Voltage Issues? Where to start?

[Jalisurr]

Right, so my '90 ZR1 has started acting up once again. It's ok, it's probably just grumpy because I've been parking it on the road recently.

Anyways, in full power mode when I get on it, it doesn't pull very hard, feels like it's not getting enough gas. Then it set the service engine soon light a little while ago. I pulled the codes and it's giving 54 and 55, so voltage issues?

I have noticed the voltage gauge dropping below 12V at idle when the car is warm. Any suggestions where to start looking? I think my first step is going to be to clean all the connections, battery, alternator, any grounds I can find, and test the voltage coming off the alternator at idle.

Any other suggestions from the great knowledge base are welcome!

[Jalisurr]

Follow up question: I see on the list on this forum that code 55 is system voltage, but code 53 is also system voltage? Other lists I've seen say code 55 is fuel lean. Anybody have any information on that?

[Dynomite]

Originally Posted by Jalisurr

Follow up question: I see on the list on this forum that code 55 is system voltage, but code 53 is also system voltage? Other lists I've seen say code 55 is fuel lean. Anybody have any information on that?

Good question

Originally Posted by Jalisurr

Right, so my '90 ZR1 has started acting up once again. It's ok, it's probably just grumpy because I've been parking it on the road recently.

Anyways, in full power mode when I get on it, it doesn't pull very hard, feels like it's not getting enough gas. Then it set the service engine soon light a little while ago. I pulled the codes and it's giving 54 and 55, so voltage issues?

I have noticed the voltage gauge dropping below 12V at idle when the car is warm. Any suggestions where to start looking? I think my first step is going to be to clean all the connections, battery, alternator, any grounds I can find, and test the voltage coming off the alternator at idle.

Any other suggestions from the great knowledge base are welcome!

OK......I will offer up some thoughts.

If your voltage is dropping below 12v may be a failing alternator/failing battery and may be then failing fuel pumps and may then be failing fuel pressure and may then be fuel lean.

Check the battery condition/voltage with key off.
Check battery voltage at high idle to see if it stays constant at around 13v.

Do exactly as you say clean all the connections, battery, alternator, any grounds I can find, and test the voltage coming off the alternator at idle.

If the LT5 starts right up with no issues then I would not think the battery is failing

You say Full power mode when I get on it, it doesn't pull very hard, feels like it's not getting enough gas which be failing fuel pumps or secondaries not functioning.