timing adjustments Saturday when our track opens for test-and-tune. Thanks for the help.

John