Check engine light came on. So I put in the jumper to test it like I've always done before on other 3rd Gens. After It does the code 12, it slowly starts to get dimmer and dimmer. By the third time it flashed the next code (33), I couldn't see it anymore. I tried it again at night and it did the same thing, it looked like 43 and 44 followed it, but I couldn't really tell for sure.

What would make it do this?

Runs like crap, by the way. Found shorted wires on my fuel pump relay, but that seemed to be a new problem. She's very difficult to start and has a strong gas smell when I try. Also bogs down sometimes while running.

I'm trying to save for a LS1 swapp in the next couple of months, but in the mean time, I need to get to work, lol. Friday morning, when I went to go start it, I couldn't stop it from trying to crank. I have a remote start system, but sometimes without even trying to use the remote start, it won't stop cranking after I turn off the key. Friday, it ran the battery dead (6 month old battery and alternator).

Thanks! You guys are great!

 

Thats a new one. Sounds like there may be a short or a high load somewhere drawing power away from the ecm and starving it. Id be willing to bet that the same thing is happenign when its running.

 

Oh boy, where should I start?

 

Start with checking the codes with a battery charger (6-10 amp) hooked up or a fresh battery from a different car hooked up.. make sure it's not the battery going south. Then I'd check the power supply to the ECU, then check for shorts.. well.. all over the place.

I'd also attempt to use an analog multimeter in place of the SES bulb since it will be more sensitive to lower voltages.

 

electrical problems are the pits... If you havnt already done so, see if you can get ahold of one of the factory f-body wiring manuals from a shop or something. Theyre rare, but in a situation like this they can be priceless. IIRC the same manual is available as a reprint in the chilton f-body manual, except its black adn white instead of color. Youll need the wiring diagrams to troubleshoot.

 

I've been thinking about it today, and wouldn't I notice other symptoms if I had a short or some kind of load bad enough to make a light bulb go dim? She seems to be pretty good otherwise as far as electrical power goes. I know I bought a cheap alternator and the lights do dim a little when my compressor kicks in for defrost or A/C, but it doesn't make sense to me that a short would cause the SES light to dim, but not the interior lights at the same time.

Is it possible? What about a bad ground? Where is the ground for that?

Thanks!

 

There are ground straps on the back of each cylinder head as well as one that runs from the cyl. head to the firewall. Check the 3 +12 volt feeds in the conenctor for the ecm as well to make sure theyre consistant. If its running like crap in addition to this then thats a good indication of the possibility of an electical problem.

 

I looked at the grounds and a few other things and everything seems fine to me. I tested it again after I fixed the fuel pump relay the other day, and it still does the same thing. Code 12 is fine all 3 times, code 33 is next. It's fine the first time, looks like 23 the second time and is fine the 3rd time again. Then it looks like code 44 comes, and that one starts off bright and goes dim by the end of the code. When I pull the jumper out, it goes solid and bright. It's got to be in the computer.

As far as it running like crap, I think it's the fuel pump. I talked to my friend that is a dealership mechanic and he described the conditions to me before I could even tell him. 161,000 miles and getting ready for a LS1 swapp, I think it's time to change it anyway. I'm considering the Racetronix / Walbro GSS340M Fuel System.

Thanks anyway guys.