Check engine light just came on

[captsteve]

Thank you for the kind words Tom.

I'm not positive that it is a vacuum leak, I know there are some vehicles that use vacuum for the speedo and it would make sense if that was the case on your rig with the brakes acting strange. A loss of vacuum would cause a CEL...


Steve

 

[Charlie 5320]

The speedos on these are electronic, pulses from the trans. I had a simular issue about a year ago. The rectifier in the alternator went out and was getting ac voltage from it. Got all sorts of crazy readings. My speedo went crazy and I thought at first the trans was slipping. I could be stopped, in nutral, rev the engine and the speedo would go up to 50/60. Pull the red wire off the back of the alternator, tape it up, because it goes to the battery.  Start the engine and measure the out put to see if it has ac or dc voltage. Make sure the ground wire on the left rear side of the engine is clean, both the block and the frame.

 

[SeilerBird]

The speedos on these are electronic, pulses from the trans. I had a simular issue about a year ago. The rectifier in the alternator went out and was getting ac voltage from it. Got all sorts of crazy readings. My speedo went crazy and I thought at first the trans was slipping. I could be stopped, in nutral, rev the engine and the speedo would go up to 50/60. Pull the red wire off the back of the alternator, tape it up, because it goes to the battery.  Start the engine and measure the out put to see if it has ac or dc voltage. Make sure the ground wire on the left rear side of the engine is clean, both the block and the frame.

Thanks for the suggestion. Would the alternator putting out AC cause the "check engine soon" light to come on?

 

[Charlie 5320]

Don't know for sure, but mine was doing some funny thing electric wise. I was driving at night and my lights were consantly flickering. Was coming home from the race track when mine went out, made it the 60 miles home without damging anything else. It's worth a try, won't take you too long to check it, while your at a place to do so. I took my alternator off and took it to a shop to have it rebuilt. Cost me $80.00 for a total rebuild.

 

[Clay L]

For anyone interested you can download a P30/454 service manual HERE

 

[WILDEBILL308]

What's the latest update?
Bill

 

[SeilerBird]

What's the latest update?
Bill

Thanks for asking Bill.

I am waiting for payday so I can take it in and have them check it out. It might be expensive and I want to be able to afford it. I just got done with two weeks in Disney World and I my funds are depleted. I don't use credit. I posted a question on this forum and on a Chevy forum and no one has given me a good answer yet. I have Googled "check engine soon" light comes on with brakes and found several other people with the same problem. Almost every single answer they get is to "run the codes". There is no code associated with mine.

The engine is running fine, the brakes are braking fine so it is not really being a problem other than being annoying. I will probably end up doing what Catblaster suggests, ignore the light and drive it till it breaks.

 

[ironrat]

The check engine light is only for emissions related issues, you have another light for brakes.

 

[SeilerBird]

The check engine light is only for emissions related issues, you have another light for brakes.

That is what makes it so confusing. The check engine light only comes on when the brake pedal is depressed to a certain point about half way down.

 

[PJ Stough]

Have you checked your brake fluid level?

Paul

 

[ironrat]

That is what makes it so confusing. The check engine light only comes on when the brake pedal is depressed to a certain point about half way down.

Does your unit have vacuum assisted brakes? If so you could have a leak in the system when the brake pedal is applied which would cause a lean condition in the engine.

 

[SeilerBird]

Have you checked your brake fluid level?

Paul

No I have not. I just had the front brakes done a month ago. Where is the brake fluid reservoir located?

 

[SeilerBird]

Does your unit have vacuum assisted brakes? If so you could have a leak in the system when the brake pedal is applied which would cause a lean condition in the engine.

I don't know if it is vacuum assisted or not. I was assuming that could be the first thing they checked. I don't have a vacuum gauge.

 

[Ernie n Tara]

The symptoms sound like a bad ground; anytime I see weird stuff like that, that is my first guess. It would likely be a corroded connection in the instrument cluster.

Ernie

 

[SeilerBird]

Yes, a bad ground is suspect. To find a bad ground in an instrument cluster means removing the cluster and testing every ground connection that they can find. I don't know whether it would be worth it to pay for so much troubleshooting or not.

 

[PJ Stough]

No I have not. I just had the front brakes done a month ago. Where is the brake fluid reservoir located?

I believe that the master cylinder which is also the brake fluid reservoir is just inside the drivers side frame rail by the drivers side front tire.  Not easy to get to.

Paul

 

[SeilerBird]

Thanks Paul, that is where I was guessing it would be. I will let the mechanic check it out on payday.

 

[jeverden]

Your issue definitely sounds confusing...  However the last time my Engine light came on it was the O2 Sensor. 

I am sure your problem is not from the O2 Sensor - however I thought I might throw that in the conversation.

Jason

 

[Conquest aka Robert]

You should be able to see the master cylider from the top look straight down next to driverside. YES extreme PAIN to get at. You mentioned you had brakes done. Mine had issue where inner brake shoe came loose and was floating inside caliper made light come on I assume because of balance differance between sides. 

Another issue was the boost switch solonoid went bad and was locking on or off at will. It was mounted right by the air cleaner. With cover off push boost button you will hear it click off and on.  Got new one at part store 10 bucks.  If you can get under and look right by the starter it should have a braided strap ground it could have come loose when they looked at the tranny. Also check battery connections for clean and tight this will also reset the computer and it might just go away. 

 

[WILDEBILL308]

I have read the rest of the post. I don?t think it is a ground on the interment panel but if you want to check there should be a primary ground wire from the back of the panel to a ground. You shouldn?t have to check each item on the panel. You don?t need a vacuum gage to check the vacuum assist on the brakes. Let the engine warm up and depress the brake pedal if it changes speed then look at the hose that goes from the booster to the intake. You could look at this first as they get hard and loose their ability to seal. You can probley get access to the master cylinder with the dog house off You might need a mirror and flashlight to see the fluid level (it wouldn?t hurt to check it) You will need the dog house off to check for vacuum leaks to. I would check all the little vacuum hoses to see if they are dry brittle or otherwise need to be replaced. You can by hose at any parts store by the foot and it?s not that expensive to change all of them.
Bill