Hello,
Recently acquired a 1990 Cutlass Supreme that has 32k on it. When warmed up it runs fabulous. However, starting it almost acts like it has a bad battery. Previous owner said he never had any trouble until he tried to install a new stereo and forgot to disconnect battery, not sure if this is just a coincidence or not. No CEL.

So this is what it does, turn key sort of acts like low battery. Turn key again, starter spins, motor turns but motor doesn't start. Try again while giving it gas and motor starts, but dies. Try again, motor starts, runs rough for a minute and then seems perfectly fine.

Any advice would be appreciated this is my first Oldsmobile. Thanks in advance.

 

Disconnect the battery for a couple minutes, then reconnect. That should reset the ECU to its default settings. Then start the car and see how it behaves.

May take 40-50 miles of driving for the ECU to "learn" your driving style, figure out fuel blend etc.

Past that, time to look into cleaning throttle body, intake sensors etc. Just because no CEL doesn't mean something's not wonky.

If that's an aftermarket stereo with add-ons, I would closely inspect the wiring and especially how it's connected. If that means hiring a professional installer to sort it out and bless it, it's money well spent. Especially since the PO admitted this mess started after he installed it WITHOUT disconnecting the battery. No telling what he fried.

 

Hello, Thanks for the advice. I was thinking about doing the plugs as well. Does that sound like a good idea?

 

Before you disconnect the battery make sure you check to see if there are any stored codes. Check out post #2 of this thread.

https://classicoldsmobile.com/forums...stions-149168/

BTW, spark plugs and spark plug wires are always the start of a good tune up procedure.

 

Excellent suggestion. I had assumed there wouldn't be any stored codes since the CEL wasn't on. However, I will check this for sure.

 

Put a voltmeter on the battery and check the voltage while cranking. If it drops below 10 volts while cranking for 5 to 10 seconds your battery is weak or bad. If voltage is good move the positive probe from the battery to the coil positive and check cranking voltage there. If voltage is dropping below your battery reading while cranking you have a voltage drop problem in your cranking circuits. If this is a TBI injection system they are sensitive to voltage drop during cranking and will act like what you are experiencing.

 

Hello,
Thanks much, I will try that. Where is the coil positive?

 

You can have the battery and coil packs tested at your local auto parts store.

 

I sincerely hope you are not having an issue with the motor hard starting then racing that going down to sputtering and barely running, then racing again, etc., till the car warms up and then it smoothens out when it is warm for the most part. This is telltale of a bad intake manifold gasket(s), a possible issue of these motors if you have a 2.8 litre

 

Doesn't seem to describe what is going on. It starts rough then runs perfectly fine after a minute or two.

 

Let us know how she runs once you finish the tune up.

 

Update. Went out and the battery was completely dead. When I removed it found acid residue in tray. Replaced the battery and car starts right up and runs. Guy we got it off of had replaced the alternator, so I assumed he would have done the battery, guess not. Thanks for all the advice folks.

 

Glad she's running again. 👍

 

Thanks much. Olds64